BIOL 142 Chapter Notes - Chapter 23-24: Purkinje Fibers, Qrs Complex, Interventricular Septum
9 Jul 2018
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Have large intercellular clefts as well as fenestrations; few tight junctions. Have incomplete basement membranes, are irregularly shaped and have larger lumens that other capillaries. Macrophages may extend processes through the clefts to catch prey or, in liver, form part o the sinusoid wall. Ares of active filtration (e. g. , kidney) or absorption (e. g. small intestine) and areas of endocrine hormone secretion. Allow small molecules, like water and ions to diffuse through tight junctions which leave gaps of unjoined membrane called intercellular clefts. Substances that can pass through - continuous capillaries. Substances that can pass through - fenestrated capillaries. Allow large molecules and even cells to pass across their walls (red and white blood cells and various serum proteins to pass using a process that is aided by a discontinuous basal lamina. Substances that can pass through - sinusoid capillaries. Autorhythmic cells cells found in the heart that are capable of spontaneously producing action potentials at regular intervals.
