Download Circulatory System - Bakersfield College

Biology 11
Mrs. Garrison
CIRCULATORY SYSTEM
Circulatory System
Function
Blood
Plasma –
Cells –
Red blood cells
White blood cells
Platelets
Organs
Heart -
Arteries –
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Veins –
Capillaries –
General blood flow pattern through body
Heart ---> arteries ---> arterioles ---> capillaries --->
venules ---> veins ---> heart
Vessels branch into capillaries in every organ
Specific flow pattern between heart, lungs and body:
Deoxygenated blood from body ---> superior & inferior vena cavae (veins) --->
right atrium of heart ---> right AV (tricuspid) valve ---> right ventricle of
heart ---> right semilunar valve ---> pulmonary artery ---> lungs (where
vessels branch into arterioles, capillaries for gas exchange, then venules)
---> newly oxygenated blood in pulmonary veins---> left atrium of heart
---> left AV (bicuspid or mitral) valve ---> left ventricle of heart --->
Left semilunar valve ---> aorta ---> body tissues (arteries, arterioles,
capillaries, venules) ---> deoxygenated blood in body’s veins
Heartbeat
Automatic for heart muscle
Regulated by sinoatrial (SA) node (pacemaker)
Electrical current passed from SA node through
cells of right & left atria to atrioventricular
(AV) node in lower right atrium
Current causes simultaneous contraction of right & left atria
Current passes from AV node through fibers in Bundle of His to
cardiac muscle cells in right & left ventricles
Current cause simultaneous contraction of right & left ventricles
Delay as current travels from SA node to Av node results in
ventricle contracting just after atria
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Delay is necessary for blood to move from atria to ventricles
Involuntary nervous system can affect SA node and cause increase or
decrease in heart rate
Average heart rate
Cardiac output
Heartbeats
Systole
Diastole
Heart valves
Blood flow through vessels
Arteries - surging flow
Capillaries - smooth flow, one cell at a time
Veins - smooth flow
Skeletal milking
Respiratory pumping
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Blood pressure - taken in artery
Systolic pressure
Diastolic pressure
Constriction and dilation of vessels
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