Chapter 25 - urinary system

Question 1

3 supportive tissues that surround each kidney (superficial to deep )

Answer 1

1. renal fascia- dense fibrous connective tissue that anchors kidneys and adrenal gland to surrounding structures
2. Perineal fat capsule- fatty mass to provide cushion
3. fibrous capsule- transparent. prevents infections from invading

Question 2

superficial region of the kidney

Answer 2

renal cortex

Question 3

the renal medulla has a pointy side called pyramid - why do they look stripped?

Answer 3

pyramid is formed of parallel bundles of tubules and capilliaries

Question 4

the inward tissue extensions inside kidneys separates medullary lobes

Answer 4

renal columns

Question 5

this part of the kidney is continuous with the ureter

also, forms branching extensions called?

Answer 5

Renal pevlis which forms 2-3 major calyces which divides to form minor calyces - this cup shaped area encloses papillae

Question 6

when renal arteries approach kidneys what does it divide into?

Answer 6

5 segmental arteries

Question 7

Segmental arteries branch off to form what? and where in the kidneys do they branch

Answer 7

interlobar arteries

they branch at the renal pelvis

Question 8

interlobar arteries branch at the cortex-medulla junxtion , into?

Answer 8

arcurate arteries that arch over the base of medullary pyramids

Question 9

after interloblar what is the remaining path way of arteries?

Answer 9

coritcal radiate arteries –> afferent arterioles –> into glomerulus capillaries –> efferent.a

Question 10

which blood vessels are associated with nephrons?

Answer 10

affterent.a glomerulus capillaries, efferent.a and peritunular capillaries or vasa recta

Question 11

2 main parts of nephrons and their location

Answer 11

renal corpuscles- in cortex

renal tubule - start at cortex pass into medulla, and move back up to cortex

Question 12

the glomerulus in renal corpuscles is a yarn of capillaries- explain its properties

Answer 12

fenstrated, so very porous allowing solute rich/ protein free fluid to pass from blood into the capsule

Question 13

filtrate is made in which part?

Answer 13

renal corpuscles

Question 14

2 layers of the glomerular capsule are parietal, visceral and. explain parietal

Answer 14

1. external- parietal layer - simple squamous epithelium does not play any part in forming filtrate

Question 15

explain visceral layer of the glomerular capsule

Answer 15

2. visceral layer- clings to capillaries, had has modified epi called podocytes which have foot processes that cling to the basement membrane of the glomerulus. in between are the filtration slits where filtrate enters the capsule space

Question 16

name the 3 major parts of the renal tubule

Answer 16

proximal convoluted tubule, nephron loop, distal “ “

Question 17

explain the walls proximal convoluted (PCT)?

Answer 17

• cuboidal epithelial cells with lots of mitochondria
• apical surface has dense microvilli which increase surface area and capacity for reabsorbing water and solutes FROM the filtrate and secreting substances into it

Question 18

Explain the DCT properities

Answer 18

thinner cuboidal cells and confined to cortex, lack microvilli

Question 19

explain the 2 types of cells in the collecting ducts

Answer 19

principal cells- more. short microvilli, responsible for maintaining water and sodium balance.
intercalated cells- are cubiodal with lots of microvilli
2 types of these cells A/ B for acid base balance

Question 20

explain the 2 types of nephrons

Answer 20

cortical- majority
juxtramedullary nephrones- play an important role in the kidneys’ ability to make urine that is concentrated (conserves water)

Question 21

this type of capillary bed reclaims most of the filtrate

Answer 21

peritubular capillaries and vasa recta

Question 22

this type of capillary bed makes filtrate

Answer 22

glomerulus

Question 23

which part drains the glomerulus capillary?

Answer 23

efferent arterioles

Question 24

how is high pressure maintained in the glomerulus capilliaries?

Answer 24

from the affterent.a feeding blood and the efferent.a draining it

Question 25

where do the efferent. a feed into?

Answer 25

vasa recta or peritubular capillaries

Question 26

this part of the nephron has low pressure, come from a type of arteriole, empty contents into near by venules and they are porous therefore they easily absorb solutes and water

Answer 26

Peritubular capillaries

Question 27

bundles of long vessels in the juxtamedullary nephrons play a role in concentration of urine

Answer 27

vasa recta

Question 28

Where in the nephrons is the juxtamedullary complex?

Answer 28

most distal portion of ascending limb lies against afferent arteriole - here both these are modified

Question 29

what 3 cells are part of the juxtaglomerular complex?

Answer 29

macula densa, granular cells, extraglomerular mesangial cells

Question 30

tall cells in ascending limb - these are chemoreceptors that monitor NaCl content of filtrate that enters the distal convoluted tubules

Answer 30

macula densa

Question 31

in the arteriol walls, these cells are big smooth muscle cells with granules that have enzymes (which enzyme?) what cells are these and what is their function?

Answer 31

renin these are granular cells of the JGC and they act as mechanoreceptors that sense blood pressure in the afferent arterioles

Question 32

name the 3 processes that make urine, and adjust the composition of blood

Answer 32

1. glomerular filtration 2. tubular reabsorption 3. tubular secretion

Question 33

where does filtration take place?

Answer 33

glomerular filtration

Question 34

a passive process where hydrostatic pressures force fluids and solutes through a membrane

Answer 34

Glomerular filtration

Question 35

the filtration membrane of the glomerulus capillaries separates it from the filtrate in the capsule, it has a porous membrane to move in water, solutes and smaller proteins passively. Explain the 3 layers of this membrane

Answer 35

1. fenestrated endothelium of the G.capillaries - allowing components of blood EXCEPT for blood cells to pass 2. Basement membrane- is in the middle, and forms a physical barrier to block all BUT small proteins 3. foot processes of podocytes of the G.capsule

Question 36

how is colloid osmotic pressure maintained?

Answer 36

by the plasma proteins staying in the capillaries

Question 37

What type of pressure promotes formation of filtrate?

Answer 37

OUTWARD ! ( hydrostatic pressure IN glomerular capillaries )

Question 38

Explain Hydrostatic pressure in the glomerular capillaries

Answer 38

- this is the main force that pushes water and solutes from blood and across filtration memb. because the BP in glomerulus is high (55mmHg) because of the high resistance efferent.a having a small diameter than the afferent.a

Question 39

What type of pressure inhibits the formation of filtrate?

Answer 39

INWARDS - 2types : Hydrostatic pressure in the capsular space, and colloid osmotic pressure in glomerular capillaries

Question 40

What is hydrostatic pressure in the capsular space?

Answer 40

this is the pressure exterted BY filtrate IN the g.capsule. this pressure is generally higher compared to other capillaries because filitrate is confined in a small space with narrow outlet (15mmHg)

Question 41

What is Colloid osmotic pressure in the glomerular capillaries?

Answer 41

this is the pressure exerted BY the proteins in the blood that SUCK water into the capillary (30mmHg)

Question 42

What is the formula for NFP?

Answer 42

net filtration pressure = (HP gc) - (HPcs + OPgc)

Question 43

What is GFR?

Answer 43

Glomerular filtration rate- is the volume of filtrate formed every minute

Question 44

3 things GFR is DIRECTLY proportional to

Answer 44

- NFP - Total surface area available for filtration - Filtration membrane permeability

Question 45

If their is an increase in GFR what follows?

Answer 45

increased urine out put -> which reduces blood volume and pressure

Question 46

When do extrinsic controls take over intrinstic controls in the regulation of glomerular filtration?

Answer 46

When mean arterial pressure is less than 80 mmHg or greater than 180mmHg

Question 47

What happens if glomerular hydrostatic pressure rises?

Answer 47

NFP rises and so does GFR

Question 48

What are the 2 types of autoregulation mechanisms?

Answer 48

myogenic and tubuloglomerular feedback

Question 49

how to kidneys maintain a constant GFR despite changes in systemic arterials?

Answer 49

Intrisic controls

Question 50

Explain myogenic mechanism

Answer 50

intrinsic control that regulates glomerular filtration - vascular smooth muscle contracts when stretched and relaxes when not being stretched. increase in systemic BP -> causes afferent.a to constrict -> this then restrict blood flow into the glomerulus and keeps the GFR and keeps it at a functional level

Question 51

Explain tubuloglomerular feedback mechanism

Answer 51

dependent on flow and is directed by the macula densa cells in the JGC . When GFR increases there isn't enough time for reabsorption therefore the concentration of salts remains high in the filtrate - the macula respond to the high salt concentrations in the filtrate by releasing vasoconstrictor chemicals (atp) that cause constriction of afferent.a --> reduces BF into glomerulus which then decreases NFP and GFR- this slow down of filtrate allows more time for filtrate processing (reabsorption of salts)

Question 52

Extrinsic controls - maintain systemic BP | explain how the sympathetic nervous system comes into play

Answer 52

if BP falls =, norepinephrine released by sympatheric nerve fibers and epinephrine from adrenal medulla --> cause vasucular smooth muscles to constrict which increases perihpheral resistance and brings BP back up to normal so the afferent.a also constrict which then decreases GFR to help restore the Blood volume and pressure syetmically

Question 53

Renin-angiotensis-aldosterone is used to increase BP. Low BP causes which cells of the juxtagloerumarl complex to relase renin?

Answer 53

Granular cells

Question 54

Explain the 3 pathways of renin-angiotensin-aldostrone

Answer 54

1. SNS- barorecepto reflex, renal nerve fibers activate and cause release of granular cells which release renin 2. Activated macula densa cells- low BP or vasoconstriction of afferent.a by SNS reduce