Urinary System Flashcards

Flashcards for key vocabulary related to the urinary system.

Kidneys

Filter blood and form urine.

Ureters

Transport urine from kidneys to urinary bladder.

Urinary bladder

Collects and stores urine.

Urethra

Conveys urine from urinary bladder to outside of body.

Kidney Functions

Filter blood and remove metabolic waste from the body, maintenance of fluid and electrolyte balance, maintenance of acid-base balance, maintenance of blood pressure, regulation of erythropoiesis, performing other metabolic functions

Location of the kidneys

Lie on both sides of vertebral column, in a depression on the posterior abdominal wall; positioned retroperitoneally (behind the parietal peritoneum).

Renal Sinus

Hollow chamber in medial depression of the kidney

Renal cortex

Outer region of kidney

Renal medulla

Inner region of kidney; composed of renal pyramids

Renal columns

Extensions of cortex that dip into medulla

Hilum

Entrance to renal sinus

Renal pelvis

Funnel-shaped sac; superior end of ureter

Major calyces

Large tubes that merge to form renal pelvis

Minor calyces

Small tubes that merge to form major calyces

Renal capsule

Fibrous capsule around kidney

Nephrons

Functional units of kidney, each of which is a site of urine production

Renal artery

Branches off abdominal aorta, enters kidney through hilum - Kidneys receive around 25% of total cardiac output.

Segmental arteries

Branch off renal artery

Interlobar arteries

Branch off segmental arteries, flow between renal pyramids

Arcuate (arciform) arteries

Branch off interlobar arteries, arch around renal pyramids

Cortical radiate (interlobular) arteries

Branch off arcuate arteries

Renal corpuscle

Filtering unit of the kidney located in the renal cortex.

Glomerulus

Fenestrated capillary cluster that filters blood to begin urine formation.

Glomerular (Bowman’s) capsule

Receives filtrate from glomerulus

Renal tubule

Extends from glomerular capsule to collecting duct

Filtrate Pathway

From Glomerular Capsule → Proximal (convoluted) tubule → Nephron loop (loop of Henle, composed of a descending and an ascending limb) → Distal (convoluted) tubule

Glomerular filtration

Performs glomerular filtration using specialized glomerular capillaries.

Tubular reabsorption

Transfer of filtered substances from renal tubules to peritubular capillaries.

Tubular secretion

Transfer of certain substances from peritubular capillaries to renal tubules.

Podocytes

Modified epithelial cells that make up the inner visceral later of the glomerular capsule. They wrap around glomerular capillaries with foot-like processes called pedicles that form filtration slits.

Fenestrae

Tiny openings in the walls of glomerular capillaries that make them more permeable to small molecules.

Glomerular filtration rate (GFR)

The amount of filtrate produced per minute by both kidneys.

Renal autoregulation

The ability of the nephrons to adjust their own blood flow and GFR without external (nervous or hormonal) control.

Renin-angiotensin-aldosterone system

A hormone-like system that controls GFR.

Macula densa cells

Cells of the juxtaglomerular apparatus (JGA) that detect decreases in blood pressure and levels of Na+, K+, and Cl-.

Nephritis

Inflammation of the kidney.

Renal plasma threshold

Concentration of a substance in plasma at which it begins to be excreted in the urine

ADH (antidiuretic hormone, or vasopressin)

Stimulates the distal convoluted tubules and collecting ducts to insert specialized water channels called aquaporins.

Countercurrent mechanism

Keeps the interstitial fluid in the medulla hypertonic, which favors reabsorption.

Urea

A product of amino acid catabolism

Uric acid

A product of nucleic acid metabolism

Renal clearance test

Measures the rate at which a chemical is removed from the plasma by the kidney; Used to determine GFR

Ureters

Tubular organs, about 25 cm long, which transports urine from kidney to urinary bladder

Urinary bladder

Hollow, distensible, muscular organ in pelvic cavity that stores urine and sends it into the urethra.

Micturition (urination)

Expulsion of urine from the urinary bladder.