Chapter 19:Neural mechanisms - Chemoreceptor reflexes
Not local response
Auto regulation is a local response, are neural mechanisms a local response?
Increase cardiac output, cause puerperal vasoconstriction to increase BP
When blood pressure falls, how do the CV centers respond?
Decrease cardiac output, and cause peripheral vasodilation to decrease BP
When blood pressure rises, how do the CV centers respond?
Vasoconstriction - controlled by adrenergic nerves (NE)
What is the vasomotor center responsible for, and what is it controlled by?
Produced by coordinating cardiovascular and respiratory activites
How are chemoreceptor reflexes produced?
Increases cardiac output with NE on Beta 1 receptors on heart (increases HR), and Alpha 1 receptors on blood vessels (increases contraction)
How does the cardioacceleratory center adjust cardiac output and peripheral resistance?
Reduces cardiac output with ACh on heart at SA node (slows heart rate)
How does the cardioinhibitory center adjust cardiac output and peripheral resistance?
Stimulates smooth muscle contraction in arteriole walls (alpha 1 receptors)
How does the vasomotor center adjust cardiac output and peripheral resistance?
Produced by constant action of sympathetic vasoconstrictor nerves
How is vasomotor tone produced?
Baroreceptor reflexes, and chemoreceptor reflexes
The cardiovascular centers monitor arterial blood pressure through monitoring tissue demand through what reflexes?
Stretch receptors
What are baroreceptors?
Cardioacceleratory center, cardioinhibitory center
What are the two centers involved in the cardiac center?
Cardiac center and vasomotor centers of medulla oblongata
What cardiovascular centers are involved in adjusting cardiac output and peripheral resistance? (resistance of arteries to blood flow)
The heart has to respond quickly, and baroreceptors lag in response
What causes orthostatic hypotension?
Changes in pH, O2, and Co2 concentrations
What do chemoreceptor reflexes respond to?
Comes from standing up too fast
What is orthostatic hypotension?
Monitor start of systemic circuit
What is the function of baroreceptors at the aortic sinuses?
Monitor end of systemic circuit (venous return)
What is the function of baroreceptors at the right atrium?
Maintain blood flow to brain
What is the function of baroreceptors in the carotid sinuses?
Responds to changes in blood pressure
What is the function of baroreceptors?
Respond to changes in chemical composition, particularly pH and dissolved gases
What is the function of chemoreceptor reflexes?
Monitor cerebrospinal fluid (CO2, O2, and pH content), control respiratory function, and control blood flow the brain
What is the function of chemoreceptors below the medulla oblongata?
Monitor blood CO2, O2 and pH
What is the function of chemoreceptors in carotid bodies and aortic bodies?
Maintains blood pressure, and can be increased or decreased based on conditions
What is the function of vasomotor tone?
Found in walls of carotid sinuses, aortic sinuses, right atrium
Where are baroreceptors found?
In carotid bodies and aortic bodies, and below medulla oblongata
Where are chemoreceptors located?
Lightheadedness due to low BP in the brain
Why do you become lightheaded in orthostatic hypotension?