Question

In: Anatomy and Physiology

Explain the neural, renal, and hormonal regulation of blood pressure.

Explain the neural, renal, and hormonal regulation of blood pressure.

Solutions

Expert Solution

Ans:

Blood pressure is defined as pressure exerted by blood on the walls of the blood vessels. It is regulated through various mechanism in the body.

(i) Neural regulation of blood pressure: It is the short term regulation of blood pressure which is achieved through the role of cardiovascular centers and baroreceptor stimulation.

  • The cardiovascular centers located in medulla oblongata forms part of the autonomic nervous system and is responsible for regulation of cardiac output. Cardiovascular center contains three distinct components: the cardioaccelerator center, the cardioinhibitor center, and the vasomotor centre. The cardioaccelerator center stimulates cardiac function by regulating heart rate and stroke volume via sympathetic stimulation from the cardiac accelerator nerve. The cardioinhibitor center slows cardiac function by decreasing heart rate and stroke volume via parasympathetic stimulation from the vagus nerve. The vasomotor center controls vessel tone or contraction of the smooth muscle in tunica media. The majority of these neurons act via the release of neurotransmitter norepinephrine from sympathetic neurons.
  • The baroreceptors are specialized stretched receptors located within thin areas of blood vessels and heart chambers. Vasular baroreceptors are found primarily in sinuses within the aorta and carotid arteries. When blood pressure rises too high, baroreceptors fire at a higher rate and trigger parasympathetic stimulation of the heart. As a results, cardiac output falls and sympathetic stimulation of the peripheral arterioles will decrease to cause vasodilation. These combined activities causes blood pressure to fall. When blood pressure drops too low, the rate of baroreceptor firing decreases. This triggers an increase in sympathetic stimulation of heart and peripheral vessels, causing increased cardiac output and vasocinstriction respectively. These combined activities causes blood pressure to rise.

(ii) Renal regulation of blood pressure: The kidney plays a central role in the regulation of arterial blood pressure. The kidney influences blood pressure by causing the arteries and veins to constrict and also by increasing the circulating blood volume. Upon constriction of blood vessels, the increase in resistance to blood flow causes increase in blood pressure. The increased Na and water reabsorption from the distal tubules reduces urine output and increases the circulating blood volume. The increased blood volume helps stretch the heart muscle and generate more pressure with each beat, thereby increasing the blood pressure. There are three mechanisms of renal regulation for control of blood pressure by:

  • Pressure diuresis: As arteriolar blood pressure increases, so flow through kidney increases, further causing increase in filtration rate and urinary output.
  • Pressure natriuresis: Increased renal perfusion pressure causes increase in sodium excretion, which further causes less water reabsorption and then blood pressure decreases.
  • Renin-angiotensin-aldosterone system (RAAS) causes increase in blood pressure via a pathway involving renin, angiotensinogen, angiotensin 1, angiotensin converting enzyme, angiotensin 2 and aldosterone.

(iii) Hormonal regulation of blood pressure: The hormonal control mechanism of blood pressure involves renin-angiotensin-aldosterone system (RAAS) of kidneys to regulate blood volume. It is a long-term regulation of blood pressure. The juxtaglomerular cells in the kidneys secrete renin into the blood in response to decreased blood pressure. Renin facilitates the conversion of angiotensinogen to angiotensin I, which is then converted to angiotensin II using angiotensin converting enzyme (ACE). Angiotensin II is a potent vasoconstrictor. It acts directly on kidneys to increase sodium reabsorption in proximal convoluted tubules. Angiotensin II further promotes the stimulation of aldosterone. Aldosterone promotes salt and water retension by acting at the distal tubule to increase expression of epithelial sodium channels. Further, aldosterone increases the activity of basolateral Na+-K+ ATPase, thus increasing the electrochemical gradient for movement of sodium ions. This ultimately results in decreased water excretion, increases blood volume and blood pressure.

Another mechanism of regulating blood pressure is by release of anti-diuretic hormone (ADH) from hypothalamus in resonse to thirst or high plasma osmolarity. Prostaglandins acts as a local vasodilators to increase GFR and reduce sodium reabsorption to control blood pressure.


Related Solutions

Describe the regulation of filtration in the nephron (renal corpuscle) in response to blood pressure, nervous...
Describe the regulation of filtration in the nephron (renal corpuscle) in response to blood pressure, nervous input, hormones, and Tubuloglomerular Feedback. (Be sure to compare activity at the afferent and efferent arterioles.)
Describe the regulation of filtration in the nephron (renal corpuscle) in response to blood pressure, nervous...
Describe the regulation of filtration in the nephron (renal corpuscle) in response to blood pressure, nervous input, hormones, and Tubuloglomerular Feedback. (Be sure to compare activity at the afferent and efferent arterioles.)
Discuss the following: The hormonal regulation of blood glucose and the effect it has on glycolysis,...
Discuss the following: The hormonal regulation of blood glucose and the effect it has on glycolysis, gluconeogenesis, and glycogen metabolism.
Neuroendocrine mechanisms control homeostasis. Describe a homeostatic regulation that involves both neural and hormonal regulations. (7...
Neuroendocrine mechanisms control homeostasis. Describe a homeostatic regulation that involves both neural and hormonal regulations. (7 pts) Provide an answer to each question below!!! All questions below correlate to the 7pt question above. In total, it is one response but divided into pieces. Name the homeostatic function to be regulated. (1 pt) Name the tissue/organ involved. (1 pt) Name the neural and hormonal factors involved. (2 pts) Describe how each of these neural and hormonal factors regulates the organ/tissue’s function....
describe the neutral and hormonal mechanism that work to maintain blood pressure after significant (hemorrhaging) blood...
describe the neutral and hormonal mechanism that work to maintain blood pressure after significant (hemorrhaging) blood loss associated with an injury
Describe the hormonal regulation of the kidney.
Describe the hormonal regulation of the kidney.
Renin is an aspartyl protease that has a role in the regulation of blood pressure. The...
Renin is an aspartyl protease that has a role in the regulation of blood pressure. The active site has two aspartyl residues, one acting as an acid (pK1 5.0) and the other acting as a base (pK2 of 4.0). If the enzyme activity is measured at pH 6.0, what fraction of the enzyme is expected to be ACTIVE A. 1% B. 9.0% C. 50% D. 90% E. 95% F. 99%
Describe the mechanisms of blood pressure regulation for renin angiotensin system.
Describe the mechanisms of blood pressure regulation for renin angiotensin system.
Hormone Secreting gland/organ Trigger for secretion Effect(s) Targets Regulation (Humoral, Hormonal, Neural) Aldosterone Calcitonin Calcitriol Cortisol...
Hormone Secreting gland/organ Trigger for secretion Effect(s) Targets Regulation (Humoral, Hormonal, Neural) Aldosterone Calcitonin Calcitriol Cortisol Erthropoietin Glucagon Insulin Parathyroid hormone Thyroid hormone
Consider the hormonal regulation of oogenesis and ovulation, as well as hormonal feedback mechanisms onto the...
Consider the hormonal regulation of oogenesis and ovulation, as well as hormonal feedback mechanisms onto the hypothalamus and pituitary gland. Please explain the hormonal action and feedback mechanisms that underlie how the birth control pill works as a hormonal contraceptive.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT