CV Flashcards
Pump
heart is one component
vascular system - stores E and promotes return to heart
skeletal muscles - promote return of blood to the heart
exchanger
vascular system - distributes and collects blood
lungs - exchange CO2 and O2, receive blood from R heart and share thorax w the heart
Extracellular v intracellular water
30/45 L intracellular
15/45 extracellular (12 interstitial, 3 in plasma)
which organ receives the most bloodflow from the heart?
lung
receives 100% from right heart
how do substances move within an organ?
diffusion - moving subsances across a cell membrane
convection
moving substances alog w the bloodflow
how to move substances from one organ to another
exchange vessels
“Exchange vessels” with slow velocity for diffusion
conduit vessels
“Conduit vessels” with rapid velocity for efficient transit time
ventricular systole
chamber is max contracted
blood out of outlet valve
ventricular diastole
chamber is max relaxed
blood in through inlet valve
P-R interval
time between delay
give ventricle and atrim time to fill with blood
atrial contraction and
“AV node” - delay to allow ventricule to fill
Q-T interval
contains ventricular contraction
heart pump
2 pumps in series - R and L
R - 100% to lungs (pulmonary = low pressure)
L - to body through arteries - most to kidney
flow to each can be independently regulated and shunted - filters (kidney, liver, GI, skin) get most blood
Forward Flow
promoted by valves
if dysfunctional - turbulence and E is lost (friction, heat)
Stroke Volume
Filled Volume (End Diastole) - Contracted Volume (End Systole)
vol of blood that leaves the heart
forward - how much goes through aortic valve
SV - forward or back through LA - valve disease
cardiac output
heart rate x stroke volume
volume/time
Flow
= Cardiac output!
change in pressure/resistance
I = V/R
V = pressure gradient, R = resistance
I = volume/time
V=IR
series v parallel resistance
series - add resistances (high)
parallel - add inverses of resistance - low
flow in the periphery
fixed throughout the system (as a result of changes inr esistance)
vasoconstricion or vasodilation to maintain relatively const flow
pressure in the periphery
plummets from aorta to R atrium - result of changing resistance
vascular stiffness
aorta stoes energy during systole and releases it during diastole (Windkessel effect)
PE converted into KE
if too stiff - E is dampened (aging, diabetes)
want it to be like a slinky
arteries
elastin and collagen
thick walls
conduit vessels
arterioles
thick walls
“resistance vessels” - regulated
more smooth muscle, less elastin
capillaries
smallest vessels, largest SA
“exchange vessels”
no smooth muscle
venules
thin walls
“capacitance vessels”
regulated
smooth muscle
veins
“capacitance vessels” - regulated
smooth muscle, valves
flow velocity changes across vascular tree
highest in arteries
lowest in capillaries
blood volume in vacular tree
highest in venules and veins , lowest in arterioles/cap
vascular resistance
highest in arterioles - shunting blood from one system to another
most regulated
poiseuille’s law
resistance = 8xlengthxviscosity/radius^4
flow is dep on radius ^4 (most imp!!)
flows toward lowest P and least R
MAP
= (2xdiastolic + systolic)/3
diastolic is 2x as important as systolic
(what organs see)
also = Cardiac output x SVR (which is resistance to blood flow by all vessels except pulmonary)
diastolic BP
pressure in the artery at rest
systolic BP
pressure in the artery during contraction
pulse pressure
systolic - distolic pressure
sympathetic stimulation
all portions of heart
norepinephrine
increase heart rate, speed of conductance, force of contraction
parasympathetic stimulation
SA node, AV node, atrial muscle
mainly Ach
decfease HR, speed of conductance, force of contraction
chronotropy
heart rate
dromotropy
speed of conductance
inotropy
force of contraction
arterial baroreceptors
in carotid sinus
increase in MAP stretches carotid sinus and leads to increased firing of baroreceptors
increase Parasym and decrease sym to bring BP down if BP is up
pressure sensor
via medulla
carotid massage
slows heart rate by vagal stimulation
main BP sensor
atrial stretch receptors
volume! (carotid is pressure)
in RA (near SVC) and LA (near pulmonary veins)
increased atrial volume - singal pituitary gland - decreas ADH and urination increases
increased atrial vol –> increase HR –> increas CO to unload heart
decrease intrathoracic P
breathe in –> increased venous return –> atrial stretch –> increased atrial baroreceptor activity –> medulla –> decreasd vagul outflow –> increase HR
increase intrathoracic pressure
breathe out –> diaphragm out –> increased P in throax –> more blood to L heart and less to R heart (bc lungs are like sponge of blood) –> less atrial stretch –> decrease HR
valsalva maneuver
expiration against a closed glottis
carotid baroreptirs
- increased thoracic P forces blood into LA
- strain (pathological!) - increased P prefects blood from returning - fall in CO and less distention of all baroreceptors (carotid and aortic)
- P release - sudden distention of aorta and pulmonary artery - shift in blood vol to great vessels decreases venous return
- equilibration - rapid increase in venous return and increased CO with stretch of baroreceotrs and fall in HR
Bezold-Jarisch Reflex
low blood volume!
sympathetic followed by parasympathetic
rigorous contraction–> stim L ventricular receptors – decrease R and vasodilation
starts w sym response (increase HR) - ventricular over stim 0 compensatory decreased HR/vascular tone
dehydration - dancing
fasting blood test and fright
conduit vessels
arteriies
resistance vessels
arterioles
exchange vessels
capillaries
capacitance vessels
venules and veins
pulse wave velocity
distance/time (measure of vascular stiffness)
