Renal Structures and Functions

What is the shape and color of the kidney?

The kidney is a bean-shaped, reddish brown organ.

Where do the kidneys lie in relation to the vertebral column?

The kidneys lie on either side of the vertebral column between the 12th thoracic and third lumbar vertebrae.

Why is the right kidney positioned lower than the left?

The right kidney is lower to make space for the liver.

What surrounds each kidney?

Each kidney is surrounded by a capsule and a fat pad.

What are the two poles of each kidney called?

Each kidney has a superior and inferior pole.

What is one of the primary functions of the kidneys?

To filter blood.

What does homeostasis include for the kidneys?

Maintaining body water balance, regulating extracellular fluid ions, maintaining plasma fluid and osmolarity, and keeping blood pH.

What do kidneys excrete?

The kidneys excrete foreign compounds, urea from proteins, creatinine from muscles, uric acid from DNA and RNA, and bilirubin from hemoglobin.

What hormone does the kidney secrete that stimulates red blood cell production?

Erythropoietin.

What condition can result from vitamin D deficiency?

A lack of calcium can lead to problems with the bone.

What is one consequence of kidney problems?

Kidney problems can lead to anemia.

What are the renal columns an extension of?

The renal columns are extensions of the renal cortex.

How much blood from circulation flows to the kidneys?

25% of the blood from circulation flows to the kidneys.

What happens if the renal vein is compressed by the renal artery?

If the renal vein is compressed, it won’t drain properly.

Why is the left renal vein longer than the right?

The left renal vein is longer as it crosses over the abdominal aorta.

What is the primary site for regulation of the glomerular filtration rate (GFR)?

The arterioles are the primary site for intrinsic and extrinsic regulation of the GFR.

What occurs within the Bowman’s capsule?

The Bowman’s capsule is a filtration barrier where ultrafiltration occurs.

What are the two main types of nephrons and where are they located?

There are juxtamedullary nephrons in the renal medulla and cortical nephrons in the renal cortex.

What is the primary area for solute and water reabsorption in the nephron?

The proximal convoluted tubule is the primary area for solute and water reabsorption.

What role does the loop of Henle play in the nephron?

The loop of Henle sets up the osmotic gradient for concentrating and diluting urine.

What is located around the distal convoluted tubule?

The distal convoluted tubule is surrounded by peritubular capillaries.

What is the histology of the PCT?

The most reabsorption occurs here. It has more microvilli to increase the surface area. It is long and thin and has lots of mitochondria.

What is the histology of the Loop of Henle?

It has thin and thick portions. The ascending and descending limbs have different permeabilities. It concentrates and dilutes the filtrate.

What is the histology of the DCT?

Has hormonally regulated actions. Has fewer microvilli. Has a low water permeability.

What is the histology of the collecting duct?

It is hormonally regulated by ADH, aldosterone and atria; natriuretic peptide. It has intercalated and principal cells.