Urinary system part 1

Question 1

what is the urinary system responsible for

Answer 1

water and electrolyte homeostasis, osmoregulation, and acid-based balance

Question 2

what is the primary secretory function of the urinary system

Answer 2

excretion of toxic and metabolic waste products, especially urea and creatinine

Question 3

what is creatinine

Answer 3

nitrogen containing compounds from metabolism of proteins

Question 4

what is urea

Answer 4

primary nitrogenous waste products in mammals, SOLUBLE

Question 5

which is soluble: urea or uric acid

Answer 5

urea

Question 6

what does BUN stand for and what does it include

Answer 6

blood urea nitrogen- includes urea, creatinine, uric acid, ammonia

Question 7

what is the kidney responsible for

Answer 7

metabolism and excretion of various drugs

Question 8

what do kidneys synthesize and how does it contribute to their function

Answer 8

renin and maintain a normal BP via renin- angiotensin- aldosterone system

Question 9

what produces erythropoietin and what does it do

Answer 9

produced by kidney, stimulates RBC production

Question 10

what converts vitamin D from its inactive to active form

Answer 10

liver and kidney

Question 11

describe the kidney

Answer 11

retroperitoneal organs with fibrous connective tissue capsule

Question 12

where do blood vessels and ureters enter/exit the kidney

Answer 12

at the hilus

Question 13

what is each kidney supplied by and what does it branch into

Answer 13

renal artery which branches to form interlobar arteries -> arcuate arteries -> interlobular arteries -> afferent arterioles to glomeruli

Question 14

what does the cortex contain

Answer 14

mostly renal corpuscles and convoluted tubules

Question 15

what does the medulla contain

Answer 15

mostly loops of henle, collecting tubules, collecting ducts

Question 16

describe the transitional epithelium unique to urinary tract

Answer 16

varying number of layers- stratified, cuboidal to polygonal with scalloped outline “umbrella cells”

Question 17

what does the highly distensible nature of the transitional epithelium allow for

Answer 17

changing urine volumes

Question 18

what is the functional unit of the kidney

Answer 18

the nephron

Question 19

what is the nephron embryologically derived from

Answer 19

nephrogenic blastema- part of the developing urogenital ridge

Question 20

what are the 3 major types of nephrons

Answer 20

-cortical or subcapsular
- juxtamedullary
-intermediate

Question 21

where are cortical nephrons located and describe their loops of henle

Answer 21

located in outer rim of cortex and have short loops of henle

Question 22

where are juxtamedullary neprhons located and describe their loops of henle

Answer 22

located adjacent to medulla, have long loops of henle

Question 23

where are intermediate nephrons located and describe their loops of henle

Answer 23

in middle of cortex, have intermediate length loops of henle

Question 24

what are the two major components to a nephron

Answer 24

renal corpuscle and renal tubule

Question 25

what does the renal corpuscle do

Answer 25

filter blood plasma

Question 26

what does the renal tubule do

Answer 26

collects filtrate

Question 27

what are the 2 components of the renal corpuscle

Answer 27

bowman's capsule and glomerulus

Question 28

describe the capsule epithelium

Answer 28

single layer of squamous epithelial cells resting on basement membrane

Question 29

what is another term for the capsule epithelium

Answer 29

parietal layer

Question 30

what does the parietal layer form

Answer 30

hollow, dilated end of proximal convoluted tubule, surrounding glomerulus

Question 31

what does the parietal layer continue onto glomerulus as

Answer 31

visceral layer

Question 32

what are podocytes

Answer 32

highly modified cells of visceral layer

Question 33

where is Bowman's space

Answer 33

between visceral and parietal layer

Question 34

what does Bowman's space do

Answer 34

collects glomerular filtrate and empties into renal tubule

Question 35

what is the glomerulus

Answer 35

network of densely packed, anastomosing, fenestrated capillaries

Question 36

what is the glomerulus supplied by

Answer 36

afferent and efferent arterioles

Question 37

what does blood plasma become after it passes through several cell layers

Answer 37

filtrate

Question 38

what is filtrate

Answer 38

water and small molecular weight molecules filtered from blood into Bowman's space

Question 39

what does the first layer of the glomerulus consist of

Answer 39

capillary endothelial cells of glomerulus and glomerular basement membrane

Question 40

why is the luminal surface of capillary endothelium negatively charged

Answer 40

due to surface layer of glycoprotein podocalyxin

Question 41

what does podocalyxin do

Answer 41

sets up negatively charged barrier, prevents loss of anions, large protein molecules

Question 42

what does the glomerular basement membrane act as

Answer 42

physical barrier and ion selective filter

Question 43

what is the subpodocyte space

Answer 43

space between capillary basement membrane and second layer of cells

Question 44

what do podocytes surround

Answer 44

glomerular capillaries that possess cytoplasmic extensions known as foot processes

Question 45

what do long primary foot processes give off

Answer 45

secondary foot processes called pedicels

Question 46

what are the spaces between processes called

Answer 46

filtration slits

Question 47

what do filtration slits contain

Answer 47

slit diaphragms made of nephrin

Question 48

what do slit diaphragms do

Answer 48

act as additional barrier and restrict passage of large macromolecules, proteins, negatively charged molecules and blood cells

Question 49

what is the function of podocytes

Answer 49

phagocytic and can remove trapped macromolecules

Question 50

what is resultant glomerular ultrafiltrate passed to

Answer 50

renal tubule

Question 51

what are the 4 distinct zones of the renal tubule

Answer 51

-PCT -loop of henle - DCT - collecting tubule/duct

Question 52

what is the renal tubule lined by

Answer 52

simple, cuboidal epithelium

Question 53

what is the primary function of renal tubule

Answer 53

selective resorption of water, inorganic ions, and large molecules from glomerular filtrate and concentration of waste products

Question 54

where is the PCT located

Answer 54

in the cortex only

Question 55

what happens in the PCT

Answer 55

primary site of water resorption (also Na and Cl, and proteins, AAs, and sugars)

Question 56

what is the water resorption in the PCT facilitated by

Answer 56

aquaporins

Question 57

what are aquaporins

Answer 57

integral proteins forming specialzied pores or channels for transport of H2O in brush border of epithelial cells

Question 58

describe the epithelium in the PCT

Answer 58

simple cuboidal epithelium with apical microvilli

Question 59

what are the 4 parts of the loop of henle

Answer 59

-pars recta (thick descending limb) - thin descending limb - thin ascending limb - thick ascending limb

Question 60

where is the loop of henle located

Answer 60

bulk of loop extends into medulla

Question 61

describe the length of thin limbs in juxtamedullary nephrons and cortical nephrons

Answer 61

long in juxtamedullary nephrons and short in cortical nephrons

Question 62

describe the epithelium of the thin limb and thick limb

Answer 62

thin limb has simple squamous epithelium and thick limb has simple cuboidal epithelium

Question 63

describe the epithelium of the pars recta

Answer 63

brush border of apical microvilli

Question 64

what is the loop of henle surrounded by

Answer 64

vasa recta

Question 65

what is the function of the countercurrent multiplier

Answer 65

functions to genreate high osmotic pressure in ECF of renal medulla via Na-K pumps in thick ascending limb of loop of Henle

Question 66

how is the cortico-medullary interstitial gradient formed

Answer 66

higher extracellular Na in medulla combined with water resorption by PCT in cortex

Question 67

what does the cortico-medullary interstitial gradient produce

Answer 67

counter current multiplier system of urine concentration

Question 68

what does the counter current multiplier system of urine concentration result in

Answer 68

production of hypertonic urine

Question 69

what is the DCT

Answer 69

a continuation of thick ascending limb of loop of henle

Question 70

where is the DCT located

Answer 70

in the cortex

Question 71

describe the epithelium of the DCT

Answer 71

simple cuboidal epithelium with short apical microvilli but lacks distinct brush border

Question 72

what is the function of the DCT

Answer 72

responsible for active resorption of Na and Ca coupled with secretion of H and K ions

Question 73

what 2 cell types is the DCT controlled by

Answer 73

principal cells and intercalated cells

Question 74

what do principal cells do

Answer 74

resorb Na and water, secrete K

Question 75

what do intercalated cells do

Answer 75

resorb K and secrete H

Question 76

what hormone controls the DCT

Answer 76

aldosterone

Question 77

what is the collecting tubule

Answer 77

terminal portion of the nephron

Question 78

what do several collecting tubules converge to form

Answer 78

collecting duct

Question 79

what are collecting tubules visible as

Answer 79

medullary rays

Question 80

what epithelium lines collecting tubules

Answer 80

thick, simple cuboidal to columbar epithelium

Question 81

where do the collecting tubules converge

Answer 81

at renal papilla

Question 82

what is the function of collecting tubules

Answer 82

Na resorption, maintenance of acid-base balance, K secretion and resorption

Question 83

what cells do collecting tubules contain

Answer 83

principal and intercalated cells

Question 84

are the epithelial cells of the collecting duct permeable to water

Answer 84

no, however in presence of ADH collecting tubules become permeable and will resorb water

Question 85

what secretes ADH

Answer 85

posterior pituitary

Question 86

what 3 things work together to form counter current exchange mechanism to concentrate urine

Answer 86

loop of henle, collecting tubule, and vasa recta

Question 87

what is the difference between PCT and DCT

Answer 87

PCT are twice as long and much more convoluted

Question 88

what are most tubules in cortex

Answer 88

PCT

Question 89

describe the appearance of PCT and DCT in cross section

Answer 89

round with cuboidal epithelium with or without brush border

Question 90

describe the difference in appearance of DCT and PCT

Answer 90

- DCT are more oval to elongate with thinner, flatter but still cuboidal epithlium - DCT lighter staining cytoplasm, nuclei are more prominent

Question 91

what is mostly seen in the medulla

Answer 91

mostly loop of henle, fewer collecting tubules, and occasional collecting ducts and surrounding blood vessels

Question 92

how do you identify loop of henle in cross section

Answer 92

smallest tubules with squamous to cuboidal epithelium

Question 93

how do you identify collecting tubules in cross section

Answer 93

medium sized

Question 94

how do you identify collecting ducts in cross section

Answer 94

largest, with simple cuboidal epithelium