Overview of Key Concepts from Chapters 26, 27, and 18

Flashcards covering key concepts from the chapters on the urinary system, fluid balance, and the endocrine system.

Renal capsule

A transparent membrane that serves as the outermost layer of the kidney, maintaining its shape.

Bowman’s capsule (Glomerular capsule)

A double-walled epithelial cup at the beginning of the nephron that collects glomerular filtrate.

Glomerulus

A ball-like network of capillaries where blood filtration occurs, formed between afferent and efferent arterioles.

Kidney functions

Regulates blood ionic composition, pH, osmolarity, glucose, volume, and pressure; releases erythropoietin and calcitriol, and excretes metabolic wastes.

Podocytes

Specialized cells in Bowman’s capsule that wrap around glomerular capillaries; have foot-like projections called pedicels.

Glomerular filtration rate (GFR)

The volume of filtrate formed per minute, averaging 125 mL/min.

Tubular reabsorption

The return of water and solutes to the blood, primarily occurring in the proximal convoluted tubule.

Antidiuretic hormone (ADH)

Increases water permeability of principal cells by inserting aquaporin-2 channels.

Osmosis

The movement of water following electrolytes to maintain balance between compartments.

Acid-base balance

The blood pH must be maintained between 7.35 and 7.45, regulated by buffers, CO2 exhalation, and kidney excretion of H+.

Oxytocin

Hormone that stimulates uterine contractions and milk ejection.

Insulin

Hormone stimulated by high blood glucose; promotes glycogenesis and glucose uptake.

Aldosterone

Hormone secreted by the adrenal cortex that stimulates Na+ and Cl- reabsorption and K+ secretion.

Calcitonin (CT)

Hormone produced by parafollicular cells that lowers blood calcium by building bone.

Glucosuria

Condition where glucose is present in urine, occurs when blood levels exceed 200 mg/mL.

Hyponatremia

Condition characterized by low sodium blood levels.

Hyperkalemia

Condition characterized by high potassium blood levels.