The NREM period (non-rapid eye movement) is the first stage of sleep which lasts anywhere from 1 to 7 minutes. At this stage, brain activity changes from wakefulness to mixed-frequency waves. The second phase lasts for around 10 to 25 minutes, and it gets longer with each period. SWS refers to the third and fourth stages (Slow-wave sleep). Because of the increased protein synthesis, cell division is rapid during this process. Two biological mechanisms mediate the sleep-wake cycle. They engage and provide each other with a sense of equilibrium. The circadian rhythm, which regulates internal body functions, and sleep-wake homeostasis, which generates homeostatic sleep drive, are the two mechanisms (Saladin & Miller, 2008).
The afferent neurons convey stimulus to the brain from the sensory stimulus while the efferent neurons convey the motor stimulus from the brain to the muscles.
Afferent = Receive and Efferent = Act.
Spinal reflex maintains balance and posture, which controls trunk and limb muscles. In order to move a limb, it is imperative to know the starting position of the limb. Receptors form components of the spinal reflex and these elements are important for clinical diagnosis and in understanding principles of motor control (Saladin & Miller, 2008).
Pain is a sensation that is either physical or emotional that causes discomfort. Nociceptors are the pain receptors that detect pain from the damaged part. There are four types of nociceptors; skin nociceptors, joint, visceral and silent nociceptors. Fast and slow pain fibres include A-delta and C: They control the speed at which nociceptive conduct nerve impulses (Saladin & Miller, 2008).
Light from the object is reflected to the eye through the cornea. The light then progresses to the pupil which is the circular opening in the colored iris. The pupil changes in size due to variability in lighting (Tortora & Derrickson, 2009). When light intensity is high, it gets smaller due to pupillary response. As the light gets dimmer the pupil enlarges.
Normal vision is when the eye clearly focuses objects both at a shorter distance and at a long distance. Myopia is the defect where objects at a long distance cannot be focused properly. On the other hand, hyperopia is a defect of the eye where objects at a long distance cannot be focused clearly (Tortora & Derrickson, 2009).
The retina is a complex tissue, which contains important components with numerous sensitive nerves cells called cones and rods. Cones secrete iodopsin pigment, which is mostly effective in the bright light (Tortora & Derrickson, 2009). They provide color vision. In contrast, the rods secrete visual purple or rhodopsin substance, which provides vision in dim light. Thalamus is a small structure located in the forebrain and it has extensive nerve fibres projecting out of the cerebral cortex. It relays sensory signals to the cerebral cortex.
The external part of the ear contains Pinna, which forms the outermost part of the organ. The external auditory tube connects the middle and outer ear. The middle part of the ear comprises of stapes, malleus, and ossicles. The inner ear contains cochlea, Vestibule and Semicircle canals. When sound is made, it travels to the external auditory tube to middle ear through membrane (Tortora & Derrickson, 2009). The sound impulses are then converted into electrical impulses to enable us to decode the message.
The physiological processes that result in taste and smell deception can be procedurally described as follows. Chemical recognition on the tongue sends a signal to the brain. Thereafter, the processes give us an idea on which food we are dealing with which allows us to take certain decisions of modifying behaviour accordingly. Like taste, smell is a chemical sense called chemoreceptors and it is detected by sensory cells, which sends impulses to the brain (Young, 2010). The brain interprets patterns in electrical activity, which allows us to recognize the smell.
Movement is controlled by the primary motor cortex, an organ that controls the motor pathway. Alpha motor neurons in the spinal encode the force of contraction of muscles using rate code and size principle. The pyramidal pathway serves as a tract for upper neuronal signals originating from the cerebral cortex. Motor impulses originate in betz cells which form the upper motor neurons (Tortora & Derrickson, 2009). Thereafter, peripheral motor neuron relays signals to the skeletal muscles which enhances movement.
Smooth muscles are the involuntary non-striated muscles that form the supporting tissue for hollow internal organs. It is generally divided into a single and multi-units. Its contraction and relaxation is caused by the sliding of actin filaments and myosin filaments over each other. The movement of the filaments form cross bridges (Moorjani, 2017). Cardiac muscles are involuntary, striated tissues that are usually located in the walls of the myocardium. The sliding of myosin and actin filaments causes contraction and relaxation of the cardiac muscle.
Unlike the skeletal muscle, the nerves that excite the smooth muscle arises from a number of sources. These places like teachers and Gal tract have the amount of independent nervous system capable of controlling the smooth muscles in these areas. The muscle needs some signal before starting a contraction (Moorjani, 2017). Smooth muscles receive input from the central nervous system known as extrinsic innervation. The input always comes from the autonomic nervous system.
The heart pumps blood through contraction and relaxation of the cardiac muscles in the process known as a cardiac cycle. Blood flows from the left atrium to the right atrium through atrioventricular valves (Saladin & Miller, 1998). The RA receives blood from the body through vena cava. Equally, left ventricle receives oxygenated blood through the pulmonary veins. Both atria contact and propel blood to the ventricles.
The first heart sound is normally created by shutting of mitral and tricuspid valve flyers. The following heart beats are delivered by the end of the aortic and pulmonic valve flyers (Moorjani, 2017). This heart sound is unsplit when the subject is holding his or her breath at top termination. Regularly, blood stream is laminar. However, under states of high stream, in aorta, laminar stream can be upset and may end up plainly turbulent.
Cardiovascular output is the measure of blood pumped by the heart by unit time. At the point when heart rate increases, diastolic filing diminishes proportionately, henceforth bringing down volume of blood ejected. Raised heart rate can expand contractility autonomous of sympathetic impact (Moorjani, 2017). Exercise-prompted hypertrophy makes an expansion in the hearts limit generate substantial stroke volume. The system that controls blood flow are primarily responsible for the vascular volume of the left and right atrial pressure (Saladin & Miller, 1998).
Pressure can be exerted on the heart by the sympathetic nervous system by way of the catecholamine, adrenaline, and noradrenaline circulating in the blood. It increases heart rate and pumps a larger volume of blood. The autonomic nervous system is made up of the sympathetic and parasympathetic divisions. The important circulatory effect of parasympathetic is its control of the rate of the heart by way of parasympathetic fibres. The sympathetic system controls the viscera and gut while the parasympathetic division protects the body from injury by shutting down the gut (DelMonte & Kim, 2011).
Heart failure is a disorder where heart pumps blood inefficiently and inadequately. This usually occurs because the heart cannot contract normal (DelMonte & Kim, 2011). The heart is filled with blood but cannot pump because of the weaker muscles. Decreased Cardiac Output leads to decreased blood pressure (BP). The functioning of systole is reduced or unreduced, due to left ventricular systolic dysfunction. Factors that decrease heart failure include dietary discretion, diuretic dosing control and consistent exercise (Moorjani, 2017).
The heart nourishes itself through its own supply of blood from the coronary arteries. They are permeated by a very close network of capillary blood vessels which allow for nourishment. The right and left side of the heart works together causing continuous blood flow.
Atherosclerosis are fatty deposits that can clog arteries. It is also caused by deposition of atherogenic proteins and lipids in the vascular wall (DelMonte & Kim, 2011). Thrombosis is the formation of a blood clot inside a blood vessel affecting circulatory flow of the blood. It occurs in veins and arteries leading to congestion and consequent damage of tissues. Ultimately, clotting hampers blood supply by the heart.
When the cardiac output is decreased, blood pressure also decreases because there is less force on the vessel walls leading to reduced blood flow (Robb & Robb, 1942). When the cardiac output increases, the blood pressure also increases because of the increase in the force applied on vessel walls. When volume of blood is reduced, blood pressure is also is reduced. Similarly, pressure rises when the blood volume increases. More so, when peripheral resistance increases, blood pressure escalates.
Mean arterial pressure is caused by combined forces form the arterial blood pressure, multifaceted interactions of the cardiac output, resistance created by arterioles and blood viscosity. Next, baroreceptor pressure is caused by the size and force of the vessels. Feedback mechanism alters heart rate and blood pressure (DelMonte & Kim, 2011). Principally, the autonomic nervous system creates the smooth muscles to contract and through this skeletal muscle, pumping is activated, which guides in the control of the vascular compliance.
Hypertension can be classified into primary HBP and secondary HBP. Primary HBP is caused by the nonspecific lifestyle, for instance, too much salt; secondary blood pressure is caused by conditions that affect other organs for instance kidneys and endocrine system. An example of a secondary causative is chronic kidney disease (Moorjani, 2017).
Homeostasis is a process that inhibits blood loss in case of injury. It can be explained by vasoconstriction; a reflex action in which blood vessels narrow to increase the pressure of blood (DelMonte & Kim, 2011). During the process, thrombin activates platelets enabling formation of temporary, loose platelet plug at the site of injury, which initiates clotting. Intrinsic and extrinsic factors that lead to a fibrin clot. Intrinsic processes are activated by external trauma while intrinsic pathways are activated by trauma within the vascular system.
An antibody is also referred to us the immunoglobin (Ig) produced by B-lymphocyte that is used in the immune system. An antigen is the foreign target recognized by the antibody. It induces an immune response in the host, and as a result, they are targeted by antibodies. Paratope is found on each tip of “Y” of an antibody that is particular epitope on an antigen. It is part of an antibody and acts an antigen binding site.
A primary response is initiated by antigen specific T cells. The necessary response is when Immunoglobin appears in plasma, which is not potent enough to prevent illness. During secondary response, B cells (memory cells) are promptly activated in response to an antigen which leads to release of Ig antibodies thereby eliminating pathogens before any symptoms occur (Tortora & Derrickson, 2008).
Active immunity is an indication of antibodies formed through a direct antigen exposure, while passive immunity results from passage of antibodies down to the recipient even without exposure to an antigen.
T-cells accounts for 80% of the total lymphocytes and they make up the secondary branch of the immune system. T-cells complete their development in the Thymus and thus the name T-cells. There are three types of T-cells namely lymphocytes, Cytotoxic, Suppressor, and Helper (Tortora & Derrickson, 2008). The first process of destruction is germ cell removal, which eliminates around 25% of pre-meiotic germ. The second phase processes the bulk of cytoplasmic contents and different spermatids are removed in a process involving active apoptotic caspases. The third process removes sperm mitochondria.
Significant histocompatibility complex is an arrangement of cell surface vital for the adaptive immune system. MHC cells bind peptide fragments from pathogens and consequently, macrophages are activated to kill harmful micro-organisms (Saladin & Miller, 2008). This process initiates different immune responses. MHC class I are found on the cell surface and occur on the platelets and red blood cells. Their main function is to trigger response from the immune system against non-self-antigens. MHC class II cells are found on antigen-present cells such as endothelial and B cells. They initiate immediate immune responses.
DelMonte, D. W., & Kim, T. (2011). Anatomy and physiology of the cornea. Journal of Cataract & Refractive Surgery, 37(3), 588-598.
Moorjani, N. (2017). Operative mitral and tricuspid valve surgery. Springer.
Robb, J. S., & Robb, R. C. (1942). The normal heart: anatomy and physiology of the structural units. American Heart Journal, 23(4), 455-467.
Saladin, K. S., & Miller, L. (2008). Anatomy & physiology. New York (NY): WCB/McGraw-Hill.
Tortora, G. J., & Derrickson, B. (2009). Principles of anatomy and physiology. Hoboken, NJ: John Wiley & Sons.
Tortora, G. J., & Derrickson, B. H. (2008). Principles of anatomy and physiology. John Wiley & Sons.
Young, D. B. (2010). Control of cardiac output. San Rafael, Calif.: Morgan & Claypool Life Sciences.