Urinary System ch 26

Flashcards covering key vocabulary and concepts from the lecture on the urinary system.

Urinary system

Removes most metabolic wastes produced by body's cells.

Kidneys

Paired organs that produce urine by removing metabolic wastes from circulation.

Urinary tract

Eliminates urine; consists of ureters, urinary bladder, and urethra.

Urination (micturition)

Process of eliminating urine from the body.

Excretion

Removal of metabolic wastes from body fluids.

Elimination

Discharge of wastes from the body.

Homeostatic regulation

Regulation of volume and solute concentration of blood.

Erythropoietin

Hormone released by kidneys that stimulates red blood cell formation.

Renin

Enzyme involved in regulating water and sodium balance.

Calcitriol

Active form of vitamin D that regulates calcium ion levels.

Renal capsule

Layer of collagen fibers covering the outer surface of each kidney.

Perinephric fat

Thick layer of adipose tissue surrounding the fibrous capsule of the kidney.

Renal fascia

Dense fibrous outer layer that anchors the kidney to surrounding structures.

Hilum

Medial indentation of the kidney where blood vessels and nerves enter and exit.

Renal sinus

Internal cavity within the kidney lined by the fibrous capsule.

Renal cortex

Superficial region of the kidney in contact with the fibrous capsule.

Renal pyramids

Triangular structures in the renal medulla that produce urine.

Renal column

Tissue bands that separate adjacent renal pyramids.

Kidney lobe

Consists of a renal pyramid, overlying renal cortex, and adjacent renal columns.

Minor calyx

Structure that collects urine from renal papillae.

Major calyx

Formed by several minor calyces; funnels urine into the renal pelvis.

Renal pelvis

Funnel-shaped chamber that collects urine from the major calyces and drains into the ureter.

GFR (Glomerular Filtration Rate)

Amount of filtrate produced by the kidneys each minute, approximately 125 mL.

Filtration membrane

Consists of fenestrated endothelium, basement membrane, and foot processes of podocytes.

Podocytes

Cells in the visceral layer of the glomerular capsule that wrap around glomerular capillaries.

Renal corpuscle

Spherical structure consisting of the glomerular capsule and glomerulus.

Nephron

Microscopic functional unit of the kidney, consisting of renal corpuscle and renal tubule.

Proximal convoluted tubule (PCT)

First segment of the renal tubule, primarily involved in reabsorption.

Distal convoluted tubule (DCT)

Third segment of the renal tubule, involved in reabsorption and secretion.

Juxtaglomerular complex (JGC)

Regulates blood pressure and filtrate formation.

Collecting ducts

Receive fluid from many nephrons and transport it to the renal pelvis.

Cortical nephrons

Nephrons primarily located within the cortex of the kidney.

Juxtamedullary nephrons

Nephrons that extend deep into the medulla, involved in the concentration of urine.

Urea

Most abundant organic waste, primarily from protein breakdown.

Creatinine

Waste product from the breakdown of creatine phosphate in muscles.

Uric acid

Waste product from the recycling of nitrogenous bases of RNA.

Filtration

Process where blood pressure forces water and solutes across the glomerular capillaries.

Reabsorption

Movement of water and solutes from filtrate back into the blood.

Secretion

Transport of solutes from blood into the filtrate.

Hydrostatic pressure

Fluid pressure that drives glomerular filtration.

Colloid osmotic pressure

Pressure exerted by proteins in the blood that draws fluid back into the capillaries.

Renin-angiotensin-aldosterone system (RAAS)

Hormonal system that regulates blood pressure and fluid balance.

Atrial natriuretic peptide (ANP)

Hormone produced by the heart that decreases blood pressure and increases GFR.

Ureters

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

Urinary bladder

Hollow muscular organ that temporarily stores urine.

Detrusor muscle

Muscle layer of the bladder that contracts to expel urine.

Urethra

Tube that transports urine from the bladder to the outside of the body.

Internal urethral sphincter

Muscular structure that provides involuntary control of urine discharge.

External urethral sphincter

Skeletal muscle valve that provides voluntary control of urination.

Micturition reflex

Neural reflex that stimulates contraction of the bladder and relaxation of the sphincters.

Urine composition

Reflects filtration, reabsorption, and secretion activities of nephrons.

Blood urea nitrogen (BUN) test

Measures urea in blood to assess kidney function.

Creatinine clearance

Measurement comparing creatinine levels in urine and blood to estimate GFR.

Pyelogram

Image of urinary system obtained via X-ray after dye administration.

Transitional epithelium

Type of epithelium lining the urinary bladder and ureters, allowing stretching.

Peristaltic contractions

Muscular movements that propel urine towards the urinary bladder.

Incontinence

Inability to control urination voluntarily.

Glucosuria

Presence of glucose in urine, indicating exceedance of renal threshold.

Aminoaciduria

Presence of amino acids in urine, indicative of a renal threshold issue.

Reabsorption at PCT

Process where 60-70% of filtrate is reabsorbed, including nutrients and electrolytes.

Sodium ion reabsorption

Key process in renal tubule function; often linked to water movement.