Lecture 32- Friday, March 26 , 2010
Tomoko Takano, MD, PhD
You are not responsible for the material in the textbook not covered in lectures.
Anatomy of the Kidney
Functions of the Kidneys
1. Regulation of water, inorganic ion balance, and acid-base balance.
2. Removal of metabolic waste products from the blood and their excretion in the
3. Removal of foreign chemicals from the blood and their excretion in the urine.
4. Production of hormones/enzymes:
a. Erythropoietin: hormone that controls erythrocyte production
b. Renin: enzyme that controls the formation of angiotensin and influences blood
pressure and sodium balance
c. 1,25-dihydroxyvitamin D: active vitamin that influences calcium balance
-Kidneys are paired organs: ~150 grams each. If one stops working, you can live
with using just one.
-Behind the peritoneum on either side of the vertebral column against the posterior
-Renal = pertaining to the kidneys
-Location of kidneys very close to the small of your back. Picture is of a pregnant
female. Kidneys are attached to bladder by ureters. Blood comes from abdominal aorta.
At the end of travel, everything leaves through the renal vein.
-Each kidney contains ~1 million subunits called nephrons -Each nephron consists of:
o Glomerulus (capillary loops)
o Bowmans Capsule
-Final composition of the urine is very different than whats filtered here.
-Composition: as if corpuscle is punching into the balloon of the Bowman’s Capsule. -Visceral layer is a mono layer of cells called podocytes.
-Juxtaglomerular Apparatus important. Juxtaglomerular cells are rennin secreting
cells. -Glomerulus is the place where the first filtration occurs. See arrows for filtration
pathway. The three layers are called the filtration barrier. Barriers make sure that
nothing that shouldn’t be excreted is (eg: proteins)
-Entangled capillary loops surrounded by Bowman’s Capsule
-Capillary walls consist of:
glomerular basement membrane
visceral epithelial cells (podocytes)
-Glomerulus filters blood to make urine. Goes from cortex medulla cort