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Heart is located within…
the mediastinum just above the diaphragm
the heart is enclosed in a…
pericardium
the heart is a hollow…
muscle double pump
the heart is divided into…
4 chambers
left and right chambers of the heart have a…
collecting chamber and a pumping chamber
collecting chamber
atrium
pumping chamber
ventricle
three principal circulatory divisions in the cardiovascular system:
systemic circulation
pulmonary circulation
coronary circulation
systemic circulation carries oxygenated blood from the…
left ventricle through the body, and returns venous blood to the right atrium.
pulmonary circulation carries venous blood from the right ventricle through the lungs (blood undergoes oxygentation) and delivers oxygentaed blood through…
4 pulmonary veins into the left atrium
coronary circulation delivers oxygenated blood for the…
heart through the coronary arteries
venous blood from the heart through the cardiac veins collects into…
the coronary sinus and empties into the right atrium
both pumps contract at the same time and both sides pump…
equal volumes of blood with each cycle of contraction (systole) and relaxation (diastole)
general organization of the circulatory system
Closed System
Heart
Arterial System
Venous System
Microcirculation
Systemic Circulation
Pulmonary Circulation
blood movement through the heart:
starts with?
systemic circulation (venous blood)
blood movement through the heart:
systemic circulation (venous blood) →
superior/ inferior vena cava
blood movement through the heart:
superior/ inferior vena cava →
right atrium
blood movement through the heart:
right atrium →
right ventricle
blood movement through the heart:
right ventricle →
pulmobary arteries (l/r)
blood movement through the heart:
pulmonary arteries (L/R) →
pulmonary circulation
blood movement through the heart:
pulmonary circulation →
pulmonary veins
blood movement through the heart:
pulmonary veins →
left atrium
blood movement through the heart:
left atrium →
left ventricle
blood movement through the heart:
left ventricle →
aorta
blood movement through the heart:
aorta →
systemic circulation (arterial blood)
pericardium
composed of fibrous pericardium + visceral and parietal layers
epicardium
superficial visceral layer of the serous pericardium
myocardium
composed of the contractile cells- part which actually contracts
endocardium
composed of epithelial and connective tissue + elastic fibers
skeletal muscles are composed of
a big numbers of muscle fibers (cells).
each (skeletal) muslc fiber has the…
the same length as a muscle
skeletal muscle fibers have a significant number of…
nuclei (myonuclei), which are located just beneath the sarcolemma.
cardiac muscle cells
myocytes
myocytes are arranged in…
layers and are shorter than skeletal muscles
cardiac muscle has properties of…
skeletal muscle and of a smooth muscle
somatic nervous system affects?
skeletal muscle
autonomic nervous system affects?
cardiac and smooth muscle
cardiac muscle cell has only ___ nuclei (myonuclei)
1-2
cardiac muscle cells are connected through…
intercalated discs
cardiac muscle cells (myocytes):
gap junctions in the intercalated discs are similar to those in the…
smooth muscles
cardiac muscle is a…
syncytium
cardiac muscle cells (myocytes):
gap junctions in intercalated discs provide…
low electrical resistance
step 1? cardiac muscle is a ___
syncytium
step 2? intercalated discs separate…
cardiac cells
step 3? gap junctions in intercalated discs explain...
low electrical resistance
step 4? ___ synctiumm
atrial
step5? ____ syncytium
ventricular
myocyte is surrounded by the…
plasma membrane - sarcolemma
cytoplasm of the cardiac cell contains…
contractile proteins (myofilaments)
myofilaments - actin and myosin have a…
parallel orientation along the axis of a fiber/ myocyte
thin filament (actin) is anchored to the …
z disc (z-line)
distance between two z-lines is a…
functional unit of a cardiac cell - sarcomere
between myofibrils abundant _____ are found
mitochondria
the smooth endoplasmic reticulum (sarcoplasmic reticulum) is a strong site of…
calcium ions in the cell
_____ also contains carbohydrate glycogen
cytoplasm
resting membrane potential in cardiac cells
-85 to -95 mV
resting membrane potential in conductive ribers
-90 to - 100 mV
resting potential is ____
stable
Action potential in a cardiac muscle:
Phase 0
depolarization (Na enters in about 2 msec)
Action potential in a cardiac muscle:
Phase 1
early repolarization (sodium channels start to inactivate)
Action potential in a cardiac muscle:
Phase 2
plateau (Ca enters about 200 msec)
Action potential in a cardiac muscle:
Phase 3
Repolarization (K channels open)
Action potential in a cardiac muscle:
Phase 4
ion distribution restored (Na/K pump)
Action Potential in a Cardiac Muscle:
Prolonged AP and…
plateau in cardiac muscle
Action Potential in a Cardiac Muscle:
Opening of fast …
sodium channels (open 1/1000 s)- phase 0
Action Potential in a Cardiac Muscle:
Opening of slow …
calcium channels (open 1/10 s) - Phase 2
Action Potential in a Cardiac Muscle:
mainatined a prolonged period of _____
depolarization
Action Potential in a Cardiac Muscle:
very long (250ms)…
refractory period (impossible to cause summation of contractions)
Excitation-Contraction Coupling:
step 1
action potential
Excitation-Contraction Coupling:
step 2
calcium transients
Excitation-Contraction Coupling: Calcium transients
resting cytosolic calcium is ___
increased
Excitation-Contraction Coupling: Calcium Transients
10% of calcium enters via…
calcium influx through T-tubules into the sarcoplasmic reticulum
Excitation-Contraction Coupling: Calcium Transients
calcium is released from the…
sarcoplasmic reticulum
Excitation-Contraction Coupling:
step 3
calcium combines with troponin
Excitation-Contraction Coupling:
step 4
tropomyosin’s inhibition is removed
Excitation-Contraction Coupling:
step 5
cross-bridges are formed
Excitation-Contraction Coupling:
step 6
contraction
sarcoplasmic reticulum of cardiac cell is…
less developed than of skeletal muscles
t-tubules of cardiac cells have a large diameter
5 times more than of skeletal muscles
electronegative mucopolysaccharides bind…
calcium ions in T-tubules
T-tubules open directly to the…
outside of cardiac cells
extracellular calcium significantly affects…
cardiac cell contraction
cardiac cycle
atrial contraction
isovolumic (isometric) ventricular contraction
ventricular ejection (rapid ejection period and slower ejection period)
isovolumic (isometric) ventricular relaxation
passive ventricular filling
time it takes for systole
250-300 ms
time it takes for diastole
500-550 ms
what initiates atrial contraction ?
generation of action potential in the sinus node
atrial contraction
Mitral valve is opened
Aortic valve is closed
75% of blood flows directly from atrias into ventricles
25% of blood flows into ventricles due to atrias contraction
isovolumic (isometric) ventricular contraction
Mitral valve is closed
Aortic valve is closed
Volume of blood in ventricles remains constant
Ventricles contract. Pressure in the ventricles is building
ventricular ejection (rapid ejection period and slower ejection period)
mitral valve is closed
aortic valve is opened
ventricles continue contracting
isovolumic (isometric) ventricular relaxation
Mitral valve is closed
Aortic valve is closed
Ventricles Relaxing
Pressure rapidly drops to diastolic values
passive ventricular filling
Mitral valve is opened
Aortic valve is closed
Blood collects in atrias
Blood fills the ventricles
75% of blood flows directly from atria into ventricles
ESP
end systolic pressure
120 mmHg
EDP
end diastolic pressure
0mmHg
ESV
end systolic volume
EDV
end diastolic volume
SV
stroke volume
65 mL
when valves close…
pressure gradient develops
the surrounding tissue, fluids, and blood vessels ___
vibrate
sound travels through the…
chest
frequency of I think heart sounds
3 Hz - 40 Hz - 500 Hz
Note 
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