The Kidney

Location:

The kidneys are not located level to one another, the right kidney is inferior in position to the left kidney, because the liver is located immediately superior to it.

The kidneys are located retroperitoneally, or behind the pareital peritoneum. They are held in place by two things:

1. Renal fascia- a fibrous connective tissue that helps anchor the kidneys.
2. Adipose capsule (tissue)- helps keep the kidneys in place. People going through rapid weight loss can lose this tissue, causing the kidneys to drop and put a kink in the ureters. This results in backflow of urine, as well as other complications, and requires surgery to fix.

Parts of the Kidney:

Renal Capsule- the covering of the kidney.

Renal Cortex- outer, light-colored layer within the kidney. It produces filtrate, and alters the contents of the filtrate.

Renal Medulla-darker, guitar pick or pyramid-shaped portion of the kidney. It adjusts the [ ] of the urine.

Collecting Ducts-collect urine from the nephrons and allow it to flow to the bladder.

• Pathway: minor clayx (calyces) --> major calyx --> renal pelvis --> ureter --> bladder --> urethra.

Nephrons-the structural and functional units of a kidney that form urine.

The Nephron:

Consists of the following parts:

• Glomerulus-a capillary bed that has holes in the epithelial walls for filtration.
• Glomerular (Bowman's) Capsule- white structure that surrounds the glomerulus.
• Renal Corpuscle- Glomerulus + capsule.
• Glomerular Epithelium-makes up the walls of the filtration capsules.

Blood enters the capillary pressure, which forces small solutes through the capillary walls.

Nephrons extend into the renal medulla, however, some extend further than others.

Path of the filtrate: Glomerulus/Renal Corpuscle (forms the filtrate) --> proximal convoluted tubule (saves sugar, amino acids, and some water. It also expels some other solutes.) --> Loop of Henle (saves water and salts) --> distal convoluted tubule (dumps acids and toxins into urine) --> collecting ducts (tranports urine to minor calyx, determines final [ ] of urine).

Note: Antidiuretic Hormone (ADH) affects the amount of water found in the urine.