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Module 15 in the Syllabus
Curriculum

The Urinary System Images
Image gallery for study with links to larger teaching JPEGs for classroom presentation

Question Drill for The Urinary System
Conceptual Vocabulary Self-Test

Basic Terms Crossword Puzzle

Basic Puzzle Solution

Conceptual Vocabulary
Urinary systemThe urinary system is the organ system that produces, stores, and eliminates urine. In humans it includes two kidneys, two ureters, the bladder, and the urethra.
UrineUrine is a liquid produced through the kidney, and is collected in the bladder and excreted through the urethra.
KidneyThe kidneys are organs that filter wastes, such as urea, from the blood and excrete them, along with water, as urine.
Urinary bladderThe urinary bladder is a hollow, muscular, and distensible organ that collects urine excreted by the kidneys prior to disposal by urination.
UrinationUrination, known by physiologists as micturition ot voiding, is the process of disposing urine from the urinary bladder through the urethra.
NephronA nephron is the basic structural and functional unit of the kidney.
Proximal tubuleThe proximal tubule is the portion of the duct system of the nephron leading from Bowman's capsule to the loop of Henle.
Bowman's capsuleBowman's capsule is a cup like sac at the beginning of the tubular component of a nephron in the kidney. A glomerulus is enclosed in the sac.
GlomerulusA glomerulus is a capillary tuft surrounded by Bowman's capsule in nephrons of the vertebrate kidney which receives its blood supply from an afferent arteriole of the renal circulation.
Loop of HenleIn the kidney, the loop of Henle is the portion of the nephron that leads from the proximal convoluted tubule to the distal convoluted tubule. The main function of this structure is to reabsorb water and ions from the urine.
Distal convoluted tubuleThe distal convoluted tubule is a portion of kidney nephron between the loop of Henle and the collecting duct system.
Collecting duct systemThe collecting duct system of the kidney consists of a series of tubules and ducts that connect the nephrons to the ureter.
UrethraThe urethra is a tube which connects the urinary bladder to the outside of the body.
Bicarbonate buffering systemThe bicarbonate buffering system is the most important buffer solution for maintaining a relatively constant pH in the plasma.
UreterThe ureters are the ducts that carry urine from the kidneys to the urinary bladder.
Renal cortexThe renal cortex is the outer portion of the kidney between the renal capsule and the renal medulla.
Renal medullaThe renal medulla is the innermost part of the kidney.
Countercurrent exchangeCountercurrent exchange is a mechanism used to transfer some property of a fluid to another across a semipermeable membrane.
UltrafiltrationUltrafiltration occurs at the barrier between the blood and the filtrate in the renal corpuscle or Bowman's capsule in the kidneys.
Glomerular filtration rateThe glomerular filtration rate is the volume of fluid filtered from the renal glomerular capillaries into the Bowman's capsule per unit time.
DiuresisDiuresis is increased production of urine by the kidney.
Renal compensationRenal compensation is a mechanism by which the kidneys can regulate the plasma pH.
Juxtaglomerular cellThe juxtaglomerular cells are cells that synthesize, store, and secrete the enzyme renin.
Juxtaglomerular apparatusThe juxtaglomerular apparatus is a microscopic structure in the kidney which regulates the function of each nephron.
Renal pyramidsRenal pyramids are cone-shaped tissues of the kidney within the renal medulla, which is made up of 8 to 18 of these conical subdivisions.
Renal corpuscleA renal corpuscle is the initial filtering component of a nephron consisting of a glomerulus and a Bowman's capsule.
AquaporinAquaporins are a class of major intrinsic proteins that form pores in the membrane of biological cells which selectively conduct water molecules in and out, while preventing the passage of ions and other solutes.
Renal blood flowRenal blood flow is the volume of blood delivered to the kidneys per unit time.
ClearanceThe renal clearance of a substance is the inverse of the time constant that describes its removal rate from the body divided by its volume of distribution.
Macula densaThe cells of the macula densa within the juxtaglomerular apparatus are sensitive to the ionic content and water volume of the fluid in the distal convoluted tubule within the kidney.
Renal papillaThe renal papilla is the location where the Medullary pyramids empty urine into the renal pelvis.
Juxtamedullary nephronA juxtamedullary nephron is one where the proximal convoluted tubule and its associated loop of Henle occur at a deep position compared to most other nephrons.
Sodium-glucose transport proteinsSodium-glucose transport proteins are a family of glucose transporter found in the intestinal mucosa of the small intestine and the proximal tubule of the nephron.
Peritubular capillariesPeritubular capillaries are tiny blood vessels that travel along side nephrons allowing reabsorption and secretion between blood and the inner lumen of the nephron.
Glomerular basement membraneThe glomerular basement membrane is the basal laminal portion of the glomerulus which performs the actual filtration with the renal corpuscle, separating the blood on the inside from the filtrate on the outside.
Advanced terms that may appear in context in MCAT passages
PodocytePodocytes are cells of the visceral epithelium in the kidneys and form a crucial component of the glomerular filtration barrier, contributing size selectivity and maintaining a massive filtration surface.
Filtration slitsFoot processes of podocytes of the glomerulus interdigitate with one another forming filtration slits that, in contrast to those in the glomerular endothelium, are spanned by diaphragms.
Trigone of urinary bladderThe trigone is a smooth triangular region of the internal urinary bladder formed by the two ureteral orifices and the internal urethral orifice.
Minor calyxThe minor calyx is a structure surrounding the apex of the malpighian pyramids into which urine formed in the kidney passes before passing into the major calyx.
Major calyxThe major calyx is a structure surrounding the apex of the malpighian pyramids into which urine formed in the kidney passes after passing into the minor calyx.
Band 3Anion Exchanger 1 or Band 3 is a transport protein responsible for catalysing the electroneutral exchange of chloride for bicarbonate across a plasma membrane.
Davenport diagramThe Davenport Diagram is a graphical tool that allows a clinician or investigator to describe blood bicarbonate concentrations and blood pH following a respiratory and/or metabolic acid-base disturbance.
Titratable acidTitratable acid is a term to describe acids such as phosphoric acid, sulfuric acid which are involved in renal physiology, a term used explicitly to exclude ammonium as a source of acid.
Renal capsuleThe renal capsule is a tough fibrous layer surrounding the kidney and covered in a thick layer of perinephric adipose tissue.



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