BIOL 208 Lecture Notes - Lecture 19: Vasoconstriction, Coronary Sinus, Arachnoid Granulation
12 Apr 2017
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Document Summary
Sinusoids (sinusoidal capillaries, discontinuous) different from other two capillaries. Veins less elastic and smooth muscle but more white collagenous fibers thinner walls larger lumens valves in extremities pressure of venous blood returning is low. When blood goes up, can"t go back down low pressure system - valves prevent backflow. Made up of endothelial cell - support for other cells. ** structures that are flattened vessels w/ thin walls of only endothelium, which are supported by connective tissue that surrounds them dural sinus - superior sagittal sinus coronary sinus - medial sagittal sinus. Medial sagittal sinus- collect blood supplying brain and cerebrospinal fluid choroid plexus - tight capillary beds that produce cerebrospinal fluid arachnoid granulations- removes cerebrospinal fluid. Varicose veins varicosity - abnormal dilations form rough surface - platelets break clots prevent normal blood flow. Factors that influence blood pressure p. 708 - 710 blood pressure varies directly w/: ** blood flow resistance by friction force b/w blood and vessel walls.
