Draw a nephron, label the following, and describe the function of each:
B. Bowman's Capsule
C. Proximal Convoluted Tubule
D. Descending Loop of Henle
E. Ascending Loop of Henle
F. Juxtaglomerular Apparatus
G. Distal Convoluted Tubule
H. Collecting Duct
I. Renal Pelvis
A. Glomerulus: Capillary bed of the nephron. The amount of filtrate is related to the hydrostatic pressure of the glomerulus.
B. Bowman's Capsule: Hydrostratic pressure forces some plasma into the Bowman's Capsule. Blood cells and large proteins are prevented from entering. The fluid that enters is called the filtrate.
C. Proximal Convoluted Tubule: Most reabsorption takes place here (nearly all glucose, most proteins, and other solutes). Drugs, toxins, and other solutes are secreted into the filtrate. Osmolarity does not change.
D. Descending Loop of Henle: As filtrate descends into the medulla, water passively diffuses out of the loop and into the medulla. The descending loop has low permeability to salt, so filtrate osmolarity goes up.
E. Ascending Loop of Henle: As the filtrate rises out of the medulla, salt diffuses out of the ascending loop, passively at first, then actively. The ascending loop is nearly impermeable to water.
F. Juxtaglomerular Apparatus: Monitors filtrate pressure in the distal tubule.
G. Distal Convoluted Tubule: Reabsorbs Na⁺, and Ca²⁺ while secreting K⁺, H⁺, and HCO₃⁻. Aldosterone acts on the distal tubule cells to increase sodium and potasssium membrane transport proteins. The net effect of the distal tubule is to lower the filtrate osmolarity.
H. Collecting Duct: Carries the filtrate into the highly osmotic medulla. The collecting duct is impermeable to water, but sensitive to ADH, which makes is permeable to water allowing it to passively diffuse into the medulla.
I. Renal Pelvis: funnel-like dilated proximal part of the ureter in the kidney. The major function of the renal pelvis is to act as a funnel for urine flowing to the ureter.
J. Ureter: propel urine from the kidneys to the urinary bladder.