Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

bio spec > homeostasis and response > Flashcards

homeostasis and response Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

define homeostasis

A

the regulation of the internal conditions of a cell or organism to maintain optimum conditions for function in response to internal and external changes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

why must the body regulate the core body temperature of 37ºC

A

because this is the optimum temperature for enzyme action and all cell functions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what happens if body temperature falls too high or above optimum

A

enzymes will denature and metabolic processes can’t take place, so cells will die

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what does homeostasis control

A

blood glucose concentration, body temperature and water levels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what two types of response can control systems have

A

chemical or electrical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what do all control systems include

A

receptors, coordination centres and (effectors, muscles or glands)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

function of receptors

A

they detect stimuli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

define stimuli

A

changes in the environment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

function of coordination centres e.g. brain, spinal cord, pancreas

A

they receive and process information from receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

function of effectors, muscles or glands

A

they bring about responses which restore optimum levels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what does the nervous system enable

A

it enables humans to react to their surroundings and to coordinate their behaviour

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

how does information get from receptors to the CNS

A

the information from receptors passes along neurones as electrical impulses to the CNS.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

function of the CNS and what it is made up of

A

our CNS is made up of our brain and spinal cord; the brain coordinates the response of effectors to the stimulus, which may be muscles contracting or glands secreting hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

order of stimulus to response

A

stimulus -> receptor -> coordinator -> effector -> response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

examples of stimuli

A

temperature, light, position, sound, touch, etc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

sensory neurone function

A

they transmit messages from sense receptors e.g. eye or nose, to the brain or spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

motor neurone function

A

they transmit messages from the brain and spinal cord to the muscles and organs, which are effectors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

define a reflex arc

A

the nervous pathway that a nerve impulse takes during a reflex action

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

relay neurone function

A

they connect motor neurones to sensory neurones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is a synapse

A

gap between two neurones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

function of a synapse

A

allows the nerve cells to pass on their electrical impulse to another cell; also controls the direction in which impulses travel, as they can only travel one way through a synapse.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

function of neurotransmitters

A

they carry chemical signals from one neuron (nerve cell) to the next target cell; this can be another nerve cell, a muscle cell or a gland

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

why are reflex actions important

A

because reflex actions are automatic and rapid (they do not involve the conscious part of the brain), meaning they protect our body from danger

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what is the brain

A

an organ that controls complex behaviour; it’s made of billions of interconnected neurones and has different regions that carry out different functions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what does the cerebral cortex control

A

it’s responsible for higher-order processes such as intelligence, memory, consciousness and personality

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what does the cerebellum control

A

it’s responsible for balance, muscle coordination and movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what does the medulla control

A

it controls unconscious activities such as heart rate and breathing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

why is treating brain disorders very difficult

A

because the brain is very complex and delicate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

how have neuroscientists been able to map the regions of the brain to particular functions

A

by studying patients with brain damage, electrically stimulating different parts of the brain, and using MRI scans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

pros and cons of electrically stimulating different parts of the brain

A

PROS:
- helps control your movement symptoms when your medications aren’t working as well as they used to
- doesn’t damage brain tissue

CONS:
- could cause stroke
- temporary pain and swelling at the implantation site

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

pros and cons of MRI scans

A

PROS:
- non-invasive and doesn’t use radiation
- no side-effects

CONS:
- very expensive
- may cause peripheral muscle or nerve stimulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what is the eye

A

a sense organ containing receptors sensitive to light intensity and colour

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

define accommodation

A

the process of changing the shape of the lens to focus on near or distant objects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

function of retina

A

contains light-sensitive cells which convert light that enters your eye into electrical signals your optic nerve sends to your brain which creates the images you see

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

function of optic nerve

A

a nerve composed of many sensory neurones carrying impulses from the retina to the brain which creates the images you see

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

function of sclera

A

tough white protective outer layer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

function of cornea

A

refracts light through the pupil as it enters the eye

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

function of iris

A

alters the size of the pupil, controlling the amount of light entering the eye

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

function of ciliary muscles

A

they control the thickness of the lens to allow focussing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

function of suspensory ligaments

A

attach the ciliary muscles to the lens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

how does the eye focus on near objects

A

the ciliary muscles contract, the suspensory ligaments loosen, therefore the lens is then thicker and refracts light rays strongly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

how does the eye focus on distant objects

A

the ciliary muscles relax, the suspensory ligaments are pulled tight, therefore the lens is then pulled thin and only slightly refracts light rays

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

why does myopia (short sightedness) and hyperopia (one sightedness) occur

A

rays of light do not focus on the retina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

how is myopia and hyperopia treated

A

they’re generally treated with spectacle lenses which refract the light rays so that they do focus on the retina. MYOPIA - treated using a concave lens, HYPEROPIA - treated using a convex lens
- new technologies now include hard and soft contact lenses, laser surgery to change the shape of the cornea and a replacement lens in the eye

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

what does the thermoregulatory centre do, how does it work and where is it found

A

it is found in the hypothalamus; it monitors and controls body temperature; the thermoregulatory centre contains receptors sensitive to the temperature of the blood. the skin contains temperature receptors and sends nervous impulses to the thermoregulatory centre

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

what happens if body temperature is too high

A

blood vessels dilate (vasodilation) and sweat is produced from the sweat glands. both these mechanisms cause a transfer of energy from the skin to the environment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

what happens if body temperature is too low

A

blood vessels constrict (vasoconstriction), sweating stops and skeletal muscles contract (shiver).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

4 things that cool us down on a hot day

A

1) vasodilation - capillaries get wider so a larger amount of blood can flow near the skins surface, heat is lost to the environment
2) hairs and hair erector muscles are relaxed
3) evaporation of sweat from the sweat glands which takes heat energy away from the body
4) no shivering

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

4 things that heat us up on a cold day

A

1) vasoconstriction - capillaries get thinner so less blood can flow near the skin surface, heat is kept near to the body
2) no sweat is produced, which reduces the amount of heat energy taken away from the body
3) body starts to shiver to produce heat for the body
4) hairs and hair erector muscles stand on end to trap a layer of air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

function of the endocrine system

A

it secrets hormones directly into the bloodstream; the blood carries the hormone to a target organ where it produces an effect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

function of the pituitary gland and where it’s found

A

it is found in the brain and secretes several hormones into the blood in response to body conditions; these hormones in turn act on other glands to stimulate other hormones to be released, to bring about effects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

what does the pancreas secrete and why

A

it secretes insulin and glucagon to regulate blood glucose concentration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

what hormone does the thyroid produce and why

A

it produces thyroxine which controls the basal metabolic rate and plays a role in growth and development

54
Q

what hormone do the adrenal glands release and why

A

they release adrenaline in times of stress or fear by increasing heart rate and boosting delivery of oxygen and glucose to the brain and muscles in order to activate fight or flight

55
Q

what hormone do the ovaries produce and why

A

they produce oestrogen to control female reproduction

56
Q

what hormone do the testes produce and why

A

they produce testosterone to control male reproduction

57
Q

name all the endocrine glands

A

pituitary gland, pancreas, thyroid, adrenal gland, ovary, testes

58
Q

difference between the endocrine system and the nervous system

A

the endocrine system relies on hormones while the nervous system relies on electrical impulses. the hormones are transported by the blood whilst impulses are carried along hormones

59
Q

similarity between the endocrine system and the nervous system

A

they both send information around the body in order to carry out homeostasis

60
Q

which sends information faster out of the endocrine system and the nervous system

A

compared to the nervous system, the endocrine system transports hormones slower than the nervous system sends electrical impulses, but hormones act for longer

61
Q

what happens if blood glucose concentration is too high

A
  • increase in blood glucose concentration is detected by pancreas cells
  • the pancreas produces the hormone insulin that causes glucose to move from the blood into the cells
  • in the liver and muscle cells, excess glucose is converted to glycogen for storage
62
Q

what happens if blood glucose concentration is too low

A
  • decrease in blood glucose concentration is detected by the pancreas cells
  • the pancreas produces the hormone glucagon which binds to liver and muscle cells
  • in the liver and muscle cells, glycogen is converted back into glucose and released into the blood
63
Q

why must glucose levels be kept at a constant level by homeostasis

A

because glucose is needed by every cell to carry out respiration and release energy to stay alive

64
Q

what happens to cells if there is too little glucose

A

too little glucose could cause cells to die due to a lack of respiration and energy

65
Q

what happens to cells if there is too much glucose

A

too much glucose will affect solute concentration outside cells, affecting osmosis, and causing too much water to be drawn out of cells; this causes them to shrivel up and die

66
Q

when does blood glucose concentration rise

A

after a carb-rich meal

67
Q

what is type 1 diabetes

A

a disorder in which the pancreas fails to produce sufficient insulin

68
Q

what is type 1 diabetes characterised by and how is it treated

A

uncontrolled high blood glucose levels and is normally treated with insulin injections after meals to reduce blood glucose concentration when it rises

69
Q

what is type 2 diabetes

A

where the body cells no longer respond to insulin produced by the pancreas

70
Q

why should you get injections in type 1 diabetes and not pills

A

because insulin is a protein (like all hormones) that would be destroyed by enzymes

71
Q

treatment for type 2 diabetes

A

a carbohydrate controlled diet and a regular exercise regime to keep blood glucose levels at a minimum

72
Q

why can people with type 2 diabetes not get insulin injections

A

because the cells stop responding to the insulin

73
Q

risk factors for type 2 diabetes

A
  • MAIN RISK FACTOR: obesity; as obesity levels increase, more people are getting type 2 diabetes
  • age: >40
  • genetics: having a close relative with the condition
  • ethnicity: South Asian, Chinese, African-Carribean or black African
74
Q

other treatment options for diabetes

A

TYPE 1 DIABETES:
- pancreas transplants so that they don’t have to reject insulin (immune rejection
and immunosuppressants)
OR
- stem cell research/artificial pancreases

TYPE 2 DIABETES:
- eating balanced diet
- lose weight
- regular exercise
- drugs to help insulin work better

75
Q

explain the negative feedback loop of blood glucose concentration

A
  • blood glucose concentration of a normal person rises slightly and falls slightly over the course of the day; this is because the blood glucose concentration is controlled by a balance between insulin and glucagon
  • so, when blood glucose levels fall, glucagon is released and when the blood glucose levels are too high, insulin is released – forming a negative feedback loop
76
Q

why is it important that the body keeps the blood water concentration relatively constant

A

if the blood becomes too dilute, water will move into cells by osmosis, causing them to burst – and, if blood becomes too concentrated, water will move out of cells by osmosis, causing them to shrivel. in both scenarios, if body cells gain or lose too much water by osmosis, they will not work efficiently

77
Q

what three ways do we lose water. state whether they’re controlled or uncontrolled

A

1) water leaves the body via the lungs during exhalation (uncontrolled)
2) sweating, as the sweat glands produce sweat on the skin and it evaporates (uncontrolled)
3) through urine which is produced by the kidney. if blood is too dilute, kidney will remove this water and produce a greater volume of dilute urine (controlled)

78
Q

what is removed via the kidneys in the urine

A

water, ions and urea

79
Q

what is removed via the sweat glands in sweat

A

water, ions and urea

80
Q

what does the digestion of protein from the diet cause

A

it results in excess amino acids which need to be excreted safely. in the liver, these amino acids are deaminated to form ammonia. ammonia is toxic and so it is immediately converted to urea for safe excretion

81
Q

what happens when there is a low blood water concentration

A

1) the brain detects the low water levels and pituitary gland releases the hormone ADH as a result
2) ADH then travels through the blood and triggers kidney tubules to become more permeable
3) as the kidney tubules become more permeable, more water is reabsorbed back into the blood during selective reabsorption
4) this increases blood water levels back to normal and produces a small amount of concentrated urine

82
Q

what is the function of ADH

A

to increase permeability of kidney tubule

83
Q

what happens when there is a high blood water concentration

A

1) pituitary gland detects high blood water levels and stops releasing ADH
2) this means that kidney tubules are less permeable so that less water is reabsorbed into the bloodstream during selective reabsorption
3) this decreases blood water levels back to normal because lots of dilute urine is produced that takes water away from the body

84
Q

how do the kidneys produce urine

A

by filtration of the blood and selective reabsorption of useful substances such as glucose, some ions and water

85
Q

describe filtration

A

as the blood enters the kidney, all small molecules are filtered out of the blood and into the kidney (filtration) - these include water, urea, mineral ions, amino acids and glucose

86
Q

why can proteins and blood cells not be filtered

A

proteins and blood cells are too large to diffuse through and remain in the capillaries

87
Q

what does the release of more ADH cause

A

it causes more water to be reabsorbed back into the blood from the kidney tubules; this is controlled by negative feedback

88
Q

what happens after filtration takes place

A

selective reabsorption takes place; this is where useful substances are reabsorbed back into the bloodstream i.e. all of the glucose (and all amino acids) some of the ions and some of the water is reabsorbed back into the blood through kidney tubules

89
Q

what happens to the molecules not reabsorbed into the blood

A

they are released as urine and this includes urea, excess ions and excess water

90
Q

why do glucose levels not change after the kidney filters it

A

because although it is filtered out of the blood, it is all reabsorbed

91
Q

why does the concentration of ions decrease after the kidney filters it

A

because excess ions are not reabsorbed

92
Q

why is there no urea in the blood after the kidney filters it

A

because urea is a waste product, none is reabsorbed back into the blood because we don’t need it

93
Q

how can kidney failure be treated

A

kidney transplants or dialysis

94
Q

what happens during dialysis

A

during dialysis, the patient’s ‘impure’ blood with excess water, mineral ions and urea is passed through a dialysis machine which contains a semi-permeable membrane that separates the blood and the dialysis fluid; this membrane will only allow smaller molecules like water, ions and urea through but will not allow larger molecules like blood cells and proteins through

95
Q

what does dialysis fluid contain

A

it contains the concentrations of water, ions and urea of healthy blood – meaning it contains no urea, some water and some ions

96
Q

why does the dialysis fluid need to have specific amounts of each substance

A

because it forms a concentration gradient between the patient’s blood and the dialysis fluid, causing all the urea to diffuse from patient’s blood into fluid, some ions to diffuse from blood to fluid and some water to move by osmosis into the fluid across the semi-permeable membrane

97
Q

why are both the dialysis fluid and the blood of the patient constantly replenished and replaced

A

to maintain a steep concentration gradient for urea to diffuse across; this causes the patient’s blood to contain no urea and to contain normal levels of ions and water

98
Q

pros and cons of dialysis

A

PROS:
- no need to wait for donor
- no risk of immune rejection
- no immunosuppressants

CONS:
- it is expensive
- you have to eat a controlled diet (to not produce too much urea)
- inconvenient and time consuming; need to visit a hospital several times a week for several hours
- there is a risk that excess ions, water and urea will build up between sessions which can be dangerous

99
Q

pros and cons of kidney transplants

A

PROS:
- allows patient to lead normal life with little inconvenience
- cheaper than dialysis in the long-run

CONS:
- risk of immune rejection
- immunosuppressants; could forget to take AND increases risk of other infections
- shortage of kidney donors, so long waiting list; some could die before even getting a transplant

100
Q

problems with the kidneys that require dialysis or transplants

A
  • damaged due to injury
  • polycystic kidneys (genetic)
  • bacterial infections
  • kidney failure
101
Q

what happens during puberty

A

reproductive hormones cause secondary sex characteristics to develop

102
Q

what is the main male reproductive hormone

A

testosterone produced by the testes and it stimulates sperm production

103
Q

what is ovulation

A

eggs beginning to mature and one being released approximately every 28 days

104
Q

what does FSH cause

A

maturation of an egg in the ovary, and also stimulates ovaries to produce oestrogen

105
Q

what is FSH secreted by

A

the pituitary gland

106
Q

what does LH cause

A

stimulates the release of the egg from the ovary, triggering ovulation

107
Q

what is LH secreted by

A

the pituitary gland

108
Q

what is oestrogen secreted by

A

the ovaries

109
Q

what does oestrogen cause

A

it stimulates the uterus lining to grow again after menstruation; also inhibits the release of FSH; also stimulates the release of LH

110
Q

what is progesterone secreted by

A

an empty egg follicle

111
Q

what does progesterone cause

A

it helps maintain a pregnancy if the egg is fertilised; also inhibits the release of both FSH and LH

112
Q

what is progesterone’s secondary role

A

it maintains the uterus lining in the second half of the cycle so it’s ready to receive a developing embryo if the egg is fertilised

113
Q

describe the trend in blood oestrogen level

A

it increases to prepare for ovulation and decreases when ovulation begins

114
Q

how do oral contraceptives work

A

they contain hormones to inhibit FSH production so that no eggs mature

115
Q

how do injections, implants and skin patches work

A

they slow release progesterone to inhibit the maturation and release of eggs for a number of months or years

116
Q

how do barrier methods work

A

barrier methods such as condoms and diaphragms which prevent the sperm reaching an egg

117
Q

how do intrauterine devices

A

they prevent the implantation of an embryo or release a hormone

118
Q

how do spermicidal agents work

A

they kill or disable sperm

119
Q

when would you abstain from intercourse (as a method of contraception)

A

when an egg may be in the oviduct

120
Q

surgical process for males and females as a contraceptive

A

sterilisation

121
Q

what is IVF

A

IVF is a treatment that involves giving a mother FSH and LH to stimulate the maturation of several eggs

122
Q

how does IVF work

A

1) mother is given FSH and LH to stimulate maturation of several eggs
2) the eggs are collected from the mother and fertilised by sperm from the father in the laboratory
3) the fertilised eggs develop into embryos
4) at the stage when they are tiny balls of cells, one or two embryos are inserted into the mother’s uterus (womb)

123
Q

cons of IVF

A
  • it is very emotionally and physically stressful
  • the success rates are not high
  • it can lead to multiple births which are a risk to both the babies and the mother
124
Q

why do plants produce hormones

A

to coordinate and control growth and responses to light (phototropism) and gravity (geotropism)

125
Q

what happens to a plant when there are unequal distributions of auxin

A

this causes unequal growth rates in plant roots and shoots

126
Q

why are gibberellins important

A

they initiate seed germination

127
Q

why is ethene important

A

it controls cell division and ripening of fruits

128
Q

how do negative feedback systems work

A

they work to maintain a steady state; if a factor in the internal environment increases, changes take place to reduce it and restore the original level; if a factor in the internal environment decreases, changes take place to increase it and restore the original level

129
Q

what are plant growth hormones used in

A

agriculture and horticulture

130
Q

what are auxins used as

A
  • as weed killers
  • as rooting powders
  • for promoting growth in tissue culture
131
Q

what are ethenes used for

A

they’re used in the food industry to control ripening of fruit during storage and transport

132
Q

what can gibberellins be used to

A
  • end seed dormancy
  • promote flowering
  • increase fruit size

bio spec (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions