The Urinary System

Vocabulary flashcards based on Chapter 23 covering the anatomy and physiology of the urinary system.

Urinary System

An organ system that includes the kidneys, ureters, urinary bladder, and urethra.

Kidney Functions

Filters blood plasma, regulates blood volume, pressure, and osmolarity, secretes hormones.

Renal Corpuscle

The structure in the nephron that filters blood plasma, composed of glomerulus and Bowman's capsule.

Glomerulus

A ball of capillaries located in the renal corpuscle where filtration occurs.

Bowman's Capsule

A double-walled structure that encases the glomerulus.

Proximal Convoluted Tubule (PCT)

The part of the nephron coming directly off the renal corpuscle, where most reabsorption of water, ions, and nutrients occurs.

Distal Convoluted Tubule (DCT)

Segment of the nephron involved in secretion and variable reabsorption of sodium and water.

Nephron Loop (Loop of Henle)

Part of the nephron responsible for creating osmotic gradients for water reabsorption.

Cortical Nephrons

Nephrons with short loops mostly located in the renal cortex.

Juxtamedullary Nephrons

Nephrons with long loops extending into the renal medulla; important in urine concentration.

Filtration Membrane

Structure composed of fenestrated endothelium, basement membrane, and filtration slits, enabling filtration.

Glomerular Filtration Rate (GFR)

The rate at which filtrate is produced in the kidneys, typically about 125 mL/min.

Renin

An enzyme secreted by juxtaglomerular cells in response to low blood pressure.

Erythropoietin

A hormone produced by the kidneys that stimulates red blood cell production.

Ureters

Muscular tubes that transport urine from the kidneys to the urinary bladder.

Urinary Bladder

A muscular sac that stores urine before it is expelled from the body.

Urethra

The tube through which urine passes from the bladder to the outside of the body.

Micturition Reflex

The reflex that coordinates the contraction of the bladder and relaxation of the sphincters to enable urination.

Diabetes Insipidus

A condition caused by inadequate secretion of antidiuretic hormone (ADH), leading to excessive urination.

Diabetes Mellitus

A metabolic disorder characterized by high blood sugar levels due to insulin issues, resulting in polyuria.

Renal Calculus

Solid masses formed from crystals in urine, causing pain and potential obstruction.

Urinary Tract Infection (UTI)

An infection in any part of the urinary system, often presenting with dysuria and frequent urination.

Hematuria

The presence of blood in urine, potentially indicating infection or kidney stones.

Anuria

Absence of urine production, typically less than 100 mL per day.

Oliguria

Reduced urine output, defined as less than 500 mL per day.

Polyuria

Excessive urine production, often exceeding 2 L per day.

Acidosis

An excessive concentration of acid in the body fluids, often managed by bicarbonate intake in renal failure.

Renal Failure

Condition where kidneys cannot effectively filter waste products from the blood.

Dialysis

A medical procedure that removes waste products from the blood when kidneys are unable to do so.

Peritubular Capillaries

The network of small blood vessels surrounding the renal tubule, playing a role in reabsorption.

Vasa Recta

Capillaries that supply the juxtamedullary nephrons and help maintain the osmotic gradient.

Countercurrent Multiplication

Mechanism in the nephron loop that establishes an osmotic gradient for reabsorption.

Obligatory Water Reabsorption

Water reabsorption that occurs via osmosis regardless of hydration state, occurring primarily in the PCT.

Facultative Water Reabsorption

Water reabsorption that can be adjusted based on the body's hydration state, occurring in DCT and collecting ducts.

Renal Fascia

The connective tissue layer that anchors the kidneys to prevent movement.

Perirenal Fat Capsule

Adipose tissue surrounding the kidney for cushioning and support.

Fibrous Capsule

A protective layer of connective tissue enclosing the kidneys.

Intercalated Cells

Cells in the DCT and collecting duct that regulate acid-base balance by secreting hydrogen and bicarbonate ions.

Principal Cells

Cells in the DCT and collecting duct involved in sodium and water reabsorption.

Nephrons

The functional units of the kidney, responsible for urine formation.

Retroperitoneal

The anatomical location of the kidneys and ureters, behind the peritoneum.

Hilum

The entry and exit point of renal blood vessels, nerves, and ureters in the kidney.

Tubular Secretion

The process of transporting solutes from the blood into the tubular fluid.

Tubular Reabsorption

The process of reclaiming water and solutes from tubular fluid back into the blood.

Metabolic Waste

Substances produced by the body that are no longer useful, which the kidneys help to eliminate.

Podocytes

Specialized cells in the glomerulus that wrap around the capillaries and play a crucial role in filtration, forming filtration slits that prevent the passage of large molecules.