Chapter 23: The Urinary System practice vocabulary flashcards

This set of 200 vocabulary flashcards covers the comprehensive anatomy, physiology, and pathology of the urinary system as detailed in Chapter 23, including nephron structure, urine formation stages, and hormonal regulation.

Urinary System

A body system containing six principal organs: two kidneys, two ureters, the urinary bladder, and the urethra.

Kidneys

Two principal organs of the urinary system that filter blood and process it into urine.

Ureters

Two muscular tubes that convey urine from the kidneys to the urinary bladder.

Urinary bladder

A muscular sac that provides temporary storage for urine.

Urethra

A tube that conveys urine out of the body from the urinary bladder.

Waste

Any substance that is useless to the body or present in excess of the body’s needs.

Metabolic waste

A waste substance produced by the body.

Nitrogenous wastes

Highly toxic metabolic wastes that contain nitrogen.

Urea

A nitrogenous waste produced from protein catabolism.

Uric acid

A nitrogenous waste produced from nucleic acid catabolism.

Creatinine

A nitrogenous waste produced from creatine phosphate catabolism.

Blood filtration

One of the diverse functions of the kidneys involving the removal of toxic metabolic wastes.

Blood volume regulation

The kidney function of managing the amount of fluid in the blood to control pressure and osmolarity.

Erythropoietin

A hormone secreted by the kidneys that stimulates the production of red blood cells.

Acid–base balance

One of the regulatory functions of the kidneys involving electrolytes and pH.

Glucose synthesis

A kidney function occurring during starvation where glucose is made from amino acids.

Renal cortex

The granular-appearing outer region of the internal kidney anatomy.

Renal medulla

The region internal to the renal cortex, composed of cone-shaped medullary pyramids.

Medullary (renal) pyramids

Cone-shaped structures within the renal medulla.

Papilla

The tip of a renal pyramid that points internally toward the minor calyx.

Renal columns

Inward extensions of cortical tissue that separate the renal pyramids.

Kidney Lobe

A structure consisting of one medullary pyramid and its surrounding cortical tissue; there are about eight per kidney.

Minor calyx

A little cup-shaped structure that surrounds the papilla of each pyramid and collects its urine.

Major calyx

A structure formed by the convergence of 2 or 3 minor calyces.

Renal pelvis

A structure formed by the convergence of 2 or 3 major calyces that leads to the ureter.

Urine Flow Pathway

Renal pyramid → minor calyx → major calyx → renal pelvis → ureter.

Cardiac Output to Kidneys

Approximately 21% of the total cardiac output is received by the kidneys.

Renal artery

The artery that brings blood into the kidney for cleansing and waste removal.

Segmental arteries

The first branches of the renal artery inside the kidney.

Interlobar arteries

Arteries that pass through the renal columns between the pyramids.

Arcuate arteries

Arteries that curve over the tops of the renal pyramids at the corticomedullary junction.

Cortical radiate (interlobular) arteries

Arteries that branch off the arcuate arteries and travel into the renal cortex.

Afferent arterioles

Smaller vessels that branch from cortical radiate arteries and lead into the glomerulus.

Glomerulus

A capillary network where blood is filtered and turned into filtrate.

Efferect arterioles

Vessels through which blood leaves the glomerulus after filtration.

Peritubular capillaries

Capillaries that arise from efferent arterioles and wrap around renal tubules in the cortex.

Vasa recta

Capillaries that arise from efferent arterioles serving juxtamedullary nephrons and function in urine concentration.

Nephron

The functional and structural units of the kidney that form urine.

Nephron Count

Each kidney contains approximately 1.2 million nephrons.

Renal corpuscle

The part of the nephron that filters the blood plasma.

Renal tubule

A long, coiled tube in the nephron that converts filtrate into urine.

Glomerular capsule

A cup-shaped hollow structure surrounding the glomerulus, also known as Bowman’s capsule.

Proximal convoluted tubule (PCT)

The part of the renal tubule closest to the renal corpuscle and the site of most reabsorption.

Nephron loop

The U-shaped part of the renal tubule consisting of descending and ascending limbs; also called the loop of Henle.

Descending limb

The part of the nephron loop permeable to water but not to solutes.

Ascending limb

The part of the nephron loop impermeable to water but where solutes such as $Na^+$, $K^+$, and $Cl^-$ leave.

Distal convoluted tubule (DCT)

The part of the renal tubule farthest from the renal corpuscle that drains into a collecting duct.

Collecting duct

A duct that receives filtrate from many nephrons and gives the renal pyramids their striped appearance.

Cortical nephrons

The majority of nephrons, characterized by short nephron loops that dip only slightly into the medulla.

Juxtamedullary nephrons

Nephrons close to the medulla with very long nephron loops, comprising about 15% of all nephrons.

Glomerular filtrate

The fluid in the capsular space, similar to blood plasma but containing almost no protein.

Tubular fluid

The fluid from the proximal convoluted tubule through the distal convoluted tubule.

Urine

The fluid within the collecting duct and beyond, which undergoes little alteration except for water content changes.

The kidneys process approximately _____ of blood/filtrate per day.

180L

Glomerular filtration

The first stage of urine formation where blood is filtered to form protein- and cell-free filtrate.

Tubular reabsorption

The second stage of urine formation where 99% of the substances from the filtrate are returned to the blood.

Tubular secretion

The third stage of urine formation where substances are moved from the blood into the fluid in the renal tubules.

Water conservation

The fourth stage of urine formation where water is removed from the urine and returned to the blood.

Filtration membrane

A three-component barrier through which filtered fluid passes, including the endothelium, basement membrane, and filtration slits.

Fenestrated endothelium

The layer of glomerular capillaries containing large filtration pores that allow small substances to pass.

Basement membrane

Occurring in the filtration membrane, this layer is negatively charged and repels negatively charged proteins.

Filtration slits

Negatively charged gaps between the podocyte foot processes that wrap around the capillaries.

Podocytes

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

Parietal layer

The outer layer of the glomerular capsule.

Visceral layer

The layer of the glomerular capsule that consists of podocytes covering the capillaries.

Obligatory water reabsorption

Water reabsorption that occurs in the PCT where aquaporins are always present.

Aquaporins

Water-permeable channels used in the renal tubules for reabsorption.

PCT nutrient reabsorption

The proximal convoluted tubule reabsorbs all nutrients, including glucose and amino acids.

PCT water and sodium reabsorption

The proximal convoluted tubule reabsorbs approximately $65\%$ of water and sodium.

Uric acid reabsorption

Almost all uric acid is reabsorbed in the PCT, though it may later be secreted.

Urea recycling

About half of urea is reabsorbed in the PCT and later secreted back into the filtrate.

Hormonal regulation of reabsorption

The process that occurs in the DCT and collecting duct, fine-tuning the reabsorption of water and salt.

Antidiuretic hormone (ADH)

A hormone released by the posterior pituitary that increases water reabsorption by inserting aquaporins into the collecting ducts.

Facultative water absorption

Water absorption in the collecting duct that only occurs if ADH is present.

Aldosterone

A hormone that fine-tubes reabsorption of sodium and promotes the secretion of potassium in the DCT and collecting duct.

Atrial natriuretic peptide (ANP)

A hormone released by cardiac atrial cells that inhibits sodium reabsorption to decrease blood volume and pressure.

Parathyroid hormone (PTH)

A hormone that acts on the DCT to increase calcium reabsorption.

Secreted substances

Substances moved from peritubular capillaries into the renal tubule, such as K+, H+, drug metabolites, and urea.

Secretion of K+

An effect of aldosterone to rid the body of excess potassium items.

Blood pH control

A kidney function achieved by altering the secreted amounts of $H^+$ or $HCO_3^-$ in the urine.

Hypertonic urine

Concentrated urine produced during states of dehydration when ADH levels are high.

Hypotonic (dilute) urine

Abundant urine produced when well-hydrated and ADH secretion falls.

Urochrome

A yellow pigment from the breakdown of hemoglobin that gives urine its color.

Urine pH

Typical urine ranges from $4.5$ to $8.2$, though the average is $6.0$ (mildly acidic).

Chemical composition of urine

Urine consists of approximately $95\%$ water and $5\%$ solutes.

Renal calculi

Kidney stones composed of crystallized calcium, magnesium, or uric acid salts.

Renal calculi risk factors

Factors including obesity and elevated blood calcium levels that contribute to stone formation.

Female urethra

A tube approximately $3$ to $4\,cm$ long, bound to the anterior wall of the vagina.

Male urethra

A tube approximately $18\,cm$ long with three distinct regions.

Prostatic urethra

The region of the male urethra that passes through the prostate gland, approximately $2.5\,cm$ long.

Membranous urethra

The short region of the male urethra ($0.5\,cm$) that passes through the pelvic cavity floor.

Spongy (penile) urethra

The longest portion of the male urethra ($15\,cm$) passing through the penis in the corpus spongiosum.

Renal insufficiency

A state in which kidneys cannot maintain homeostasis due to extensive destruction of nephrons.

Hemodialysis

The procedure for artificially clearing wastes from the blood when the kidneys fail.

Minimum kidney survival

A person can survive on as little as one-third of one kidney.

Urine cloudiness

A property that could suggest a urinary tract infection, trauma, or stones.

Ammonia in urine

An odor produced as bacteria degrade urea.

Interlobar vein

A vein that drains blood from the arcuate veins in the renal circulation pathway.

Arcuate vein

A vein located at the corticomedullary junction that drains blood from cortical radiate veins.

Cortical radiate vein

A vein that collects blood from the peritubular capillaries and vasa recta.