BIOL 1080 Chapter Notes -Thoracic Cavity, Pulmonary Artery, Pulmonary Circulation
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Transports nutrients, respiratory gases, wastes and heat.
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Transports immune cells and antibodies
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Transports hormones
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Regulates pH
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Functions
Blood is carried AWAY from the heart in ARTERIES
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Blood is carried TOWARDS the heart in veins
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Heart-->Arteries--> Arterioles-->Capillaries ( Allows exchange of materials between blood and cells)
Capillaries-->Venules-->Veins-->Heart
Lining of blood vessels is the ENDOTHELIUM. Interior of blood vessels is the LUMEN.
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Inner endothelium wall.
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Middle elastic fiber and smooth muscle layer. Allows artery to stretch and adapt to pressure
changes to keep a relatively even pressure within the artery.
Relaxed: Vasodilation
Contracted: Vasoconstriction
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Outer layer is sheath of connective tissue containing fibers and collagen. Outer layer adds
strength to wall and anchors to tissue.
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Our pulse is created by this expansion and recoil of arteries.
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Aneurysm: Weakened arterial wall leading to the artery wall swelling outwards. Biggest risk is
that the aneurysm will burst or clot.
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Arteries:
Connects arterioles and venules
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Thin walls to allow substances to move between the blood and fluid outside capillary.
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Plasma membrane in endothelial cells is selective barrier
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Network of capillaries for a particular area are the CAPILLARY BED.
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PRECAPILLARY SPHINCTERS: Valves that open and close capillary beds
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Blood flows slower through capillaries because of the small size, but large cross sectional area
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Capillaries:
Walls are thinner then arteries with lumen larger to allow veins to hold a large volume of
blood.
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Valves in veins prevent backflow of blood to allow blood from lower parts of the body to make
it back up to heart.
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Skeletal muscle contractions squeezes veins to push it up towards heart.
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Breathing changes pressure. Chest cavity increase in inhalation reduces pressures in thoracic
cavity causing blood to move towards the area of lower pressure (towards heart).
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Veins:
MYOCARDIUM is the wall of the heart
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ENDOCARDIUM is the thin lining in heart cavities
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PERICARDIUM is thick sac that holds the heart in the center of the thoracic cavity
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RIGHT SIDE-->Lungs to be oxygenated. Through the pulmonary circuit.
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Right atrium-->AV valve-->Right ventricle-->Pulmonary semilunar valve-->Pulmonary trunk-->
Pulmonary arteries-->Lungs-->Left atrium
LEFT SIDE-->Pumps oxygenated blood to cells. Through the systemic circuit.
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Heart:
Page 215-238: Cardiovascular System
Cardiovascular System Page 1