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37 Cards in this Set

  • Front
  • Back
What are the three components of the cardiovascular system?
heart, blood vessels and blood
What are the two circuits of the cardiovascular system?
pulmonary circuit and systemic circuit
What is the pulmonary circuit?
carries blood to/from gas exchange surfaces of lungs
What is the systemic circuit?
carries blood to/from the body
Blood alternates between _____ and _____
pulmonary circuit; systemic circuit
arteries
carry blood away from heart
veins
carry blood to heart
capillaries
networks between arteries and veins
"exchange vessels" exchange materials (e.g. dissolved gases, nutrients, wastes) between blood and tissues
What are the four chambers of the heart?
left and right atrium, left and right ventricle
Blood travels from:
1. superior vena cava
2. inferior vena cava
3. coronary sinus to the right atrium
Blood travels from the right atrium to the right ventricle:
1. pulmonary trunk
2. left pulmonary arteries
3. right pulmonary arteries
Blood travels from the right and left pulmonary veins to:
the left atrium
Blood travels from the left atrium to the left ventricle:
1. ascending aorta
2. aortic arch
3. descending aorta
heart valves
ensure unidirectional blood flow through the heart
AV (atrioventricular valves)
-prevent backflow into atria when ventricles contract
-chordae tendineae anchor AV valves to papillary muscles (prevent prolapse)

1. R AV valve (tricuspid valve)
2. L AV valve (bicuspid valve, mitral valve)
Semilunar valves
-prevent backflow of blood into the ventricle

3. Aortic valve - lies between L ventricle & the aorta
4. Pulmonary valve - lies between R ventricle & pulmonary trunk
aortic valve
lies between L ventricle & the aorta
pulmonary valve
lies between R ventricle & pulmonary trunk
Heart valves
cordae tendineae
"heart strings"
Atrioventricular Valve Function
1) Blood returning to the heart fills atria, putting pressure against atrioventricular valves; atrioventricular valves are forced open
2) As ventricles fill, atrioventricular valve flaps hang limply into ventricles
3) Atria contract, forcing additional blood into ventricles

1) Ventricles contract, forcing blood against atrioventricular valve cusps.
2) Atrioventricular valves close.
3) Papillary muscles contract and chordae tendineae tighten, preventing valve flaps from everting into atria
Semilunar Valve Function
a) as ventricles contract and intraventricular pressure rises, blood is pushed up against semilunar valves, forcing them open.
b) As ventricles relax and intraventricular pressure falls, blood flows back from arteries, filing the cusps of semilunar valves and forcing them to close.
Why is the left ventricle larger than the right ventricle?
The bulk of the myocardium consists of cardiac muscle cells. What are two types?
contractile cells and autorhythmic cells
cardiac contractile cells
provide the pressure that pumps blood through the body
desmosomes
mechanical connection allows forceful contractions
gap junctions
electrical connection allows heart to act as one unit
Two types of autorhythmic cells
intrinsic and extrinsic
intrinsic
control heart rate
extrinsic
effects on heart rate are through nerves & hormones
What are the five main types of autorhythmic cells?
1. sinoatrial node
2. atrioventricular node
3. atrioventricular bundle
4. R/L bundle branches
5. Purkinje fibers
Authrhythmic cells: intrinsic conduction system
1) Initiate and 2) Distribute electrical impulses that stimulate contraction
automaticity
autorhythmic cells contracts automatically
pacemaker potential
("drift") unstable resting membrane potential authrhymic cells automatically and gradually depolarize toward threshold
SA node depolarizes first, establishing heart rate
-SA node generates 80-100 action potentials per minute (intrinsic rate)
Parasympathetic stimulation slows heart rate
-AV node generates 40-60 action potentials per minute (intrinsic rate)
Sequence of Excitation/Depolarization (1 of 2)
Pacemaker cells of SA node depolarize

Electrical activity travels rapidly to AV node via internodal pathways

Depolarization spreads across atria AV node delays impulse ~ 0.1 second
**allows atria to contract before ventricles do
Sequence of Excitation/Depolarization (2 of 2)
Depolarization wave travels down AV bundle and L/R bundle branches

Depolarization wave travels thru ventricles via Purkinje fibers

Ventricular contractile cells depolarize & contract