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Biology paper 2 > homeostasis > Flashcards

homeostasis Flashcards

1
Q

what is homeostasis

A

the regulation of the bodies internal conditions so the it can work at an optimum rate

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2
Q

what is a stimulus

A

a change in the environment

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3
Q

what organs form the censtal nervous system

A

the brain and the spinal cord

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4
Q

what is the cerebral cortex and its function

A

it is the folded outermost part of the brain and holds the information for language memory and consciousness

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5
Q

what is the cerebellum and its function

A

it controlls are balance and coordinates our movements and is found underneath the cerebral cortex

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6
Q

what is the medulla and its function

A

it controls our heart rate and breathing rate and other subconscious actions

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7
Q

how can you investigate the brain

A
  1. look at brain damadge and its affect on the person
  2. electrically stimulate certain areas of the brain
  3. use MRI scanning
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8
Q

what is the cornea

A

the transparent front of the eye that allows light to pass through

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9
Q

what is the lens

A

the function of the lens is to focus the light rays onto the retina at the back of the eye. the lens can change shape to focus on distant or near objects (acoomodation

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10
Q

what is the retina

A

the retina contains receptor cells for light intensity and colour which then sends electrical impulses down the optic nerve to the brain

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11
Q

what is the sclera

A

it is the white part of the eye which is the tough outer layer to protect the eye

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12
Q

what are the cilliary muscles and the suspensory ligament’s function

A

they allow us to focus on distant or near objests

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13
Q

what is the iris

A

the coloured part of the eye which controls the size of the pupil

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14
Q

what is the pupil

A

the pupil is the center of the iris which light passes through

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15
Q

how do we focus on near objects

A

the cilliary muscles contract and the suspensory ligaments relax causing the lens to become thicker and refreact light more

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16
Q

how do we focus on distant objects

A

the cilliary muscles relax and the suspensory ligaments contract causing the lens to become thin not refracting light as much

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17
Q

how can we correct hyperopia (long sighted)

A

people with long sight have no problem focussing on distant object. This is usually caused by have an eyeball that is too short whcih causes the light to be focussed at a point behind the retina . This can also be caused by having a lens taht is less elastic. hyperopia can be corrected using a convex lens

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18
Q

how can we correct myopia (short sighted)

A

people with short sight have no problem focussing on nearby object. This is usually caused by have an eyeball that is too long whcih causes the light to be focussed at a point infront the retina . This can be because the lens is too thick. myopia can be corrected using a concave lens

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19
Q

how does the body respond to having high temperatures

A

1) the sweat glands release sweat which evapotaes which takes energy out of the body
2) the body can cool itself through flushing. This is when the blood vessels supplying the capilaries dialate to increase amount of heat loss. this is called vasodilation

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20
Q

how does the body respond to having low temperatures

A

1) the body can cool itself through flushing. This is when the blood vessels supplying the capilaries constric to decrease amount of heat loss. this is called vasoconstriction
2) we also shiver. this constrics our skeletal muscles by increasing the rate of respiration

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21
Q

what are the differences between the endocrine system and the nervous system

A

the nervous system uses electrical impulses whereas the endorcrine system uses chemicals (hormones)
the nervous system uses neurones whereas the endocrine system uses the bloodstream
signaling in the nervous system is very fast whereas in the endocrine system it is very slow

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22
Q

what is the function of the thyroid gland

A

it is located in the neck and produces hormones involved in growth and in regulating the bodies base metabolic rate

23
Q

what is the function of the adrenal glands

A

they are located above easch kidney and produce adrenaline in times of fear or stress

24
Q

what is the function of the pituitary gland

A

it is located in the brain and releases a number of different hormones into the blood which affect other glands triggering a range of different effects in the body

25
Q

what hormone is produced when the pancreas detects a rise in levels of glucose

A

insulin

26
Q

what is the function of insulin

A

it triggers body cells to take up glucose from the blood and also triggers liver and muscle cells to store excess glucose in the form of glycogen

27
Q

why does type 1 diabetes affect the body

A

it is because the person’s pancreas does not produce enough insulin causing a high blood sugar level

28
Q

why does type 2 diabetes affect the body

A

it is because the patients body cells do not respond to the insulin

29
Q

how does the body respond to low blood sugar levels

A

the pancreas releases the hormone glucagon t

30
Q

what is deamination

A

when the liver breaks down excess amino acids into ammonia (this is then converted to urea)

31
Q

how do the kidneys ensure that useful molecules do not get lost

A

they selectively reabsorb molecules into the bloodstream using active transport such as glucose and mineral ions

32
Q

what is the function of testosterone

A

it stimulates the testes to produce sperm

33
Q
A
34
Q

what is the function of oestrogen and where is it produced

A

Stops FSH being produced (so that only one egg matures in a cycle). Repairs, thickens and maintains the uterus lining. Stimulates the pituitary gland to release LH.

35
Q

what happens in ovulation

A

the uterus lining becomes spongy. then an egg travels down the fallopian tubes. if sperm is present the egg becomes fertilised and implants into the uterus wall. If not the egg and uterus lining are released

36
Q

what is FSH

A

it causes the egg to mature in the ovary and stimulates the ovaries to release LH

37
Q

what is LH

A

causes ovulation (an egg to be released)

38
Q

what is the function of oestrogen and progesterone in the menstrual cycle

A

involved in maintaining the lining of the uterus

39
Q

how do the reproductive hormones interact with eachother

A

first the pituitary gland releases FSH which travells to the ovaries to mature the eggs. FSH triggers the ovaries to produce oestrogen which causes the lining of the uterus to become thick and also stops the pituitary gland from releasing FSH and instead releases LH which triggers ovulation. Once the ovary has released its egg it triggers the pituitary glands to release progesterone wich stops the pituitary gland from releasing LH and FSH to prevent anymore eggs from being released

  1. FSH causes eggs to mature and triggers production of oestrogen.
  2. LH is released to trigger ovulation and causes release of progesterone to stop production of LH and FSH
40
Q

how do oral contraceptive pills work

A

oral pills stop the body from producing FSH therefore inhibiting the eggs from maturing. These are very effective however needs to be taken daily and some have side effects such as breast cancer or blood clots and does not protect agains STD’s

41
Q

how do hormonal contraceptives such as implants skin patches and injections work

A

these contain progesterone which stops egges from maturing or being released. These last for longer implants last for 3 years. The injection lasts for 3 weeeks and the skin patch lasts for a week.these do not protect agains STD’s

42
Q

what are barrier methods and how do the work

A

these include condoms and diaphrams and provide a physical barrier to ensure the sperm does not reach the egg. There is not risks from STI’s or side effects. They however can break.

43
Q

what is a spermicide

A

it is a chemical that can kill or disable sperm and can be paired with barrier methods to increase effectiveness

44
Q

what is an IUD (intrauterine device)

A

it prevents embryos from implanting by releasing copper and some can release hormones to further reduce the chances of fertilistation. This has very few side effects however does not preotect the user from STI’s.

45
Q

what is steralisation

A

in women it prevents the egg from reaching the uterus and in men prevents the sperm leaving the penis. This is very difficult to reverse and does not protect from STI’s

46
Q

how can infertility be solved in women

A

take an injection containing LH and FSH to cause the woman to ovulate more

47
Q

what are the disadvantages of IVF

A

IVF is expensive
low succes rates
emotionaly stressfull
physically demanding
can lead to multiple births
not all of the embryos are transferred

48
Q

what is the independant, dependant and control variables in the plant hormones practical

A

indpendant - light intensity
dependant - height of seedling
control varialbes - amount of seeds, water, temperature

49
Q

how do we conduct the plant hormones practical

A

first place cotton wool in three petri dishes and soak them with water
then place 10 of the same type of seed in the cotton wool
then ensure that there is the same amount of seedling in each petri dish
then use a ruler to measure the height of the seedlings ensuring the stem is straight without damadging the seedlings
then place the seedling in different light intensities

50
Q

what will happen to seedling in the dark

A

they will grow rapidly as seeds usually germinate underground trying to reach light

51
Q

how can auxins be used

A

weedkillers
rooting powers
promoting growth in tissue culture

52
Q

how can gibberellins be used

A

ending seed domancy
encouraging plants to flower
causes fruit to grow larger

53
Q

how can ethene be used

A

One use is in bananas where they are transported before they are ripe and then ethene is used to ripen them

Biology paper 2 (4 decks)

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