Week 1: Thursday Flashcards
what are 4 properties similar to skeletal muscle
of cardiac muscle
- striated
- Ca2+/troponin/tropomyosin regulation of crossbridge cycle
- sarcoplasmic reticulum stores and releases Ca2+
- T tubules
what are 2 properties similar to smooth muscle
of cardiac muscle
- gap junctions
- extracellular Ca2+ is required for contraction (Ca2+ induced Ca2+ release)
what does the L-type Ca channel do (Ca2+L)
allows for Ca2+ ro emter cell
what does the Ryanodine receptor (RyR2) do
allows for Ca2+ to move from SR to sarcoplasm
what does the sarco/edoplasmic reticulum calcium ATPase (SERCA) pump do
allows for Ca2+ to move back into SR
what does the Calcium ATPase pump do
actively pumps Ca2+ out of cell
what does the sodium calcium exchanger (NCX) do
pumps Ca2+ out of cell in exchange for Na+
what does the sodium potassium ATPase (NK ATPase) pump do
actively pumps NA+ out of cell and K+ into cell
what does the right side of the heart do
pumps pulmonary circuit
what does the left side of the heart do
pumps systemic circuit
what is the cardiac cycle
events associated with the flow of blood through the heart during a single complete heartbeat
what is systole
contraction of ventricles
what is diastole
relaxation of ventricles
why do valves open passively
due to pressure gradients
what is end-diastolic volume (EDV)
volume of blood in ventricle at the end of diastole
what is end-systolic volume (ESV)
volume of blood in ventricle at the end of systole
what is stroke volume and the equation
volume of blood ejected from ventricle each cycle
SV = EDV - ESV
what is ejection fraction (EF) and its equation
- measures heart efficiency
- fraction of EDV ejected during a heartbeat
- EF = SV/EDV
what is cardiac output (CO) and its equation
- measures blood output per minute
- CO = SV x HR
volumes and blood flow rates are ____ for the left and right sides of the heart
similar
what is the systolic pressure on the left ventricle
~120 mmHG
what is the systolic pressure on the right ventricle
~20 mm HG
how does the difference in pressure impact cardiac muscle function of the left and right sides
the left side of the heart has to work harder - why left ventricular wall is so much thicker
what is the “Lub” S1 sound
backflow hitting AV valves after they close at the start of ventricular systole
what is the “dub” S2 sound
backflow hitting the aortic and pulmonary valves at the start of diastole
* briefer, sharper, higher pitched
what is the split second heart sound (split S2)
the second heart sound (dub) is split into two sounds
* can be normal (inspiration)
* can be pathological
C - point A marks the beginning of isovolumetric contraction
what is preload
strickly
the tension in the wall produced by the end-diastolic pressure
what is preload
loosely
the end diastolic pressure
what is afterload
strickly
the tension in the wall produced at the time of the opening of the aortic valve (during systole)
what is afterload
loosely
the pressure at the time of the opening of the aortic valve
what should occur in a healthy heart
Frank-Starling Relationship
- increased volume (pressure) results in increased force of contraction
- stroke volumes of the left and right ventricles remain balanced
what happens if balance is not maintained in the heart
blood accumulation in pulmonary or systemuc circulation can result
what is the importance of length-tension relationship in cardiac muscle
- wide dynamic range that takes advantage of the increased active tension at longer lengths
- large passive tenssion at peak active tension length
- passive tension limit the degree of heart filling
what two things can increase the force of contraction (tension)
- adjust length
- adjust contractility (Ca2+ concentration or sensitivity)
what is the sympathetic response on the heart
- increase heart rate
- increase contractility
what is the parasympathetic response on the heart
- decreases heart rate
- does not impact contractility
where does norepinephrine bind and what division of the autonomic nervous system is this
- B-adrenergic receptors
- sympathetic response
where does acetylcholine bind and what division of the autonomic nervous system is this
- muscarinic cholinergic receptors
- parasympathetic
what is EDV affected by
- venous return
- vetricular compliance
- diastolic filling time
what is ESV affected by
- ventricular contractility
- afterload
what are murmurs
abnormal disruptions in flow (turbulence) that can be auscultated
can occur in diastole, systole, or continuous
what does incompetent or insufficient mean
murmur
valve that failts to close completely
diastole
what is regurgitation
backflow across the incompetent valve
what is stenosis
valve fails to open widely enough
systole
what is thrill
when murmur is so extreme that it can be palpated
the defects that cause the murmur can lead to: (list 3)
- abnormal blood flow
- abnormal blood pressure
- cardiac hypertrophy
