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Biology A2 > Organisms Response to Change - Kidneys > Flashcards

Organisms Response to Change - Kidneys Flashcards

1
Q

what are the roles of the kidneys?

A

osmoregulation

excretion

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2
Q

how do the kidneys carry out osmoregulation?

A

by controlling the volume and concentration of urine produced

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3
Q

how do the kidneys carry out excretion?

A

by removing waste products from the metabolism

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4
Q

what is a nephron?

A

the functional unit of a kidney

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5
Q

what is the fibrous capsule?

A

the outer membrane that protects the kidney

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6
Q

what is the cortex?

A

the lighter coloured outer region consisting of renal capsules, convulated tubules and blood vessels

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7
Q

what is the medulla?

A

darker coloured inner region of the kidney consisting of the loops of henle, collecting ducts and blood vessels

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8
Q

what is the renal pelvis?

A

a funnel-shaped cavity that collects urine into the ureter

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9
Q

what is the ureter?

A

a tube that carries urine to the bladder

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10
Q

what is the renal artery?

A

the artery that supplies the kidney with blood

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11
Q

what is the renal vein?

A

the vein that returns blood to the heart from the kidney

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12
Q

what are the main components of a nephron?

A

renal capsule

proximal convulated tubule

loop of henle

distal convulated tubule

collecting duct

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13
Q

what is the renal capsule?

A

closed end at the start of the nephron

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14
Q

what is the structure of the renal capsule?

A

cup-shaped and surrounds the glomerulus

inner layer consists of podocytes - specialised cells

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15
Q

what is the proximal convulated tubule?

A

series of loops surrounded by blood capillaries

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16
Q

what is the structure of proximal convulated tubule?

A

walls consist of epithelial cells containing microvilli

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17
Q

what is the loop of henle?

A

long, hairpin loop extending from the cortex into the medulla and back again

surrounded by blood capillaries

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18
Q

what is the distal convulated tubule?

A

series of loops surrounded by blood capillaries, but less than proximal convulated tubule

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19
Q

what is the collecting duct?

A

tube that distal convulated tubules empty into

becomes increasingly wide as it empties into pelvis of kidney

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20
Q

what is the structure of the collecting duct?

A

lined with epithelial cells

becomes wider as it empties into pelvis of the kidney

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21
Q

what are the different blood vessels present in a nephron?

A

afferent and efferent arterioles

glomerulus

blood capillaries

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22
Q

what is the afferent arteriole?

A

vessel from the renal artery that supplies the nephron and glomerulus with blood

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23
Q

what is the glomerulus?

A

branched knot of capillaries between the afferent and efferent arterioles

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24
Q

what is the efferent arteriole?

A

blood vessel attached to the glomerulus, carrying blood away from the renal capsule

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25
describe the blood capillaries present in a nephron
concentrated network surrounding: distal/proximated convulated tubules loop of henle they merge to form the renal vein
26
what are the 2 processes involved in the production of urine?
ultrafiltration selective readsorption
27
label this diagram of a nephron
A - afferent arteriole B - glomerulus C - efferent arteriole D - distal convulated tubule E - renal capsule F - proximal convulated tubule G - ascending loop of henle H - descending loop of henle I - collecting duct
28
describe the process of ultrafiltration
high pressure created in glomerulus water and small molecules are forced out of the blood and into renal capsule
29
how is a high pressure created in the glomerulus?
efferent arteriole has a narrower diameter than the afferent arteriole coiling of capillaries in the glomerulus restricts blood flow
30
what is the pathway for filtration in the renal capsule?
glomerular capillary endothelium basement membrane renal capsule epithelium / podocytes
31
what components of the filtrate cannot pass through the glomerular capillary endothelium in ultrafiltration?
red blood cells
32
which components of the filtrate cannot pass through the basement membrane in ultrafiltration?
plasma proteins
33
which components of the filtrate can pass through the filtration pathway in ultrafiltration?
water glucose electrolytes amino acids fatty acids nitrogenous wastes
34
what components of the nephron are involved in selective readsorption?
proximal convulated tubule loop of henle distal convulated tubule collecting duct
35
how much of the filtrate is readsorbed in the proximal convulated tubule?
85%
36
what is the role of the loop of henle in selective readsorption?
allows water to be readsorbed from collecting duct
37
what is the role of the distal convulated tubule in selective readsorption?
makes final adjustments toxic substances are secreted into the filtrate water readsorption
38
what is the role of the collecting duct in selective readsorption?
water readsorption
39
what is readsorbed in the proximal convulated tubule?
water ions glucose amino acids + small proteins urea
40
which substances are readsorbed through facilitated diffusion / active transport in the PCT?
ions glucose amino acids
41
how is water readsorbed in the PCT?
osmosis
42
how is urea readsorbed in the PCT?
passively due to the movement of water by osmosis
43
what are the adaptations of the PCT for selective readsorption?
microvilli and infoldings to increase surface area mitochondria for active transport/facilitated diffusion
44
which substances are readsorbed by co-transport in the PCT?
glucose amino acids
45
describe how glucose and amino acids are readsorbed by co-transport in the PCT
1. Na+ actively transported from PCT into blood and are carried away 2. Na+ diffuse into PCT cells from lumen of PCT by facilitated diffusion 3. glucose or amino acid carried with the ion 4. glucose/amino acid and Na+ then diffuses into blood from PCT
46
what % of water and ions have been readsorbed at the end of the proximal convulated tubule?
65%
47
what % of glucose and amino acids have been readsorbed at the end of the proximal convulated tubule?
100%
48
what change is there to the concentration of urea at the end of the proximal convulated tubule?
conc will have increased
49
how does the loop of henle allow water to be readsorbed in the collecting duct?
makes the medulla concentrated with ions, lowering water potential, promoting readsorption by osmosis
50
why is the water potential high at the start of the loop of henle?
all of the glucose and amino acids were readsorbed in the PCT so the filtrate is less concentrated
51
what are the 2 regions of the loop of henle?
descending limb ascending limb
52
what are the differences between the descending and ascending limbs of the loop of henle?
descending: narrow, thin walls that are highly permeable to water ascending: wider, thick walls impermeable to water
53
describe what happens in the descending limb of the loop of henle
water potential lowered so water diffuses out of descending limb and into blood capillaries filtrate moves along descending limb, becoming more concentrated
54
how is the water potential lowered in the descending limb of the loop of henle?
Na+ actively transported out of ascending limb, some passively diffuse into the descending limb, but most accumulate in interstitial region
55
what is the interstitial region?
region between the cortex and medulla of the kidney
56
describe what happens in the ascending limb of the loop of henle
at bottom of the limb - sodium ions diffuse out as filtrate moves along limb, sodium ions actively transported out filtrate becomes less concentrated and water potential increases
57
what is the countercurrent multiplier?
filtrate in collecting duct with a low water potential meets interstitial fluid with lower water potential ensures water potential gradient exists for entire length of collecting duct
58
where is ADH produced?
hypothalamus
59
where is ADH stored and secreted from?
posterior pituitary
60
how does the hypothalamus detect low water potential in the blood?
osmoreceptors in the hypothalamus shrink
61
describe what happens when low water potential is detected in the hypothalamus
impulses sent to posterior pituitary ADH released into blood and travels to kidneys
62
how does ADH cause the kidneys to change the water potential of the blood?
ADH binds to receptors of distal convulated tubule and collecting duct, activating phosphorlyase phosphorylase causes vesicles in the cells to move and fuse will cell membrane, inserting aquaporins into the membrane permeability to water + urea of collecting duct increased more water passes into medulla fluid and blood vessels urea passes into medulla fluid, lowering water potential
63
how do osmoreceptors respond to thirst?
impulses sent to thirst centre of the brain increasing intake of water
64

Biology A2 (15 decks)

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