Urinary System Anatomy

Question 1

Describe the general locations of the kidneys within the body.

Answer 1

R kidney lower (liver)
retroperitoneal
superior lumbar region between T12 and L5

Question 2

3 layers supportive tissue of kidneys

Answer 2

superficial to deep - renal fascia, perirenal fat capsule, fibrous capsule

Question 3

Describe the anatomy of a nephron

Answer 3

renal corpuscle = Bowman’s capsule + glomerulus, proximal convoluted tubule, nephron loop, distal convoluted tubule, collecting duct

Question 4

Trace the blood supply through the kidney, beginning with the ab aorta and ending with the IVC

Answer 4

ab aorta, renal a, segmental a, interlobar a, arcuate a, cortical radiate a, afferent arteriole, glomerulus, efferent arteriole, peritubular capillary/vasa recta, cortical radiate v, arcuate v, interlobar v, renal v, IVC

Question 5

List the three cell populations found in the juxtaglomerular apparatus.

Answer 5

macula densa of ascending nephron loop, granular cells in afferent arteriole, extraglomerular mesangial cells

Question 6

Describe the structure of the filtration membrane as it relates to its function in the kidney.

Answer 6

between blood and interior of glomerular capsule. Porous to allow water and solutes < plasma proteins, disallows larger than 5nm to maintain colloid osmotic pressure of blood to prevent loss of all water, 3 layers: fenestrated endothelium of glomerular capillaries, basement membrane, foot processes of podocytes of glomerular capsule

Question 7

Describe the general location, structure, and function of the ureters

Answer 7

bring urine from kidneys to bladder, begin at L2 as continuation of renal pelvis, goes down behind peritoneum and runs obliquely through posterior bladder wall to prevent backflow, mucosa + muscularis (inner longitudinal and outer circular) + adventitia, actively propels urine, peristalsis adjusted to rate of urine formation, smooth muscle responds to stretch

Question 8

Define urinary tract infection

Answer 8

bacteria enters through external urethral orifice and travel length of urethra

Question 9

Describe the histological structure of the nephron as it relates to its function.

Answer 9

proximal convoluted tubule cells are cuboidal with brush border for reabsorption and secretion, have lots of mitochondria for ATP for active transport, thin descending limb of nephron loop has simple squamous ep with aquaporins for water permeability, thick limb lets salts through but not water, distal convoluted tubule cells are cuboidal with sparse microvilli because more secretion and less absorption, collecting duct cells are either principal for salt-water balance or intercalated for acid-base balance

Question 10

explain why urinary tract infections are more common in females than males.

Answer 10

3-4 cm urethra in women, 19-20 cm in men, so bacteria has to travel much further to take up residence and ejaculate washes bacteria out after intercourse, whereas women have to urinate to get that benefit

Question 11

Describe the general location, structure, and function of the urinary bladder

Answer 11

retroperitoneal on pelvic floor posterior to pubic symphysis, trigone is area formed by the 3 interior openings, mucosa with transitional ep for distention + muscular layer with inner and outer longitudinal and middle circular + fibrous adventitia, superior surface covered by peritoneum

Question 12

Describe the general location, structure, and function of the urethra.

Answer 12

thin-walled muscular tube that drains urine to convey it out of body, mostly pseudostratified columnar ep, some transitional ep near bladder, 3-4 cm long in women, 19-20 in men, prostatic urethra, membranous, spongy

Question 13

internal gross anatomy of kidneys

Answer 13

superficial grainy light renal cortex, dark renal medulla with renal pyramids with base and papilla, one minor calyx for each pyramid, major calyx when minors converge, renal pelvis in middle

Question 14

lobe of kidney

Answer 14

one pyramid and half renal column on either side

Question 15

trace filtrate/urine path

Answer 15

renal pyramids > minor calyx > major calyx > renal pelvis > ureter > urinary bladder > urethra > out

Question 16

tissue type of parietal layer of Bowman’s capsule

Answer 16

simple sqamous ep

Question 17

filtration membrane components

Answer 17

glomerular endothelium and podocyte foot processes with basement membrane in between (aka visceral layer of Bowman’s capsule)

Question 18

cortical nephrons

Answer 18

85% of nephrons in kidneys, shorter nephron loop, closer to fibrous capsule, more superficial and almost all in cortex

Question 19

juxtamedullary nephron

Answer 19

closer to renal pyramids, longer nephron loop,

Question 20

medullary gradient

Answer 20

nephron loops + vasa recta, essential for making concentrated urine to avoid losing too much water

Question 21

granular cells physiology

Answer 21

in juxtaglomerular complex, wall of afferent arterioles, act as mechanoreceptors that sense stretch, have secretory granules packed with renin which is released in response to increased stretch

Question 22

macula densa cells

?

Answer 22

ascending limb of nephron loop facing afferent and efferent arterioles, have chemoreceptors to sense salt concentration, monitor [NaCl], effectively measuring blood pressure, what does it do with that information?

Question 23

extraglomerular mesangial cells

Answer 23

interconnected with gap junctions, thought to be communicating across other two cell types (granular and macula densa)

Question 24

glomerular mesangial cells

Answer 24

contractile to control some of the function of glomerulus

Question 25

If you see renal corpuscles on a kidney histology slide, is it the cortex or medulla?

Answer 25

renal cortex, because never find corpuscles in medulla

Question 26

histology of ureter

Answer 26

transitional ep with umbrella cells that allow for distention, round when ureter collapsed and no fluid, cells transition to squamous when ureter filled with fluid

muscularis has two layers of smooth muscle - outer circular & inner longitudinal for peristaltic waves to propel urine

adventitia dense CT because retroperitoneal

Question 27

In which of the following renal areas would you find the majority of nephron loops (loops of Henle)?

Answer 27

renal pyramid (medulla)

Question 28

indicate the correct flow of filtrate through the nephron.

Answer 28

Fluid is Pulled from the Blood

Bowman’s space

proximal convoluted tubule

loop of Henle (descending limb)

loop of Henle (ascending limb)

distal convoluted tubule

collecting duct

Urine Drains from Renal Papillae

Question 29

indicate the flow of urine through the kidney.

Answer 29

Urine Drains from Renal Papillae

minor calyx

major calyx

renal pelvis

ureter

urinary bladder

urethra

Urine Exits the Body

Question 30

which has a larger diameter, the afferent arteriole or the efferent arteriole?

Answer 30

An afferent arteriole supplies blood to a glomerulus and has a larger diameter than the efferent arteriole which drains blood from the glomerulus

Question 31

Compare cortical nephrons to juxtamedullary nephrons

Answer 31

Compared to cortical nephrons, juxtamedullary nephrons have long nephron loops that deeply invade the medulla, the ascending limb has both thick and thin segments, and the glomerulus is closer to the cortex-medulla junction.

Question 32

granular cells

Answer 32

Granular cells are specialized mechanoreceptors.

Granular cells [also called juxtaglomerular (JG) cells] are in the arteriolar walls. They are enlarged smooth muscle cells with prominent secretory granules containing the enzyme renin. Granular cells act as mechanoreceptors that sense the blood pressure in the afferent arteriole.