unit 3: nephron anatomy

glomerulus

• a ball of capillaries where blood is filtered

• high blood pressure pushes ions, water, glucose, amino acids, and waste out of the blood 

afferent arteriole

• carries blood into the glomerulus

efferent arteriole 

• carries blood out of the glomerulus 

Bowman’s capsule

• cup shaped structure surrounding the glomerulus 

• collects the filtrate and sends it to the tubules 

proximal tubule

• the first and major reabsorption section

• reabsorbs 60% of water, salts, electrolytes, glucose, etc.

loop of henle — descending limb 

• permeable to water only

• water gets reabsorbed, leaving filtrate more concentrated 

loop of henle — ascending limb 

• permeable to ions only 

• pumps out Na+, K+, Cl-, filtrate becomes more diluted 

distal tubule 

• selective reabsorption of Na+, Ca2+

• some hormones act here 

collecting duct

• last structure the filtrate passes through before becoming urine 

• reabsorbs water depending on ADH and diuretics

ADH

• releases more water back into the blood stream, leaving the urine more concentrated

• makes collecting duct more water permeable