B3- Organism Level Systems

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Biology

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45 Terms

1
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what is in the central nervous system?

  • brain and spinal chord

2
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what does a sensory neurone do?

  • send electrical impulses from receptors to the CNS

3
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what do motor neurones do?

  • carry electrical impulses from the CNS to the effectors

4
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what do effectors do?

  • they are all your muscles and glands which respond to the nervous impulses and create a response

5
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what is the order of co-ordinating a response?

  • stimulus —> receptor —> sensory neurone —> CNS (+ relay neurone) —> motor neurone —> effector —> response

6
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what is a synapse?

  • the connection between 2 neurons (gap in between)

7
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how are signals transferred through synapses?

  • when an impulse reaches a synapse it releases chemicals which diffuse across the gap from a receptor to a neurone

  • this triggers a new electrical impulse which travels through the next neurone

8
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what is a reflex arc?

  • when reflexes are automatic responses to the stimuli and don’t involve the brain but goes down the spinal chord so it is quicker

9
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what does the reflex arc do?

  • used to quickly protect your body

10
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what is an example of a reflex arc response?

  • touching a hot object and moving your hand away quickly

11
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what is the order of a reflex arc?

  • stimuli —> receptor —> sensory neurone —> spinal chord —> relay neurone —> motor neurone —> effector —> response

12
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what does a relay neurone do?

  • pass on electrical impulses to the motor neurone

13
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what are hormones?

  • hormones are chemical messengers produced by endocrine glands

14
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what does the endocrine system do?

  • produce hormones which are released directly into the blood and to the target organs which need it then the hormones bind to receptor cells on organ

15
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where are the glands located?

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16
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what does the pituitary gland produce?

  • it is the ‘master gland’ and it acts on other glands to produce hormones

  • also produces LH, FSH, growth hormone, ADH (water content of blood)

17
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what does the thyroid gland produce?

  • thyroxine which regulates metabolism, heart rate and temp.

18
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what does the adrenal gland produce?

  • adrenaline, used for fight or flight response

19
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what does the pancreas produce?

  • insulin which regulates blood glucose levels

20
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what do ovaries produce?

  • oestrogen and progesterone, involved in menstrual cycle

21
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what do the testes produce?

  • testosterone, controls puberty and sperm production

22
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what are the hormones in the menstrual cycle?

  • FSH, oestrogen, LH, progesterone

23
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what does the FSH do?

  • stimulates egg to mature and stimulates ovaries to produce oestrogen

24
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what does oestrogen do?

  • causes lining or wall of the uterus to grow

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what does LH do?

  • stimulates release of an egg at day 14 (ovulation)

26
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what does progesterone do?

  • maintains the lining of the uterus, when progesterone levels fall- lining breaks down

27
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describe what happens on each day of the menstrual cycle

  • day 1-4= uterus lining breaks down, period

  • day 4-14= oestrogen causes lining of uterus thicken full of blood

  • day 14= ovulation- LH causes release of an egg

  • day 15-28= uterus wall is maintained ready for fertilized egg, if no fertilized egg cycle starts again

28
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how does FSH work in contraceptives?

  • no egg will be developed or released also no oestrogen will be made so egg development will stop

29
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how does progesterone work in contraceptives?

  • stimulates production of thick mucus in cervix, preventing sperm from reaching egg

30
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are hormonal contraceptives effective?

  • they are 99% effective but don’t protect against STDs

31
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what are the hormonal methods of contraception?

  • IUD- placed in uterus and releases progesterone- plastic or copper version doesn’t release hormones but kills sperm

  • contraceptive implant- implanted into the arm, released progesterone, lasts up to 3 years

  • contraceptive injection- releases progesterone, lasts 2-3 months

  • contraceptive patch- released oestrogen and progesterone, lasts up to 1 week

32
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are non- hormonal contraceptive methods effective?

  • they are 98% effective as they stop sperm from meeting the egg and protect against STDs

33
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what are the non-hormonal methods of contraception?

  • condoms (male and female)= protect against sperm meeting the egg

  • diaphragm= fits over cervix and blocks sperm from entering- unreliable has to be used with spermicide- kills sperm

  • sterilisation- women= cutting/tying fallopian tubes, men= sperm ducts cut/tied

  • sex at certain times of the month- unreliable

34
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what does homeostasis mean?

  • maintaining internal body environment constant

35
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why does the body need to control levels of water, glucose and salts?

  • to ensure chemicals can be transported effectively into and out of cells by osmosis and active transport

36
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why does temperature have to remain constant?

  • so chemical reactions can be catalysed by enzymes and they function best at their optimum temp

37
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what are blood sugar levels controlled by?

  • by the pancreas which produces insulin

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what does insulin do?

  • causes cells to become more permeable to glucose so glucose can move from blood into the cells

  • also causes the liver to turn excess glucose into glycogen

39
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what happens if blood glucose levels are too high?

  • insulin is secreted by pancreas to blood and this removes glucose from the blood and turns it into glycogen

40
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what happens if blood glucose levels are too low?

  • glucagon is secreted by pancreas to blood which makes the liver turn glycogen back into glucose

41
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what is metabolism?

  • sum of all chemical reactions that happen in an organism

42
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what is type 1 diabetes?

  • it’s when little or no insulin is made so blood glucose levels are too high and it develops at young age or birth

43
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treatments for type 1 diabetes?

  • insulin injections to remove glucose from blood, limit carbs and exercise more and eat healthy

44
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what is type 2 diabetes?

  • insulin is still produced but the person becomes resistant to their own insulin and it develops gradually through life due to unhealthy diet

45
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treatments of type 2 diabetes?

  • eating healthy, exercise and maybe medication