Advanced Cardiovas Physiology

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Advanced Cardiovas Physiology
Question one
According to Turner, the human body reacts differently to various physiological changes. For example, in the case of a “flight response”-a physiological change that occurs when a person is under threat, the body reacts through the neural activities and the blood stream (435). The hypothalamus in the brain activates the sympathetic nervous system and the adrenal-cortical system (Turner, 437). The nervous system sends impulses through the nerve paths, and the adrenal system uses the blood circulatory system. After the impulses are sent to the adrenaline glands and the cardiac muscle, adrenaline and noradrenaline hormones are released into the blood. The combination of the two increases the heart rate, which consequently elevates the blood pressure.
Notably, the cardiovascular centers of the brain play a very significant role in auto-regulation of the blood pressure. These centers that are located in the medulla oblongata include the cardio-accelerator that stimulates the cardiac functions to reduce the heart rate. It also has the cardio-inhibitor that reduces blood pressure through simulations transmitted by the vagus nerve.
Question two
Atenolol (Tenormin), which falls under the beta blockers, is a drug that is popularly used to address hypertension medically. Weber refers to them as blocking agents, as they are very efficient in reducing the level of blood pressure in patients (12). This drug works by reducing the effects of the sympathetic nervous system and hormone epinephrine, adrenaline.

When the activities of adrenaline are blocked, the amount of oxygen and blood that moves to the heart is reduced. That automatically results in a slowed heart rate, and a reduced pressure with which blood is pumped to other parts of the body. It is also evident that the drug also blocks the kidney organs from secreting angiotensin II hormone, which stimulates the release of aldosterone that drives up the blood pressure (Weber, 14). With that, the drug results in lowering the blood pressure in affected patients. It is advisable to administer Atenolol with other hypertension drugs. Some doctors claim that it may not sufficiently reduce blood pressure without the supplement of other medications.
Question three
Named after two physiologists, Ernest Starling and Otto Frank, it is the law which states that “the force of contraction of the cardiac muscle is equal to the stretching length of the muscles in the ventricular wall.
The law implies that the diastolic expansion of the heart is directly equal to the systolic contraction of the heart (John, 1). John further states that the theory is satisfied when an unusual amount of blood enters the heart to cause the stretching of the myocardial length and tension increase of the cardiac muscle (1). The myocardial tension increases in accordance to the length-tension. As a result, an increase in the stroke volume and the cardiac stroke work is realized.
Question four
Frank-Starling mechanism is defined by John Solaro in his article “Mechanisms of the Frank-Starling Law of the Heart: The Beat Goes On” as a primary adaptive response that helps to adjust each ventricular blood output to its inflow, by facilitating the shrinking of the myocardium proportionately to stretching of the muscle fibers. He adds that this mechanism helps to describe the linear relation between the diastolic volume and the systolic pressure that is clearly outlined in the Starling’s law.
When the heart is filled with more blood in the human body, the force with which the cardiac muscles contract increases. That is owing to the strain on each fiber muscle. The strain then enhances the sensitivity of calcium by the myofibrils; as a result, a high amount of actin-myosin come together to form the muscle fibers, that consequently lead to the contraction of the muscles. The force generated by these muscles is proportionate to the preload, and the stretch of the individual muscles is equally attributed to the diastolic capacity of the ventricles.

Work Cited
John Solaro, R. “Mechanisms of the Frank-Starling Law of the Heart: The Beat Goes On.”Biophysical Journal, vol 93, no. 12, 2007, pp. 4095-4096. Elsevier BV,
doi:10.1529/biophysj.107.117200.
Turner, J. Rick. “Cardiovascular Reactivity and Stress.” 1st ed., Boston, MA, Springer US,
2013.
Weber, Michael A. “Hypertension Medicine.” Totowa, N.J: Humana, 2001. Internet resource.