Regulation of Arterial Pressure and CPR Endocrinology

Question 1

Describe baroreceptor as a reflex.

Answer 1

• Detector: detect movement from set point
• Afferent pathway
• Coordination center in brain stem
• Efferent pathway
• Effectors: correct movement from set point

Question 2

Where are the locations of the baroreceptors and what nerves are used, where does they lead to?

Answer 2

• Carotid sinus:
  
  • CN IX
• Aortic sinus
  
  • Vagus
• Both lead to nucleus tractus solitarus

Question 3

What happens with the afferent signal in this senario: Person is suffering from massive blood loss.

Answer 3

• Pressure decreases
• Stretch decreases
• Baroreceptor firing rate decreases
• Goal is to increase pressure

Question 4

What happens with afferents when a person is hypertensive?

Answer 4

• Increase pressure
• Increase stretch
• Increase firing rate
• Goal to decrease pressure

Question 5

What are afferents most responsive to?

Answer 5

Rate of change in pressure rather than magnitude

Question 6

Which baroreceptor has higher threshold for activation?

Answer 6

Aortic

Question 7

What nucleus is associated with parasympathetic activity with CV fxn?

Answer 7

Dorsal motor nucleus of vagus and Nucleus ambiguus

Question 8

What part of the brainstem is assoc. with sympathetic activity assoc with CV fxn?

Answer 8

Rostral ventrolateral medulla

Question 9

When does the sympathetic nervous system respond?

Answer 9

• activated by decreaed pressure and decreased baroreceptor firing rates
• influences heart muscles, SA node directly, vessels and adrenal gland via splanchnic nerve

Question 10

what receptors are used in sympathetic influence on constricting arterioles and veins

Answer 10

alpha

Question 11

What receptor plays a role in increasing heart rate and contractility?

Answer 11

Beta1

Question 12

What activates parasympathetic nervous system?

Answer 12

• activated by increased pressure and increased firing rate

Question 13

Orthostatic hypotensioin?

Answer 13

• Supine to standing
• lightheaded and dizzy on standing
• Blood pools in legs when lying down and venous return and CO decreases
• MAP decreases activating baroreceptor response
• Venous pooling can occur in edema also

Question 14

How does hypertension impact baroreceptors?

Answer 14

• It resets baroreceptors to regulate pressure at a higher set point

Question 15

What does RAAS do?

Answer 15

• Renin is secreted from kidney due to decrease in BP
  
  • Released by B1 adrenergic receptor activation
  • Decrease NaCl at macula densa
• Renin causes Angiotensinogen converted to angiotensin I
• Angiotensin I converted to angiotensin II in lungs by ACE
• Compensation for low BP begins

Question 16

What secretes renin?

Answer 16

• Juxtaglomerular cells in walls of renal afferent arterioles in response to low BP and symp stimulation

Question 17

What does aldosterone do?

Answer 17

• Causes Na retention and water by kidney
• Increases BV, preload/SV, CO, and BP

Question 18

What does ADH do?

Answer 18

• increases TPR and water retention
• released in response to angiotnsin II, atrial receptors with low preload, increased osmolality of blood, symp activation

Question 19

Natriuretic peptides?

Answer 19

Atrial Brain or C type

• increased secretion by excessive preload of atria and ventricles
• causes:
  
  • arteriolar dilation decreasing TPR
  • Increases fluid loss decreasing preload
  • Inhibits renenin decreasing TPR and preload

Question 20

What are the comensatory responses to decreased blood volume?

Answer 20

• Carotid sinus nerve firing decreases
• Heart rate contractility cardiac output increases
• Unstressed volume decreases
• TPR increases
• Epi, ADH, renin, angiotensin II, aldosterone all increase

Question 21

How does chronic Htn change your body?

Answer 21

• Increased Na concentration and osmolarity
• Water retention
• Increases SNS activity, CO, TPR

Question 22

How do chemoreceptors change during aerobic exercise?

Answer 22

If they are normal chemoreceptors they shouldn’t change