5.3 Kidney Structure, Ultrafiltration & Reabsorbtion Flashcards

1
Q

The kidneys are supplied with blood from which arteries?

A

Renal arteries from abdominal aorta

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2
Q

Blood is removed from the kidneys by what?

A

The renal vein draining into the inferior vena cava

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3
Q

How much blood passes through the kidneys every minute?

A

90 - 120cm3

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4
Q

How much blood does the kidneys filter a day and how much urine is produced?

A

Blood - 180dm3

Urine - 1-2dm3

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5
Q

Urine leaves the kidneys via what?

A

The ureters it’s collected in the bladder when full the sphincter opens and urine passes through urethra

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6
Q

What is the cortex?

A

Dark outer layer
Where filtering of blood takes place
Sense capillary network

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7
Q

What is the medulla?

A

Lighter region

Contains tubules of nephrons forming pyramids and collecting ducts

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8
Q

What is the pelvis?

A

Central chamber where urine collects before passing down ureter

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9
Q

What do the nephrons do?

A

Filter blood
Remove urea
Balance mineral ions and water balance

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10
Q

What is the bowmans capsule and what does it contain?

A

Cup shaped structure

Contains glomerulus - tangle of capillaries

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11
Q

What is the proximal convoluted tubule?

A

1st coiled region in cortex where many substances needed are reabsorbed into blood

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12
Q

What is the loop of Henle?

A

Loop of tubule in the medulla creating a region of high solute conc in tissue fluid

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13
Q

What is the distal convoluted tubule?

A

2nd twisted tubule controlling water balance of the body, ph regulation and ion balance
ADH permeable walls

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14
Q

What is the collecting duct?

A

Where urine passes down from medulla to pelvis

Water balance takes place here walls are ADH sensitive

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15
Q

What is ultrafiltration?

A

Removal of nitrogenous waste and osmoregulation of blood resulting it tissue fluid formation in capillary beds

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16
Q

(Ultrafiltration) 1. The glomerulus is supplied with blood from where?

A

Arteriolar from Renal artery

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17
Q

(Ultrafiltration) 2. Blood leaves the glomerulus through where? What does this do?

A

Narrow efferent arteriole

Creates a lot of pressure in the capillaries of the glomerulus

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18
Q

(Ultrafiltration) 3. What does the high pressure do?

A

Forces blood through capillary wall (sieve)

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19
Q

(Ultrafiltration) 4. Blood then passes through where?

A

Basement membrane - made up of collagen fibres and proteins (2nd sieve)

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20
Q

(Ultrafiltration) 5. Most plasma contents pass though the basement membrane but what happens to blood cells and proteins?

A

Retained in capillaries due to their size

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21
Q

(Ultrafiltration) 6. What are the cells in the walls of the bowmans capsule called and what do they have?

A

Podocytes

Extensions called pedicels

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22
Q

(Ultrafiltration) 7. What do pedicels do?

A

Wrap around capillaries forming suits ensuring any proteins or blood cells that have managed to get through don’t go into the tubule

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23
Q

(Ultrafiltration) 8. The filtrate entering the capsule contains what?

A

Glucose, salt, urea and other substances

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24
Q

(Ultrafiltration) 9. What is the vol of blood filtered through known as?

A

The glomerular filtration rate

25
Q

(Reabsorption) as well as removing urea what does ultrafiltration remove from blood?

A

Glucose salt water

Necessary substances

26
Q

(Reabsorption) what is the main function of the nephron?

A

To return filtered substances to the blood

27
Q

In the proximal convoluted tubule what are moved back to the blood by active transport?

A

Amino acids
Glucose
Vitamins
Hormones

28
Q

In the proximal convoluted tubule how much sodium chloride and water is reabsorbed?

A

85%

29
Q

In the proximal convoluted tubule Na moves out by which process?

A

Active transport

30
Q

In the proximal convoluted tubule what do Cl and water do?

A

Follow Na passively down concentration gradients

31
Q

The cells lining the proximal convoluted tubule are lined with what? What does this do?

A

Microvilli

Increases surface area over which substances can be reabsorbed

32
Q

The cells lining the proximal convoluted tubule have many what and why?

A

Mitochondria

To provide ATP for active transport

33
Q

substances removed from nephron diffuse into capillaries down steep conc. gradients maintained by what?

A

constant flow of blood through the capillaries

34
Q

filtrate reaching the loop of henle is isotonic to tissue fluid and blood, what does this mean?

A

same concentration

35
Q

the loop of henle is the section of the kidney tubule which allows mammals to do what?

A

produce urine more concentrated than their blood

36
Q

what is one feature of the loop of henle that is central to its function?

A

different areas of the loop having different permeabilities to water

37
Q

the loop acts as a countercurrent multiplier what does this mean?

A

using energy to create concentration gradients resulting in the movement of substances e.g water

38
Q

the descending limb is the region where water moves where?

A

out of the filtrate down a concentration gradient

39
Q

is the descending limb permeable to water?

A

upper area is impermeable

lower are is permeable

40
Q

as filtrate travels down the descending limb what happens to the water?

A

diffuses into surrounding tissue fluid by osmosis, then diffuses into the blood of surrounding capillaries

41
Q

what is the descending limb not permeable to and what does this mean?

A

Na- and Cl- ions so no active transport takes place here

42
Q

filtrate reaching the bend of the loop of henle is very concentrated, and is what in comparison to blood in capillaries?

A

hypertonic

43
Q

is the first section of the ascending limb permeable or impermeable to Na- and Cl- ions?

A

permeable - they move out the concentrated solution by diffusion down a concentration gradient

44
Q

in the second section of the ascending limb what happens to Na- & Cl- ions?

A

they are actively pumped into the medulla tissue, increasing ion concentrations in the medulla tissue

45
Q

what is the ascending limb impermeable to?

A

water so H20 cant follow Na and Cl down a concentration gradient

46
Q

what happens to the fluid left in the ascending limb and the tissue fluid of the medulla?

A

filtrate left in the ascending limb becomes more dilute

tissue fluid of medulla develops high conc of ions

47
Q

what is the high conc of ions in the medulla essential for?

A

the kidney to produce urine more concentrated than the blood

48
Q

fluid reaching the top of the ascending limb is hypotonic to the blood -what does this mean?

A

lower osmotic pressure

49
Q

what happens in the distal convoluted tubule?

A

balancing of H20 needs of the body

50
Q

the permeability of the walls of the distal convoluted tubule and collecting duct varies with what?

A

ADH levels

51
Q

how is the distal convoluted tubule adapted for active transport?

A

many mitochondria

52
Q

if the body lacks salt what can the distal convoluted tubule do?

A

actively pump Na ions out with CL following passively down a conc gradient

53
Q

what happens at the collecting duct?

A

concentration and volume of urine is determined

54
Q

what does water do as it passes through the collecting duct?

A

diffuses out down a concentration gradient as it passes through medulla resulting in it becoming more concentrated

55
Q

why can water be removed from the collecting duct along its length?

A

because the level of Na ions in the surrounding fluid increases through the medulla

56
Q

what is one factor the ability to produce concentrated urine depends on?

A

length of loop of Henle

57
Q

which mammals tend to have long loops of henle?

A

desert animals to conserve more water

58
Q

fish have no loop of henle so they cant do what?

A

produce urine more concentrated than their blood