Cardiac (Exam 3) Flashcards
What is systolic and diastolic bp?
systolic: how much pressure blood exerts against the artery walls when LV is beating/ contracting.
diastolic: how much pressure blood exerts against the artery walls when LV is resting/ relaxed.
what is mean arterial pressure
average pressure in arteries during cardiac cycle
What factors affect MAP
blood volume, effectiveness of heart as a pump (cardiac output)), resistance of the system to blood flow, relative distribution of blood between arterial and venous blood vessels.
What kind of pressure do venous blood vessels have?
low
What determines blood volume?
fluid intake
fluid loss: could be passive or regulated at kidneys
What determines the effectiveness of the heart as a pump (cardiac output)
the heart rate and stroke volume
What determines the resistance of the system to blood flow
The diameter of the arterioles
What determines the distribution of blood between arterial and venous blood vessels
the diameter of the veins
What 2 organ systems influence blood volume
Nervous and renal
What are the fast and slow responses of raised blood pressure
fast: compensation by cardiovascular system
slow: compensation by kidneys
How does the cardiovascular system compensate for high bp
it causes vasodilation or opening of blood vessels and lowers cardiac output, allowing the bp to go back down to normal
How do the kidneys compensate for high bp?
it causes more excretion of fluid in urine causing the blood volume to lower, bringing bp back down to normal
What makes blood volume go up and how does it affect bp
blood volume can go up if a diet has too much salt in it, causing bp to increase
How does cardiac output affect bp
by changing the amount of blood in the arteries, if cardiac output goes up, bp goes up
How does vessel length affect bp
the longer the vessel, the less resistance which lets bp stay down
How does vessel diameter affect bp
if diameter is small, resistance increase and bp goes up. if diameter larger resistance decreases and bp goes down
What blood born substances cause vasoconstriction? And what controls the levels of these substances
epinephrine and norepinephrine. sympathetic nervous system
How does resistance in the arterioles affect the body
affects mean arterial pressure and determines the relative blood flow to the organs
What are the systemic controls that affect blood distribution
hormones or nervous signals
What directs blood by local control
pre-capillary sphincters
What is the systemic control of vessels
the brain and endocrine system
Where does blood flow if the precapillary sphincters are relaxed
all the capillaries in the bed
Where does blood flow if the precapillary sphincters are constricted?
the metarterioles, the arteriole and the venule
Where are the capillaries
in the endothelium
What are the 2 types of capillaries
continuous and fenestrated
What are the characteristics of the 2 types of capillaries
continuous: low permeability, leaky junctions
fenestrated: high permeability, large pores
Where are the 2 types of capillaries found
continuous: muscle, connective tissue, neural tissue
fenestrated: kidney and intestine
What are the 3 ways something can move across a capillary
difussion, transcytosis, cell junctions
What stays in, moves out of and moves into the capillaries through diffusion
stay: proteins
out: water, O2, glucose
in: CO2, nitric waste, water
How does most capillary exchange happen?
diffusion and transcytosis
What is it called when bulk flow does into the capillary? out?
in: absorption
out: filtration
What is the net average of fluid that filters out of the capillaries? where does it go?
3, lymph vessels then returns to circulation
When there is net absorption where does the fluid go?
the venules
When there is net filtration where does the fluid go?
the lymph vessels or it can be reabsorbed
At the entrance of the capillary is the net pressure positive or negative? at the end of the capillary
entrance: net positive, filtration
end: net negative, absorption
What factors affect bp reading
rate of cuff deflation, diurnal rhythm, posture
