KINE 3012 Lecture Notes - Pacemaker Potential, Sympathetic Nervous System, Parasympathetic Nervous System
16 Oct 2011
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Document Summary
Pulmonary circulation takes the blood to the lungs via the pulmonary arteries and back to the heart via the pulmonary veins. Systemic circulation takes the blood throughout the body through arteries and returns back to the heart through the veins. Hematocrit is the concentration of rbc found in a sample of blood: anemia is an insufficient hematocrit, polycythemia is an elevated hematocrit. Primary polycythemia is a tumour-like condition of the bone marrow which causes unregulated erythropoiesis. The spiralling pattern of cardiac muscle allow the ventricles to contract upwards and physically push the blood out of the heart: only contain one nucleus for cells. Has intercalated discs which are composed of desmosomes (tight junctions) and gap junctions which allow for easy transmission of electrical impulses. All cardiac cells are excitable and must be excited in the correct order: some cells are more excitable than others (pacemaker cells which can spontaneously depolarize) Interatrial pathway causes simultaneous contraction of the atria.
