Cardiovascular Flashcards
___ in the cardiac myocyte transfer force between cells
desmosomes
____ _____ in the cardiac myocyte transfer current via calcium between cells
gap junctions
what ion is transferred between gap junctions?
calcium
cardiac cells are ____ than skeletal cells
smaller
how many nucleus are in a cardiac myocyte?
1
the ____ is the cardiac contractile unit
sarcomere
what two zones on the sarcomere disappear during contraction?
H zone, I band
where is calcium stored in the sarcomere?
sarcoplasmic reticulum
what act occurring in the sarcomere causes contraction?
calcium binds to troponin
what filament is the outer layer of the sarcomere?
actin/thin
what filament is the inner layer of the sarcomere?
myosin/thick
there are ____ mitochondria in cardiac cells than skeletal cells
more
mitochondria are ____ in cardiac cells than skeletal cells
larger (in volume)
calcium enters the sarcolema through what?
dihydrogen pyrimidine receptor
where in the cell does excitation-contraction coupling take place?
sarcolema (plasma membrane of the cardiac cell)
how do the stores of calcium leave the sarcoplasmic reticulum?
through the ryanadine receptor
where is the DHPR located in the sarcolema?
T-tubule
what triggers the release of calcium from the stores in the SR?
calcium entering the cell through DHRP
describe calcium induced calcium release
calcium entering the sarcolema through DHRP triggers calcium to be released from the SR through the RYR
what does calcium bind to once it is in the sarcolema?
troponin on the sarcomere
what is the name for contraction of the sarcomere?
systole
what is the name for relaxation of the sarcomere?
diastole
what causes diastole of the sarcomere?
calcium releasing from troponin
how does calcium re-enter the SR during diastole/relaxation?
Ca ATP-ase pump
how does calcium leave the sarcolema altogether during relaxation/diastole?
Na/Ca exchanger
when calcium leaves the sarcolema, what molecule enters?
3 molecules of sodium
when sodium enters the sarcolema during relaxation, how does it leave?
through Na/K ATP-ase
what enters the cell as sodium leaves during relaxation?
2 molecules of potassium
how does potassium leave the cell during relaxation?
voltage-gated sodium channels
what percent of calcium enters the sarcolema through DHRP from the ECF?
20%
what percent of calcium enters the sarcolema through RYR from the SR?
80%
force generation in the myocyte is directly proportional to what?
number of actin crossbridges (binds of calcium and troponin)
_____ is a word that describes how the length of sarcomeres affects force of contraction
contractility
what causes the cardiac cell action potential to plateau?
voltage-gated calcium channels open
what mV is the cardiac cell at while in rest?
-90 mv
what mV causes an action potential in the cardiac cell?
+20 mV
how long does it take to complete one cardiac action potential?
.8 seconds
can cardiac muscle undergo tetany?
no
what node of the heart beats 70 bpm?
sinoatrial (SA)
what node of the heart beats 50-60 bpm?
atrioventricular (AV)
why does the AV node beat slower than the SA node?
fever gap junctions to relay currents
where is the heart does it beat 40 bpm?
purkinje fibers
why do purkinje fibers have a high electrical current even though they have 40 bpm?
high nodule cells, high level of gap junctions
___ ____ transfer current from the SA to cardiac myocytes
gap junctions
what is the general flow of current through the heart?
SA node, AV node, bundle of his, bundle branches, purkinje fibers
what is the reference value for electrical activity?
ground
what is the name of the shape/layout of leads on the heart?
Beethoven’s triangle
how many leads does it take to detect heart rhythm?
3
if a positive lead depolarizes, what direction is the deflection?
up
if a negative lead depolarizes, what direction is the deflection?
down
if a positive lead repolarizes, what direction is the deflection?
down
if a negative lead repolarizes, what direction is the deflection?
up
what is it called when the deflection is a flat line?
isoelectric/perpendicular
what lead produces a wave most similar to that of an ECG?
lead 2
what lead produces a wave most perpendicular to an ECG?
lead 3
all four valves can be ___ at the same time but not ____ at the same time
closed, open
valves are shaped in a way that ensures what?
one-way flow
how many heart valves are able to be open at the same time?
2
___ ____ is the filling of the ventricles with blood
ventricular diastole
what valves are closed during ventricular diastole?
aortic, pulmonary
what valves are open during ventricular diastole?
both AV valves
____ _____ is the ventricles ejection blood
ventricular systole
what valves are open during ventricular systole?
aortic, pulmonary
what valves are closed during ventricular systole?
both AV valves
what is the name of the valve between RA and RV?
tricuspid (Right AV valve)
what is the name of the valve between LA and LV?
mitral (Left AV valve)
what type of blood enters the RA?
deoxygenated
what type of blood leaves the pulmonary artery?
deoxygenated
what type of blood enters the LA?
oxygenated
what type of blood leaves the aortic valve?
oxygenated
what valves closing makes the LUB sound?
AV valves
what valves closing makes the DUB sound?
aortic and pulmonary
what is the S1 heart sound?
LUB
what is the S2 heart sound?
DUB
cardiac cells have an ____ resting membrane potential
unstable
why do cardiac cells have an unstable resting membrane potential?
funny channels are permeable to both sodium and potassium
a ____ is two connected electrodes
lead
what electrical activity occurs at the P wave?
atrial depolarization
what mechanical activity occurs at the P wave?
contraction/systole of the atria
what is occurring during the PR segment?
AV nodal delay, allows for ventricles to fill and for all of the blood to exit the atria
what two electrical activities occur during the QRS complex?
ventricular depolarization, atrial repolarization
what two mechanical events occur during the QRS complex?
ventricular contraction/systole, atrial relaxation/diastole
what occurs during the ST segment?
ventricles are fully depolarized/contracted
what electrical event occurs during the T wave?
ventricular repolarization
what mechanical event occurs during the T wave?
ventricular relaxation/diastole
ventricles are _____ with blood between T wave and the next P wave?
filling
the T wave is a _____ deflection
positive
depolarization of ventricles during the QRS complex goes from ____ to _____
endocardium, epicardium
repolarization of ventricles during the T wave goes from ____ to ______
epicardium, endocardium
the ___ ____ _______ determines the position of the heart
mean ventricular axis
how do you calculate heart rate from an ECG?
beats (cycles) / time
what is the unit for heart pressure change?
mmHg
the parasympathetics ____ heart rate
decrease
the sympathetics _______ heart rate
increase
_____ ANS comes from the brainstem/medulla
parasymathetic
____ ANS comes from the lower spinal cord
sympathetics
sympathetics release _____ NTX
norepinephrine
parasympathetics release ____ NT
acetylcholine
what do the sympathetics do to the IF?
make more permeable to sodium, higher chance of action potential
what do the parasympathetics do to the IF?
make more permeable to potassium, lower chance of action potential
___ ____ is the amount of blood ejected from the heart in one minute
cardiac output (CO)
how do you calculate cardiac output?
heart rate (bpm) * stroke volume (mL)
what is the normal resting cardiac output?
about 5L/min
___ ____ is the volume of blood ejected per beat
stroke volume
how is stroke volume calculated?
end diastolic volume (EDV) - end systolic volume (ESV)
how are the valves positioned during isovolumetric contraction?
all valves closed
how are the valves positioned during ESV?
all closed
SV/EDV * 100%= ______ ______
ejection fraction
what is the normal range of ejection fraction?
50-80%
what 3 factors regulate stroke volume?
preload, contractility, afterload
______ is the degree of stretch on the heart, prior to ejection of blood
preload
preload is the same as ____
EDV
____ is the force and intensity of contraction, specifically related to calcium concentration and the SR calcium concentration and the subsequent crossbridges
contractility
_____ is the pressure required to eject blood from the ventricles to the aorta or pulmonary artery
afterload
____ reflects systemic blood pressure/mean arterial pressure
afterload
what is the Frank-Starling law of the heart?
the more that you fill the ventricles, the more forceful the ejection
as you increase EDV, you ____ stroke volume
increase
what three things influence venous return?
skeletal muscle pump, respiratory pump, sympathetic innervation of veins
___ ____ must be equal to cardiac output
venous return
EDV is determined by what?
venous return
_____ is influenced by the degree of stretch
preload
the more you increase EDV, the more that you will ____ stroke volume up to a point
increase
the overstretching of sarcomeres leads to decreased crossbridges, decreased tension, and overall ___ ____
heart failure
contractility can be affected by ____
inotropes
positive change in contractility leads to what?
increased calcium sensitivity with calcium
in contractility, norepinephrine, epinephrine/adrenaline, and caffeine are _____ factors
positive
positive stroke volume inotropes do what?
increase SV without changing EDV
negative stroke volume inotropes do what?
decrease SV without changing EDV
in contractility, beta blockers and DHPR are ____ factors
negative
the sympathetic nervous system has a _____ inotropic effect
positive
protein kinase A adds ____ to RYR, CA ATPase, and troponin to lead to a faster reaction
phosphate
what occurs when a phosphate group is added to troponin?
decrease calcium sensitivity, can turn on and off faster
G protein activates ___ ____
adenylate cyclate
the ATP released when G protein activates adenylate cyclate activates what?
protein kinase A
_______ is a representation of systemic blood pressure
afterload
what is the average pressure of the left ventricle?
80 mmHg
what is the average pressure of the right ventricle?
20 mmHg
hypertension _____ the afterload force and makes the heart work harder to open pulmonary and aortic valves
increases
hypertension _____ stroke volume
decreases
the greater the afterload, the ______ the velocity of shortening
slower
ohm’s law relates what three variables?
blood flow (Q), change in pressure (P), and resistance (R)
blood flow (Q) is _____ to the change in pressure
proportional
blood flow (Q) is _____ to resistance
inverse
if there is no pressure change, what is the flow of blood?
there is none
poiseulle’s law relates what three variables to reisitance?
length (L), viscosity (n), and radius (r)
resistance is _____ to length
proportional
resistance ____ as we age because the blood vessels are getting longer
increases
resistance is _____ to viscosity
proportional
as we increase RBC count, viscosity ____
increases
resistance is _____ to radius
inverse
____ is the biggest influence on resistance
greatest
if you increase radius, resistance ____, blood flow ____, and this is known as vasodilation
decrease, increase
capillaries are ____ layer(s) thick
one
what type of blood vessel has the most smooth muscle?
arteries/arterioles
what type of blood vessel has the greatest radius?
venioles, veins
2/3 of human body blood is stored where?
veins
compliance of the aorta occurs during what?
ventricular contraction/systole
____ is the ability of the aorta to stretch due to pressure change
compliance
compliance ____ as we age
decreases
____ are the blood vessel that is the most compliant
veins
___ ____ is the ability of the aorta to return to it’s normal shape
elastic recoil
____ is what keeps the aorta closed during elastic recoil
pressure
the aorta recoils during what stage?
ventricular relaxation/diastole
how is pulse pressure calculated?
systolic value-diastolic value
how is mean arterial pressure (MAP) calculated?
diastolic value + 1/3(pulse pressure)
the dichromic notch is the closing of the ____ ____
aortic valve
____ flow is the smooth and quiet flow of blood
laminar
____ flow is the noisy and bouncing flow of blood
turbulent
____ are the resistance vessels
arterioles
high resistant vessels have ____ control of their radius
high
resistance vessels such as arterioles are innervated with ____ neurons only for the smooth muscle
sympathetic
the percentage of blood flow to organs during different activities is controlled by ______
arterioles
at rest, ____% of blood flow is to the brain, ____% to kidneys, _____% to skeletal muscle, and ____% to the GI tract
15, 20, 20, 20
during heavy exercise, ____% of blood flow is to the brain, ____% to kidneys, _____% to skeletal muscle, and ____% to the GI tract
10-13, 1, 80, 1
what are the 3 kinds of capillaries?
continuous, discontinuous, fenestrated
this type of capillary has no holes, no clefts, and is in the lungs for gas exchange
continuous
this type of capillary has holes, clefts, the cells are not always in contact, and are in the liver
discontinuous
this type of capillary has small holes located in the endothelial cells that allow small molecules such as glucose and ions to pass and are found in most tissues (skeletal muscle, kidneys, etc.)
fenestrated
increase in CO2 and decrease on O2 are intrinsic factors that allow for _____
vasodilation
metabolites and endothelian are intrinsic factors that allow for _____
vasoconstriction
the total combined area of ____ is the largest out of all blood vessels
capillaries
blood flow ____ in the capillaries
slows
what is the resistance vessel?
arterioles
there is more ____ than ______ occurring in vessels
filtration, absorption
___ ____ is due to filtration across capillary walls
bulk flows
hydrostatic pressure gradient and oncotic pressure gradient affect ___ ____
bulk flow
____ L of interstitial fluids are drained into lymph vessels daily
3
edema occurs when ____ exceeds ____
filtration, absorption
when muscles are _____, vein valves open and venous return is increased
contracted
during inhalation, blood is being pumped to the ___ via vena cava
heart
only the ____ ANS innervates blood vessels
sympathetic
what five things lead to venous return?
venous pressure gradient, one way flow of venous valves, skeletal muscle pump, respiratory pump, sympathetic innervation
the following conditions lead to what?
-thin and relaxed smooth muscle
-increased CO2
-increased metabolites
-increased nitric oxide
-systemic decrease in O2
vasodilation (increased radius)
the following conditions leads to what?
-thick and contracted smooth muscle
-decreased CO2
-increased endothelian
-decreased O2 in lungs only
vasoconstriction (decreased radius)
norepinephrine binding to _____ causes vasodilation
B2 adrenergic receptor
norepinephrine binding to B2 adrenergic receptor occurs mostly where?
in skeletal muscle
what hormone leads to vasodilation?
nitric oxide
norepinephrine binding to ____ causes vasoconstriction
a1 adrenergic receptor
norepinephrine binding to a1 adrenergic receptor occurs in what two locations?
small intestine, kidney
what hormone leads to vasoconstriction?
angiotensin 2
where are the two locations of baroreceptors?
carotid, aortic arch
baroreceptors respond to blood pressure change by ____
stretch
stretch response from baroreceptors leads to generation of an ____ _____
action potential
increased stretch from baroreceptors occurs from ____ blood pressure
increased
what three things are innervated by sympathetics in the baroreceptor reflex arch?
SA/AV nodes, myocardium in the ventricles, vascular smooth muscle
what is the only thing innervated by parasympathetics in the baroreceptor reflex arch?
SA/AV nodes
the baroreceptor reflex arch is a ____ feedback mechanism
negative
____ pressure is fluid and gravity
hydrostatic
____ pressure affects the distribution of blood throughout the body
hydrostatiC
there is even distribution of blood and hydrostatic pressure when someone is in what position?
supine
when standing, what is the body distribution of blood?
lowest in head, highest in feet, none at heart
____ _____ is a failure of baroreceptors to respond quickly
orthostatic hypotension
what three factors could lead to orthostatic hypotension?
age, low resting blood pressure, blood volume from dehydration
_____ reflexes occur relatively fast and react to changes in body position
neuronal
_____ reflexes occur slower and are more long term
hormonal
the korotkoft sound is during ____ flow
turbulent
