The pituitary gland is a major gland of the endocrine system. It excretes hormones in charge of other endocrine organs and different tissues within the body. It is approximated to be a third of an inch in diameter and found at the base of the brain. In addition to that pituitary and hypothalamus are located close to each other because they have intertwined functions. They are joined by the pituitary stalk or, more biologically, the infundibulum. The pituitary glands are composed of the posterior lobe and anterior lobe (Peate & Nair, 2017). The posterior lobe is not responsible for the production of hormones by itself. However, hormone production is done by nerve cells in the hypothalamus and posterior lobe, releasing them to circulation by the pituitary gland. On the other hand, the anterior lobe is responsible for excreting many hormones.
Hormones of the Gland
The pituitary gland hormones usually signal other endocrine glands to inhibit or stimulate their hormone manufacture. This section aims to discuss anterior and posterior lobe hormones, explain what triggers the release of these hormones, identify characteristics these hormones have in common, and classify which hormones are considered tropic hormones.
Anterior Lobe Hormones
The interior lobe releases hormones after getting inhibiting hormones from the hypothalamus. These hypothalamic hormones are responsible for notifying the anterior lobe if it should release more of a particular hormone or stop the manufacture of the hormone (Nagata et al., 2019). The hormones produced by the anterior lobe after being notified are discussed below.
Prolactin hormones– These are hormones responsible for stimulating breast milk production.
Adrenocorticotropic hormones (ACTH) – These are hormones that stimulate the adrenal gland to produce hormones.
Thyroid-stimulating hormones (TSH) – These are hormones that stimulate the thyroid gland to manufacture hormones.
Growth hormones (GH) are crucial hormones in the early years of humans because they maintain healthy body composition and growth in children. In adults, GH helps in healthy muscle and bone and distributes fat.
Follicle-stimulating hormones (FSH) – These are hormones that work closely with LH to ensure that ovaries and testes are functioning normally.
Luteinizing hormones (LH) – These are hormones that work with FSH to ensure that the testes and ovaries operate normally.
Posterior Lobe Hormones
The posterior lobe has nerve cells that are from the hypothalamus. The hypothalamus transmits hormones direct to the posterior lobe through the nerve cells, as well as the pituitary gland releases the transmitted hormones (Chapman, Singhal, Gaddamanugu & Prattipati, 2020). The hormones discussed below are contained in posterior lobe hormones.
Oxytocin– These are hormones involved in different procedures such as stimulating breast milk production and contracting the uterus during childbirth.
Anti-diuretic hormones (ADH) – These are hormones that make kidneys increase water absorption in the blood.
The release of hormones can be triggered by neurological stimuli, changes in the blood, or by the action of other hormones. For instance, the endocrine glands excrete different types of hormones that control the development and regulation of the reproductive system (Peate & Nair, 2017). This type of action by the endocrine gland triggers the production of various hormones. All the hormones due to this have similar characteristics, such as low molecular weight. They are water-soluble, transported to target cells through circulation, and chemical entities produced by special cells of endocrine glands. Although they have similar characteristics, their classification is different such that TSH, ACTH, GH, FSH, and LH are classified as tropic hormones.
Summary
In some instances, the pituitary gland is also referred to as the master gland because it controls the functions of many of the other endocrine glands. The gland is also attached to the hypothalamus by nerve fibers and blood vessels (Nagata et al., 2019). However, this perspective can be misleading and incorrect because some individuals might think this gland does not receive instructions from other glands. The reality is that it receives signals from the hypothalamus to release more pituitary hormones.
References
Chapman, P., Singhal, A., Gaddamanugu, S., & Prattipati, V. (2020). Neuroimaging of the Pituitary Gland. Radiologic Clinics of North America, 58(6), 1115-1133. Web.
Nagata, Y., Takeuchi, K., Yamamoto, T., Ishikawa, T., Kawabata, T., & Shimoyama, Y. et al. (2019). Peel-off resection of the pituitary gland for functional pituitary adenomas: pathological significance and impact on pituitary function. Pituitary, 22(5), 507-513. Web.
Peate, I., & Nair, M. (2017). Fundamentals of anatomy and physiology for nursing and healthcare students (2nd ed., pp. 479-510). New Jersey: Wiley Blackwell.
The lungs major function is to offer uninterrupted exchange of gas between the blood in circulation and inspired air, as well as taking out carbon dioxide through expiration and bringing in oxygen (Roberts, 2000). This process is known as respiration and is managed by the brain areas comprised of apneustic, pheumotaxic and medullary inspiratory Centre that “stimulate the contraction of the diaphragm and the intercostal muscles” (Roberts, 2000).
Circulation is “the movements of body fluids inside the animals from the place of formation to the place of its utilization” in a one-celled animal (unicellular), cells exchange materials directly with the environment; this implies that it has no circulatory system and the cells have to be close to the immediate medium of exchange (Universereview.ca, 2010). On the other hand, large multi-cellular animals have circulatory system to carry oxygen and nutrients to the body tissues and to carry away waste products; blood and lymph are the key body fluids used in circulation of materials (Universereview.ca, 2010).
The following section shows the similarities and differences amongst the worms, insects, fish, and human in anatomy and physiology of circulation and respiration.
Anatomy and Physiology of circulation and respiration in;
Worms
Worms such as earthworms usually have a closed circulation system while flatworms and roundworms have no circulation system. This means that they have no respiratory organ thus oxygen is taken in through the skin, body cavity or osmosis (Chandra, 2010).
The earthworm uses its skin as breathing organ; this is enabled by its moist skin which allows effective absorption of oxygen. The oxygen diffuses through the body and enters into the blood contained in the dense capillary network that is positioned next to the skin. The blood transport oxygen to other body cells (Universereview.ca, 2010). In the body cells the carbon dioxide diffuses to the blood and it is then transported to the capillaries on skin where it finally diffuses to the body surface. Therefore, skin is an efficient respiratory organ in worms which have a “high surface area to volume ratio” (Universereview.ca, 2010). Worms have no heart chamber except earthworms which have five hearts that pair off (Chandra, 2010).
Flatworms mostly lives in water thus remove waste through osmosis and they have organ that get rid of surplus water in the body. This organ contains series of intersecting canals, which are on each side of the body and usually run through the length of the worm while roundworms have single opening for digestion that act as mouth as well as anus (Chandra, 2010). On the other hand, earthworms have two Nephridia openings; one gathers coelomic fluid and the other act as exit to the body wall and between these two openings waste is removed from the blood vessels (Chandra, 2010).
Insects
Insects have open circulation system in which circulation fluid in the body cavity known as hemocoel directly feeds the organs and thus no difference between interstitial fluid and the blood. The collective fluid is known as haemolyph or hemolymph (Chandra, 2010). An insect usually has one chamber of heart implying that its circulation system is not very well developed (Universereview.ca, 2010).
Tracheae are used to allow the oxygen in to the body tissue (Chandra, 2010). These tracheae have pores known as spiracles which allow the air to enter the insect’s body. The spiracles are located on the sides of the abdomen and each section of abdomen contains pair of spiracles (Farabee, 2001). The air from the atmosphere passes through the tracheae which stem into lesser and lesser tubes, similar to human bronchioles found in the lungs. These tracheae ends into the respiring body tissues, the oxygen is taken in and the carbon dioxide is taken out of the tissue and it’s expelled out of the body through the tracheae. The breathing process for the insects is very slow but very active and large insects thrust their abdomen to assist the quickening of the air movement (Farabee, 2001).
The excretory system of terrestrial type conserves water; malphighian tubules gather waste in the blood and absorb water again to make sure that only material that is dry is removed (Chandra, 2010).
Fish
Fish uses closed circulation system meaning that blood is contained in the blood vessels system implying that blood does not leave the blood vessels system (Chandra, 2010). Fish usually has two heart chambers meaning that it has a single circulation system. The water passes through the mouth to the gills and the oxygen is absorbed. The oxygenated blood in the gills is transported to the body tissues and carbon dioxide is taken out of the tissues to the blood and transported to the gills and as the water passes through the gills carbon dioxide is removed (Chandra, 2010).
Waste is filtered from blood by the kidney and removed through anal fin or external opening to reproductive tract and digestive urinary (Chandra, 2010). The kidney is very significant in modifying salt and water concentrations in the body of the fish, thus allowing specific species of fish to live in saltwater or freshwater or both (Farabee, 2001).
Humans
Human beings have closed circulation system implying that blood does not leave the blood vessels system which consists of veins, arteries and capillaries (Universereview.ca, 2010). Humans have four heart chambers resulting to a two circuits that is pulmonary and systemic (Double circulation system).
The air enters through the nostrils to lungs then to the heart, is absorbed in the blood arteries which transports oxygen (apart from pulmonary arteries) to the body (Chandra, 2010). The carbon dioxide from the body tissues is carried by blood through the veins (except pulmonary veins) to the heart to the lungs and finally to nostrils (Chandra, 2010).
The major excretory organ for humans is the kidney. It separates toxin, urea and other forms of waste out of the blood, at the same time salt, electrolytes and water are regulated at suitable levels; the kidney has nephrons which filter wastes (Chandra, 2010).
In conclusion, survival is reliant on process of respiration, circulation, excretion and digestion, therefore, these processes which together form part of the body system must be consistent, continuous and efficient, under all environmental conditions or when suffering from a disease.
The nervous system is the major communicating, regulatory, controlling system in the body. The nervous system is the center of all mental activities including memory, learning, and thought. In conjunction with the endocrine system, the nervous system is in charge of maintaining and regulating homeostasis. The objective of this laboratory report is to dissect, identify the internal cavity of a rat, and examine the different sensory organs of a rat. Additionally, this report examines the neuron anatomy from the prepared microscope slides in the laboratory. Although humans and rats seem to be entirely different, they tend to share some physiognomies, which may include biological, psychological, or behavioral. Like other body systems, the nervous system comprises organs such as the ganglia, nerves, spinal cord, and brain.
Background Information
According to Snyder and others (2018), the nervous systems are developed from glia and neurons. Neurons are the key functional cells while glia plays a range of primary support roles. Subsequently, the nervous system develops as an interconnected network of cells. The brains of vertebrates are the largest nervous organs, while other simple animals such as jellyfish have nerve nets (Mastorakos & McGavern, 2019). Researchers posit that self-awareness or consciousness is one critical concept of the nervous system, and helps to differentiate between perception and sensation. This report explores the anatomy and physiology of the nervous system of a rat.
According to the National Institute of Neurological Disorders and Stroke (2018), the nervous systems are different in every animal and are crucial for interpreting and detecting information, regulating body functions, making important decisions, and movement. Therefore, the physiology and anatomy of the nervous systems of rats and that of humans are considerably similar. For that matter, rats tend to sense and react similarly to their stimuli, such as touch, injury, or disease. Through testing rats, healthcare personnel has made tremendous steps in the advancement of medicine (MedlinePlus, 2016). Through dissecting a rat we can see exactly how similar a rat’s anatomy and physiology of the nervous system is to that of a human being (National Institute of Neurological Disorders and Stroke, 2018). This report reviews the cellular structures and functions and investigates several fundamental neural networks within the body. Furthermore, this report uses a combination of exercises and models, physiological, anatomical dissection, and microscopic analysis to examine the nervous system.
Relevant Observation
This experiment involves two exercises, which include: (1) Dissecting a rat to examine the internal organs including the sensory organs, and (2) examining the microscope slides to learn about the anatomy of neurons using a light microscope. Several relevant observations were made from this experiment. From the first exercise, the major sensory organs were all observed including the eyes, skin, tongue, nose, ears, the spinal cord, the brain stem, and the brain. From the second exercise, the following parts were observed; myo-neural junction, cerebellum, and the spinal cord.
Figure 1: An overview of the components of the nervous system.
Hypotheses
The physiology and anatomy of the nervous systems of rats and that of humans are considerably similar.
Rats sense and react similarly to their stimuli, such as touch, injury, or disease.
Materials and Methods
Equipment and Supplies
Forceps
Scissors
A dissecting tray
Disposable gloves
Probes
Dissecting pins and twins
Freshly killed rat
Arm bone cutter
Microscope
Masks
Steps
Exercise 1
Pin the rat to the wax of the dissecting tray by placing the dorsal side down
By using scissors make an incision on the median line of the animal
Complete incision from pelvic to the jaw
Try to expose the underlying muscles
By using scissors cut through the abdominal skin
Now lift the skin and cut through the muscle layer from the pubic region to the bottom of the rib cage
Near rib cage make two lateral cuts so that the thin membrane inside should be visible
The membrane is the diaphragm which separates thoracic and abdominal cavities
Cut the diaphragm where it attaches to the ventral ribs
Lift the ribs to see the thoracic cavity clearly
Cut across the flap at the level of the neck and remove the rib cage
To expose the brain and the roots of the cranial nerves make a hole at the junction of frontals and parietals with a pointed arm bone cutter
Remove the bones carefully not to damage the roots of the 12 pairs of cranial nerves
Exercise 2
Steps
Turn the revolving nosepiece to click the lowest power objective lens into position.
Put the microscope slide on the stage and hold it using the stage clips.
Observe the objective lens and the stage sideways and adjust the focus knob to move the stage up. Move it upwards to maximum but the objective lens should not touch the coverslip.
Look through the eyepiece and adjust the focus knob to focus the image.
Tune the condenser for maximum light intensity.
Adjust the microscope slide until the specimen is in the field of view.
Use the coarse and fine adjustment knobs to focus the specimen and readjust the light intensity and condenser.
When the image comes into clear view with the lower power objective, you can readjust to the next objective lenses, either the specimen or lighting can be adjusted. Repeat steps 3 to 5 with the higher power objective lens if the image is not clear.
Lower the stage when finished, click the lower power lens into position, and remove the slide (MedlinePlus, 2016).
Results
Exercise 1
The major sensory organs observed include the eyes, skin, tongue, nose, ears, the spinal cord, the brain stem, and the brain. These organs have specialized cells and tissues which receive raw stimuli and translate them into signals that can be used by the nervous system (NINDS, 2018). Please see the figures below:
Figure 2: A dissected rat.
Similar to other body systems, the nervous system comprises organs such as the nerves, spinal cord, and brain. Consecutively, these organs comprise tissues such as connective tissues, blood, and nerves. Collectively, these tissues and organs perform the complex activities of the nervous system.
Figure 3: Labelled parts of a rat’s brain. Source: Mastorakos & McGavern, (2019).
Exercise 2
The microscope slides showed several details of the neuron anatomy. The neuron anatomy of a rat and that of a human are closely similar in several ways including:
Motor end plate –when viewed through the microscope, the synaptic connection between a skeletal muscle cell and motor neuron can be seen.
Figure 4: Myo-neural junction- is a specialized synapse responsible for the voluntary control of movement. Source: (Snyder et al., 2018).
Cerebellum – in both cases of the human and rat’s nervous systems, the cerebellum has folded gray and white matter that can be distinguished with the eyes.
Spinal cord – in both cases, a cross-sectional view of the spinal cord shows central gray matter and peripheral gray matter.
Figure 5: Cerebellar gray matter, with Purkinje neurons and multiple synapses (Snyder et al., 2018).
Data Presentation and Analysis
The data are in this report are presented in form of figures and pictures. According to the figure and pictures shown above of the nervous systems of a rat, it can be seen that a rat’s nervous system is closely related to that of a human being (Zeisel et al., 2018). It is determined that there are similarities in the shapes of the organs and the systems and the types of the organs responsible for the nervous system functions. It was examined that the nervous system of a rat and a human being are closely related.
Discussion and Conclusion
From the first exercise, the major sensory organs were all observed including the eyes, skin, tongue, nose, ears, the spinal cord, the brain stem, and the brain. According to Snyder and others (2018), these organs have specialized cells and tissues which receive raw stimuli and translate them into signals that can be used by the nervous system. The nervous system has two main parts: the Central Nervous System (CNS) and the Peripheral Nervous System (PNS). The CNS is comprised of the spinal cord and the brain while the PNS comprises nerves branching from the spinal cord and extend to all parts of the body. The nervous system transmits information from the brain to the rest of the body and vice versa (Mastorakos & McGavern, 2019). As a result, the activities of the nervous system control the ability to think, see, breathe, and move.
From the second exercise, the following parts were observed; myo-neural junction, cerebellum, and the spinal cord. Firstly, the Motor end plate can be viewed at the synaptic connection between a skeletal muscle cell and motor neuron (NINDS, 2018). Additionally, structures like motor endplates, myelin sheath of Schwann cells on axons, skeletal muscle cells with sarcomere, and axons; all look similar in both the human nervous system and in the rat nervous system. Secondly, the Cerebellum has folded gray and white matter that can be distinguished with the eyes (MedlinePlus, 2016). Subsequently, within the gray matter, there are three distinct layers of neurons namely: molecular, Purkinje, and granular layer, which discloses organizational structures. Lastly, a cross-sectional view of the spinal cord shows central gray matter and peripheral gray matter, which in turn has small central canal with ependymal glia.
Zeisel et al. (2018) state that large motor neuron cells are situated in the ventral gray matter. Moreover, sensory neurons are located in the dorsal root ganglia, and their axons develop into the roots of the spinal nerves. The nervous system keeps us in touch with the internal and external environment (temperature, sound, light, pH, and oxygen levels). Therefore, just like in humans, the rat’s nervous system performs the same functions- sensory, integrated, and motor functions.
References
Mastorakos, P., & McGavern, D. (2019). The anatomy and immunology of vasculature in the central nervous system. Science immunology, 4(37).
Snyder, J. M., Hagan, C. E., Bolon, B., & Keene, C. D. (2018). Nervous system. In Comparative anatomy and histology (pp. 403-444). Academic Press.
Zeisel, A., Hochgerner, H., Lönnerberg, P., Johnsson, A., Memic, F., Van Der Zwan, J., Haring, M., Braun, E., Borm, L.E., Manno, G.L., Codeluppi, S., Furlan, A., Lee, K., Skene, N., Harris, K.D., Hjerling-Leffler, J., Arenas, E., Ernfors, P., Marklund, U., & Linnarsson, S. (2018). Molecular architecture of the mouse nervous system. Cell, 174(4), 999-1014.
A neuron has a cell body that contains the cell nucleus, as well as unique extensions known as axons and dendrites. Nerves are axons throughout the body and neurons can interact across great distances because of axons and dendrites (NIH, 2018). The Action Potential is used by neurons to transmit electrical impulses, and the influx of positively charged ions across the neural membrane causes this phenomenon; for example, these impulses go through the brain or a person’s spinal cord. When neurons are activated, an electrical impulse is sent. The following steps are taken: stimulus, dendrite, cell body, axon, axon terminal, stimulus passage, termination, and when a nerve impulse reaches the end of an axon, the axon releases substances known as neurotransmitters.
Subcortical Structures
The major components of the subcortical structure are the thalamus, epithalamus, subthalamus, and hypothalamus. Each of these structures plays a variety of important functions in the human body’s survival and proper functioning, so let’s become acquainted with their architecture.
Dopamine enhances the pleasure experience and also aids in learning and memory, both of which are crucial aspects in the transition from liking something to being addicted to it.
The substantia nigra (SN) is a midbrain region of highly pigmented cells that affects movement and coordination. The SN is split into two parts: the substantia nigra pars compacta (SNc), and the substantia nigra pars reticulata (SNr) (SNr) (“Neurotransmitter receptors,” n.d.). Dopamine is produced by SNc neurons and encourages movement. In contrast, depending on the input signal, GABAergic neurons in the SNr can either stimulate or inhibit movement. The SN regulates movement by being a component of the basal ganglia, which is a network of neurons essential for motion or memory. The basal ganglia also include “the putamen, the subthalamic nucleus, the caudate, and the globus pallidus, which is split into the globus pallidus interna (GPi) and the globus pallidus externa (GPe) (Gpe)” (“Neurotransmitter receptors,” n.d., para. 1).
Glia
Glia is a non-neuronal cell in the central nervous system, namely the brain and spinal cord, and the peripheral nervous system, which does not generate electrical impulses. They have four primary functions: they surround and maintain neurons in place, they feed nutrition and oxygen to neurons, they insulate one neuron from another, and they eliminate infections and remove dead neurons. They are also involved in neurotransmission and synaptic connections, as well as physiological activities such as respiration.
Communication of Neurons
Communication between neurons occurs at synapses, which are microscopic gaps where specialized parts of two cells, such as presynaptic and postsynaptic neurons, meet within nanometers of one another to allow for chemical transmission. The presynaptic neuron releases a chemical known as a neurotransmitter, which is recognized by specific proteins known as neurotransmitter receptors in the postsynaptic neuron. Neurotransmitter molecules attach to receptor proteins, causing the postsynaptic neuronal function to change.
Neuroplasticity
Neuroplasticity, also known as neural plasticity or brain plasticity, is a process in which the brain undergoes adaptive structural and functional changes. Puderbaugh and Emmady (2022) define it as “the ability of the nervous system to change its activity in response to intrinsic or extrinsic stimuli by reorganizing its structure, functions, or connections” (para 12). It is described as the nervous system’s capacity to reorganize its structure, functions, or connections in response to intrinsic or external stimuli, such as a stroke or traumatic brain damage (TBI). This exercise explains neuroplasticity, its evaluation and management, and the role of the interprofessional team in enhancing patient care.
References
Neurotransmitter receptors in the substantia nigra & the tuberomammillary nucleus. (n.d.). Web.
NIH. (2018). What are the parts of the nervous system? Web.
Puderbaugh, M., & Emmady, P. (2022). Neuroplasticity. NCBI. Web.
The evolution of humans dates back to an uncountable number of years. Mankind came into being primarily as a similar genre to what we physically are today. Those species were called the ‘homo Erectus, the modern form of which we have named the ‘homo sapiens, or “us”.
Homo Erectus and Homo Sapiens
Homo erectus refers to an ‘upright man’. The other homo species are now extinct in the world, which includes australopithecines and the hominid genre. They were found to initiate in Africa, from where their fossils are detected by anthropologists and archaeologists (“Human Evolution”).
When the homo Erectus was initially discovered by their fossils, they were found to be the smallest brained of the fossil hominins. But with time, it was researched and studied that the homo erectus fossils found in the 1930s were larger brained, and more similar to us humans (Anton, S., 2003). They were larger and this enlarged size probably called for an adequate diet for its growth and development too. The homo erectus seems to be the first hominids to have left Africa and move further out into the world.
The homo sapiens migrated to other parts of the world including the Middle East and parts of Asia, about 120,000 years ago (Miller, T., Hackman, D., Knight, T. & Boboc, D.). Some cold periods followed, halting the migration, but as far back as 50,000 years ago, the homo sapiens moved to the remaining portions of the world, like China and Europe.
Modern humans are called homo sapiens sapiens. They seem to have softer diets and more delicate physiques than the preceding species, like the homo erectus and the Neanderthals.
Similarities between the Homo Erectus and the Homo Sapiens Sapiens
These homo species both possess more or less the same features and traits, with just a modification of the form. The homo erectus had smaller brains than the modern man. The ridges of the eyes of homo sapiens are smaller in size compared to those of the homo erectus (“The Rise of Anatomically Modern Homo Sapiens”). The bones of the brains are thinner in the homo sapiens, and the forehead height is also smaller. The chin of the homo sapiens became more distinct than those of the former species. It can be seen that the present-day human form is a modification of the ape-like species, both of which possess free limbs and five grasping digits, i.e., the fingers.
The homo erectus had large builds, which demanded more intake of food. Their teeth were bigger and the jaw cavity was roomier than those of the homo sapiens, which so easily accommodate a fine set of teeth. Researchers have seen the fossils to be large, giving us the notion that they fed on tough food items, like raw meat, etc.; their teeth were strong enough to chew on hard eatables. The homo sapiens differ from them, they cook their food until extremely tender, and chewable. The digestive abilities of the homo erectus were stronger, being able to take in raw forms of food, which were mostly hunted animals. The modern man on the other hand has to think before eating and be very cautious of dietary intakes due to risks of indigestion.
The developmental rates of the homo erectus seem to be faster than the homo sapiens. The vaulted shape is greater in the latter case, appearing taller and more rounded. The lifestyles of the two species were different according to the available liabilities. The homo sapiens began to feed on fish meat, due to the emergence of new tools with time. These new tools included fishing hooks and nets, which distinguished the diet patterns of the homo sapiens. As time passed, the agricultural revolution took place, which enabled humans to feed on specific plant growths.
The historical finds of researchers suggest the adornment of the earlier species of mankind. Sets of bones and teeth have been found on human remains, which signify the orderly setting of things adapted by the early people. Bone needles have been seen, which show us that the homo erectus probably stitched animal skins to cover themselves from the weather’s harshness, and to create some form of clothing for protection.
Earlier, the tools used for hunting were of high speed, as the spearhead. These days such activities are not carried out on a need basis, but for enjoyment. Formerly, coordinated group hunting would take place to search and kill an animal for a meal. Later, the bow and arrow and harpoons were made for ease.
Conclusion
The homo erectus and homo sapiens were physically similar to one another. Their lifestyles and behaviors, with time and advancements, kept changing and are still being updated with the further evolution of humans. Time has changed the form of the ape-looking structure, to the modern good-looking man, which will further transform into some sort of an alienated species.
Works Cited
Anton, S. “Natural History of Homo Erectus” 2003. Web.
“Human Evolution”. 2008. Web.
Miller, T., Hackman, D., Knight, T. & Boboc, D. “Homo Sapiens Sapiens: The Beginning”. 2008. Web.
“The Evolution of Primates: Chapter 22”. 2008. Web.
“The Rise of Anatomically Modern Homo Sapiens” 2008. Web.
Menopause is associated with several changes, which may be anatomical, physiological, and hormonal. Menopause is characterized by a reduction in the production of certain hormones, such as estrogen and progesterone, which affect the anatomical structure of organs such as the uterus and ovaries. After menopause, fertility ends, but women can continue living healthy lives. Reproductive functions are associated with hormones indicating that changes in hormone production levels can affect the anatomy of some body parts. It is estimated that the ratio of the body to the cervix reduces to 1:1 in a majority of women (Jee, 2021). Menopause can cause a decrease in the size of the uterus and thickness of the endometrium walls, which can be attributed to low estrogen levels.
Discussion
Ovaries ease to produce eggs after menopause, making them inactive. Additionally, ovaries reduce as one ages; hence, the same trajectory is expected to continue after menopause. According to a study, ovaries shrink in size and may become wrinkled following menopause. Additionally, the cortex becomes thinner with the increased production of stromal cells, which are secretory (Jee, 2021). The fallopian tubes become atrophic as cilia and plicae disappear. The vagina losses elasticity hence becoming narrower while the vaginal epithelium thins. Some women experience atrophic features on the vulva while the labia may flatten, causing the introitus to be narrow (Jee, 2021). The bladder and urethra shrink in size and may experience dysuria or stress incontinence. Due to a loss of muscle tone, an individual may experience pelvic relations and changes in the structure of the urethra.
Conclusion
Generally, menopause causes a reduction in estrogen and progression, which are associated with the structure or anatomy of reproductive body parts. This affects different body organs, causing changes in anatomy such as size shrinkage and loss of elasticity. All these are effects of age, but the changes in anatomy may differ in individuals due to variations in the aspects of body function, such as the production of hormones.
Reference
Jee, K. O. (2021). Menopause and homoeopathy. International Journal of Menopause and Homoeopathy, 5 (4), 379-382.
Explain by giving one example of why it is important to understand the relationship between the extracellular compartments and the intracellular compartment.
Intracellular compartments comprise at least 40% of body fluids that make 2/3 of the total body’s water. Its primary constituents are proteins, potassium, and organic anions. Cellular metabolism determines the inner constituents and cell membranes control the flow of ions and other constitutes into and out of the cell. Every different cell of the body might have a different ionic constitution depending upon the location, tissue, and functioning of the cell. It also depends on the extracellular fluid that surrounds the cell in a particular location of the body. ECF is only 20% of the body weight that makes up 1/3 of body fluids. It is primarily composed of NaCl and NaHCO3 ions. These fluids in ICF and ECF are highly balanced. Their importance and relation to each other are determined when fluid disturbances in ICF and consequently in ECF (vice versa) result in different clinical conditions.
ECF and ICF are in osmotic equilibrium. In ECF hypo-osmotic condition ECF volume is increased hence the osmolality is reduced. It is called hypo-osmotic expansion. In another condition, hyposmotic contraction occurs due to excessive salt wastage from the kidney due to some kidney disease. This also decreases osmolality and also reduces ECF fluids.
Identifying Tissue Types Lab
Mitosis is a body process in which a cell separates chromosomes in its cell nucleus, into two identical daughter cells. It is usually followed by Cytokinesis. Morphology in biology is termed as the shape, structure of organs.
Q #1: Give two examples of how the morphology of the tissue type gave an advantage to the function of the organ
Ans #1: Morphology of tissue type plays a vital role in the functioning of a human organ, For Example, in women’s Shukra tissue use for the reproductive system, and if its size and structure get disturbed it causes infertility in women. Tissues help a lot in keeping women’s reproductive system effective. Human skin has also many tissues which reconstruct themselves, skin tissues recover human skin if it gets heal or cut. With the help of the morphology of tissue, skin is always able to regrow.
Phases of Mitosis
Q # 1 What does the percent of each phase suggest in terms of time spent by the cell in each stage?
Ans # 1: Around 70% of each phase suggests that the cell spends most time in interphase, the most of remaining time in prophase, and least time in Metaphase. Cell spent 50-60% of the remaining time in prophase. The total percentage of time that plants and animals undergo mitosis is 67% and 56.4% respectively.
Question# 2 How can the above information be used to estimate the amount of time the cell spends in mitosis?
Ans. On basis of the above observation, we can say that overall very little cell is spent in mitosis. E.Coli completes its prophase stage in 19 minutes and 20 seconds, 30 seconds to complete metaphase, and 15 seconds to complete anaphase and telophase.
Time Spent in each phase of mitosis can also be calculated with the aid of the following formula:
Percentage= # of cells in phase________
# of cells undergoing mitosis
Question# 3 How can this information be extrapolated to the cellular behavior of normal vs. cancerous cells?
Ans # 3: Above information can be explored to cellular behavior of normal cell vs. cancerous cells, on the basis of time spent in mitosis, if there is any disturbance in cell timing spent in mitosis, it causes, protein reactions, protein secretion, etc. this information can also helpful in estimating following facts:
Cancerous cells are growing slow or fast?
What kind of mitosis pattern is expected in the next sixty days?
Is the pattern of tissue periodic or erratic?
Skeletal System Part 1 Lab (Axial)
Question # 1 What advantages do the sutures of the skull give to the skull of the newborn?
In the human skull, known as “cranium”, there are multiple fibrous joints, anterior fontanelle and coronal suture, sagittal suture and lambdoid suture, and sagittal suture which are assistive to maintain elasticity and fibrous strength of the skull. Normally the bones of the skull in infants are very flexible and soft ones which are strengthened in grown-up individuals as cranial sutures may turn into strong bones thoroughly. The sutures of the skull play an instrumental role to support all functional activities of infants like supervision of intracranial pressure, cerebral oxygenation, blood flow, and alacrity of the brain. The sutures of the skull are assembled to locate every sensor on the opposite position for the performance of their functional actions and infants’ skulls also provide protection against any kind of injury which may cause brain impairment.
Question # 2 What advantages do the curvatures of the vertebra offer to the overall erect axial skeleton?
According to the anatomical terms, the vertebral column comprises a column of 24 vertebrae, intervertebral discs, sacrum, and coccyx in dorsal and this vertebral column is known as the spinal cord or spinal canal. This vertebral column is divided into several curvatures at different positions including cervical, thoracic, lumbar, and pelvic ones. All these curvatures of the spinal cord are assistive to erect the human skeleton and trigger the proper movements of all bodily parts easily. All these curvatures are flexible and easy to bend down wherever individual moves and also straighten the whole bodily structure which is the main advantage of such curves.
Cardio-Vascular Studies Lab
List concluding comments as asked for on:
Question # 1 What implication does this have regarding the left and right ventricular ability to generate blood pressure?
The left and right ventricular is very assistive device to pump blood pressure in the balanced form by going through different phases of all mechanism of blood circulatory system of human body. The medical scientists and researchers have observed by different devices that forceful waves of blood flows occurs in Right and left ventricular and pulmonary artery within the range of 0 to 300 ms as all these parts of circulatory system is composed to pump blood flow via right and left ventricular and pulmonary artery. The contraction and expansion of ventricular muscles helps to generate balanced flow of blood pressure in normal hearts of human beings.
Question # 2 Notice the presence of thin strands tethering the valves to the ventricular wall. These are the chordae tendinae. They pull the values towards the ventricles when the ventricles contract. What could their purpose be?
The chordae tendineae are thin cord like strands which are connected with papillary muscles, tricuspid valve and the mitral valve, presented in human heart. The main function of these valves and the chordae tendineae is to prevent backflow of blood into right artrium during the process of ventrical contraction when blood pressuer is pushed forward towards the tricuspid valve, blood flow is prevented to enter in right artrium with the help of flapping of these thin strands like structure, chordae tendineae. The chordae tendineae is composed of 80% collagen, having almost 20% of elastin and endothelial cells which supports the function of contraction due to its greater elasticity.
Question # 3 In what phase of the cardiac cycle do the coronary arteries fill?
Cardiac cycle is taken as whole process of blood circulation or flow from the initial phase of heart beat to last one, showing the heart rate. There are three main stages of blood flow including atrial systole, ventricular systole, cardiac diastole etc. there is a series of decrease and increase in blood flow during the cardiac cycle which are essential to create normal blood pressure. The coronary arteries are a network of arteries which supply blood to all chambers of heart during the cardiac cycle. These arteries are divided into branches from aorta at the joint point of aorta and left ventrical. The right coronary arteries are responsible to supply blood to right artrium and ventrical and vice versa.
Anatomy of the Digestive System Lab
Question # 1 What would be the impact of sympathetic overtones on Gl motility?
Investigation in gastrointestinal motility has given new orientation to the medical researchers with great interest to observe the developmental processes of gastrointestinal motility. The nitric oxide plays important role in neutral transduction and gastrointestinal motility which are regularized various physiological functions. The gastrointestinal (Gl) motility in immature stage in fetus development may cause some impairment of oral feeing or incoming necrotizing enterocolitis. The basic role of muscarinic system is important to demonstrate a particular developmental muscarinic receptor subtype and regulation of Gl motility to treat the preterm fetus or newborn properly on time.
Question # 2 How would this explain a doctor or nurses interest in the presence of bowel sounds on a patient post-surgically?
The presence of bowel sounds help the doctors or nurses to identify the series of events taking place inside the stomach. Such movements might enema or ulcerative colitis in a patient. Post surgery the whole system is more agitated therefore the bowel sounds are more enhanced aswell.
Question # 3 Can you offer a logical mechanism for fecal impaction based on the chief function of the colon?
Fecal impaction is the most common cause of fecal incontinence in elderly and children. However, it can be controlled with some education and training. The condition also responds to the laxatives. It can be easily identified with physical examination and history.
colon is basically responsible for the fecal impact in a person. The main changes that might occur maybe due to diarrhea mostly in children & often in adults as well. As aging occur the smooth muscle layers, for eg. The longitudinal and circular along with an augmentation in the elastic and connective tissues may result in constipation and fecal impaction as well.
The disruption of internal anal sphincter (IAS) and external anal sphincter (EAS) is the main cause of this impaction.
Reproductive System Lab
Question # 1 Can you compare the prostate and the uterus?
There is a great difference between prostate and the uterus, though both are main part of human reproductive system. The prostate is a multifaceted exocrine gland of reproductive systems of male mammalians which vary from species to species in functionality, composition of chemical substances and physiological shapes. The prostate is categorized into three parts, Posterior (urethra and rectum), Superior (upper surface of urogenital diaphragm and urinary bladder) and Lateral (anterior fibers of levator ani muscle).
The prostate plays functional role to secrete and store the most important male sex hormone, semen, comprising spermatozoa, composition of 10-30% of the volume of the seminal fluid and slightly alkaline (pH 7.29) fluid. The prostate supports some muscular strength to secret semen during ejaculation and neutralize the acidity of vaginal tract in order to place sperm for long time. The uterus is the main part of female reproductive system in all mammals, particularly in humans. The uterus is attached with one end of cervix, opening in vaginal tract while other is linked with the Fallopian tubes. The uterus is also known as womb where all process of fertilization takes place, undergoing multiple stages of development of embryo, fetus, gestates and fully grown up child.
Question # 2 How can one suspect prostate infection or tumor?
The growth of cell cancer in the prostate gland causes the prostate infection or tumor. The uncontrollable division of the prostate cells shows the symptoms of incoming danger of cancer. When division of cell occurs continuously without any control or order and this mass of tissue or cells causes the growth of tumor in the prostate. If you suspect such kind of tumor growth in your body, you should consult doctor for immediate treatment. You should be alarmed when you feel some symptoms like frequent urination, painful or burning urination or inability to urinate, weakness to interrupt flow of urine, aching ejaculation or inability to erect male sex organ, bleeding in semen or urine or frequent stiffness in lower back, thighs and hips etc.
Question # 3 What role would the junctional epithelia play in women’s susceptibility to cervical cancer?
The medical research has shown the close link of squamous and columnar epithelia with anal canal and cervix uteri of postnatal period and fetus which are interconnected with each other. The junctional epithelium is a epithelial lining, midway part which comprises multi-layers of epidermoid cells. The ultrasonic research shows that junctional epithelium helps to develop anal basaloid carcinomas and some cervical squamous carcinomas. When a woman undergoes a cervical cancer, this is vulnerable due to Loss of gap junctional intercellular communication (GJIC) which affects the normal functionality and behavior of cervical carcinoma cells, causing the abnormal functions of cervix cells.
Question # 4 What missing ingredient in non-pregnant women (and men too) would be found in the urine pregnant women (the basis of pregnancy detection kits)?
In early pregnancy there’s one hormone called “human chorionic gonadotropin” (hCG) released by the placenta when embryo (fertilized egg) implants in the uterus. Hence, it can be detected with 6 days after conception. After the egg is fertilized in fallopian tube, it travels towards the uterus and implants there on the uterus wall. Placenta develops and starts producing hCG in abundance. From the time of fertilization till implantation it takes a week. Non-pregnant women and men do not have this hormone in their urine.
The human body comprises different parts that perform distinct and coordinated functions. In conjunction with the brain, the body parts respond accordingly to both internal and external environments. The excellent functionality of the different parts of the body, including the hand, thigh, neck, girdle, pectoral, and legs, are critical for the normal functioning of a human being. The brain is considered the command center of the body. According to Ramadan and Vasilakos (2017), it is equal to the computer’s central processing unit (CPU) because it controls everybody’s duty and action. This paper aims to understand how the human hand and the specific muscles work in partnership with the brain.
Types of Muscles
Interossei Muscles
The interossei have both the palmar and dorsal small muscles. The muscles commence between the bones of the hand, towards the fingers. The muscles allow the bending of the metacarpophalangeal joint, where the finger bones intersect the hand ones. Burin et al. (2017) opine that the dorsal interossei enable people to spread their fingers away from each other while the palmar interossei pull their fingers together. It is regarded as the first muscle to shrink among patients with cubital tunnel syndrome (Urits et al., 2019). The dorsal interosseous pulls the thumb close to the index finger, providing stability when pinching. Therefore, the interossei muscles are part of the muscles which form the human hand.
Hypothenar
The hypothenar muscles are the other muscles which form part of the hand. The flexor digiti minimi, opponens digiti minimi, and equally the abductor digit minimi from the hypothenar muscles (May, 2020). These muscles form a bulk on the small finger. Specifically, the abductor allows the little finger to pull sideways from the ring finger (May, 2020). The opponents enable a person to cup hands, bringing the small and thumb fingers together.
Elbow Muscles
The elbow contains four muscles, including the biceps, brachialis, triceps brachii, and lacertus. According to Gaspar et al. (2018), the biceps help an individual rotate the palm down and up. They equally help the brachioradialis and the brachialis to bend the elbow. The brachialis is another muscle that is deep and large in the arm’s front, lying beneath the biceps muscle, attaching to the ulna’s coronoid process (Van Den Bekerom et al., 2016). The triceps are three-headed in the arm’s back, delivering the critical role of elbow strengthening (Alves et al., 2018). Therefore, a person can throw items and push up a chair due to the strength of the triceps.
Sensory Stimulus Pathways
There are several unconscious processes that an individual goes through to sense an external stimulus. Whether in the presence or absence of light, the human hand skin must feel different external stimuli, including the crawling of bugs on the hand. First, skin on the human hand has multiple anodes that help one develop a feeling that something has touched them. Anodes are at the epidermis and dermis, which are the topmost layers of the skin. Villard et al. (2017) allude that receptors are small in size, collecting accurate information regarding touch. Conduits often sense pain, pressure, friction, temperature, and even stretch.
The idea of feeling a bug crawling on the skin allows an individual to flick it off before biting the skin. According to Yu and Smith (2017), the hairs that project from the follicles in the hand skin sense different environmental changes. It is the root plexus that surrounds the follicle base that senses any interference and disturbance on the skin (Yu & Smith, 2017). As a bug crawls on the skin, it touches the hairs on the hand and sends a signal to the follicles, simultaneously transferring the same signals to the plexus and back to the skin that something is crawling. The hair root plexus sends the received information to the central nervous system (CNS), which incorporates the brain and the backbone. Subsequently, the CNS responds by activating the eyes’ skeletal muscles and removing the bug.
The skin acts as a critical sense organ due to the dermis, epidermis, and hypodermis, containing the nerves’ specialized sensory structures, sensing and detecting touch. These receptors are concentrated on the fingertips, especially the Pacinian corpuscle, which responds to skin vibrations (Yu & Smith, 2017). The Merkel cells in the stratum basale are equally regarded as the touch receptors. Sensory nerves are connected to each hair follicle throughout the hand skin. The motor nerves innervate the glands and arrector pili muscles, which helps humans sense the bug. The initiation point of the tracts starts at the epidermis and its termination is at the peripheral nerves where neurons are located. Chemical synapses occur in the epidermis, releasing neurotransmitters which bind receptors on the postsynaptic cell, making the hand quick to respond to external stimuli.
Adduction Movement
Adduction is one of the multiple hand muscle movements which take place in the fingers. As Assi et al. (2016) assert, adduction is a critical motion that brings all the hand fingers towards the middle finger. In other words, the movement involves the act of closing the finger together, for example, when one wants to slap another or when holding an object tight. Palmar interossei are the prime mover in adduction, helping humans to make a fist, whereas the antagonist for this kind of movement is the dorsal interossei. Extensors of the wrist form part of the synergist muscles that help and coordinate the movement of the fingers, whereby one of them is the extensor carpi radialis longus. For example, when one makes a fist flexed forwards towards their palm and equally makes another while the wrist is extended back, it becomes evident that the fist becomes strong when the wrist is extended back. Thus, it becomes clear that the wrist extensors aid the palmar interossei to close the hand fingers, hence considered to be palmar interossei synergists.
Stroke
In the primary somatosensory cortex and the primary motor cortex, the stroke will not affect the hand region’s anatomy. It will affect the functioning and ability of the hand. The hand becomes feeble in case of a stroke, because of the weakness of the biceps, triceps, and the other muscles. In the scenario of a stroke in the primary somatosensory cortex, the hand’s ability to sense different somatic sensations, including pain, vibration, touch, heat, and pressure, will be impaired. The hand becomes paralyzed, hence unable to sense different internal and external stimuli, for example, an internal cache, which enables a person to seek medical attention. Externally, the hand cannot sense pain or the crawling of a bug on the skin. An individual will realize that an insect is crawling on their hand when they only see it. A person cannot respond to external stimuli including excessive heat. Stroke is a devastating incident that can occur in the human body considering that it makes people susceptible to bodily danger because they cannot sense external stimuli apart from becoming weak to respond.
Conclusion
In conclusion, it is paramount to note that the removal of a crawling bug on the hand involves the sensory input and the motor output to respond. The nervous system has a tremendous impact on the muscular system. The hand has critical muscles including the elbow, hypothenar, and interossei muscles. Moreover, adduction is one of the movements that take place in the hand. It allows a person to bring fingers together to form a fist.
The upper limb: the ventral tissue serves as the site for the development of the flexor group of the shoulder muscles and the entire musculature of the palmar side of the forearm and palm.
The lower limb (thigh): the ventral tissue provides all the muscles of the anterior surface, the extensors.
The lower limb (tibia): due to the pronator turn, the ventral tissue turns into the back and the sole; these muscles are flexors (Iannotti and Parker 19).
Dorsal Group
The upper limb: the dorsal tissue develops the muscles of the back of the shoulder and the rear (extensor) side of the forearm and hand.
The lower limb (thigh): develops the muscles of the back of the thigh; the flexors.
The lower limb (tibia): located on the front side, the extensor group (Iannotti and Parker 19).
Pectoral Girdle vs. Pelvic Girdle
Both girdles support the limbs, yet the pelvis has a more rigid structure (Scheumann 100).
Superficial muscles of the pectoral girdle:
Anterior extensors – pectoralis minor (pulls the shoulder blade, raises the ribs) and serratus anterior (pulls the scapula, performs rotational movement around the sagittal axis).
Posterior extensors – trapezius (pulls the humeral girdle), levator scapulae (pulls the scapula), rhombus (pulls the scapula when contracting medially and upwards).
The pelvic girdle is almost immovably articulated with the sacral spine, so there are no muscles that set it in motion; muscles located in the pelvic girdle move the leg in the hip joint and the spine.
The pelvic muscles are more developed in humans due to the upright manner of walking; they ensure balance.
Ventral group: iliopsoas (flexes the hip in the hip joint, rotates it outward, tilts the trunk forward).
Dorsal group: gluteus maximus (unbends the thigh, rotates it outward, unbends the trunk), gluteus medius (pulls the hip, turns the thigh inward and outward).
Shoulder Girdle vs. Thigh Muscles
The muscles of the thigh perform static and dynamic functions when standing and walking.
Having a large mass and considerable length, they can develop great strength, acting on both the hip and knee joints.
The anterior group (hip flexors): quadrice psfemoris, sartorius.
The medial group: adductors – lead, bend, and rotate the hip.
The posterior group (thigh extensors): hamstrings (biceps femoris, semitendinosus, and semimembranosus).
Muscles of the free upper limb act mainly on the elbow joint, support movement around the frontal axis.
Ventral group (flexors): Biceps.
Dorsal group (extensors): Triceps.
The muscles that attach to the scapula (deltoid, teres major and minor, etc.) not only set it in motion − with simultaneous contraction of antagonistic muscle groups, but they also fix the scapula (Hartwig 357).
Forearm vs. Tibia Muscles
Most of the muscles of the forearm are multiarticular since they act on several joints: ulnar, radicular, radiocarpal, and distal joints of the hand and fingers (MacLester and St. Pierre 329).
Muscles of the forearm are divided into anterior/flexor – flexor carpi radialis, flexor carpi ulnaris, – and posterior/extensors – extensor carpi radialis longus and extensor carpi ulnaris.
Most of the ventral muscles start at the medial epicondyle of the shoulder and fascia of the forearm, and the muscles of the posterior group originate from the lateral epicondyle and also from the fascia of the forearm.
Muscles of the shin, like the muscles of the hip and pelvic girdle, are relatively well developed because they are exposed to a load due to the upright walking, supporting-motor function of the lower limb; the muscles influence the knee, ankle and foot joints.
Anterior: tibialis anterior – unbends and supins the foot, tilts the tibia forward.
Lateral: peroneus longus – flexes the foot, raises its lateral edge, strengthens the transverse arch.
Posterior group: gastrocnemius, soleus, tibialisposterior – bend, lead, and supinate the foot.
Works Cited
Hartwig, Walter Carl. Fundamental anatomy. Lippincott Williams & Wilkins, 2008.
Iannotti, Joseph P., and Richard Parker. The Netter Collection of Medical Illustrations: Volume 6. Elsevier Health Sciences, 2013.
MacLester, John, and Peter St. Pierre. Applied biomechanics: concepts and connections. Thomson Wadsworth, 2014.
Scheumann, Donald W. The Balanced Body: A Guide to Deep Tissue and Neuromuscular Therapy. Lippincott Williams & Wilkins, 2007.
The chest is a cavity in the upper region of the body located between the neck and the waist or the abdomen. In human beings, it is commonly known as the thoraxic cavity. The chest’s major function is to protect the major organs in the body found in the thorax. The heart and lungs are the major organs protected by the chest (Wijkstrom-Frei, El-Chemaly, & Ali-Rachedi 2003).
However, there are many other organs in the region, including the major and minor pectoral muscles, trapezius muscles, the neck muscles and part of the spine. The chest itself is supported and protected by various muscles covering the ribcage, the spine, and shoulders. All these organs and muscles function together to ensure proper body function.
To understand the structure and importance of the chest, a study of the various organs found in the chest paramount. For the purpose of this study, emphasis will be given to the heart as the ‘engine’ of blood circulation and the organs of the respiratory system such as the lungs, the trachea and diaphragm (Frank, Netter & Carlos 2007).
The Heart Structure and Function
The heart is located in the middle of the thorax (mediastinum) between the lungs and is more inclined to the left below the sternum. This is because the left half is bigger because it is responsible for pumping blood to the whole body. Because of this reason, the left lung is smaller than the right one (Romer, Parsons & Thomas 1997).
The Heart cells (called cardiomyocytes) develop into muscle fibers that aid in the conduction of electrical impulses. The first and prime organ in the chest is the heart. It is about the size of a clenched fist and is located between the lungs in a camber that is well protected by the rib cage. It is made of a special muscle called the cardiac muscle and is the only organ that has that kind of muscle (Jardins 2012).
The heart slows or speeds in response to automatic signals from the brain, in line to the needs of the body. It has the sole work of ensuring that every cell in the body gets the necessary nutrients and oxygen needed for sustenance. It does this by pumping oxygenated blood from the lungs and nutrients from the alimentary canal to the cells.
Once the waste products and the carbon dioxide are released, the heart then helps to pump this blood back to the lungs and kidneys where carbon dioxide and urea are emitted respectively. Analogically, the heart is the organ that sustains life (Jardins 2011). The heart works automatically throughout the human life. The heart is made up of three muscles or layers.
The function of the outer part of the heart (the pericardium) is to keep the heart in its right position. The pericardium has two functional and structural layers. The first layer is a fibrous pericardium made up of great vessels and a posterior surface of the sternum and majorly supports the heart in its position. The inner layer of the pericardium is also made up of two layers (Guyton & Hall 2006).
The outer layer is called the parietal layer. I functions by providing coverage to the outer fibrous sac and the inner or visceral layer. In turn, the visceral layer covers the heart muscle. When the heart beats, the serous membrane produces serous fluid in the space between the visceral and parietal layers. This fluid is functionally important because it minimizes the friction between the membranes (Travis, Conway & Zabner 1999).
The middle layer of the heart is called the myocardium and it is made of a specialized muscle called the cardiac muscle. In addition, it is worth noting that this is the position in which blood circulation takes place. It is thickest in the left ventricle, thinner towards the right ventricle and thinnest in the artrium.
The endocardium is the innermost lining of the heart, which is much thinner and smoother. This phenomenon is results from the nature of the flattened epithelial cells that cover the entire region, including the valves and line of the blood vessels (Jardins 2008).
The Structure of the Heart
The heart is partitioned into two regions- the left and the right side. A major muscle called the septum is the chief anatomical feature that provides this partitioning. Each of the two partitions is then divided an upper and lower chamber. The upper chambers are the auricles or atriums while the lower chambers are the ventricles. The auricles receive blood from the veins, while the ventricles expel it to the arteries (Campbell 2005).
The artrio-ventricular valve separates the ventricles and artriums. These valves ensure the blood flow is in one direction from the auricles to the ventricles.
The right valve is called the tricuspid and it has three flaps. The valve on the left is known as the mitral valve and has two flaps. The valves open with the blood pressure. However, they are prevented from opening the opposite way by the Chordate tendineae or cords found on the walls of the ventricles (Hicks 2000).
Figure 1: Anatomy of the human heart (Jardins 2007)
The Circulation of the blood
The flow of the blood happens in three phases the first phase is called the pulmonary circulation. It is responsible for movement of deoxygenated blood from the right ventricle via the pulmonary artery to the lungs and then the oxygenated blood is taken from the lungs to the left auricle of the heart via the pulmonary veins (Maton, Jean, Charles, McLaughlin, et al 1993).
The pulmonary veins then take the blood to the left artrium. The second phase of blood circulation is known as the systemic circulation, which is responsible for supplying nutrients and oxygen to the body and then taking the deoxygenated blood back to the heart. It happens from the left ventricle then to the main artery or the aorta that then transports the blood to the rest of the body.
It is then brought back to the right auricle via the superior and inferior venacava (Maton, et al 1993). The final phase of circulation is known as the portal circulation and which takes place in the digestive system from the spleen, pancreas and the gall bladder whose veins join to form the portal vein that then takes the blood to the liver and leaves via large hepatic veins that join the inferior Vena Cava to the heart (Marieb 2003).
The structure of the Lungs
In nature, the two human lungs are located on the chest region, each on one side of the heart. Although they are similar, the right lung has three lobes while the left one has two (Richardson, Randall & Speck 2005). The lobes are divided into partitions, which are further subdivided to lobules. Each of the lung lobes is surrounded by the pleural cavity, which is made up of two pleurae.
They are the parietal pleura that lie on the rib cage, and the visceral pleura that lie on the surface of the lungs (Frank, Netter & Carlos 2007). The trachea branches to the two main bronchi in the left and the right lungs respectively (Cecie, Christine & Lisa 2009). They then progressively divide to smaller of bronchi and bronchioles until subsequently the alveoli are reached.
Gaseous exchange happens in the alveoli. The central nervous system, the diaphragm and chest wall muscle, and the circulatory system (Jardins 2007) coordinate the whole process. The muscular diaphragm controls breathing. This diaphragm is located at the bottom of the thorax.
The diaphragm functions by contracting and relaxing, which increases the lungs ability to breathe in and out. The opposite happens when air is exhaled out through the nose (Macdonald 2009). The oxygen-rich blood returns to the heart via the pulmonary veins to be pumped back into systemic circulation (Crigg & Johansen 1987).
Figure 2: Anatomy of the Human lungs (Jardins 2012)
Although a mention of the pleura has already been made, it is necessary to look at the anatomical aspect of them in a deeper manner. Anatomically, the pleura are serous membranes surrounding each of the two lungs. They are found in doubled-layers in nature and provide mechanical protection to the lungs.
Noteworthy, the lungs are an important organ that provides a concise and maintained source of oxygen, an important gas required for various biochemical and physiological functions. In fact, living things can barely survive without oxygen. The connection between the lungs and the source of oxygen (the air) is a vital anatomical aspect worth discussion.
The lungs must have a system and method of protecting themselves from irritants and other dangerous objects inhaled along with air. Therefore, it is worth looking at the upper respiratory region as a functional part of the chest anatomy. First, the inner linings of breathing tubes (bronchus and bronchioles) are covered with a layer of mucus-producing cells. Such cells produce a thin layer of mucus in form of phlegm.
The phlegm is involved in trapping irritants inhaled along with the air before they reach the lungs. The phlegm, together with its contents, is then swept up the upper respiratory system towards the mouth. Noteworthy, the inner lining of the upper respiratory tract, including the nose, have a large covering of cilia. The cilia, normally appearing as small hairs, aid in the exit of the mucus and its contents from the tubes to the mouth.
The epiglottis is yet another important anatomical region worth discussion. It functions as a “gate” through which inhaled air passes on its way to the lungs. The epiglottis is highly innervated because it responds to the presence of irritants in the system.
It is connected to the parasympathetic system for the function of ‘fight-or-flight’ mechanism. It must open up to allow an upwards sweep of undesired contents in the inhaled air. This is not a voluntary mechanism, which means that innervations are necessary.
Bronchioles
The bronchioles are major anatomical features in the chest region. Anatomically, they are small tubes that branch from the tertiary bronchi. It is worth noting that the difference between the two is based on their sizes. While the bronchioles are smaller, the bronchi are relatively larger (Cecie, Christine & Lisa 2009). In addition, the composition of their walls forms another source of anatomical difference.
For instance, bronchioles have a dense composition of elastic fibers as well as smooth muscles. On the other hand, the bronchi have hyaline cartilaginous rings that make up the largest part of their walls. For the purpose of their functionality, the bronchioles have a potential to increase and decrease their diameter.
When large volumes of oxygen are in demand within the body, the bronchioles must expand and increase their diameter, which allows an increase in the volume of air entering the lungs. In addition, the bronchioles can constrict in response to pollutants entering the system, which protects the lungs from infection and mechanical damage caused by irritants.
The alveoli
These are the chief anatomical parts of the lungs involved in the entry of air in and out of the lungs (Campbell 2005). They are found in alveolar sacs, some small clusters at the end of the bronchiole. They are hollow in nature, with a cup-like cavity surrounded by a large number of blood capillaries.
Conclusion
The study of the anatomy of the chest is very important because the importance of the heart and lungs is seen. These organs are most important in sustaining life. We are also able to know the structure of the chest and its other organs.
References
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Cecie, SL, Christine, E, & Lisa, S 2009, Biology: Today and Tomorrow with Physiology, Cengage Learning, Mason, OH
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Frank, H, Netter, W & Carlos, AG 2007, Regions and Planes of Adbomen: The Interactive Atlas of Human Anatomy, Saunders, Belmont, CA
Guyton, A & Hall, J, 2006, Textbook of Medical Physiology, Elsevier Saunder, Philadelphia
Hicks, G 2000, Cardiopulmonary Anatomy and Physiology, Cengage Learning, New Jersey
Jardins, T 2007, Cardiopulmonary Anatomy & Physiology: Essentials for Respiratory Care, Cengage Learning, New Jersey
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MacDonald, M 2009, Your Body: The Missing Manual, Sebastopol, Pogue Press, Belmont, CA.
Marieb, E, 2003, Human Anatomy & Physiology, Upper Saddle River: Pearson Education, Los Angeles.
Maton, A, Jean, H, Charles, W, McLaughlin, S, & Wright, J 1993, Human Biology and Health, Englewood Cliffs Prentice Hall, New Jersey.
Richardson, D, Randall, C & Speck, F 2005, IMS: Cardiopulmonary Physiology, 2nd ed. Macmillan Publishers, New York
Romer, A, Parsons, W, & Thomas S 1977, The Vertebrate Body, Holt-Saunders International, Philadelphia
Travis, SM, Conway, BA, Zabner, J 1999, “Activity of abundant antimicrobials of the human airway”, American Journal of Respiratory Cell and Molecular Biology, vol. 20, no. 5, pp. 872–9.
Wijkstrom-Frei, C, El-Chemaly, S, & Ali-Rachedi, R 2003, “Lactoperoxidase and human airway host defense”, American Journal of Respiratory Cell and Molecular Biology vol. 29 no. 2, pp. 206–12