W16 (LEC): URINARY SYSTEM

These small, dark red organs with a kidney-
bean shape lie against the dorsal body wall in a
retroperitoneal position (beneath the parietal
peritoneum) in the superior lumbar region; they extend
from the T12 to the L3 vertebra, thus they receive
protection from the lower part of the rib cage.

Kidney

Because it is crowded by the liver, the __________ is positioned slightly lower than the left.

right kidney

An ______________ is about 12 cm (5 inches) long, 6
cm (2.5 inches) wide, and 3 cm (1 inch) thick, about the
size of a large bar of soap

adult kidney

Atop each kidney is an ____________,
which is part of the endocrine system is a distinctly
separate organ functionally.

adrenal gland

A transparent ___________ encloses
each kidney and gives a fresh kidney a glistening
appearance.

fibrous capsule

A fatty mass, the _____________, surrounds each kidney and acts to cushion it against blows.

perirenal fat capsule

The _________, the outermost capsule, anchors the kidney and helps hold it in place against the muscles of the trunk wall.

renal fascia

The outer region, which is light in color, is the ____________.

renal cortex

Deep to the cortex is a darker, reddish-brown area, the ________.

renal medulla

The medulla has many basically triangular
regions with a striped appearance, the renal, or ____________; the _________ of each pyramid faces toward
the cortex while its tip, the ____, points toward the inner
region of the kidney.

1.) medullary pyramids
2.) broader base
3.) apex

The pyramids are separated by extensions
of cortex-like tissue, the _____________.

renal columns

Medial to the hilum is a flat, basin like cavity, the _________, which is continuous with the ureter leaving the hilum.

renal pelvis

Extensions of the pelvis, _______, form cup-shaped
areas that enclose the tips of the pyramid and collect urine,
which continuously drains from the tips of the pyramids into
the renal pelvis.

calyces

The arterial supply of each kidney is the _________, which divides into ____________ as it approaches the hilum, and each segmental artery gives off several branches called ______________.

1.) renal artery
2.) segmental arteries
3.) interlobar arteries

At the cortex-medulla junction, interlobar arteries give off _____________, which curve over the medullary pyramids

arcuate arteries

Small _____________ then branch off the arcuate arteries and run outward to supply the cortical tissue.

cortical radiate arteries

Each kidney contains over a million tiny structures called _________, and they are responsible for forming urine.

nephrons

One of the main structures of a nephron, a __________ is a knot of capillaries.

glomerulus

Another one of the main structures in a nephron is the __________.

renal tubule

The closed end of the renal tubule is
enlarged and cup-shaped and completely surrounds the
glomerulus, and it is called the ________ or ___________.

1.) Bowman’s capsule
2.) glomerular

The inner layer of the capsule (glomerular) is made up of highly modified octopus-like cells called ____________.

podocytes

Podocytes have long branching processes called ____________ that intertwine with one another and cling to the glomerulus.

foot processes

As the tubule extends from the
glomerular capsule, it coils and twists before forming a
hairpin loop and then again becomes coiled and twisted
before entering a collecting tubule called the ____________, which receives urine from many nephrons.

collecting duct

This is the part of the tubule that is near to the glomerular capsule.

Proximal convoluted tubule.

The _______________ is the hairpin loop following the proximal convoluted tubule.

loop of Henle

After the loop of Henle, the
tubule continues to coil and twist before the collecting
duct, and this part is called the _____________________.

distal convoluted tubule

Most nephrons are called _______________ because they are located almost entirely within the cortex.

cortical nephrons

In a few cases, the nephrons are
called __________________ because they are situated
next to the cortex-medullary junction, and their loops of
Henle dip deep into the medulla.

juxtamedullary nephrons

The ___________, which arises from a cortical radiate artery, is the “feeder vessel”.

afferent arteriole

The ___________________ receives blood that has passed through the glomerulus.

efferent arteriole

They arise from the efferent arteriole that drains the glomerulus.

Peritubular capillaries

• The ___________ are two slender tubes each 25 to 30
  cm (10 to 12 inches) long and 6 mm (1/4 inch) in diameter.

• passageways that carry urine from the kidneys to the bladder through contraction of the smooth muscle layers in their walls that propel urine into the bladder by peristalsis and is prevented from flowing back by small valve-like folds of bladder mucosa that flap over the ureter openings.

ureters

located retroperitoneally in the pelvis just posterior to the symphysis pubis. It is for urine storage

Urinary Bladder

The smooth triangular region of the bladder base
outlined by these three openings is called the ________,
where infections tend to persist.

trigone

The bladder wall contains three layers
of smooth muscle, collectively called the ___________,
and its mucosa is a special type of epithelium, transitional
epithelium.

detrusor muscle

At the bladder-urethral junction, a thickening of the smooth muscle forms the _______________, an involuntary sphincter that keeps the urethra closed when the urine is not being passed.

internal urethral sphincter

A second sphincter, the
_______________________________, is fashioned by skeletal
muscle as the urethra passes through the pelvic floor
and is voluntarily controlled.

external urethral sphincter

The ____________ is about 3 to 4
cm (1 1/2 inches) long, and its external orifice, or
opening, lies anteriorly to the vaginal opening.

female urethra

the urethra is approximately 20 cm (8 inches) long and has three named regions: the prostatic, membranous, and spongy (penile) urethrae; it opens at the tip of the penis after traveling down its length.

Male urethra

Identify the organs:
1.) 12 cm long (5 inches)
2.) 25 to 30 cm long (10-12 inches)
3.) 3-4 cm (1 ½ inches)
4.) 20 cm (8 inches)

Answer key:
1.) Adult kidney
2.) Ureters
3.) female ureters
4.) male urethra

it opens at the tip of the penis after traveling down its length

urethrae

Water and solutes smaller than proteins are forced through the capillary walls and pores of the glomerular capsule into the renal tubule.

Glomerular filtration

Water, glucose, amino acids,
and needed ions are transported out of the filtrate
into the tubule cells and then enter the capillary
blood.

Tubular reabsorption

Hydrogen, potassium, creatinine,
and drugs are removed from the peritubular blood
and secreted by the tubule cells into the filtrate.

Tubular secretion

In 24 hours, the marvelously complex kidneys filter some _________ of blood plasma through their glomeruli into the tubules

150-180 L

In 24 hours, only about 1.0 to 1.8 liters of urine are produced.

Daily volume

Urine contains _______ and __________ substances

1.) nitrogenous wastes
2.) unneeded

Freshly voided urine is generally ____ and ___ to _________.

1.) clear
2.) pale
3.) deep yellow

When formed, urine is ______ and _______, but if allowed to stand, it takes on an ___________ caused by the action of bacteria on the urine solutes.

1.) sterile
2.) slightly aromatic
3.) ammonia odor

Urine pH is usually ________ (around __),
but changes in body metabolism and certain
foods may cause it to be much more acidic or
basic.

1.) slightly acidic
2.) 6 pH

Whereas the specific gravity of pure water is 1.0, the specific gravity of urine usually ranges from ___________.

1.001-1.035

Solutes normally found in urine include
____ and _________, _____, etc.

1.) sodium
2.) potassium ions
3.) urea

the act of emptying the bladder

Micturition/Voiding

Ordinarily, the bladder continues to collect urine until about _______ have accumulated.

200 ml

At about this point (200 ml of urine have accumulated), stretching of the
bladder wall activates _____________.

stretch receptors

• An abnormally low urinary output

• if it is between 100 and 400 ml/day.

Oliguria

• An abnormally low urinary output

• it is less than 100 ml/day

Anuria

Low urinary output usually indicates that___________ is __________ to cause filtration, but anuria may also result from _______ and __________ or from crushing injuries to the kidneys.

1.) glomerular blood pressure
2.) too low
3.) transfusion reactions
4.) acute inflammation

When urine becomes extremely concentrated, solutes such
as uric acid salts form crystals that precipitate in the renal pelvis.

kidney stones or renal calculi

inflammation of the urethra

urethritis

bladder inflammation

cystitis

kidney inflammation

pyelonephritis

Symptoms of urinary tract infection (UTI) include _____ (painful urination), __________, _____,
and sometimes__________. When the kidneys are involved, back pain and a severe headache are
common.

1.) dysuria
2.) urinary urgency and frequency
3.) fever
4.) cloudy or blood-tinged urine

occurs when a person is unable to voluntarily control the external sphincter.

Incontinence

bladder is unable to expel its contained urine- opposite of incontinence.

Urinary retention

When urinary retention is prolonged, a slender flexible drainage tube called a ________ must be inserted
through the urethra to drain the urine and prevent bladder trauma from excessive stretching.

catheter

degenerative condition that appears to run in families. One or both kidneys enlarge, sometimes to the size of a football, and have many blister-like sacs (cysts) containing urine. These cysts interfere with renal function by obstructing but initially not stopping urine drainage. Currently, little can be done for this condition except to prevent further kidney damage by avoiding infection.

Adult polycystic kidney disease

Adult polycystic kidney disease eventual outcome

Renal failure

In the rarer, infantile form of the disease (Adult polycystic kidney), the kidney has blind pouches into which the filtrate flows, totally
blocking drainage. The disease progresses rapidly, resulting in death by ______ of age.

2 years

condition found in male babies only- occurs when the urethral orifice is located on the ventral surface of the penis. Corrective surgery is generally done when the child is around 12 months old.

Hypospadias

Hormone that kidney produces, which stimulates red blood cells production in bone marrow

erythropoietin

Enzyme that kidney produces, they help regulate blood pressure.

renin