Maintaining blood pressure
What kind of receptors respond to blood pressure?
Mechanoreceptors - respond to stretch
What are the type of mechanoreceptors in the arteries? Heart chambers?
Arteries - baroreceptors
Heart - cardiopulmonary receptors
Where does integration of regulatory information occur?
Brainstem - upper medulla
Secondary - spinal cord
Where are baroreceptors most sensitive
Carotid sinus, aortic arch
Pressure differential across a vessel wall
What is the dominant effector in baroreceptor reflex?
Decreases excitation with increased pressure
How does sympathetic NS activity effect venous return
Increased excitation --> increased venous return
How does parasympathetic effect heart?
Heart rate decrease
Small decrease in contractility
Describe endocrine role in baroreceptor reflex
gland releases norepinephrine
NE increases heart rate and contractile state
releases angiotensin (vasocontrictor)
releases vasopressin (vasocontrictor)
What are the purpose of atrial mechanoreceptors?
Supply information as to volume state of venous system
Receptors and roles in atrium
Type A - detect stretch during atrial contration (A wave)
Type B - detect stretch during atrial filling (V wave)
Both modulate release of vasopressin, ADH
CNS ischemic reflex
Sympathetic vasoconstriction with increased heart rate in response to poor CNS perfusion
The Cushing Response
Vasocontriction with Vagal bradycardia
Caused by CSF pressure is close to MAP
Exposure of nasopharynx (CN V) to wet/cold
Bradycardia and vasoconstriction to non-essential organs