Urinary Tract

Question 1

what are the layers of the kidneys?

Answer 1

• cortex
• medulla
• pelvis

Question 2

what does the renal cortex contain?

Answer 2

• glomeruli
• proximal convoluted tubules
• distal convoluted tubules
• medullary rays

Question 3

what are medullary rays?

Answer 3

collection of loops of Henle and collecting ducts that originate from the nephrons that have their renal corpuscles in the outer part of the cortex

Question 4

what does the renal medulla contain?

Answer 4

• loops of Henle

- collecting ducts

Question 5

what is the glomerulus?

Answer 5

tuft of convoluted fenestrated capillaries

Question 6

what is the glomerulus lined by?

Answer 6

podocytes

Question 7

what are the 3 layers of the glomerular basement membrane?

Answer 7

• fenestrated capillary endothelial cells
• basement membrane
• foot processes of podocytes

Question 8

what are podocytes made of and what do they do?

Answer 8

• made of several proteins

- project onto basement membrane, creating a gap where filtrates can pass through

Question 9

what are the components of the JGA?

Answer 9

• granular cells
• macula densa
• lacis cells

Question 10

what is the function of the granular cells in the JGA?

Answer 10

• sense blood pressure
• secrete renin in response to low blood pressure
• interact with cells of macula densa

Question 11

what is the function of the macula densa cells in the JGA?

Answer 11

• regulates tubuloglomerular feedback
  
  • senses NaCl concentration
  • if filtration is slow, more sodium is absorbed
  • sends signal to reduce afferent arteriole resistance & increase glomerular filtration
• interact with granular cells to cause renin secretion

Question 12

what does the PCT reabsorb?

Answer 12

• NaCl
• proteins, polypeptides, AAs
• glucose

Question 13

what is the epithelial lining of the PCT?

Answer 13

simple cuboidal

Question 14

describe the structure of the PCT

Answer 14

• round central/basal nuclei
• brush border of microvilli at apical end on luminal surface
• lots of mitochondria

Question 15

what is the epithelial lining of the loops of Henle?

Answer 15

thin segments: simple squamous

thick segments: low cuboidal

Question 16

what is the function of the DCT?

Answer 16

• regulates acid-base

- regulates sodium levels

Question 17

how does the DCT regulate acid-base?

Answer 17

• secretes H+
• absorbs HCO3-
  via cellular carbonic anhydrase

Question 18

how does the DCT regulate sodium levels?

Answer 18

exchanges Na+ for K+

mediated by aldosterone

Question 19

what is the epithelial lining of the DCT?

Answer 19

low cuboidal

Question 20

what are the similarities between the PCT and DCT?

Answer 20

• cuboidal epithelium

- lots of mitochondria

Question 21

what are the differences between the PCT and DCT?

Answer 21

• DCT has very few microvilli (=> no prominent brush border)

- DCT is much shorter

Question 22

what are the functions of the collecting duct and which cell performs each function?

Answer 22

• water reabsorption (principal)
• sodium balance (principal)
• acid-base balance (intercalated)

Question 23

what are the shape of nuclei in collecting ducts?

Answer 23

round central

Question 24

what is the epithelial lining of the collecting ducts?

Answer 24

cuboidal

Question 25

what cells are found in the epithelia of collecting ducts?

Answer 25

- principal cells | - intercalated cells

Question 26

what are the functions of the principal cells in the collecting ducts?

Answer 26

- respond to aldosterone by exchanging Na+ for K+ | - respond to ADH by increasing insertion of aquaporins into apical membrane

Question 27

what are the functions of the intercalated cells in the collecting ducts?

Answer 27

alpha cells: secrete acid | beta cells: secrete bicarbonate

Question 28

what is the function of the renal pelvis?

Answer 28

transmits filtrate from nephron to ureter

Question 29

what type of epithelia lines the renal pelvis?

Answer 29

urothelium

Question 30

where is urothelium found?

Answer 30

collection and drainage parts of urinary tract

Question 31

what is urothelium?

Answer 31

multi-layered stratified epithelium - umbrella cells on surface - overlies pseudostratified layer of polygonal cells

Question 32

what are the functions of urothelium?

Answer 32

- tight intracellular junctions prevent passage of urine | - can stretch in 3 dimensions

Question 33

what is the function of the ureter/

Answer 33

convey urine via peristalsis from kidney to bladder

Question 34

what is the ureter lined by?

Answer 34

urothelium

Question 35

describe the structure of ureters

Answer 35

- spiral muscular tube | - loose fibrocollagenous adventitia

Question 36

what are the layers of the spiral muscular tube in the ureter?

Answer 36

- smooth muscular coat - inner - longitudinal - outer - circular

Question 37

what is the bladder lined by?

Answer 37

urothelium

Question 38

what are the layers of the bladder?

Answer 38

- lamina propria - muscularis mucosa - submucosa - muscularis propria - subserosa - serosa

Question 39

where is the muscularis propria most easily discerned in the bladder?

Answer 39

bladder neck

Question 40

what creates the valve in the bladder?

Answer 40

passage through muscularis propria

Question 41

how long is the urethra in females?

Answer 41

4-5cm

Question 42

what is the female urethra lined by?

Answer 42

proximally - urothelium | distally - non-keratinising stratified squamous epithelium

Question 43

what glands open into the female urethra?

Answer 43

paraurethral and periurethral glands

Question 44

how long is the male urethra?

Answer 44

20cm

Question 45

what are the divisions of the male urethra and what are they lined by?

Answer 45

prostatic: urothelium membranous: urothelium penile: - proximally: pseudostratified - distally: stratified squamous

Question 46

describe the blood supply to the kidney

Answer 46

1. abdominal aorta 2. renal (L1) 3. anterior & posterior segmental 4. interlobar 5. arcuate 6. interlobular 7. afferent arterioles (feed into glomerulus)

Question 47

describe the passage of blood leaving the glomerulus

Answer 47

1. efferent arteriole 2. peritubular capillaries 3. vasa recta 4. renal veins 5. inferior vena cava