Biology Worksheet: Cardiovascular and Respiratory Physiology Questions

This assignment provides answers to worksheet questions focusing on human physiology. Question 1 explains orthostatic hypotension, detailing the drop in arterial blood pressure when transitioning from a supine to a standing position, the shift in blood volume due to gravity, and the compensatory responses of the nervous and renin-angiotensin systems, along with changes in body temperature and glucose levels. Question 2 defines hyperventilation, its causes, and its impact on carbon dioxide levels and blood pH, leading to respiratory alkalosis. The answer also describes the role of the respiratory system in maintaining homeostasis through gas exchange and regulation of blood pH, specifically addressing how the system responds to hyperventilation to reduce high carbon dioxide levels. The assignment includes references to relevant research articles.

Worksheet questions 3

CONTENTS
QUESTION – 1..........................................................................................................................1
QUESTION – 2..........................................................................................................................1
REFERENCES...........................................................................................................................3

QUESTION – 1
The transition or changing of position from supine to standing by an individual results
into a drop in the arterial pressure of blood. It has been observed that there is around at least
20 mm Hg fall in the systolic blood pressure (SBP) and around 10 mm Hg fall in diastolic
blood pressure (DBP) being observed within three minutes of standing. This is being referred
as orthostatic hypotension. It takes place because of 500 to 1000 ml of shifting of blood from
the upper body to the lower body. This happens mainly because of the gravitational force. As
a result of this, there is a decrease in venous return which leads to decrease in volume of
stroke along with pressure in the arterial blood pressure and with the passage of time, cerebral
blood flows (Patel and et.al., 2016). Due to this, there is a compensatory influence which
activates the compassionate nervous system and the renin-angiotensin system and release in
succeeding aldosterone. Other than this, there is an overall change in the control system. For
example, when an individual moves from supine position to standing position, the body
temperature along with body glucose also changes. Even the control centres also respond to
these changes in postures and stimulus by sending the signals to the effectors.
QUESTION – 2
a). Hyperventilation is being defined as a fast or profound breathing generally instigated
through terror or nervousness. Such type of over breathing can many a time might actually
leave an individual feeling breathless.
b). At the time of hyperventilation, the rate of removal of CO2 from the blood is increased.
Since, there is a decrement in the partial pressure of carbon dioxide in the blood, problems
related to respiratory alkalosis might occur along with reduced acidity. The pH level also
increases. When an individual breathes, he or she inhale oxygen and exhale carbon dioxide.
Excessive breathing in case of hyperventilation result into decrease in the carbon dioxide
level in the blood which results in different symptoms that might feel that one is
hyperventilating (O'Shea, Lackner and Rössler, 2015).
c). An individual who is hyperventilating, the respiratory system plays a very important role.
It helps in maintenance of homeostasis in the body. There are mainly two ways in which the
respiratory system responds and achieves homeostasis in the body that is through exchange of
gases and through regulation of the blood pH. The exchange of gas is being carried out by
respiratory system through elimination of carbon dioxide. Through cellular respiration, a
waste product is being given off. This is being responded and achieved through exchanging
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of gas in the lungs. Such kind of gaseous exchange of oxygen as well as carbon dioxide that
occurs in alveolar sacs present in the lungs. In addition to this, in the situation of
hyperventilation, the rate of removal of CO2 from the blood is increased. The respiratory
system thus, helps in reducing this high level of carbon dioxide in the blood which in turn
helps in lowering down the pH levels and comes to a normal level (Bull and et.al., 2019).
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REFERENCES
Books and journals
Bull, J.L., Tredici, S., Fujioka, H., Komori, E., Grotberg, J.B. and Hirschl, R.B., 2019.
Effects of respiratory rate and tidal volume on gas exchange in total liquid ventilation.
ASAIO J. 55(4). pp.373-81.
O'Shea, D., Lackner, H.K. and Rössler, A., 2015. Influence of bed rest on plasma galanin
and adrenomedullin at presyncope. Eur J Clin Invest. 45. pp.679–685.
Patel, K., Rössler, A., Karl, L.H, Irhad, T., Charles, L., Lorr, D., Green, D., Hinghofer-
Szalkay, H. and Goswami, N., 2016. Effect of postural changes on cardiovascular
parameters across gender, Medicine.95(28). p.4149.
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