SFOS 20/21

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Define homeostasis

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
Transmural pressure

Pressure differential across a vessel wall
What is the dominant effector in baroreceptor reflex?
- Sympathetic NS
- 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
- Adrenal gland releases norepinephrine
- NE increases heart rate and contractile state
- Kidney releases angiotensin (vasocontrictor)
- Hypothalamus 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
Diving Reflex
- Exposure of nasopharynx (CN V) to wet/cold
- Bradycardia and vasoconstriction to non-essential organs

Author

zf2010

80238

Card Set

SFOS 20/21

Description

SFOS 20/21

Updated

2011-04-18T00:04:06Z

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