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Biology A Level > Homeostasis > Flashcards

Homeostasis Flashcards

1
Q

What causes molecules to be forced through the glomerulus into the Bowman’s capsule?

A

the afferent arteriole being wider than the efferent arteriole; increases blood pressure

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2
Q

What might cause a lower glomerular filtration rate?

4 reasons

A
  1. kidney disease
  2. cancer
  3. dehydration
  4. low blood pressure/loss of blood
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3
Q

What is reabsorbed in in the proximal convuluted tubule?

A

water and glucose

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4
Q

What part of the loop of henle is permeable to ions?

A

ascending limb

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5
Q

What part of the loop of henle is permeable to water?

A

descending limb

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6
Q

What does ADH stand for?

A

anti-diuretic hormone

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7
Q

if ADH levels increase, what happens to urine output?

A

decrease

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8
Q

What is the effect of ADH on the collecting ducts permeability to water and why?

A

increases permeability because increase the number of aquaporins

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9
Q

if ADH levels are lowered, what happens to the aquaporins?

A

get broken down by lipsomes

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10
Q

What is present in the glomercular filtrate?

A

urea, water, glucose, inorganic ions, amino acids

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11
Q

Where is the loop of henle located?

A

medulla

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12
Q

Where is the proximal convuluted tubule located?

A

cortex

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13
Q

What supplies the kidney with blood?

A

the renal artery

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14
Q

Why does water move out of the descending limb?

A

due to concentration gradient between the descending limb and the interstitial fluid. there is a higher water potential inside the limb than outside, causes water to move out via osmosis

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15
Q

What connects the renal pelvis to the bladder?

A

ureter

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16
Q

What is negative feedback?

A

a process in which a change in some parameter brings about processes which return it back to normal/homeostasis

17
Q

What is positive feedback?

A

a process in which a change in some parameter brings about processes that move its level further in the direction of the initial change

18
Q

Define homeostasis.

A

the maintenance of a relatively constant internal environmental for the cells within the body

19
Q

What is a set point?

A

ideal value of a pyhsiological factor that the body controls in homeostasis

20
Q

Why is deaminiation useful?

A

because excess protein is not needed, and is not stored, but the energy from proteins should still be utilised

21
Q

What happens in deamination?

A

-NH2 group (amine group) and H+ is removed from the amino acid, producing NH3 and a keto acid

22
Q

What happens with the ammonia produced in deamination?

A

combines with carbon dioxide to produce urea and water

23
Q

Why is important that ammonia is converted into urea?

A

because ammonia is damaging in high quantities; urea is less toxic and less soluble

24
Q

What happens to the keto acid left after deamination?

A
  • enter Kreb’s and be aerobically respired
  • converted to glycogen/fat for storage
  • converted to glucose
25
Q

Where does deamination occur?

A

liver

26
Q

What does a keto acid look like?

A

R
I
HOOC - C=O

27
Q

What kind of blood does the renal artery carry?

A

oxygenated

28
Q

What kind of blood does the renal vein carry?

A

Deoxygenated

29
Q

What is present in the renal artery?

A

urea, glucose, inorganic ions, large proteins, blood cells, salts

30
Q

What occurs across the glomerulus and the Bowman’s capsule?

A

ultrafiltration

31
Q

Where does selective reabsorption occur?

A

PCT, loop of henle

32
Q

What is the benefit of the pedicels on the podocyte cells of the Bowman’s capsule?

A

increase SA for increased filtration rate =? diffusion?

33
Q

What is the function of the basement membrane?

A
  1. seperates the podocytes from the arteriole
  2. stops large proterins from getting through = filter
34
Q

Why does the basement membrane have gaps?

A

allow fluid through -> liquid part of blood into the glomercular filtrate

35
Q

What are the adaptations of the PCT?

4 points

A
  1. microvilli which increases SA for greater reabsorption
  2. one cell thick walls (thin) for short diffusion/active transport distance
  3. tight junctions to hold adjacent cells together to prevent leakage; fluid HAS to flow through cells and be filtered
  4. many mitochondria for active transport

Biology A Level (9 decks)

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