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biology > B7 | homeostasis > Flashcards

B7 | homeostasis Flashcards

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1
Q

definition of homeostasis

A

the process of maintaining constant internal environment

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2
Q

which gland secretes adrenaline?

A

adrenal gland

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3
Q

how does adrenaline work?

A

binds to receptors in the heart causing it to beat faster and with more force

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4
Q

what does adrenaline cause your body to do?

A
  • increased heart rate
  • increased blood pressure
  • increased blood flow
  • increased oxygen/glucose supply to cells
  • increased respiration
  • increase in energy needed for muscle contractions
  • allows you to “fight or flight”
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5
Q

which gland secretes thyroxine?

A

thyroid gland

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6
Q

what does thyroxine do?

A

regulates basal metabolic rate

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7
Q

basal metabolic rate definition

A

the speed of chemical reactions in the body while it is at rest

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8
Q

what happens when there are low levels of thyroxine in the blood?

A
  • hypothalamus releases TRH
  • pituitary gland releases TSH
  • thyroid produces thyroxine to increase metabolic rate
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9
Q

what happens when there are high levels of thyroxine in the blood?

A
  • hypothalamus inhibits production of TRH
  • pituitary gland reduces production of TSH
  • thyroid produces less thyroxine to decrease metabolic rate and for thyroxine concentration in the blood to drop
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10
Q

what happens when you have an underactive thyroid (hypothyroidism)?

A
  • less thyroxine produced
  • metabolic rate drops
  • less energy available
  • more fat stored
  • weight gained
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11
Q

what happens when you have an overactive thyroid (hyperthyroidism)?

A
  • more thyroxine produced
  • metabolic rate increases
  • more energy available
  • less fat stored
  • weight lost
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12
Q

which gland produces FSH and LH?

A

pituitary gland

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13
Q

which gland produces oestrogen and progesterone?

A

ovary glands

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14
Q

what happens during day 1-5 of the menstrual cycle?

A
  • uterus lining breaks down

- pituitary gland releases follicle stimulating hormone (FSH) causing concentration of FSH in the blood to increase

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15
Q

what happens during day 5-14 of the menstrual cycle?

A
  • FSH targets the egg follicle in the ovary, causing it to start to mature and prepare an egg cell for release
  • as the egg follicle matures, oestrogen is released causing concentration of it in the blood to increase
  • as levels of oestrogen increase, levels of FSH decrease and pituitary gland releases luteinising hormone (LH) instead
  • high levels of oestrogen also cause uterus lining to thicken in preparation for a fertilised egg
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16
Q

what happens during day 14 of the menstrual cycle?

A
  • levels of FSH and LH peak causing an egg cell to be released (ovulation)
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17
Q

what happens during day 14-21 of the menstrual cycle?

A
  • empty egg follicle (corpus luteum) in the ovary releases oestrogen and progesterone to maintained the thickened uterus lining
  • as levels of progesterone increase, pituitary gland stops production of FSH and LH to prevents the maturing of another egg/ovulation
18
Q

what happens during day 21-28 of the menstrual cycle?

A
  • if the egg cell is not fertilised, progesterone levels decrease in order for the uterus lining to break down
  • levels of FSH increase and the cycle starts all over again
  • if the egg is fertilised, progesterone levels stay high in order to maintain the lining of the uterus for pregnancy
19
Q

how does the pill act as contraception?

A
  • contains oestrogen which inhibits production of FSH preventing egg cell from maturing and being released (ovulation)
  • contains progesterone which thickens cervical mucus preventing sperm from getting into the uterus
20
Q

side effects of hormonal methods of contraception

A

headaches, nausea, irregular period, mood swings

21
Q

how does clomifene therapy work?

A
  • taken by women who don’t ovulate (regularly) during days 1-5 of the menstrual cycle
  • contains FSH which stimulates egg to mature in follicle and stimulates release of oestrogen
  • also contains LH which initiates ovulation of mature egg
22
Q

how does IVF (in vitro fertilisation) work?

A
  • woman is given FSH and LH to stimulate egg maturation and ovulation
  • eggs cells are collected and fertilised with sperm cells
  • the fertilised eggs mature into embryos and are implanted back into the mother’s uterus (more than one is implanted to improve chances of pregnancy)
23
Q

disadvantages of IVF

A
  • more than one embryo implanted can lead to multiple births which can lead to pregnancy complications (especially for women over 40)
  • hormones gives at the start of the treatment can have side effects, and stopping these hormones reduces the chance of pregnancy
24
Q

optimum body temperature

A

37 C

25
Q

how does shivering maintain body temperature?

A
  • muscles contract and relax rapidly
  • cells are required to respire more
  • respiration produces heat energy which is transferred to the blood to warm you up
26
Q

how do muscles cause hairs to stand up/flatten?

A

erector muscles at base of hair contract/relax

27
Q

what is glycogen?

A

large insoluble store of glucose

28
Q

what is glucagon?

A

hormone which turns glycogen back into glucose

29
Q

what happens if there is a high concentration of water INSIDE a cell and a low concentration of water OUTSIDE of it?

A

water moves out of the cell via osmosis and the cell shrinks/becomes smaller

30
Q

what happens if there is a high concentration of water OUTSIDE a cell and a low concentration of water INSIDE of it?

A

water moves into the cell via osmosis and cell swells/becomes bigger

cell could even burst (lysis) and die

31
Q

how are high levels of water in the blood regulated?

A
  • high levels of water detected by hypothalamus
  • pituitary gland releases less ADH
  • drop in ADH detected by kidney which becomes less permeable and less water is reabsorbed into the blood
32
Q

how does vasoconstriction help to regulate body temperature?

A
  • blood vessels get smaller/constrict
  • this prevents blood from travelling to the skins surface
  • which prevents heat from being radiated from your blood
  • which keeps you warm
33
Q

how does vasodilation help to regulate body temperature?

A
  • blood vessels get wider/dilate
  • this increases amount of blood from travelling to the skins surface
  • which increases amount of heat from being radiated from your blood
  • which cools you down
34
Q

what is the epidermis?

A

outer layer of skin

35
Q

what is the dermis?

A

deep layer of skin

36
Q

how does the hypothalamus monitor body temperature?

A

receptors in the hypothalamus detects any changes in body temp from 37°C and initiates a negative feedback to return the body temp back to normal

37
Q

what happens when blood glucose levels are too high?

A
  • pancreas detects high levels of glucose and secretes insulin into the blood
  • liver detects insulin and absorbs excess glucose
  • this excess glucose is converted into glycogen and stored in the liver
  • blood glucose levels return to normal
38
Q

what happens when blood glucose levels are too low?

A
  • pancreas detects low level of glucose and secretes glucagon into the blood
  • liver detects glucagon and converts glycogen back into glucose which is passed back into the blood
  • blood glucose levels return to normal
39
Q

how is type 1 diabetes caused?

A

when the pancreas is unable to produce insulin

this leads to excess glucose which isn’t converted into glycogen

leading to build of glucose

leading to hyperglycaemia

40
Q

how is type 1 diabetes treated?

A
  • insulin injections
  • limit glucose intake (less carbs and sugars)
  • regular exercise to lower blood glucose levels through using this sugar for metabolism/cell respiration
41
Q

how is type 2 diabetes caused?

A

when a person’s body becomes resistant to insulin

typically in 40+ year olds and makes up most cases of diabetes

obesity & constant intake of high glucose foods tires the pancreas out leading to less production of insulin and eventually insulin resistance

42
Q

how can type 2 diabetes be treated?

A
  • losing weight which will lead to an increased insulin production
  • reduce glucose intake to prevent sharp rises in blood sugar levels
  • exercise regularly to increase metabolism/cell respiration which will use up excess glucose in the blood

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