Chapter 24: Urinary System
Renal Pelvis
A flat, funnel-shaped tube that is simply an expanded superior part of the ureter.
Renal Medulla
A frontal section of the kidney deep to the cortex which consists of cone-shaped masses.
Renal Cortex
A frontal section of the kidney that is more superficial, light in color and has a granular appearance.
Filtration Membrane
Actual filter that lies between the blood in the glomerulus and the capsular space consisting of three layers.
Internal Urethral Sphincter
An involuntary smooth muscle that keeps the urethra closed when urine is not being passed and prevents dribbling of urine between voidings.
Major Calices
Branching extensions of the renal pelvis form two or three _____ _______.
Peritubular Capillaries
Capillaries that surround the tubules in the kidney.
Filtration
During this mechanism of urine production, a filtrate of blood leaves the kidney capillaries and enters the renal tubule. It resembles tissue fluid because it contains small molecules of blood plasma.
Reabsorption
During this mechanism of urine production, most of the nurients, water, and essential ions are recovered from the filtrate and returned to the blood of capillaries in surrounding CT.
Visceral Layer
Layer that clings to the glomerulus and consists of unusual, branching epithelial cells called popcytes.
Cortical Nephrons
Represent 85% of nephrons, located mostly within the cortex
Nephron
Smallest functional unit in the kidney; Produces urine.
Macula Densa
Terminal portion of the nephron loop adjacent to the granular cells that consists of tall, packed epithelial cells that act as chemoreceptors for monitoring solute concentrations in filtrate.
Renal Corpuscle
Where filtration occurs in the nephron.
Trigone
A triangular region on the posterior wall of the bladder formed by openings for ureters and the urethra.
Vasa Recta
Capillary-like blood vessels that supply the loops of Henle and collecting ducts in the medulla of the kidney.
Extraglomerular Mesanglial Cells
Cells that interact with cells of the macula densa and granular cells to regulate blood pressure.
Minor Calices
Major Calices divide to form several ______ ______ which are cup shaped tubes that enclose the papillae of the pyramids.
Capsular Space
The hollow interior of the glomerular capsule that accepts large quantities of fluid and small molecules from the capillary blood.
Ureter
Tube that carries urine from the bladder to the exterior.
Proximal Convoluted Tubule
Tubule confined entirely to the renal cortex; is most active in resorption and secretion.
Distal Convoluted Tubule
Tubule confined to the renal cortex that is specialized for the selective secretion and resorption of ions.
Nephron Loop (loop of Henle)
U-shaped loop that consists of a descending limb and an ascending limb.
Micturition
Urination or voiding; emptying the bladder.
Arcuate Vein.
Vein that blood leaving the cortex drains into that drains into the interlobar vein.
Interlobar Vein
Vein that blood leaving the cortex drains into that drains into the renal vein.
Renal Veins
Vein that the blood leaving the cortex drains into and exits the kidney at the hilum and empties the inferior vena cava.
Cortical Radiate Vein
Veins that blood leaving the cortex drains into that are branching along the cortex that drains into the arcuate vein.
Interlobar Arteries
Within the renal sinus, each segmental artery divides into __________ _________ which lie in the renal columns between the renal pyramids.
Renal Columns
Inwards extensions of the renal cortex that separate adjacent pyramids.
Granular Cells
Modified smooth muscle cells with secretory granules containing a hormone called renin.
Podocytes
Octopus shaped epithelial cells that surround the glomerular capillaries; they help produces and maintain the basement membrane (a filtration membrane in the kidney).
Collecting Ducts
Receives urine from several nephrons and runs straight through the cortex into the deep medulla.
Kidneys
Red-brown, bean shaped organs that lie behind the parietal peritoneum in the superior lumbar region of the posterior abdominal wall.
Juxtamedullary Nephrons
Represent 15% of nephrons, their renal corpuscles lie near the cortex-medulla junction.
Glomerular Arterioles
The arteries of the kidney give rise to ____________ _________ which feed into the peritubular capillaries.
Renal Pyramids
The cone shaped masses that make up the renal medulla.
Detrusor
Thick, muscular layer that forms the middle layer of the bladder consisting of smooth muscle fibers; contraction of this muscle squeezes urine from the bladder during urination.
Filtration Slits
Thin clefts between the foot processes.
Urethra
Thin-walled tube that drains urine from the badder and conveys it out of the body.
Renal Arteries
Arteries that branch at right angles from the abdominal aorta to reach the kidney.
Cortical Radiate Arteries
Arteries that radiate outward from the arcuate arteries and supply the cortical tissue.
Segmental Arteries
As each renal artery approaches the kidney, it divides into five _________ ________ that enter the hilum.
Arcuate Arteries
At the medulla-cortex junction, the interlobar arteries branch into _______ _______ which arch over the bases of the renal pyramids.
Parietal Layer
External layer of the glomerular capsule made of simple sqamous epithelium that contributes to the structure of the capsule,
Renal Fascia
External to the perirenal fat capsule is an envelope of ______ ______ which contains an external layer of fat which cushions the kidney against blows and keeps it in place.
Perirenal Fat Capsule
External to the renal capsule is the _______ _______ _______.
Afferent Arteriole
Feed and drain the glomerulus; Arise from the cortical radiate arteries that run through the renal cortex
Efferent Arteriole
Feed and drain the glomerulus; narrower arteriole which results in higher blood pressure and forces the filtrate out of the blood and into the glomerular capsule.
Papillary Ducts
Formed by collecting ducts; empties into the minor calices.
Renin
Hormone released by the kidneys that is involved with raising blood pressure, blood volume, and the sodium concentration in blood.
Tubular Secretion
In this mechanism of urine production, additional undesirable molecules are moved into the tubule from the blood of surrounding capillaries.
Glomerulus
A ball of capillaries forming part the nephron in the kidney; forms a filtrate that will be modified into urine.
Bladder
A collapsible, muscular sac that stores and expels urine.
Glomerular Capsule (Bowman's Capsule)
A cup-shaped hollow capsule that surrounds the glomerulus.
External Urethral Sphincter
A skeletal muscle used to inhibit urination voluntarily until the proper time.
Hilum
A slit on the surface of an organ through which the vessels and nerves enter and leave; organs include spleen, lungs, kidneys, lymph nodes, and ovaries.
Juxtaglomerular Complex (apparatus)
A structure that functions in the regulation of blood pressure; an area of specialized contact between the terminal end of the nephron loop and the afferent arteriole.
Fibrous Capsule
A thin, tough layer of dense CT that adheres directly to the kidney's surface, maintaining its shape and forming a barrier than inhibits the spread of infection from surrounding areas.