Blocking agents:
Anticholinergic - atropine
- scopolamine
CARDIOVASCULAR REFLEXES (CVR)
Reflex
= regular response of the organism to stimulation mediated through central nervous
systém
Reflex arc:
1)
receptor (sense organ);
2)
afferent neuron;
3)
center;
4)
efferent neuron;
5)
effector (in CVR – heart and vessels)
Receptors (for CVR):
1) Interoceptors
– for perception of the internal environment:
a)
Baroreceptors
b) Chemoreceptors
Baroreceptors
– low – pressure receptors
- high pressure receptors
a) Low – pressure receptors
– atrial stretch receptors:
2 types - „A“ – they discharge primarily during atrial systole
- „B“ - - “ - atrial filling,
peak – at the end of atrial diastole.
The discharge is increased when venous return is increased = volumoreceptors for monitoring
venous return.
Effects of the increased stimulation of the atrial baroreceptors:
Vasodilatation – an accumulation of the blood in the periphery – a fall in BP.
Bainbridge Reflex – rapid infusion to the right atrium – changes in HR.
Initial basal increased HR – effect: bradycardia
- “ - decreased HR – effect: tachycardia
Two components:- reflex – through atrial baroreceptors
-
mechanical – local stretch – effect on the SA node
b) High – pressure receptors
- carotid sinus
- aortic arch
- LV