Lecture 44: Tubular Reabsorption and Secretion

These flashcards cover key vocabulary and concepts related to renal function, particularly focusing on tubular reabsorption and secretion.

Renal tubule

Part of the nephron that performs crucial functions in urine formation including reabsorption and secretion.

Proximal convoluted tubule (PCT)

Segment of the nephron where most reabsorption and some secretion occur.

Glomerular filtration rate (GFR)

The rate at which blood is filtered through the glomeruli, typically around 120 mL/min.

Polyuria

Excessive urination, often a symptom of diabetes mellitus.

Polydipsia

Excessive thirst, commonly associated with diabetes mellitus.

Glycosuria

Presence of glucose in the urine, indicating that glucose transport capacity has been exceeded.

Transmembrane transport proteins

Proteins that facilitate the movement of substances across the cell membrane.

Osmotic gradient

A difference in solute concentration that leads to the movement of water.

Co-transporter

A transport protein that moves two or more molecules or ions across a membrane in the same direction.

Counter-transport

A transport mechanism where one solute moves in while another moves out.

Carbonic anhydrase

An enzyme that catalyzes the conversion of carbon dioxide and water to bicarbonate and protons.

Endocytosis

Process by which cells internalize substances by engulfing them in membrane-bound vesicles.

Sodium-potassium ATPase

An enzyme that pumps sodium out of and potassium into cells, crucial for maintaining electrochemical gradients.

Epithelial transport

Movement of molecules across epithelial layers, essential for nutrient absorption and waste excretion.

Ammonium ion (NH4+)

An ion involved in nitrogenous waste excretion, produced in the renal tubules.

Glucose transporter (GLUT)

Proteins that facilitate the transport of glucose across cell membranes.

Micturition

The process of urination, involving the expulsion of urine from the bladder.

Diabetes mellitus

A metabolic disorder characterized by high blood glucose levels and associated urinary symptoms.

Peritubular capillaries

Small blood vessels that surround the nephron and facilitate reabsorption and secretion.

Nephron loop

A section of the nephron involved in the concentration of urine.