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Control of blood pressure
control of blood flow
46
Anatomy
Undergraduate 1
09/30/2008

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Term
What four mechanisms regulate tissue perfusion
Definition
cardiovascular center, hormonal controls, neural controls, autoregulation
Term
What does the cardiovascular center control in the heart
Definition
contractility, heart rate, stroke volume
Term
What does the cardiovascular center control in the blood vessels
Definition
blood vessel diameter, blood flow, blood pressure
Term
What feedback systems does the cardiovascular center control
Definition
hormonal, neural, and local feedback systems
Term
What does the cardiovascular center receive signals from
Definition
baroreceptors, chemoreceptors, proprioreceptors
Term
Which neurons are involved with the cardiovascular center
Definition
sympathetic and parasympathetic neurons of the autonomous nervous system
Term
What does an increase in sympathetic stimulation cause
Definition
an increase in heart rate, cardiac output, and blood pressure
Term
What does an increase in parasympathetic stimulation cause
Definition
a decrease in heart rate, cardiac output, and blood pressure
Term
What is vasomotor tone and what sets it
Definition
vasomotor tone is the partial constriction of arterioles at all times. It is set by the cardiovascular center and is responsible for the resting level of systemic vascular resistance
Term
What are the two reflexes involved in the neural control of blood flow
Definition
baroreceptor reflex and chemoreceptor reflex
Term
What does the baroreceptor reflex do
Definition
it monitors and responds to changes in blood pressure
Term
How do baroreceptors detect changes in blood pressure
Definition
by sensing the degree of stretch in the vascular walls of expandable organs
Term
Where are the baroreceptors located
Definition
the carotid sinus, aortic sinus, and right atrium
Term
what happens when the baroreceptors sense and increase in blood pressure
Definition
vasodilation and a decrease in cardiac output which decreases blood pressure
Term
What happens when baroreceptors sense a decrease in blood pressure
Definition
vasoconstriction and an increase in cardiac output which increases blood pressure
Term
What do chemoreceptor reflexes do
Definition
they monitor and detect changes in the chemical composition of blood
Term
What chemicals are monitored by chemoreceptors
Definition
oxygen, carbon dioxide and pH
Term
Where are chemoreceptors located
Definition
carotid body and aortic body
Term
What conditions does the chemoreceptor reflex respond to
Definition
increased carbon dioxide or decreased oxygen and pH
Term
How does the chemoreceptor reflex respond
Definition
increases respiratory rate, blood pressure, and cardiac output. causes vasoconstriction
Term
What are the four hormonal controls of blood pressure
Definition
RAA system, ADH, ANP, epinephrine-norepinephrine
Term
What does RAA system stand for
Definition
renin angiotensin aldosterone system
Term
When does RAA system appear in the blood
Definition
when blood pressure in the kidney is low
Term
What is the first step in the RAA system
Definition
renin and angiotensin converting enzymes produce angiotensin II
Term
What does angiotensin II cause
Definition
vasoconstriction and the secretion of aldosterone
Term
What does aldosterone cause
Definition
an increase in blood sodium which increases reabsorption in capillaries and increases blood volume
Term
What does the Raa system do to blood pressure
Definition
it increases it through vasoconstriction and an increase in blood volume
Term
Where is norepinephrine and epinephrine secreted from
Definition
adrenal medulla
Term
What is epinephrine and norepinephrine released in response to
Definition
stimulation from the sympathetic division of the autonomic nervous system
Term
What does the release of epinephrine and norepinephrine cause
Definition
vasoconstriction, vasodilation, an increase in cardiac output
Term
Where does vasoconstriction occur when epinephrine and norepinephrine is released
Definition
skin and abdominal organs
Term
Where does vasodilation occur when epinephrine and norepinephrine are released
Definition
cardiac and skeletal muscle
Term
What does ADH stand for
Definition
anti diuretic hormone
Term
What releases ADH
Definition
pituitary gland
Term
When is ADH released
Definition
when the blood pressure is low
Term
What does ADH cause
Definition
vasoconstriction and decrease in water loss through the kidneys which increases blood volume and increases blood pressure
Term
When is atrial natriuretic peptide secreted
Definition
when high blood pressure stretches the walls of the right atrium
Term
What secretes ANP
Definition
cells in the right atrium
Term
What does ANP cause
Definition
vasodilation and an increase in sodium and water elimination in the kidneys which decreases blood pressure
Term
What is autoregulation
Definition
the ability of tissue to automatically adjust blood flow through local vasodilation and vasoconstriction
Term
What factors does autoregulation depend upon
Definition
physical changes and the presence of vasodilating and vasoconstrictiong chemicals
Term
What are the two main physical changes in autoregulation and what do they cause
Definition
warming causes vasodilation, cooling causes vasoconstriction
Term
What are two vasodilating chemicals
Definition
histamine, nitric oxide
Term
What are two vasoconstricting chemicals
Definition
thromboxane and prostaglandins
Term
What causes the pulse
Definition
the alternate expansion and recoiling of vascular walls after each ventricular contraction
Term
What is blood pressure measured with
Definition
sphygmomanometer
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