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51 Cards in this Set

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  • Back
importance of cardiovascular system:
1. delivers oxygen and nutrients ( AA, glucose, lipids)to organs and removes carbon dioxide and waste products
2. transports hormones
3. regulation of temperature
4. transport drugs
5. regulation of blood pressure
3 main components of circulatory system:
heart, blood vessels, blood
Heart =
pump
blood vessels =
connecting tubes
(arteries, arterioles, veins, venules, capillaries)
blood =
tissue composed of water, solutes, cells, and formed elements
the circulatory system is arranged into :
pulmonary circulation and systemic circulation
pulmonary circulation
blood carried between heart and lungs
systemic circulation
blood carried between heart and organ systems.
heart, pulmonary and systemic circulations are arranged in :
series. blood flows through a sequence
individual vascular beds are arranged in:
parallel. the total blood volume is divided among different vascular beds
the body can dynamically adjust blood flow through:
different vascular beds
arterial system:
blood vessels that carry blood from the heart to capillaries
venous system:
blood vessels that carry blood back to the heart from the capillaries
pulmonary system carries:
deoxygenated blood thru lungs for gas exchange
systemic circulation carries:
oxygenated blood to tissues of organ systems
usually, arteries carry oxygenated blood and veins carry deoxygenated blood. an exception:
pulmonary artery carries deoxygenated blood and the pulmonary veins carry oxygenated blood
blood pressure:
the force that causes blood flow thru vessels
pressure (P) =
force exerted by pumped blood on a vessel wall
flow (F):
occurs in response to difference in pressure gradient in vessels = (P1-P2)
resistence (R):
opposes blood flow
F =
(P1-P2)
_______
R
pulmonary circulation:
low pressure and low resistance
systemic circulation:
high pressure and high resistance
blood flow occurs because of:
pressure and resistance
for flow to occur, you need a :
pressure gradient
blood flow within organs is determined by:
1. arterial pressure ( generated by pumping action heart against a systemic vascular resistance) and 2. changes in diameter of blood vessel (via contraction or relaxation) within organs
right ventricle is less muscular than left ventricle
left ventricle is more muscular bc increased pressure and resistance = it must work harder
# of heart valves =
4 (2 atrioventricular and 2 semilunar). they ensure that blood flows in the proper direction.
if the pressure is greater behind the valve:
the valve opens
if pressure is greater in front of the valve:
it closes. it does not open in the opposite direction
pressure gradient:
opens valve and prevents backflow
AV valve :
atrioventricular valve
ventricular filling =
when atrial pressure is greater than ventricular pressure, the AV valve opens. this allows blood to flow from the atria into the ventricles.
ventricular emptying:
when ventricular pressure is greater than artial pressure, the AV valves close. this prevents blood from flowng backwards.
semilunar valves are located:
between ventricles and arteries
semilunar valves open when:
the ventricular pressures are greater than pressures in the pulmonary arteries and aorta
semilunar valves close when:
pressure in ventricles is greater than the pressure in aorta and pulmonary arteries. this prevents the blood from flowing backwards
the heart wall is primarily composed of
spirally arranged cardiac muscle fibers
the heart wall consists of 3 layers of muscle fibers
endocardium, myocardium, epicardium
endocardium:
inner layer of epithelium. it lines the entire circulatory system.
myocardium:
middle layer of cardiac muscle. it is the bulk of the heart wall
epicardium:
external membrane covering heart. the coronary vessels are located in this layer
heart wall is surrounded by:
pericardial sac
cardiac muscle fibers are interconnected to form:
branching fibers
cardiac muscle-branching fibers:
adjacent cells joined end to end at specialized structures called intercalated discs
there are 2 types of membrane junctions within discs:
1. desmsomes - mechanical adherence
2. gap junctions-electrical spread
desmosomes and gap junctions form:
functional syncytia
functional syncytia are:
a group of interconnected muscle cells that function electrically and mechanically as a unit
the cardiovascular system aids in the transfer of:
heat and energy
blood flow within the organs is determined by:
arterial pressure and blood vessel diameter
gap junction:
an electrical conducting pathway that allows action potentials to spread from 1 cardiac muscle to another