Nephron Anatomy Quiz: Structure and Function

Study Notes

Aquaporins

Specialized integral membrane proteins that act as water channels, facilitating rapid movement of water molecules across cell membranes
Regulate water balance and osmotic pressure in various tissues and organs, including the kidneys
Enable water reabsorption in response to hormonal signals such as antidiuretic hormone (ADH)

Aldosterone

Steroid hormone produced by the adrenal glands, primarily the adrenal cortex
Regulates electrolyte balance, particularly sodium and potassium levels, in the body
Acts on the distal convoluted tubules and collecting ducts of the nephron to increase sodium reabsorption and potassium secretion
Stimulated by low blood pressure, low sodium levels, and high potassium levels

Antidiuretic Hormone (ADH)

Peptide hormone produced by the hypothalamus and released by the posterior pituitary gland
Regulates water balance by increasing the permeability of the renal collecting ducts to water, allowing for water reabsorption back into the bloodstream
Conserves water and concentrates urine, preventing excessive water loss and maintaining proper hydration levels

Nephron

Functional unit of the kidney responsible for filtration, reabsorption, and secretion of substances to regulate electrolyte balance, fluid volume, and waste excretion
Consists of a renal corpuscle (glomerulus and Bowman's capsule) and a renal tubule (proximal convoluted tubule, loop of Henle, distal convoluted tubule, and collecting duct)

Filtration, Reabsorption, and Secretion

Filtration: occurs in the glomerulus, where blood pressure forces water and solutes from the blood into the renal tubules to form filtrate
Reabsorption: takes place predominantly in the renal tubules, where essential substances such as water, glucose, ions, and amino acids are reabsorbed from the filtrate back into the bloodstream
Secretion: occurs in the renal tubules, involving the movement of substances from the blood into the filtrate to be eliminated from the body

Sodium Reabsorption

Highest amount of sodium reabsorption occurs in the proximal convoluted tubule of the nephron
Reabsorbs approximately two-thirds of the filtered sodium along with water, glucose, amino acids, and other solutes, playing a crucial role in maintaining electrolyte balance and fluid volume

Description

Learn about the functional unit of the kidney, the nephron, and its components such as the renal corpuscle and renal tubule. Understand how nephrons work together to regulate electrolyte balance, fluid volume, and waste excretion in the body.