Short Term Control Of Blood Pressure 1

Question 1

Describe the fundamental equation of cardiovascular physiology mentioned in the content.

Answer 1

Mean arterial pressure equals cardiac output times total peripheral resistance.

Question 2

What is the significance of mean arterial pressure in the cardiovascular system?

Answer 2

It is the driving force pushing blood through circulation and needs to be regulated to ensure adequate perfusion of tissues and organs.

Question 3

How does low mean arterial pressure affect the body, particularly the brain?

Answer 3

Low mean arterial pressure can lead to inadequate perfusion of tissues and organs, potentially causing fainting (syncope) as the brain is particularly sensitive to this.

Question 4

Explain the physiological response when someone faints due to low mean arterial pressure.

Answer 4

Fainting due to low mean arterial pressure can lead to pooling of blood in the legs, reducing preload, stroke volume, and consciousness. Restoring the individual to a lying position helps restore these parameters.

Question 5

What are the long-term health risks associated with high mean arterial pressure (hypertension)?

Answer 5

Long-term hypertension increases the risk of coronary heart disease and stroke.

Question 6

Define the arterial baroreflex and its components.

Answer 6

The arterial baroreflex coordinates the regulation of mean arterial pressure. It involves baroreceptors in the aortic arch and carotid sinus sensing changes, an integrating center processing this information, and effectors producing responses to maintain mean arterial pressure within the normal range.

Question 7

Describe the role of baroreceptors detecting changes in pressure.

Answer 7

Baroreceptors detect changes in pressure indirectly by sensing stretch in the carotid sinus and aortic arch.

Question 8

What happens to the firing rate of baroreceptors when pressure increases?

Answer 8

The firing rate of baroreceptors increases when pressure increases.

Question 9

How do aortic arch baroreceptors and carotid sinus baroreceptors send their signals to the brain?

Answer 9

Aortic arch baroreceptors send signals via the vagus nerve, while carotid sinus baroreceptors send signals via the glossopharyngeal nerve.

Question 10

Define the integrating center for baroreceptor signals in the brainstem.

Answer 10

The integrating center for baroreceptor signals is located in the medulla oblongata, specifically known as the medullary cardiovascular centers.

Question 11

Describe the response of the medullary cardiovascular centers to changes in mean arterial pressure.

Answer 11

The medullary cardiovascular centers can produce responses to regulate mean arterial pressure, including parasympathetic outflow via the vagus nerve.

Question 12

What is the role of the nucleus tractus solitarius in the context of baroreceptor function?

Answer 12

The nucleus tractus solitarius is involved in processing baroreceptor information, although it may be oversimplified as there are likely multiple nuclei and neurons involved.

Question 13

Describe the role of acetylcholine in the parasympathetic nervous system on heart function.

Answer 13

Acetylcholine binds to cholinergic muscarinic receptors on pacemaker cells, hyperpolarizing them and leading to decreased heart rate or bradycardia.

Question 14

What effect does noradrenaline have on heart rate and contractility in the sympathetic nervous system?

Answer 14

Noradrenaline binds to beta one receptors, causing pacemaker cells to depolarize faster, increasing heart rate, and also increases contractility of the ventricular muscle.

Question 15

Define vasoconstriction and its impact on blood vessels.

Answer 15

Vasoconstriction refers to the contraction of smooth muscle in blood vessels, leading to venoconstriction and arteriolar constriction, ultimately increasing mean arterial pressure.

Question 16

How does the sympathetic nervous system influence stroke volume in the heart?

Answer 16

Sympathetic stimulation increases the release of calcium, leading to more actin and myosin crossbridges forming, resulting in increased strength of excitation-contraction coupling, stronger force of contraction, and increased stroke volume.

Question 17

Describe the role of adrenaline in the sympathetic nervous system on heart function.

Answer 17

Adrenaline, released from the adrenal medulla, acts on beta one receptors in the heart, increasing heart rate and contractility, and also causes vasoconstriction by binding to alpha one receptors on smooth muscle of blood vessels.

Question 18

What is the difference between the parasympathetic and sympathetic nervous system in their effects on heart function?

Answer 18

The parasympathetic system primarily decreases heart rate through acetylcholine release, while the sympathetic system increases heart rate and contractility through noradrenaline and adrenaline release, respectively.

Question 19

Describe the effect of venoconstriction on cardiac output according to Starling’s law.

Answer 19

Venoconstriction increases end diastolic volume, preload, force of contraction, stroke volume, and ultimately cardiac output.

Question 20

Explain the relationship between mean arterial pressure, cardiac output, and total peripheral resistance.

Answer 20

Mean arterial pressure equals cardiac output multiplied by total peripheral resistance. Increasing cardiac output or total peripheral resistance will lead to an increase in mean arterial pressure.

Question 21

Define the impact of arteriolar constriction on total peripheral resistance.

Answer 21

Arteriolar constriction increases total peripheral resistance by making it harder to push blood from arteries into arterioles.

Question 22

How do arterial baroreceptors contribute to the regulation of cardiovascular function?

Answer 22

Arterial baroreceptors provide crucial input to the medullary cardiovascular centers, helping regulate blood pressure by sensing changes in arterial pressure.

Question 23

Describe the role of cardiopulmonary baroreceptors in monitoring blood volume.

Answer 23

Cardiopulmonary baroreceptors, located in the atria and vessel walls of the lungs, sense blood volume changes by detecting vessel stretching and adjusting their firing rate.

Question 24

Explain the function of central chemoreceptors in respiratory regulation.

Answer 24

Central chemoreceptors monitor changes in carbon dioxide and oxygen levels, activating to stimulate respiratory drive, leading to increased breathing to enhance oxygen intake.