Lecture 8 Unit 1 Flashcards
What are the levels of control of blood pressure and blood flow?
- neural control
- hormonal control
- local control
what makes up neural control?
cardiovascular reflexes
what makes up hormonal control?
- catecholaminies, ADH, angiotensin II, and aldosterone
- ANP
- histamine
where is the main center for neural control?
cardiac centers of the medulla oblongata
what happens in the CV center?
it includes a collection of gray matter regions (nuclei) : 2 cardiac centers and the vasomotor center
what does the CV center help regulate
HR, SV and the blood vessel diameter
what higher brain centers does the CV center receive input from?
the cerebral cortex, the limbic system, and the hypothalamus
what peripheral afferent nerve fibers does the CV center receive input from?
baroreceptors, chemoreceptors, and proprioceptors
what are the 3 major functional regions in the CV center?
- cardioacceleratory center
- cardioinhibitory center
- vasomotor center
what is the cardioacceleratory center?
a collection of sympathetic neurons that increase heart rate and contractility
what is in the cardioinhibitory center?
collection of parasympathetic neurons that decrease heart rate
what is in the vasomotor center?
a collection of vasomotor neurons that regulate blood vessel diameter via sympathetic nerves that synapse on arteriolar smooth muscle and cause vasoconstriction
cardiovascular reflexes are produced by afferent signaling of what?
- baroreceptors
- chemoreceptors
- proprioceptors
what are the most important receptors in cardiovascular regulation?
baroreceptors and chemoreceptors
where are high pressure baroreceptors located?
in the carotid sinus and aortic arch
how do baroreceptors enter the CV center/
via cranial nerves IX and X
where are low pressure baroreceptors located and how do they enter the CV center?
located in the walls of the right atrium and vena cavae and enter via cranial nerve X
what is a baroreceptor?
initiated reflex in response to decreasing blood pressure
where are chemoreceptors located?
in the carotid sinus and in the walls of the ascending aorta
how do chemoreceptors in the carotid sinus signal the medulla
via cranial nerve IX
how do chemoreceptors in the aortic bodies signal the medulla?
va cranial nerve X
what do chemoreceptors respond to?
increased hydrogen ion content, increased CO2 and most strongly to hypoxia
what do Chemoreceptors do?
activate the sympathetic division leading to increased HR, SV and vasoconstriction
what are catecholamines?
(NE and epinephrine) circulate and bind directly to cardiac muscle fibers and to blood vessel smooth muscle cells
