cardiovascular Flashcards
contrast and compare skeletal muscle cell vs contractile myocardial cell
similarity: striated,has mitochondria, requires C2+ to contract
sksletal are cylindrical cells, motor neuron AP
contractile are branched and electrically connected
pathway that AP travel throughout the heart
- sinotrial node depol
- atrial muscle
- atriovencular node (aV)
- bundle of His
- Bundle branches 9L & R)
- Purkinje fibre
- ventricular muscle
resting heart rate
70 beats / min
how to calculate max heart rate
220-age
how PSNS change heart rate
Ach binding its recep will:
< K+ permeability (more K+ leaves)
bt > Na+ ^& Ca2+’s (less them leaving)
how SNS affect heart rate
NE (norepinephrine) bidns to receptor will:
< Na+ & Ca2+ permeability
=> release epinephrine to heart
how heart rate goes up (100 -> 130) and down (100 -> 70) if one is on a run
- controlled by SA node, intrinsic rate
RUN: 100 beats/min -> sympathetic activates -> beats 130
REST: 100 beats/min -> parasympathetic ativates -> 70
describe 1st phases in the cardiac cycle
atrial systole
ECG: [ wave occurs before
atrial pressure oincreases
valves open
ventricular vol increase
describe 2nd phase in cardiac cycle \
early ventricular systole (isovlumetric)
- QRS wave before
ventricular p increases (exceed atrial [P bt lower than oartic)
all valves closed
no vol change
describe 3rd phase in cardiac cycle
ventricular systole (rapid ejection period)
- ventroicular P < (higher than aortic and atrial)
aortic valves open
ventriuclar vol >
describe 4th phase in cardiac cycle
early ventriuclar diastole (isovolumetric)
- ECG: T waves before
- ventricular P decrease
- all valves closed, no vol change
5th phase in cardiac cycle
late ventricular diastole
ventricular P decrease
AV valves open
ventricular vol increase
how PSNS & SNS affecgt stroke volume
PSNS release ACh to innervate cardic contractile cells
=> >Cà+ permeability which > weaker contraction & less SO
SNS: via the release of NE / epinephrine to innercate vemtroci;ar ,isc;e ce;;s
=more Ca comes in whihc stronger contraction & more SO
describe the 3 layers in arteries and veins
tunica externa = of fibrous connective tissue
-> tunica media = smooth muscle and eleastic fibres
-> tunic interna endothelial cells
3 differences btw aorta + arteries vs arterioles vs capillarie vs venules
1/ large diameter 2/ small diameter 3/ smallest
1/ thin walls to 2/ thick walls 3/ very thin walls
1/ has very high BP 2/ drop in bP 3/low BP & lsmall dro in bp
net filtration pressure of cardiovascular
Kf [(Pc + TTIF) + [(Pif + TTc)
why you will pass out when you hyperventilate?
via medtabolic theory, more CO2 removed from blood => less PCO2 in bloods
blood vesel contract => less blood flower to brain -> pass out
compare SNS vs PSNS’s on neural contraol mechanism
PSNS: innervates SA AV nodes
=? decrease HR
SNS: innvervates SA & AV node and fentricular muscle
-> increase HR SV vasocontriction
what is MAP and how to find it?
diastolic P + 1/3(systolic -diastolic P)
calculate cardiac output
= heart rate (bpm) x Stroke Volume (mL)
group these agents of humoral regulation into 2 groups: angiotensin II, ANP, ADH, epinephrine
agents involved in vasocontriction:
- epinephrine / angiotensin II / ADH
agents involved in vasodilation:
- epinephrine / ANP
why is gap junction so important in the myocardial cells?
to allow ions and AP to read so whole cell can contract
desribe a typical SA nodal action potential
pacemaker potential: membrane slowly and spontaneously depol to threshold (-60 to -40)
-> aP triggers
depol: Ca VG channels open for influx of Ca
repoil; K+ VG channels and k+ leaves -> go back to RMP
_________ myocardial cells can _____ generate _____. It is divided into 2 types: ____ & _____ (which has minimal actin & __-)
self-excitable / spontaneously / AP / contracttile heart cells / nodal & conducting cells/ myosin
compare effect of PSNS and SNS on stroke volume
via release of ACh / release of NE & epinephrine
decrease Ca+ permea / more Ca+ enters
weaker contraction so less SO / stronger contraction so higher SO
if you have an increased EDV, what is the effect?
< in EDV = < in preloaed
requires larger stretch of ventricular contractile cells
stronger contraction of these cells upon systole
more blood ejected from heart
higher SO =higher cardiac output
descrine the relationship btw blood flow, pressure and resistance in a sentence and a calculation
blood flows down a pressure gradient bt resistance decrease flow
blood flow = P gradient / 1/r^4 (resistanc)
why is blood velocity the lowest in capill?>
since blood velocity is inversely proportional to total cross-sectional area, and capill requires the largest TCA blood move slowest here
which Starling forces promotes filtration? reabsorption?
filtration:
- Pc
- Pif when negative
- TT if
reabsorption:
- TTc
- Pif when positive
vasocontriction: ___ flow, ___ P VS vasodilation: ____
overall, PSNS __ HR, SO, and cause ____
overall SNS ____ HR, SO and cause ____
- decrease/ vasodilation
- increase / vasocontriction
