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Cardiovascular System
A&P
55
Physiology
Undergraduate 2
04/15/2009

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Cards

Term
Intercalated discs of cardiac muscle tissue....
Definition
join adjacent cardiac muscle cells
Term
Gap Junctions of the cardiac muscle tissue...
Definition
provide electrical connections between cells
Term
autorhythmic fibers
Definition
1% of heart muscle that spontaneously depolarize, setting the pace for beating of heart
Term
Contractile fibers of the heart
Definition
99% of heart muscle responsible for pumping
Term
The order the electrical signals travel in the cardiac conductive system...
Definition
SA node, AV node, AV bundle, bundle branches, purkinje fibers
Term
SA node
Definition
sinoatrial node; group on contractile autorythmic muscle cells located in right atrium; controls heart rate
Term
Pace maker potential in SA node
Definition
ability to depolarize spontaneously, resulting in a pacemaker potential
Term
What produces the refractory period in myocardium?
Definition
surge in Ca+
Term
What does the stimulus cause in the depolarization of myocardium?
Definition
voltage regulated Na+ gates to open and Na+ rushes in
Term
myocytes are?
Definition
muscle cells of the heart
Term
What happens during depolarization of myocardium?
Definition
K+ channels open, and K+ leaves the cell
Term
Refractory period
Definition
when cells cannot generate an action potential
Term
P wave
Definition
produced when a signal from the SA node spreads through the atria and depolarizes them causing atrial systole
Term
QRS comlex
Definition
occurs when AV node fires, ventricles depolarize causing ventricular systole
Term
atrial distole in QRS complex caused by...
Definition
atrial repolarization
Term
T wave
Definition
ventricles repolarize causing ventricular diastole
Term
systole
Definition
contraction of a chamber
Term
diastole
Definition
relaxation of a chamber
Term
Systolic blood pressure
Definition
peak pressure in arterial system, due to ventricular systole
Term
Diastolic blood pressure
Definition
lowest pressure in the arterial system, due to ventricular diastole
Term
where is blood pressure lowest?
Definition
in right atrium
Term
Where is blood pressure highest?
Definition
in aorta
Term
What are the 3 main factors that influence blood pressure?
Definition
cardiac output, peripheral resistance, blood volume
Term
What is peripheral resistance?
Definition
resistance to blood flow as blood travels away from the heart
Term
What does peripheral resistance result from?
Definition
friction of blood against the walls of the vessels
Term
What three ways are peripheral resistance affected?
Definition
buy the vessels diameter, length of the vessel/how far the blood has to travel, and the blood viscosity
Term
Cardiac output definition
Definition
amount of blood ejected per ventricle per min
Term
Stroke volume
Definition
amount of blood ejected per ventricle per beat
Term
Cardiac output = ______x______
Definition
heart rate x stroke volume
Term
Is cardiac output increased or decreased by exercise?
Definition
increased
Term
Short term blood pressure regulation
Definition
counteracts fluctuations in BP by altering peripheral resistance
Term
what mediates short term blood pressure regulation?
Definition
the nervous system
Term
Long term BP regulation
Definition
hormonal control and renal mechanisms that change blood volume
Term
BP regulation that alters blood volume?
Definition
long term BP regulation
Term
BP regulation that alters peripheral resistance?
Definition
short term BP regulation
Term
baroreceptors
Definition
pressure sensors in blood vessels
Term
chemoreceptors
Definition
chemical receptors in blood vessels that send messages to vasomotor center in the medulla oblongata
Term
How does vasomotor center regulate blood vessels diameter?
Definition
by impulses sent to vascular smooth muscle to cause either vasoconstriction or vasodialation
Term
What keeps the blood vessels partially contracted?
Definition
sympathetic nervous system
Term
where is the vasomotor system?
Definition
in the brain stem under ANS
Term
What is angiotensinogen produced by?
Definition
liver
Term
ACE inhibitors
Definition
block ACE-lower BP
Term
Angiotensin II
Definition
potent vasoconstrictor, increases blood volume and pressure by secretion of aldosterone which causes a retention of Na and H2O
Term
aldosterone is secreted by...
Definition
adrenal gland
Term
where does the exchange of nutrition take place in the organization of the blood vessels?
Definition
in the capillary bed
Term
what controls blood flow to capillaries of the capillary bed?
Definition
precapillary sphincters
Term
Baroreflex
Definition
changes in BP detected by stretch receptors(baroreceptors) in large arteries above the heart
Term
where are chemoreceptors located?
Definition
aortic arch, subclavian arteries, external carotid arteries
Term
Chemoreflex
Definition
autonomic response to chemical changes in the blood
Term
Primary and secondary role of chemoreflex?
Definition
adjust respiration, vasodialation or constriction
Term
Chemoreflex
Definition
autonomic response to chemical changes in the blood
Term
Mechanisms involved in capillary exchange?
Definition
diffusion, pino and exocytosis, filtration and reabsorption
Term
where does capillary filtration occur?
Definition
at arterial end
Term
where does capillary reabsorption occur?
Definition
at venous end
Term
venous return/inhalation
Definition
thoracic cavity expands-pressure goes down.abdominal pressure goes up forcing blood up
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