Introduction
High blood pressure is a significant risk factor for heart disease and all-cause death. Increased physical activity has been shown to reduce blood pressure in a range of individuals with hypertension in studies that looked at the relationship between the two. In addition, numerous studies have documented the beneficial effect of physical activity, health, and dietary programs on people. Physical exercise and lifestyle habits are followed into adulthood; consequently, it is critical to investigate blood pressure patterns among children in the school and community environment to develop and execute effective policies and programs to encourage physical activity among youth. In this way, people can appreciate the significance of physical activity concerning lowering the prevalence of non-communicable diseases such as diabetes, blood pressure, and diabetes.
Living thing Hierarchy
Organized and structured living organisms follow a hierarchical framework that may be studied from the micro to the macro scale. The atom is the tiniest and most basic unit of matter (Prykhodko et al., 2017). The nucleus encircled by electrons is the core of this particle (Prykhodko et al., 2017). Polymerization is a common method for constructing macromolecules, which are huge molecules with biological significance (Prykhodko et al., 2017). Deoxyribonucleic acid is an example of a macromolecule since it holds the blueprints for the construction and function of all living things.
In certain cells, macromolecules encased in membranes form what is known as an organelle. Inside each cell, there are tiny structures known as organelles. Organelles contain chloroplasts and mitochondria which perform a variety of functions. Cells are the basic building blocks of all living things. They are the smallest and most basic structural and functional element in all living beings (Prykhodko et al., 2017). Since viruses do not have cells, they are not considered alive. A live cell’s ability to replicate must be hijacked for viruses to access the ingredients they require to increase
In bigger organisms, cells are grouped to form tissues, which are collections of cells that perform similar or related tasks. Tissues are paired together to fulfill a particular task in an organ. Plants and animals both have organs, which are similar in function. A group of organs working together to accomplish single or multiple functions in the body are called “organ systems” (Prykhodko et al., 2017). For example, blood is transported from and to the lungs in the circulatory system, and organs like the heart are involved (Prykhodko et al., 2017). Organisms exist in the living world as independent and self-contained entities..
An entire population of a species is defined as the members of that species who live within a certain geographic region. Different populations can also coexist in the same geographical location. A community is defined as the total of all people who live in a certain region (Prykhodko et al., 2017). In and of itself, a forest constitutes an ecosystem that is the first level of organization in which non-living characteristics of a specific region influence the live things that exist in that habitat. The biosphere is the highest level of organization, consisting of all ecosystems and representing all life zones on Earth.
Structure of the Cardiovascular System
The cardiovascular system is one of the first major organ systems to emerge and fully function far before forming any other crucial organ system. The cardiovascular system is made up of two components: the heart, which is a muscle pump, and a closed system of vessels known as capillaries, veins, and arteries. As the name indicates, the circulatory system’s blood is propelled by the heart along a circular circuit of vessels, repeatedly passing through the body’s circulations.
The Heart
The heart has four chambers: the left ventricle (the ventricle that pumps blood into the body), the right ventricle (the ventricle that pumps blood out). There are two thin-walled compartments in the atria that end up receiving blood from the venous system. A serous membrane covers the heart and keeps it safe as part of the pericardium (Hoskins et al., 2017). Three layers of tissue from the heart wall: epicardium, the outer layer, myocardium, the middle layer, and endocardium, the inner layer (Hoskins et al., 2017). The portion of the myocardium present in each chamber determines how much force is generated when it comes to wall thickness.
The heart is equipped with two kinds of valves that ensure blood flows in the proper direction. Atrioventricular valves are located between the auricles and ventricles. In contrast, semilunar valves are located at the bases of the massive vessels exiting the ventricles (Hoskins et al., 2017). The tricuspid is located on the right atrioventricular valve, while the mitral is located on the left (Hoskins et al., 2017). The semilunar connects the right ventricle to the pulmonary trunk. At the same time, the aortic valve connects the left ventricle to the aorta.
An extensive network of blood arteries supplies oxygen to contracting heart muscle cells and removes waste products from their systems. The heart’s walls get blood from the ascending aorta’s left and right coronary arteries. After passing through the myocardium capillaries, blood penetrates a network of cardiac veins. Most of the heart’s veins are gathered in the coronary sinus located in the right atrium (Hoskins et al., 2017). Blood vessels are channels through which blood is transported to and from the body’s various organs and tissues.
The vessels are divided into arteries, veins, and capillaries. An artery’s wall is made up of three layers, which are as follows: The tunica intima is the innermost layer of the skin and is composed of a connective tissue membrane that contains elastic fibers (Hoskins et al., 2017). Typically, the middle layer, known as tunica media, which composed primarily of smooth muscle. Tunica media is the thickest layer among the three layers. It supports the vessel while also changing the diameter of the vessel, allowing blood pressure to be controlled more effectively (Hoskins et al., 2017). The tunica externa, also known as tunica adventitia, is the outermost layer of the vessel, and it is responsible for attaching the vessel to the extracellular space tissue (Hoskins et al., 2017). Various elastic and collagenous fibers are present in this layer, composed primarily of connective tissue. This layer of connective tissue is thick near the tunic media but shifts to losing connective tissue at the vessel’s periphery.
The capillaries are the tiniest blood vessels connecting the arteries carrying blood from the heart and returning blood to the heart. For the most part, capillaries are just two sets of cells in layers—an endothelium inner layer and an outer epithelial layer. For red blood cells to pass through them, they must do so in a single file since they are so small. According to estimates, billions of capillaries are estimated in the human body (Hoskins et al., 2017). The basal membrane, a protein layer that encircles the capillary, protects this layer of cells.
Veins have three layers and valves that prevent the backflow of blood through the arteries. The layers are the vein’s external, medial, and intimal tunica. Despite the presence of all layers, there is less connective tissue and smooth muscle. Therefore, the vein walls remain thinner than artery walls, which is connected to the concept that blood in veins is under reduced pressure than blood in arteries (Hoskins et al., 2017). In addition, veins may store more blood than arteries since their walls are narrower and less stiff.
Mechanism of the Pulse and the Blood Pressure
The arterial pulse is the rapid enlargement of an artery arising from the rapid influx of blood entering the aorta and subsequent distribution through the arterial system. The impulse that comes from left ventricular outflow can be transported down the aorta at a speed 20 times higher than the speed of the expelled blood bolus (Sembulingam, 2019). Blood pressure fluctuates as it moves from the heart to the rest of the body. However, systolic blood pressure rises, despite a drop in mean pressure from the central artery. Different elastic and calibers of peripheral vessels in the superior and inferior parts of the body can distort the pulse and dampen it, as can reflections, resonances, or standing waves (Sembulingam, 2019). The greater the distance between the heart and an external artery, the larger the peripheral arterial pulse’s deviation (Sembulingam, 2019). The carotid pulse’s contour must be extensively investigated to understand how the vascular system impacts the pulse’s shape.
The body has several systems for controlling arterial blood pressure. Baroreceptors in blood arteries sense fluctuations in blood pressure and provide signals to the brain (Sembulingam, 2019). Central nervous system information is sent to the brain to control peripheral resistance and myocardial output (Sembulingam, 2019). Both High-Pressure and Low-Pressure Baroreceptors exist in the human body. High-pressure signals are generated in reaction to the vessel’s physical deformation (Sembulingam, 2019). The sensory terminals in the tunica externa of the artery rise in nerve impulses as the vessel are stretched. An autonomic neuron is activated by these impulses and hormones that impact the cardiovascular system. When blood pressure rises, stimulation of the baroreceptor successfully blocks the sympathetic stimulation (Sembulingam, 2019). Hypovolemic shock, on the other hand, would cause the rate of a nerve impulse from the baroreceptors to be lowered due to decreased depolarization, increasing the pressure (Sembulingam, 2019). Low-Pressure Baroreceptors are found in major veins, pulmonary arteries. Volume changes have a significant effect on the receptors in the venous system. In low-pressure settings, a decrease in the frequency of action potentials releases antidiuretic hormone (ADH), aldosterone, and renin. These have a downstream influence on the regulation of arterial pressure.
High serum osmolarity, reduced blood volume, and lowered blood pressure cause the hypothalamus to generate antidiuretic hormone. ADH is primarily responsible for increasing water reuptake in the collecting ducts of the kidney nephrons, hence increasing plasma volume and arterial pressure (Sembulingam, 2019). ADH has also been proven to elicit mild vasoconstriction, raising peripheral vascular resistance and arterial pressure (Sembulingam, 2019). Ultimately, the renin-angiotensin-aldosterone system is critical for arterial blood pressure regulation. Numerous hormones are involved in the system, which raises blood volume and peripheral resistance. It begins with the generation and secretion of renin by the kidney’s juxtaglomerular cells (Sembulingam, 2019). They are stimulated by sympathetic nervous system activity, lowered blood pressure, and decreased sodium concentrations in the nephrons’ distal convoluted tubules. Next, renin is expelled from the juxtaglomerular cells and permeates the bloodstream, where it comes into touch with angiotensinogen, which the liver produces continually (Sembulingam, 2019). Renin converts angiotensinogen to angiotensin I. The angiotensin I then travel to the pulmonary arteries, where the endothelium converts it into an angiotensin-converting enzyme (ACE). ACE then converts angiotensin I to angiotensin II. Angiotensin II serves a variety of tasks in the body, including releasing ADH, increasing sodium reuptake in the kidneys, and releasing aldosterone, among others.
The Feedback Mechanism of Exercise on the Body
Exercise poses a significant threat to whole-body homeostasis, causing extensive perturbations in various tissues, cells, and organs due to or in reaction to contracting skeletal muscle’s elevated metabolic activity. Multiple coordinated and frequently redundant reactions work in concert to mitigate the homeostatic risks posed by increases in muscle activity and oxygen demand. Voluntary exercise is more than just a basic contraction of the muscles. The spinal cord recruits motor units in response to voluntary effort produced in the brain’s motor cortex (Blain et al., 2016). When skeletal muscles contract, the nervous system sends a potent signal that enables metabolic needs to be fulfilled with little interruption of homeostasis, in addition to neurological feedback from the tightening skeletal muscles themselves.
Compression of the vascular system in the working muscles by static contractions of great force but brief duration restricts blood flow and oxygen supply to the muscles while concurrently raising blood pressure. Muscle contraction demands ATP for cellular energy processes (Blain et al., 2016). Sarcolemma excitability, Ca2+ uptake, and actin-myosin cross-bridge cycling are examples of how these three processes work together to generate force (Blain et al., 2016). Although ATP drops under specific activity and environmental circumstances, the size of the change is minimal compared to the overall turnover of ATP inside active myocytes.
ATP is well preserved throughout the spectrum of intensity exercises and durations. Extra-muscular substrates must be used to keep skeletal muscle metabolic activity stable during long-term exercise (Blain et al., 2016). Hence, the liver releases glucose into the bloodstream by glycogenolysis and subsequently via gluconeogenesis (Blain et al., 2016). At the same time, the adipocyte increases the breakdown of triglyceride reserves and the flow of long-chain non-esterified triglycerides into the circulation due to this process.
When the autonomic nervous system operates effectively, the heart rate, blood pressure, and breathing rise in response to exercise, signals involved include a “central command” linked to motor output, which stimulates sections in the brainstem, cardiovascular and respiratory centers to induce a rise in heart rate, blood pressure, and airflow (Blain et al., 2016). The heart rate reaction to exercise is principally mediated by vagal withdrawal and stimulation of sympathetic activity to the heart, which is coordinated by the central command (Blain et al., 2016). Both of these variables also contribute to increased cardiac stroke volume. Despite significant homeostatic hurdles related to high exercise, the central motor drive is subject to feedback control that monitors venous, arterial blood gases, fluid status, and body temperature, as well as other physiological variables.
Conclusion
Physical exercise is essential in controlling blood pressure, especially in advanced age. The veins expand and accept the excess pressure during the activity to maintain normal blood pressure. Although the heart beats faster and the blood pressure rises somewhat, the vessels become more stretchy, assisting—and even preventing — hypertension. Not only does physical exercise help in controlling blood pressure, but it also helps prevent several diseases such as diabetes, obesity, and heart disease.
References
Blain, G. M., Mangum, T. S., Sidhu, S. K., Weavil, J. C., Hureau, T. J., Jessop, J. E.,… & Amann, M. (2016). Group III/IV muscle afferents limit the intramuscular metabolic perturbation during whole body exercise in humans. The Journal of Physiology, 594(18), 1-33. Web.
Sembulingam, K. (2019). Essentials of medical physiology: With free review of medical physiology: Thandalam, Tamil Nadu. JAYPEE Brothers MEDICAL P.
Hoskins, Peter R., Peter R. Hoskins, Patricia V. Lawford, Patricia V. Lawford, Barry J. Doyle, and Barry J. Doyle (2017). Cardiovascular biomechanics (pp.25-142). Springer.
Prykhodko, A. B., Popovich, A. P., Yemets, T. I., & Maleeva, A. Y. (2017). Molecular and cellular levels organization of living things (pp. 7-10).