BIOL 222 Lecture Notes - Lecture 12: Macula Densa, Juxtaglomerular Apparatus, Juxtaglomerular Cell
Document Summary
If gfr decreases, cells in dct (macula densa cells) notice na + and cl- levels drop. Signals juxtaglomerular cells (j. g. cells) to make renin. Renin is precursor to angiotensin 2 and aldosterone. ****** increase bp= increase flow through glomerulus = increase gfr. Mesangial cells alter blood flow into and out of glomerulus (by altering the b. f. ) Afferent constriction: decrease ghp = decrease gfr. Afferent dilation: increase ghp = increase gfr. Efferent constriction: increase ghp = increase gfr. Juxtaglomerular apparatus sends signals to juxtaglomerular cells (jg) which make renin. 2 substances move in the same direction across a membrane. One moves down concentration gradient to help a second molecule to move against concentration gradient. Na+ down concentration gradient and (example: [glucose]) against the concentration gradient. 2 substances move in opposite directions across a membrane. Need transport (carrier) protein to facilitate movement. Example: door rotating around versus regular door wide open. Only certain amount of people can go in rotating door.
