Anatomy Notes #2 - Anatomy Notes February 18, 2010...

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Anatomy Notes – February 18, 2010 Cardiovascular system Several actions Function: contraction: the only function! As a result of the contraction, we have actions 3 primary actions 1. Transportation: movement of nutrients, wastes, gases, hormones, other metabolites 2. Homeostasis: balance; helping to maintain balance within the body Ex: cytosol, in the cell, we have balance between it and the tissue fluid(extracellular; interstitial) which is in balance between the blood plasma… each of the parts is in its own balance and helps to maintain the whole homeostatic environment Cytosol tissue fluid blood plasma Lymphatics 3 major components to the cardiovascular system 1. Heart Fig 21-2, located in the thorax, in the thoracic cavity Ventral category Surrounded by the pericardial cavity which is part of the thoracic cavity Lungs on either side of the pericardial cavity Heart and pericardial cavity found in the mediastinum: central region Protected by the sternum and the ribs Behaves like a pump: pumping or contraction of cardiac muscle begins before birth in the embryo at 19-21 days after fertilization, will continue to pump throughout lifetime until death Constant contraction and relaxation Has a dual control: one of the mechanisms is a self-controlled system: it regulates itself and its beating. Second mechanism is the nervous system which can speed up and slow down the heart as necessary Membrane around the heart: pericardium; has 2 parts: (like a balloon) Has a visceral pericardium segment (epicardium: on the heart): part of membrane adjacent to organ Has a parietal pericardium segment (fibrous pericardium: contains a lot of elastic and collagenous fiber): part of the membrane away from organ In between the 2 segments is the pericardial cavity Fluid inside this cavity to eliminate friction between contractions Sometimes the fluid can get out, causes problems Wall of the heart: outermost layer of the heart (Fig 21-3) all have the same layers, just different thickness
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Cardiac muscle forms the myocardium: (muscle = myo, cardium = heart) Thickness varies depending on where it is On the inside: endocardi, within the heart, connective tissue Squamous in appearance Endothelium Fibrous skeleton of the heart: connective tissue with collagenous fibers which wrap around the other fibers and keep them together Blood vessels and adipose inside Bind everything together Helps to physically and electrically isolate the chambers from one another CT also responsible for formation of valves: openings Connective tissue keeps the valve open. Structure around each valve called: annulus fibrosus: fibrous ring
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Anatomy Notes #2 - Anatomy Notes February 18, 2010...

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