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sb7 Flashcards

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1
Q

How is the water content of the blood controlled in the nephron

A

Water too high —

  1. Hypothalamus detects
  2. ADH is released from pituitary gland into the blood
  3. Collecting duct becomes more permeable
  4. More water re absorbed by osmosis

Water too low —

  1. Hypothalamus detects
  2. ADH not released
  3. Collecting duct gets less permeable
  4. Less water in blood
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2
Q

Describe the stages in the menstrual cycle

A
  1. Falling concentration of progesterone as corpus leautium ages
  2. Causes menstruation and allows release of more FSH from pituitary gland
  3. Causes an egg follicle in ovary to grow and mature
  4. This causes more oestrogen to be released from the ovaries
  5. surge in LH from pituitary gland
  6. Causes ovulation and forms a corpus luteum
  7. Rise in progesterone levels
  8. Causes thickening of uterus lining
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3
Q

What are some effects of adrenaline during the fight or flight?

A
  1. increased heart rate
    —> allows oxygen to reach muscles more quickly, so we can move away
  2. increased blood flow
    —> blood vessels dilate to allow more blood to reach them. Muscles can contract quicker
  3. Increased blood sugar levels
    —> liver breaks down glycogen into glucose which muscles can use to contract
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4
Q

What does thyroxine control?

A

The metabolic rate

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5
Q

How are thyroxine levels controlled in the blood?

A

Too low:

  • TRH released from hypothalamus
  • stimulates release of TSH from pituitary
  • stimulates release of thyroxine from thyroid gland

Too high:

  • thyroxine inhibits the production of TRH from hypothalamus
  • thyroxine inhibits production of TSH from pituitary gland
  • this inhibits release of thyroxine
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6
Q

How is blood glucose concentration regulated?

A

When it’s too high:

  • pancreas produces insulin
  • insulin makes liver join glucose molecules in a chain to make glycogen
  • this decreases glucose levels in the blood

When it’s too low:

  • pancreas releases glucagon
  • glucagon makes liver break down glycogen and release glucose into blood stream
  • increases glucose levels in the blood
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7
Q

How is type 1 diabetes caused and how is it controlled?

A
  • it is caused when the pancreas cannot produce enough insulin
  • this leads to a high glucose concentration in the blood
  • people inject insulin into blood at meal times
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8
Q

How is type 2 diabetes caused and controlled?

A
  • it is caused when cells don’t respond to insulin properly
  • blood glucose levels rise a lot
  • controlled by lifestyle changes

Excerise —> glucose used up in respiration

Healthy diet —> low sugar intake

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9
Q

How does high oestrogen prevent pregnancy?

A
  • inhibits FSH releasing
  • eggs not grown or matured
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10
Q

How does high progesterone prevent pregnancy?

A
  • thickens mucus of cervix which prevents sperm from reaching cell
  • stops ovulation by inhibiting LH releasing
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11
Q

What is done in clomiphene therapy?

A
  • increases LH and FSH levels
  • higher chance of ovulation
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12
Q

What is done in IVF

A
  1. FSH is given so egg cell matures
  2. LH is given so ovulation can happen
  3. Released egg cells are taken from ovary
  4. Sperm cells taken from the male
  5. Fertilised in the lab
  6. Develops into embryos and 1 or 2 are placed back into the uterus
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13
Q

Whats thermoregulation?

A

Act of keeping body temperature constant at 37 degrees

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14
Q

Why is thermoregulation important?

A

So enzymes are effective and don’t denature

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15
Q

Whats osmoregulation?

A

Act of keeping the concentration of water in the body constant

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16
Q

What happens when it’s too hot?

A
  1. Sweating:
    —> sweat is produced by sweat glands in the dermis of the skin and released onto epidermis . Sweat evaporates and energy is transferred away from body
  2. Vasodilation:
    —> widening of small arteries
    body loses heat by radiation
  3. Hairs on surface stays flat
    —> loses heat as no trapping insulated air
17
Q

What happens when it’s too cold?

A
  1. Shivering
    —> muscles contract and relax quickly and energy released from respiration warms you up
  2. Vasoconstriction
    —> narrowing of arteries
    Reduces blood flow close to the surface resulting in less heat lost
18
Q

How is urea produced?

A

From the breakdown of excess amino acids in the liver

19
Q

What are the steps blood takes in the urinary system?

A
  1. Blood containing impurities travels in the renal arteries to the kidney
  2. Kidneys regulate levels of urea and excess is sent to ureter and bladder for excretion
  3. Purified blood returns to body from renal vein
20
Q

What happens in the nephron?

A
  1. Filtration:
    —> molecules are filtered out from glomerulus into bowman’s capsule
  2. Selection reabsorption:
    —> specific glucose gets taken back into capillaries by active transport
  3. Water reabsorption:
    —> water gets reabsorbed by osmosis in the loop of henle
21
Q

What happens during kidney dialysis?

A
  • urea diffuses from the blood into the dialysis fluid from a partially permeable membrane
  • glucose will diffuse into the blood and water will move out by osmosis
22
Q

Why do cells not store glucose?

A
  • it will dissolve
  • osmotic effect
23
Q

What happens to the uterus lining if the egg is fertilised?

A

Thickens as progesterone levels maintained

24
Q

What are the disadvantages of treating infertility with hormones?

A
  • multiple pregnancy
  • more than one egg released
25
Q

Why does the finger’s temperature decrease as the external temp decreases?

A
  • heat lost from finger
  • less blood delivered to skins surface
  • vasoconstriction
26
Q

How can an organism die if the body temp is too high?

A
  • enzymes denature
  • affects digestion
27
Q

How does the kidney ensure that there is no protein in urine?

A

Protein is filtered out of the glomerulus as it is too big

biology gcse (9 decks)

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