HUMB1000 Lecture 21: Lecture 21
Document Summary
Urine production occurs in the kidneys via filtration of the blood and reabsorption of nutrients. Metabolic wastes and toxic molecules are excreted in urine: regulate blood volume and blood pressure. Control extracellular volume by producing large amounts of dilute urine or small amounts of concentrated urine: solute (cl-, na+, urea) concentration in the blood, extracellular ph, red blood cell synthesis, vitamin d synthesis. Sorts chemicals in the blood for removal or for return into the blood: nephrons. The structural component of the kidneys that "sorts" the blood: urine production: 3 stages. Filtration: movement of fluid, derived from blood flowing through the glomerulus, across filtration membrane, filtrate. Water, small molecules & ions that can pass through membrane. Doesn"t include red blood cells, proteins or large molecules: renal fraction. Part of total cardiac output that passes through the kidneys. Varies from 12-30% in a healthy resting adults: glomerular filtration rate (gfr): amount of filtrate produced each minute.