Kidney Pathology 101 (Basics)

Location:
paired, retroperitoneal organs wrapped in fat and Gerotas fascia

Function:
1. Filter system via removing metabolic waste products and maintaining Na+ and acid balance
2. Endocrine organ via secretion of erythropoietin and renin

Kidney's Functional Unit:
The nephron (which is made up of the cortex and the medulla).
The cortex contains the following: glomeruli, afferent/efferent arterioles, and prox/distal convoluated loops.


 The medulla contains the following: loops of Henle, vessels, and collecting ducts.

Glomerulus:
It is a group of capillaries with an incoming (afferent) and outgoing (efferent) arteriole. Its structure helps keep big proteins in the blood, while filtering out water and electrolytes into the tubules.

Juxtaglomerular Apparatus:
Secretes renin and regulate BP. Located in part of the distal convoluted tubule.

Renal Failure: Acute vs Chronic
In short, acute = reversible and chronic = irreversible. Acute is often due to an isolated insult to the organ such as ischemia or toxic injury and results in the patient developing azotemia (which also disappears once acute failure is resolved).  Chronic failure, on the other hand, comes on gradually and patients develop uremia.


Picture source: http://www.medindia.net/patients/patientinfo/acuterenalfailure.htm
Information Source: Hardcore: Pathology by Carter E. Wahl