Exam 4 (Urinary, Fluid Electrolyte Acid-Base, and Reproductive) (correct answers)

Exam 4 (Urinary, Fluid Electrolyte Acid-Base, and Reproductive)
(correct answers)
What organs comprise the urinary system? correct answers -kidneys - produce urine,
dispose of metabolic waste, maintenance of proper electrolyte concentrations and acid-
base balance in the blood/body fluids, produce and secrete renin and erythropoietin,
metabolize vitamin D to its active form
-ureters (2) - paired tubes that transport urine from the kidneys to the urinary bladder
-urinary bladder (1) - a temporary storage reservoir for urine
-urethra (1) - a tube that carries urine from the bladder to the body exterior

Identify the functions of the urinary system correct answers -produce urine,
-dispose of metabolic wastes,
-maintenance of proper electrolye concentrations and acid-base balance in the
blood/body fluids
-produce & secrete renin,
-produce & secrete erythropoietin,
-metabolize vitamin D to its active form

Describe the location an external anatomy of a kidney correct answers -lie in a
retroperitoneal position (between the dorsal body wall and the parietal peritoneum) in
the superior lumbar region; extend from approximately T12 to L3
-right kidney is crowded by the liver and lies slightly lower than the left

Identify and describe the three layers of tissue that surround the kidney correct answers
-renal fascia - outer layer of dense fibrous connective tissue that anchors the kidney and
the adrenal gland to surrounding structures
-perineal fat capsule - fatty mass that surrounds the kidney and cushions it against
blows
-fibrous capsule - transparent capsule that prevents infections in surrounding regions
from spreading to the kidney

What is the primary neural innervention of the kidney? How does the nervous system
help regulate renal function? correct answers The renal plexus, a variable network of
autonomic nerve fibers and ganglia, provides the nerve supply of the kidney and its
ureter. These sympathetic vasomotor fibers regulate renal blood flow by adjusting the
diameter of renal arterioles and also influence the formation of urine by the nephron.

Name the vessels that carry blood into and out of a glomerulus correct answers afferent
(into the glomerulus) and efferent arteriole (away from the glomerulus); this
arrangement maintains the high pressure int he glomerulus that is needed for filtration.
-afferent: larger diameter than efferent; when bp high, provide resistance to blood flow
but not a dramatic amount - about 55mmHg
-efferent: pressure falls dramatically as blood flows out of glomerulus through efferent;
the low pressure promotes reabsorption

,What are the main two parts of a nephron? correct answers renal corpuscle (all of which
are in the renal cortex) and renal tubule (begin in cortex and then pass into medulla
before returning back to cortex)

Describe the structure of the renal corpuscle correct answers each renal corpuscle
consists of a tuft of capillaries called a glomerulus (transition between afferent and
efferent arterioles) and a cup-shaped hollow structure called the glomerular capsule
(Bowman's capsule). The glomerular capsule is continuous with its renal tubule and
completely surrounds the glomerulus, much as a well-worn baseball glove encloses a
ball.

Identify the regions of the renal tubule and describe the basic histological characteristics
of each correct answers -has three major parts
It leaves the glomerular capsule as the elaborately coiled PCT, drops into a hairpin loop
called the nephron loop, and then winds and twists again as the DCT before emptying
into a collecting duct.
(1. PCT 2. nephron loop 3. DCT)
-Throughout their length, the renal tubule and collecting duct consist of a single layer of
epithelial cells on a basement membrane.
-PCT: the cells of the PCT are simple cuboidal ET, there is a prominent brush border on
the luminal surface of ET cells--increases the surface area; cells contain lots of
mitochondria--provide ATP to fuel the solute pumps into important in tubular
reabsorption
-loop of Henle (nephron loop): divided into a descending limb and an ascending limb;
each limb contains a thick segment (cuboidal or low columnar ET) and a thin segment
(squamous ET)
-DCT: cells of most of the DCT (and the collecting ducts) are cuboidal ET, have few
microvilli

Trace the tubular system of a nephron from Bowman's capsule to the renal pelvis
correct answers bowman's capsule-> proximal convoluted tubule -> loop of henley
(descending limb of nephron loop ->ascending limb of nephron loop) -> distal
convoluted tubule -> collecting duct (in medullary pyramid) -> papillary duct-> minor
calyces -> major calyces -> renal pelvis

Trace the circulatory pathway of a kidney from the renal artery to the renal vein correct
answers aorta->renal artery->segmental artery->interlobar artery->arcuate artery-
>interlobular artery->afferent arteriole->glomerulus (glomerular capillaries)->efferent
arteriole->peritubular capillaries or vasa recta->interlobular vein->arcuate vein-
>interlobar vein->renal vein->inferior vena cava

Describe the location and function of the peritubular capillaries and the vasa recta
correct answers -peritubular capillaries - cling to outside of renal tubules and almost
always drain into interlobular veins; because they arise from the efferent arterioles
(which have high resistance), they only experience low pressure. As a result, these low
pressure, porous capillaries readily absorb solutes and water from the tubule cells as

,these substances are reclaimed from the filtrate. Renal tubules are closely packed
together, so the peritubular capillaries of each nephron absorb substances from several
adjacent nephrons
-they have large cross-sectional area so blood flows more slowly
-vasa recta("straight vessels"): a specialized type of peritubular capillary; surround loops
of Henle of juxtamedullary nephrons, in the medulla ; supplies oxygen and nutrients to
the renal medulla and plays an important roll in forming concentrated urine

Based on the location and structure, what are the two types of nephrons? correct
answers -cortical nephrons account for 85% of the nephrons in the kidneys. Except for
small parts of their nephron loops that dip into the outer medulla, they are located
entirely in the cortex (renal corpuscle in outer cortex and short LOH and almost no thin
ascending limb of LOH)
-juxtamedullary nephrons (15%) originate close to the cortex-medulla junction, and they
play an important role in the kidneys' ability to produce concentrated urine. They have
long nephron loops that deeply invade the medulla, and their ascending limbs have both
thin and thick segments.

Which type of nephron is most numerous? Which type plays the most important role in
regulating urine concentration? Which type performs most of the reabsorptive and
secretory functions of the kidney? correct answers most numerous - cortical 85%
-most of the reabsorptive and secretory: cortical
cortical nephrons--because they are closer in location to the fluid/blood of the cortex
regulating urine concentration: juxtamedullary nephrons

Describe the location and general function of the juxtaglomerular apparatus (JGA)
correct answers JGA is located at a point where DCT lies against the afferent arteriole
of its own nephron (the point where the DCT begins); the wall of the tubule and the
afferent arteriole are modified at the point of contact
-functions: 1. secrete renin (by JG cells) 2. maintain blood pressure 3. macula dense
enables feedback mechanism to influence the rate of glomerular filtration

Where are the macula densa cells located? What is their function? correct answers -the
macula densa is a group of tall, closely packed cells in the ascending limb of the
nephron loop that lies adjacent to the granular cells. The macula densa cells are
chemoreceptors that monitor the NaCl content of the filtrate entering the DCT - sense
change in solute concentration of filtrate

Where are the juxtaglomerular (JG) cells located? What is their function? correct
answers the wall of the afferent arteriole contains modified smooth muscle cells called
JG cells
-function as mechanoreceptors: monitor amount of stretch in afferent arteriole wall
(sense blood pressure in afferent arteriole) and vary their renin secretion accordingly;
the JG cells have large numbers of renin-containing granules in their cytoplasm

, Identify and define the three steps involved in urine formation correct answers 1.
glomerular filtration: ("dumping into the waste container") takes place in the renal
corpuscle and produces a cell- and protein-free filtrate
2. tubular reabsorption: ("reclaiming what the body needs to keep") is the process of
selectively moving substances from the filtrate back into the blood. It takes place in the
renal tubules and collecting ducts. Tubular reabsorption reclaims almost all everything
filtered--all of the glucose and amino acids, and some 99% of the water, salt, and other
components. Anything that is not reabsorbed becomes urine.
3. Tubular secretion: ("selectively adding to the waste container") is the process of
selectively moving substances from the blood into the filtrate. Like tubular reabsorption,
it occurs along the length of the tubule and collecting duct.

Describe the filtration membrane correct answers -it lies between the blood and the
capsular space (interior of the glomerular capsule) and it is a porous membrane that
allows free passage of water and solutes smaller than plasma proteins; consists of 3
layers:
1. glomerular capillary endothelium (fenestrated endothelium of the glomerular
capillaries)
-the fenestrations (capillary pores) allow all blood components except blood cells to
pass through
2. basement membrane
-lies between the other two layers and is composed of their fused basal laminae. it
forms a physical barrier that blocks all but the smallest proteins while still permitting
most other solutes to pass. the glycoproteins of the gel-like basement membrane give it
a negative charge. As a result, the basement membrane electrically repels many
negatively charged macromolecular anions such as plasma proteins, reinforcing the
blockade based on molecular size
3. visceral membrane of the the glomerular capsule
-made of podocytes that have filtration slits between their foot processes. if any
macromolecules manage to make it through the basement membrane, slit diaphragms--
thin membranes that extend across the filtration slits-prevent almost all of them from
traveling farther.

How does the structure of the filtration membrane contribute to the process of
glomerular filtration? correct answers -fenestrated endothelium of the glomerular
capillaries and these pores allow all blood components except blood cells to pass
through
-basement mebrane - lies between two other layers and is composed of their fused
basal laminae; it forms a physical barrier that blocks all but smallest of proteins but
permits other solutes to come through; the glycoprotein of the basement membrane
gives it a negative charge - electrical repels negatively charged macromolecular anions
(any large anion such as a plasma protein because they have negative charge and so
does the plasma protein); reinforces this blockade based on molecular size
-foot processes: if any macromolecules manage to make it through the basement
membrane, call them slit diaphragms which are thin membranes that extend across