blood pressure Flashcards
(39 cards)
what is blood pressure?
force exerted against blood vessel walls by the blood in the vessels (maintains blood flow in tissues)
where is BP high and low
HIGH in arteries (blood leaving heart)
LOW in veins (blood returning to heart)
why is arterial blood pressure important?
it maintains blood flow to tissues
-arterial blood pressure fluctuates with cardiac cycle
what is systolic pressure?
measured during ventricular systole (peak pressure in arteries as blood is ejected from heart)
what is diastolic pressure?
measured during ventricular diastole (low pressure in arteries as heart fills)
what is pulse pressure?
difference between systolic and diastolic
what are the 3 factors affecting arterial pressure?
- peripheral resistance
- cardiac output
- blood volume
what is peripheral resistance?
the resistance to blood flow, if PR is high, the heart must work harder to circulate blood flow.
what are the four sources of peripheral resistance?
blood vessel diameter- decrease diameter, increases BP
blood vessel length- increase length, increase BP
blood viscosity- thicker blood, higher BP
turbulence- more turbulence, higher BP
what are the “resistance vessels”?
arterioles
-peripheral resistance is greatest in these blood vessels
what are called the blood reservoirs?
veins
if you have more venous return..?
increased cardiac output, increased volume of blood in arteries, increased BP
blood volume and BP?
if you increase blood volume, increase blood pressure
what is vasomotor control?
ALL sympathetic regulation of BP. medulla oblongata- -vasomotor center -sympathetic division (NE) -contraction of smooth muscle in blood vessels
vasoconstriction?
decreases diameter, increases BP
vasodilation?
increases diameter, decreases BP
is there parasympathetic control of blood vessel diameter?
NO, sympathetic tone maintains BP in arteries and arterioles, facilitates venous return
what type of receptor would detect changes in BP?
baroreceptor.. detects stretch and pressure
what is the baroreceptor initiated reflexes?
reflexive vasoconstriction to maintain blood pressure and ensure blood delivery
what is the carotid sinus reflex?
baroreceptors in internal carotid arteries to protect blood supply to the brain
what is the aortic reflex?
baroreceptors in aortic arch to protect blood supply to heart and body
what is the local intrinsic control of BP?
vasodilation triggered by changes in the tissue environment..
localized, nervous system is not involved
local vasodilators include?
decreased O2, increased CO2 decreased pH increased temp histamine released NO released by endothelial cells, triggers CA2+ uptake and relaxes smooth muscle
ADH and hormonal control of BP
- released from posterior pituitary in response to dehydration
- baroreceptors detect decreased blood volume, osmoreceptors detect increased solute conc.
- triggers vasoconstriction in addition to increased water reabsorption by the kidneys (increased BP)
