Page 731 - Atlas of Histology with Functional Correlations

Kidney Cells

Responsible for homeostasis of the body
Involved in forming urine through filtration, absorption, and excretion
Produce enzyme renin to regulate blood pressure and maintain proper
filtration pressure in glomeruli

Synthesize erythropoietin to stimulate erythrocyte production in red bone
marrow in response to hypoxia

KIDNEY TUBULES

Proximal Convoluted Tubules

Proximal convoluted tubules lined with brush border and absorb most of
filtrate
Basal infoldings of cell membrane contain numerous mitochondria and
sodium pumps

Mitochondria supply energy for ionic transport across cell membrane into the
interstitium
Absorb all glucose, proteins, and amino acids, almost all carbohydrates, and
75% to 85% of water

Secrete metabolic waste, hydrogen, ammonia, dyes, and drugs into the filtrate
for voiding
Longer than distal convoluted tubules and more frequently seen in cortex
near renal corpuscles

Loop of Henle

In juxtamedullary nephrons, it produces hypertonic urine owing to the
countercurrent multiplier system

Countercurrent flow of ultrafiltrate in descending and ascending loops of
Henle produces osmotic gradient in the interstitium
High interstitial osmolarity draws water from the filtrate as it flows through
the loop

Vasa recta capillaries take up water from interstitium and return it to
systemic circulation

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