Urinary System

What are the layers of supportive tissue that surround each kidney (from directly external to the kidney and out)?

1. Fibrous capsule 2. Perirenal fat capsule 3. Renal fascia (which also contains an external layer of fat called the pararenal fat)

represent 85% of all nephrons, are located almost entirely within the cortex, with their nephron loops dipping only a short distance into the medulla.

Cortical nephrons

maintain the purity and chemical constancy of the blood and other extracellular body fluids. Filters fluid from the blood, sending toxins, metabolic wastes, excess water, and excess ions out of the body in urine while returning needed substances from the filtrate to the blood

Kidneys

consists of a descending limb and an ascending limb

Loop of Henle

also called voiding or urination, is the act of emptying the bladder. It is brought about by the contraction of the bladder's detrusor muscle, assisted by the muscles of the abdominal wall, which contract to raise intra-abdominal pressure.

Mictuition

The wall of the bladder has three layers:

Mucosa Muscular layer called the detrusor Adventitia

the walls of the ureter have three basic layers:

Mucosa Muscularis Adventitia

occur strictly in the cortex; first part of nephron where filtration occurs; consists of glomerulus surrounded by glomerular capsule

Renal corpuscle

What are the two distinct regions of the kidney?

Renal cortex and renal medulla

a tube that carries urine from the bladder to the body exterior

Urethra

is a thin-walled tube that drains urine from the bladder and conveys it out of the body

Urethra

On the superior part of each kidney lies the ____________, an endocrine gland that is functionally unrelated to the kidney

adrenal (suprerenal) gland

The glomerulus is supplied by an ____________ arteriole and drained by an __________ arteriole

afferent efferent

At the medulla-cortex junction, the interlobar arteries branch into _________________, which arch over the bases of the renal pyramids

arcuate arteries

arteries supplying the bladder

are branches of the internal iliac arteries, the superior and inferior vesical arteries

The endothelium of the glomerulus is fenestrated (has pores), and thus these capillaries are highly porous, allowing large quantities of fluid and small molecules to pass from the capillary blood into the hollow interior of the glomerular capsule, the _____________.

capsular space

Urine passes from the distal tubules of the nephrons into the ________________, each of which receives urine from several nephrons and runs straight through the cortex into the deep medulla; important role is to conserve body fluids,

collecting ducts

Radiating outward from the arcuate arteries and supplying the cortical tissue are small __________________

cortical radiate arteries

Blood leaving the renal cortex drains sequentially into the ______________, ___________, ___________, and ______________ (there are no segmental veins)

cortical radiate veins arcuate veins interlobar veins renal veins

is confined to the renal cortex. It has walls of simple cuboidal epithelium and is specialized for the selective secretion and resorption of ions; is less active in resorption, and its cells do not have an abundance of absorptive microvilli

distal convoluted tubule

surrounds the urethra within the sheet of muscle called the urogenital diaphragm; is a skeletal muscle used to inhibit urination voluntarily until the proper time

external urethral sphincter

interact with cells of the macula densa and granular cells to regulate glomerular blood flow

extraglomerular mesangial cells

The filtrate passes into the capsular space through thin clefts between the foot processes, called

filtration slits

The nephron produces urine through three interacting mechanisms:

filtration, resorption, and secretion

veins draining the bladder

form a plexus on the bladder's inferior and posterior surfaces that empties into the internal iliac veins

cortical radiate arteries give rise to the __________________, which feed into the peritubular capillaries surrounding the tubules in the kidney

glomerular arterioles

The capillaries of the ___________ produce the filtrate that moves through the rest of the renal tubule and becomes urine. It differs from all other capillary beds in the body because It is both fed and drained by arterioles

glomerulus

The three capillary beds that nephrons associate with

glomerulus Peritubular capillaries Vasa recta

The walls of the afferent and efferent glomerular arterioles contain

granular cells (juxtaglomerular cells)

The renal vein exits from the kidney at the hilum and empties into the __________________

inferior vena cava

Within the renal sinus, each segmental artery divides into ________________, which lie in the renal columns between the renal pyramids.

interlobar arteries

At the bladder-urethra junction, a thickening of the detrusor forms the _______; an involuntary sphincter of smooth muscle that keeps the urethra closed when urine is not being passed and prevents dribbling of urine between voidings

internal urethral sphincter

a structure that functions in the regulation of blood pressure, is an area of specialized contact between the terminal end of the thick ascending limb of the nephron loop and the afferent arteriole

juxtaglomerular complex

remaining 15% of all nephrons are called ___________ because their renal corpuscles lie near the cortex-medulla junction. These nephrons have nephron loops that deeply invade the medulla and thin segments that are much longer than those of cortical nephrons. These long nephron loops, in conjunction with nearby collecting ducts, contribute to the kidney's ability to produce a concentrated urine.

juxtamedullary ("near the medulla") nephrons

which is the terminal portion of the nephron loop adjacent to the granular cells, consists of tall, closely packed epithelial cells that act as chemoreceptors for monitoring sodium concentrations in the filtrate

macula densa

Branching extensions of the renal pelvis form two or three ___________ each of which divides to form several __________________, cup-shaped tubes that enclose the papillae of the pyramids. They collect urine draining from the papillae and empty it into the renal pelvis.

major calices minor calices

The main structural and functional unit of the kidney is the

nephron

At the papilla of the pyramid, adjacent collecting ducts join to form larger ___________________, which empty into the minor calices.

papillary ducts

arise from the efferent arterioles draining the cortical glomeruli; lie in the interstitial connective tissue of the renal cortex, a loose areolar connective tissue that surrounds the renal tubules; cling closely to the convoluted tubules and empty into nearby venules of the renal venous system; are adapted for absorption: They are low-pressure, porous capillaries that readily absorb solutes and water from the tubule cells after these substances are resorbed from the filtrate; all molecules that are secreted by the nephrons into the urine are from the blood of nearby _________

peritubular capillaries

the capsule's visceral layer clings to the glomerulus and consists of unusual, branching epithelial cells called _______________ which end in foot processes

podocytes

In the bladder, the two ____________ angles receive the ureters

posterolateral

In males, the urethra is about 20 cm long (8 inches) and has three named regions: the __________________, which is about 2.5 cm long and runs in the prostate; _______________________________, which runs for about 2.5 cm through the membranelike urogenital diaphragm; and the _______________________, which is about 15 cm long, passes through the entire penis, and opens at the tip of the penis via the external urethral orifice.

prostatic urethra the intermediate part of the urethra or membranous urethra spongy urethra

confined entirely in renal cortex; is most active in resorption and secretion; walls are formed by cuboidal epithelial cells whose apical (exposed) surfaces have long microvilli (which increase surface area) that seem to fill the tubule lumen with a "fuzz" in photo micrographs

proximal convoluted tubule

the renal tubule consists of

proximal convoluted tubule, loop of henle, distal convoluted tubule, and collecting duct

granular cells secrete ____

reinin

supply blood to the kidneys

renal arteries

the inward extensions of the renal cortex that separate adjacent pyramids are called

renal columns

Each nephron is composed of the ____________________ and a ___________________.

renal corpuscle renal tubule

located on the medial surface of the kidney where vessels, ureters, and nerves enter and leave the kidney

renal hilum

a flat, funnel-shaped tube; is simply the expanded superior part of the ureter

renal pelvis

The nerve supply of the kidney is provided by the ____________, a network of autonomic fibers and autonomic ganglia on the renal arteries.

renal plexus

Inside the renal medulla are cone-shaped masses called

renal pyramids

a large space within the medial part of the kidney opening to the exterior through the renal hilum; is actually a "filled space" in that it contains the renal vessels and nerves, some fat, and the urine-carrying tubes called the renal pelvis and calices.

renal sinus

As each renal artery approaches a kidney, it divides into five ___________________ that enter the hilum

segmental arteries

the walls of the collecting ducts consist of a _________ epithelium which thickens to become _______________ epithelium in the papillary ducts.

simple cuboidal simple columnar

In the interior of the bladder, openings for both ureters and the urethra define a triangular region on the posterior wall called the ______________

trigone

At the bladder's anterior angle (or apex) is a fibrous band called the __________, the closed remnant of an embryonic tube called the allantois.

urachus

The main waste products excreted in urine are three nitrogenous compounds:

urea uric acid creatinine

Urine, collected from the renal calices and emptied into the renal pelvis, leaves the kidneys via _________; are slender tubes, about 25 cm (10 inches) long, that carry urine from the kidneys to the bladder

ureters

tubes that carry urine from the kidney to the bladder

ureters

The inferior angle (neck) of the bladder drains into the ______________

urethra

In females, the urethra is just 3-4 cm (1.5 inches) long and is bound to the anterior wall of the vagina by connective tissue. It opens to the outside at the external _________________, a small, often difficult-to-locate opening that lies anterior to the vaginal opening and posterior to the clitoris

urethral orifice

a collapsible, muscular sac that stores and expels urine

urinary bladder

In the deepest part of the renal cortex, efferent arterioles from the juxtamedullary glomeruli continue into thin-walled looping vessels called ________ ; descend into the medulla, running alongside the nephron loops

vasa recta