HUBS1404 Lecture Notes - Lecture 5: Bone Marrow, Hyaline Cartilage, Anterior Pituitary
19 Jul 2018
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Document Summary
Capillaries: the site where o2, co2, nutrients and metabolic wastes are exchanged. The capillary wall varies depending on the tissue being perfused. Only in special locations: kidney, small intestine: brain ventricles, eyes, endocrine glands. Allow passage of proteins and blood cells - big molecules need big holes to get through: brain does not have these - blood brain barrier. Located: liver, spleen, anterior pituitary: parathyroid, adrenals, red bone marrow. Things can leave the capillaries by: diffusion through membrane (lipid soluble substances, movement through intercellular clefts (small water soluble substances, through fenestrations where present (allows larger molecules through, transport via vesicles (transcytosis) - not common. Gas exchange: gas diffuses by transcellular route and through tissue with relative ease, capillary density is highest in tissues with highest o2 consumption (eg myocardium) Solute movement: depends on charge, size, concentration difference, size of capillary.
