Loop of HENLE

Question 1

What is the loop of henle

Answer 1

a hair pin like structure that is responsible for water being reabsorbed from the collecting duct

Question 2

what does it do to the urine

Answer 2

it concentrates it so it has a lower water potential compared to the blood

Question 3

where is it found

Answer 3

cortex extending into the medula of the kidney

Question 4

describe the descending limb

Answer 4

thin narrow long and very permeable to water

Question 5

describe the ascending limb,

Answer 5

thick and impermeable to water

Question 6

what happens first to the sodium ion

Answer 6

they are actively transported using atp in the walls of the ascending limb, from the acending limb into the interistial space between the asc/desc

Question 7

what does this do

Answer 7

create a lower water potential in the interestrial space increase the water potential in the distant convulated tubulr

Question 8

what happnes in the descending limb

Answer 8

as a result of the low water potential water moves out of the descending limb via ososmosis decreasing water potential in the filtrate

Question 9

what happens to the water

Answer 9

it enter the space and then enters the blood capillaires which take water away

Question 10

how does filtrate travel down the descending tube

Answer 10

as it goes down progressively loses water potential becoming more negative and reaches most negative at the tip

Question 11

what happens at the base of the ascending limb

Answer 11

sodium ion start to diffuse out of the filtrate into the interistrial space

Question 12

what happens as we go up the ascending limb

Answer 12

the sodium ions start getting actively transported out using active transport

Question 13

what does it do the space

Answer 13

the interestrial space between the collecting duct and the ascending limb decreases in water potential

Question 14

what exist in the interestrial space

Answer 14

there is a water potential gradient high water potential in the cortex and then water potential decreases further into the medulla as the ion concentration increases

Question 15

what is the collecting duct

Answer 15

permeable to water so water moves out via ososmosis into the blood vessels in the space and carried away

Question 16

how is flow of water maintained

Answer 16

although filtrate loses water as it moves down the collecting duct it always meet the interestrial space fluid with a lower water potential so water continues to move out throughout the whole length

Question 17

what does the counter current multiplier ensure

Answer 17

water is always being removed out of the tubule

Question 18

how does the water pass out

Answer 18

out of the collecting duct through aquapourins , which is controlled by adh

Question 19

how is urine compared to the blood

Answer 19

the urine has a lower water potential compared to the blood

Question 20

what is the role of the distal convulated tube

Answer 20

make final adjustment to the water level and salt levels, and reabsorption of any ions to maintain the ph

Question 21

how are the walls of the convulated tube adapted

Answer 21

contain many mitochomdria and microvilli to allow blood to reabsorb any material from the blood rapidly

Question 22

how does homeostatic control exist

Answer 22

achieved by hormones that act on the distal convulated tubule and the collecting duct

Question 23

what is the water potential of the blood dependent on

Answer 23

the concentration of the glucose, ions, protiencs

Question 24

why is the water potential lowered 3 reasons

Answer 24

an increase in sweating, increase in salt consumption, little water drinking

Question 25

what is the first step of osmoregulation

Answer 25

the osmorecptors in the hypothalumus detect a fall in the water potential cause these cells to shrink as a result of loss of water via ososmosis

Question 26

what does this shrinkage do

Answer 26

it leads to the production of the hormone adh which travels to the posterior pituitry gland

Question 27

what happens here

Answer 27

the adh is released into capillaries where it travels in the blood to the collecting duct

Question 28

what does it do in general to the distal convulated tube and collecting duct

Answer 28

increaes permeability to water so more water is reabsorbed into the blood

Question 29

how does this occur

Answer 29

specific proteins in the cell surface membrane bind adh which activates the enzyme phosphorylase

Question 30

what does phosphorylase do

Answer 30

causes the vesicle to bind to the cell membrane surface

Question 31

what does the vescicle contain

Answer 31

pieces of plasma membrane that have aquapourins

Question 32

what happens when they fuse

Answer 32

lead to the increase of aquarpourins on the cell surface membrane making the cell surface membrane much permeable to water

Question 33

what does this do to water

Answer 33

more water leaves the collecting duct by osomosis down a concentration gradient , and reneter the blood making urine more concentrated

Question 34

what also happens in the osmorecptors

Answer 34

sen nerve impulse to the thirst centre to encourage person to drink water

Question 35

what happens when water levels increase

Answer 35

the osmorecepttors detect an increase in water and cause less nerve impulse to the pitutity and less adh released and less permeability to water

Question 36

when does water level become too high

Answer 36

when large volumes of water is consumed | salts used in metabolism is not replaced in the diet

Question 37

what does the osmorecptors do when water is too high

Answer 37

increase the impulses sent to the pitutitry gland to decrease the secretion of adh

Question 38

what happens when there is less adh

Answer 38

less via the blood, leads to a decrease in the permeability of water in the collecting duct , less water reabsorbed and more diluted urine

Question 39

what happens to the water potential

Answer 39

the water potential in the blood falls and returns to normal and adh release is increases