week 7+8 - CNS control of cardiovascular activity

Question 1

receptors of the cardiovascular centre:

Answer 1

• Proprioceptors:
  o Joint movement
• Baroreceptors:
  o Pressure and stretch in vessel walls
• Chemoreceptors:
  o Concentration of chemicals in blood
   O2: hypoxia
   CO2: hypercapnia
   H+: acidosis

Question 2

SUMMARY OF CNS CONTROL OF CARDIOVASCULAR ACTIVITY:
input to cardiovascular center

Answer 2

from higher brain centres:
- cerebral cortex, limbic system, and hypothalamus

from sensory receptors:
- proprioceptors - monitor movements
- chemoreceptors - monitor blood chemistry
- baroreceptors - monitor blood pressire

Question 3

SUMMARY OF CNS CONTROL OF CARDIOVASCULAR ACTIVITY:
output to heart

Answer 3

cardiac accelerator nerves (sympathetic)
- increased rate of spontaneous depolarization in SA node (and AV node) increases heart rate
- increased contractility of atria and ventricles
- increases stroke volume

vagus nerve (cranial nerve, X, parasympathetic)
- decreased rate of spontaneous depolarization in SA node (and AV node) decreases heart rate

Question 4

CHEMICALS THAT AFFECT HR?
hormones

Answer 4

• Hormones that increase heart rate
  o Epinephrine and norepinephrine (enhance pumping effectiveness)
   Adrenal medullae
   Exercise, stress, excitement
  o Thyroid hormones
   Hyperthyroidism (causes tachycardia – increased heart rate)

Question 5

CHEMICALS THAT AFFECT HR?
cations

Answer 5

o Increased K+, Na+
 Decreased heart rate
* Increased Na+ causes Ca2+ to decrease
 Increases Ca2+ increases heart rate

Question 6

summary:
the blood vessels of the circulatory system are…

Answer 6

adapted to their function

Question 7

summary
blood pressure is controlled by…

Answer 7

an interplay of many factors