Biology 10 Kidney and Skin

Biology 10: Kidney and Ski Excretory (urine) Pathway Bowman’s space proximal convoluted tubule ascending limb of the loop of Henle renal pelvis ureter descending limb of the loop of Henle distal convoluted tubule bladder collecting duct urethra Kidney Kidney: Contains a cortex and medulla. Produces urine which dumps into the ureter at the renal pelvis. Urine is then collected in the bladder until it is excreted through the urethra. Nephron: Functioning unit of the kidney. Renal Portal Two capillary beds in series (glomeruli & nephron). Blood System: flow: renal artery afferent arterioles glomeruli efferent arteriole vasa recta, which surround nephron renal vein. Filtration: Bowman’s capsule moves solutes from blood filtrate. Direction and rate determined by hydrostatic and oncotic pressure differentials between the glomerulus and Bowman’s space. Secretion: The movement of solutes from blood other than Bowman’s capsule. Reabsorption: The mvmt of solutes from filtrate filtrate anywhere blood. pH: Kidney can regulate pH with bicarbonate and H+. Aldosterone: Steroid hormone synthesized in Adrenal Cortex in response to Angiotensin 2 or high [K+]. It is derived from cholesterol. Increases Na+ reabsorption in the distal convoluted tubule and collecting duct, thereby increasing H2O reabsorption. Result: "BP but no change in blood osmolarity ADH Peptide hormone synthesized by hypothalamus and (Vasopressin): released by posterior pituitary. "permeability of the collecting duct to H2O, which "H2O reabsorption. Result: "BP and ¯blood osmolarity, concentrated urine. Nephron Proximal Convoluted Site of bulk reabsorption of glucose, amino acids, Tubule (PCT): soluble vitamins, salt, and H2O. Site of secretion for H+, K+, NH3, and urea Descending Limb of the Permeable to H2O but NOT salt; therefore, as the Loop of Henle: filtrate moves into the more osmotically concentrated renal medulla, water is reabsorbed from the filtrate. Countercurrent The vasa recta and nephron flow in opposite Multiplier System: directions, creating a countercurrent multiplier system that allows maximal reabsorption of water Ascending Limb of the Permeable to salt but NOT to H 2O; therefore, salt Loop of Henle: is reabsorbed both passively and actively. The diluting segment is in the outer medulla; because salt is actively reabsorbed in this site, the filtrate becomes hypotonic compared to the blood Bladder Detrusor Muscle: Muscular lining of bladder. Parasympathetic control Internal Urethral Sphincter: Smooth muscle. Parasympathetic control External Urethral Sphincter: Skeletal muscle. Voluntary control Skin - Epidermis / Dermis / Hypodermis (subcutaneous layer) Epidermis: Stratum Basale: Stem cells keratinocytes Stratum Spinosum: Lagerhans cells Stratum Granulosum: Keratinocytes die Stratum Luciderm: Only on thick, hairless skin Stratum Corneum: Mult thin layers, flat keratinocytes Langerhans Cells: Macrophages that are antigen-presenting cells in skin Melanin: Produced by Melanocytes. Protects skin from DNA damage caused by ultraviolet radiation Distal Convoluted Responsive to aldosterone and is a site of salt Tubule (DCT): reabsorption and waste product excretion, like the PCT. Collecting Duct: Responsive to both aldosterone and ADH. Has variable permeability, which allows reabsorption of the right amount of H2O depending on the body’s needs. Dermis: Papillary layer and reticular layer. Sensory: Merkel Cells: Deep pressure & texture Free Nerve Endings: Pain Meissner’s Corpuscles: Light touch Ruffini Endings: Stretch Pacinian Corpuscles: Deep pressure & vibration Hypodermis: Fat and connective tissue. Connects skin to body Thermo- Sweating: Evaporative cooling regulation: Piloerection: Warming Shivering: Warming Vasodilation / Vasoconstriction: Cool / warm