BIOL 1080 Chapter Notes -Thoracic Cavity, Pulmonary Artery, Pulmonary Circulation

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8 Mar 2014
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Transports nutrients, respiratory gases, wastes and heat.
Transports immune cells and antibodies
Transports hormones
Regulates pH
Functions
Blood is carried AWAY from the heart in ARTERIES
Blood is carried TOWARDS the heart in veins
Capillaries-->Venules-->Veins-->Heart
Lining of blood vessels is the ENDOTHELIUM. Interior of blood vessels is the LUMEN.
Inner endothelium wall.
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
Outer layer is sheath of connective tissue containing fibers and collagen. Outer layer adds
strength to wall and anchors to tissue.
Our pulse is created by this expansion and recoil of arteries.
Aneurysm: Weakened arterial wall leading to the artery wall swelling outwards. Biggest risk is
that the aneurysm will burst or clot.
Arteries:
Connects arterioles and venules
Thin walls to allow substances to move between the blood and fluid outside capillary.
Plasma membrane in endothelial cells is selective barrier
Network of capillaries for a particular area are the CAPILLARY BED.
PRECAPILLARY SPHINCTERS: Valves that open and close capillary beds
Blood flows slower through capillaries because of the small size, but large cross sectional area
Capillaries:
Walls are thinner then arteries with lumen larger to allow veins to hold a large volume of
blood.
Valves in veins prevent backflow of blood to allow blood from lower parts of the body to make
it back up to heart.
Skeletal muscle contractions squeezes veins to push it up towards heart.
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).
Veins:
MYOCARDIUM is the wall of the heart
ENDOCARDIUM is the thin lining in heart cavities
PERICARDIUM is thick sac that holds the heart in the center of the thoracic cavity
RIGHT SIDE-->Lungs to be oxygenated. Through the pulmonary circuit.
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.
Heart:
Page 215-238: Cardiovascular System
Cardiovascular System Page 1
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