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Biology paper 2 > Homeostasis > Flashcards

Homeostasis Flashcards

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1
Q

In the human body, homeostasis controls

A

Blood glucose concentration

Body temperatures

Water levels

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2
Q

Receptors

A

Cells that detect stimuli

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3
Q

Coordination centers

A

Process the information received from the receptors

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4
Q

Effectors

A

Bring about the responses to bring the conditions in the body back to optimun levels

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5
Q

Abstinence

A

Deliberately refraining from having sexual intercourse

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6
Q

Accommodation

A

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

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7
Q

Adrenaline

A

A hormone that is produced by the adrenal glands in response to fear or stress which increases the heart rate and boosts the delivery of blood to the brain and muscles as a part of the “fight” or flight” response

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8
Q

Antidiuretic hormone (ADH)

A

A hormone that increases the re absorption of water water on the kidney tubules

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9
Q

Coordination centres

A

Areas of the body like the brain, spinal cord and the pancreas that receive and process information from receptors.

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10
Q

Deamination

A

A process occurring in the liver that removes the amino group from an amino acid to produce ammonia

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11
Q

Dialysis

A

A method of treating kidney failure or disease where the blood is artificially filtered to remove waste and toxins

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12
Q

Effectors

A

Muscles or glands which bring about responses which restore optimum levels.

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13
Q

Ethene

A

A type of plant hormone which controls cell division and the ripening of fruits

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14
Q

Follicle stimulating hormone (FSH)

A

A female reproductive hormone that causes the maturation of an egg in the ovary.

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15
Q

Geotropism/gravitropsm

A

A plants directional growth response to gravity

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16
Q

Gibberellins

A

A type of plant hormone which initiates seed germination

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17
Q

Gland

A

A group of cells that secrete chemicals called hormones directly into the bloodstream

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18
Q

Glucagon

A

A hormone produced by the pancreas that causes glycogen to be converted into glucose and released into the blood

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19
Q

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.

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20
Q

IVF

A

Fertilizing a woman’s egg using sperm outside the body

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21
Q

Hyperopia

A

A defect in the eye where nearby objects appear out of focus also called farsightedness

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22
Q

LH

A

A female reproductive hormone that stimulates the release of an egg

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23
Q

Myopia

A

A defect in the eye where distant objects appear out of focus

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24
Q

Oestrogen

A

The main female reproductive hormone which causes the uterus lining to grow and repair

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25
Q

Phototropism

A

A plants direction growth response to light

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26
Q

Reflex action

A

A rapid and automatic response to a stimulus

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27
Q

Selective reabsorbtion

A

Reabsorbing certain molecules back into the blood after they had been filtered out.

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28
Q

Stimuli

A

changes in the environment

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29
Q

Target organ

A

The organ which a hormone acts on to produce an effect

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30
Q

Testosterone

A

The main male reproductive hormone produced by the tests and it stimulates sperm production

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31
Q

The brain

A

An organ made of billions of interconnected neurones which controls complex behavior and different regions that carry out different functions

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32
Q

The CNS

A

The brain and spinal cord which coordinate the response of effectors

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33
Q

Thermoregulartory centre

A

An are of the hypothalamus in the brain which contrains blood temperature receptors and regulates body temorautes

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34
Q

Thyroxine

A

A hormone produced by the thyroid gland that increases the metabolic rate in the body

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35
Q

Type 1 diabetes

A

A disorder which the pancreas fails to produce sufficient insulin which is characterized by uncontrolled high blood glucose levels

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36
Q

Type 2 diabetes

A

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

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37
Q

Vasoconstriction

A

The constriction of blood vessels

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38
Q

Vasodilation

A

The dilation of blood vessels

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39
Q

Peripheral nervous system

A

nerve cells that carry information to or from the CNS

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40
Q

What is a bundle of neurones called

A

a nerve

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41
Q

Features of a neurone

A
  • Has a axon which is insulated by a myelin. They are also long so can carry messages up and down the body
  • Tiny dendrons which can branch further as denrites at each end. These receive incoming impulses from other neurones.
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42
Q

Why is a reflex arc faster than normal responses

A

Follows the general sequence and does not involve the conscious part of the brain, which makes it much quicker

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43
Q

Order of stimulus to response

A

Stimulus –> receptor –> sensory neurone –> relay neurone –> motor neurone –> effector –> response

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44
Q

When two neurones meet there lies a gab what is the gab called

A

A synapse

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45
Q

How does information go from one side of the synapse to the other .

A
  1. An electrical impulse travels along the first axon
  2. This triggers the nerve - ending of a neurone to release neurotransmitters.
  3. These chemicals diffuse across the synapse and bind with the receptor molecules on the membrane of the second neurone.
  4. The receptor molecules on the second neurone bind only to specific neurotransmitters released from the first neurone. This stimulates the second neurone to transmit the electrical impulse.
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46
Q

Rule drop test practical (If you don’t know it go blurt it rn bitch)

A
  1. Work with a partner
  2. Person A holds out their hand with a gap between their thumb and first finger
  3. Person B holds the ruler with the zero at the top of person A’s thumb

4.Person B drops the ruler without telling person A and they must catch it

  1. The number level with the top of person A’s thumb is recorded in a suitable table. Repeat this 10 times.
  2. Swap places and record another 10 attempts.
  3. You can use the conversion table to help convert your ruler measurements into reaction time or just record the catch in distance cm.
  4. Then repeat the practical but first drink a can of coca cola that contains caffeine
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47
Q

cerebrum

A

Outer layer is called the cerebral cortex. Which splits into two hemispheres and is highly folded it controls intelligence, personality, conscious thought and high level functions such as language and verbal memory

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48
Q

The cerebellum

A

Which controls the balance coordination of movement and muscular activity

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49
Q

Medulla

A

Controls the unconscious activities such as heart rate and breathing rate

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50
Q

Hypothalamus

A

Which is the regulating center for temperature and water balance within the body

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51
Q

EEG’s are

A

Where scientists stimulate different parts of the brain with electrical current and see what the person does to this new current

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52
Q

MRI brain scans

A

Uses strong magnetic fields and radio waves to show details of the brain structure and function. Patients are asked to perform various tasks and by looking at the scan scientists can see which parts of the brain are active when the task is carried out.

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53
Q

Neurosurgery important things to consider

A

All surgery can be deadly but the brain is so complex and delicate that doing it could leave to more damage or side effects which may effect the patients life. The should decide if it is worth it.

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54
Q

Cornea

A

Refracts light

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55
Q

Iris

A

Controls how much light enters the pupil

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56
Q

Lens

A

Further refracts light to focus it onto the retina

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57
Q

Retina

A

Contains the light receptors

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58
Q

Optic nerve

A

Carries impulses between the eye and the brain

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59
Q

Sclera

A

Tough white outer layer of the eye. Helps protect eye from injury

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60
Q

Which are more sensitive to light rods or cones.

A

Rods

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61
Q

Rods

A

are used to see levels of light

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62
Q

Cones

A

Are used to see colour

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63
Q

Pupil reflex

A

The amount of light entering the eye is controlled by a reflex action. The size of the pupil changes in response to bright or dim light. This is controlled by the muscles of the iris

64
Q

When light is dim are the radial muscles of iris contracted or relaxed

Are the circular muscles of the iris relaxed or contraccted

A

Radial muscles are contracted when dim

Circular muscles are relaxed.

65
Q

When light is bright are radian muscles of iris relaxed or contracted

Are circular muscles of the iris contracted or relaxed

A

Relaxed

Contracted

66
Q

When an eye views an object close to it how does it respond

A

Ciliary muscles contract

Suspensory ligaments slacken/loosen

Muscle tension is low

Lens shape is fat/thicker

Refraction light is strongly refracted

67
Q

When an eye views an object distant from it how does it respond

A

Ciliary muscles relax

Suspensory ligaments stretch/tighten

Muscle tension is high

Lens shape is thin

Refraction is only refracted slightly

68
Q

When someone suffers from myopia how could it be caused

A

The eyeball being elongated - so that the distance between the lends and the retina is too great

The lens being too think and curved - so that light is focused in front of the retina.

69
Q

How can myopia be corrected

A

By placing a concave lens in front of the eye

70
Q

How could hyperopia be caused

A

The eyeball is being too short so the distance between the lens and retina is too small

A loss of elasticity in the lens meaning it cannot become think enough to focus which is often age related.

71
Q

Hyperopia can be fixed how

A

By placing a convex lens in front of the eye

72
Q

Ways to fix eye problems

A

Laser surgery

Replacement lenses

73
Q

Positive tropisms

A

The plant grows towards the stimulus

74
Q

Negative tropisms

A

The plant grows away from the stimulus

75
Q

Phototropism

A

Is a response to the stimulus of light

76
Q

Auxins

A

Are a family of plant hormones.

77
Q

Where are auxins mostly made

A

Mostly made in the tips of growing stems and roots, which are known as apical meristems, and can diffuse to other parts of the stems or roots.

78
Q

What do auxins control

A

The growth of plants by promoting cell division and causing elongation in plant cells

79
Q

Stems and roots response differently to auxin how do they respond differently

A

Cells in stems grow more

Cells in roots grow less

80
Q

In a stem, the shaded side contains more auxin and grows longer, which causes the stem to ______ _____ ___ ______ and to note the plant does NOT bend towards the light

A

grow towards the light

81
Q

Required practical (to investigate the effect of light or gravity on the growth of newly germinated seedlings)

blurt it rn if u don’t know it

ur probably feeling tired get the fuck up and work I dont give a fuck anymore.

A
  1. Put the cotton wool into three petri dishes, and then add equal volumes of water into each dish
  2. Add ten seeds to each dish and place them in a warm place where they won’t be distributed
  3. Allow the seeds to germinate and add more water if the cotton wool dries out.
  4. Once the seeds have germinated ensure the petri dishes each contain the same number of seeds, and remove any extra seeds if necessary.
  5. One petri dish will sit in full light on a windowsill, the second will be in a dark cupboard, and a final dish will be placed in partial light
  6. Every day for one week, measure the height of each seedling and record the results in a table. You must record the height of the individual seedlings on each day.
  7. Calculate the mean of the seedlings each day, and compare the mean heights in three different locations
82
Q

Gibberelins

A

Are a group of plant hormones responsible for growth and development, are important for initiating seed germination.

83
Q

Germination

A

Seed begins to sprout and grow

84
Q

What can low concentrations of gibberelins be used for

A

To increase the speed of germination and they can stimulate cell elongation and cause plants to grow taller

85
Q

Gibberellins mainly used for

A

End seed dormancy

Promote flowering

Increase fruit size

86
Q

How can ethene be used in growing plants

A

It speeds up ripening in bananas and other fruit. It controls the cell division during plant growth.

87
Q

In the food industry fruit is often picked unripe and then transported. This prevents fruit from over ripening on the journey. It is ripended during storage by adding ethene and then taken to the shops (READ)

A

In the food industry fruit is often picked unripe and then transported. This prevents fruit from over ripening on the journey. It is ripended during storage by adding ethene and then taken to the shops (READ)

88
Q

Auxins can be used for

A

a weed killer

As rooting powder

For promoting growth in tissue culture

89
Q

Disadvantage of weedkillers

A

Some species of animals rely on it as a food source. This can result in a reduction of biodiversity.

90
Q

ADH
source =
organ
role
effects

A

Pitutary gland
Kidney
Controlling the water content of the blood
Increases reabsorption of water by collecting ducts

91
Q

Adrenaline
source =
organs
role
effects

A

Adrenal glands
Several targets including the respiratory and circulatory system
Preparation for fight or flight
Increases breathing rate, heart rate flow of blood to muscles conversion of glycogen to glucose.

92
Q

Insulin
source =
organs
role
effects

A

Pancreas
Liver
Controlling blood gluecose levels
Increase conversion of glucose into glycogen for storage

93
Q

Negative feed back mechanism

A

Mechanism to lower raised levels of something and to raise reduced levels of something

94
Q

Thyroxine

A

Stimulates the basal metabolic rate.

95
Q

What happens if there are low thyroid levels in the blood stream

A

It stimulates the hypothalamus to release TRH and this causes the pituitary gland to release TSH so the thyroid gland releases more thryoxine so thyroxine levels return to normal

96
Q

Normal thyroxine levels what happens

A

Normal thyroxine levels in the blood stream prevent TRH from being released from the hypothalamus and this prevents the release of TSH from the pituitary, so normal blood levels are maintained.

97
Q

Adrenaline is released into the blood stream what effects does it create

A

Increases breathing rate, heart rate, and conversion of glycogen to glucose so more energy is released in the muscles.

It diverts blood away from areas, such as the digestive system towards the muscles

98
Q

Action of insulin when there is low glucose

Effects on pancreas:

Effects on liver:

Effects on blood glucose levels:

A

Insulin not secreted into the blood

Does not convert glucose into gylocogen

Increases

99
Q

Action of insulin when there is high glucose

Effects on pancreas:

Effects on liver:

Effects on blood glucose levels:

A

Insulin secreted into the blood

Converts glucose into glycogen

Decrease

100
Q

If there is too much glucose in blood how does the pancreas respond

A

Produces insulin which enters the blood

Insulin allows glucose to be absorbed by body cells

Blood glucose reduced

101
Q

Diabetes is a condition where

A

The blood glucose levels remain too high.

102
Q

Diabetes treated how

A

By injecting insulin. The extra insulin causes the liver to convert glucose into glycogen which reduces the blood glucose level.

103
Q

Type 1 diabetes

A

Is a disorder in which the pancreas fails to produce enough insulin. This can be detected from an early age. It is characterized by uncontrolled high blood glucose levels

104
Q

Type 2 diabetes

A

In type 2 diabetes the person’s cells no longer respond to insulin produced by the pancreas. It is more common in older people. It can be controlled by a carbohydrate controlled diet an exercise regime. Carbohydrate is digested into glucose, which raises the overall bl65ood glucose level.

105
Q

controlling high blood sugar levels (negative feedback) (4)

A

The hormone insulin plays a key role. When blood sugar levels rise in the blood, insulin sends a signal to the liver, muscles and other cells to store the excess glucose. Some is stored as body fat and other is stored as glycogen in the liver and muscles.

106
Q

controlling low blood sugar levels (negative feedback) (4)

A

Whereas if the blood glucose level is too low the liver receives a message to release some of that stored glucose into the blood. This change is brought about by another hormone produced by the pancreas called glucagon.

107
Q

Puberty boys

A

Voice breaks

Hair grows on face and body

Body becomes more muscular

Testes start to produce sperm cells

108
Q

Puberty boys and girls

A

Pubic hair grows

Underarm hair grows

Sexual organs grow and develop

109
Q

Why does the menstrual cycle occur

A

prepared for pregnancy

110
Q

FSH (follicle stimulating hormone)

Produced where

Role

A

Produced : pituitary gland

Role: Cause an egg to mature in an ovary. Stimulates the ovaries to release oestrogen

111
Q

Oestrogen

produced

role

A

Ovaries

Stops FSH being produced so only one egg matures per cycle. Repairs, thickens and maintains the uterus lining. Stimulates the pituitary gland.

112
Q

LH

produced

Role

A

Triggers ovulation

113
Q

Ovulation

A

Release of a mature egg

114
Q

Progesterone

produced

role

A

Ovaries

Maintains the lining of the uterus during the middle part of the menstrual cycle during pregnancy

115
Q

Menstruation cycle steps

A

Menstruation day 7

Lining of uterus builds up day 14

Lining maintained day 21

Lining breaks down menstruation day 28

116
Q

Levels of Progesterone, LH and FSH stay for days 1-12

A

Eostrogen gradually increases and peaks on 12th day for the whole cycle.

Progesterone LH and FSH stay approximately at the same levels and begin to increase slightly from around day 12

117
Q

FSH and LH hormones levels from 12-28

A

FSH and LH patterns are very similar and peak during ovulation
at approximately 14 days during this cycle. They drop sharply on day 15 and stay constant until day 28.

118
Q

oestrogen and progesterone from day 13-21

A

Oestrogen drops during days 13 and 14, and progesterone continues to gradually increase until about day 21, when it slowly begins to decrease again. Oestreogen mirrors this shape and also has a second lower peak at about day 21

119
Q

How the oral contraceptive work or the pill

A

Contraceptive injections, implants or skin patches contain slow release progesterone to inhibit the maturation and release of eggs.

120
Q

Benefits of the pill/ oral contraceptive

A

they are more than 99% effective if taken correctly and can reduce the risk of certain cancers

121
Q

Risks of oral contraceptives

A

There are possible side effects, such as changes in weight, mood and blood pressure due to high levels of oestrogen.

122
Q

Physical barrier method

A

Condoms and diaphragms, which prevent the sperm reaching an egg.

123
Q

intrauterine devices (IUD)

A

prevents the implantation of an embryo or release of a hormone

124
Q

Spermicidal agents

A

Kill or disable sperm

125
Q

Surgical methods of male and female sterilisation

A

A vasectomy is where the sperm ducts are cut and tied

126
Q

Advantages and disadvantages of condoms

A

Easy and quick to use, but sometimes they can tear or rip

127
Q

Diaphragms advantages and disadvantages

A

Need to be put in just before sex and left in several hour afterwards

128
Q

IUD advantages and disadvantages

A

IUD can remain in position for up to 10 years.

However there is a small risk of causing an ectopic pregnancy
need to be fitted by a health professional

129
Q

Spermicidal agents advantages and disadvantages

A

Are physical agents and kill the sperm

Though some people may have a allergic reaction

130
Q

Abstaining advantages and disadvantages

A

Can be used successfully, but if the timings are not accurate the chance of pregnancy is high

131
Q

Surgical methods advantages and disadvantages

A

Cannot be reversed and is permenant

you never have to use about contraception again

132
Q

How would you help a women become pregnant if they don’t produce enough FSH to allow eggs to mature

A

Gives them drugs that contain FSH and LH, which stimulate eggs to mature in ovary

133
Q

Fertility treatments advantages and disadvantages

A

Increase the chance of a woman becoming pregnant

Although the treatments may not work and increase the boost of production of mature eggs, this increases the chance of multiple pregnancies that carry a risk of premature or underweight babies

134
Q

How may you help a women become pregnant if there are issues with the males sperm or a woman has blocked oviducts.

A

IVF can be used

135
Q

IVF process 1 - 4 steps

(4)

A

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

The eggs are collected from the mother and fertilised by sperm from the father in a dish in the laboratory

The fertilised eggs develop into embryos.

At the stage when they are tiny balls of cells one or two embryos are inserted into the mother’s uterus (womb)

136
Q

Advantages of IVF

A

It allows people to have babies of their own, who otherwise can’t due to a variety of reasons.

It has a safe track record and has been used since 1978. The embryos can be screened for genetic diseases, which is important for families that already have an affected child. Only unaffected embryos are used.

Unused eggs can be used for research or donated to other couples.

137
Q

Disadvantages of IVF

A

here are side effects form the drugs used, such as hot flushes and severe headaches.

There is a possibility of multiple births, which is dangerous for mother and babies.
Ovarian hyper-stimulation syndrome (OHS), when too many eggs develop in the ovaries.

It is very emotionally and physically stressful.

The success rates are not high.

138
Q

Ethical concerns of IVF

A

Some people believe couples only want designer babies with desirable qualities so may only want certain fertilised eggs.

Also, the embryos that are not used may be destroyed. Some people consider embryos to be new lives and view their destruction as unethical

139
Q

Why does the human body want to maintain a temperature of 37 degrees

A

because this is the optimum temperature for enzymes

140
Q

What controls the bodies temperature

A

The process is controlled by the thermoregulatory centre, which is contained in the hypothalamus in the brain

141
Q

How is temperature felt

A

by receptors on the skin

142
Q

What occurs when we get too hot

A

Sweat glands in the skin release more sweat. The sweat evaporates, transferring heat energy from the skin to the environment.

Blood vessels leading to the skin capillaries become wider - they dilate - allowing more blood to flow through the skin, and more heat to be lost to the environment. This is called vasodilation.

143
Q

What occurs when we get too cold

A

Skeletal muscles contract rapidly and we shiver. These contractions need energy from respiration, and some of this is released as heat.

Blood vessels, which lead to the skin capillaries, become narrower - they constrict – which allows less blood to flow through the skin and conserve the core body temperature. This is called vasoconstriction.

Hairs stand on end to create an insulating layer, trapping warm air

Skeletal muscles contract rapidly (shivering) to generate heat from respiration

144
Q

How do our hairs stand up

A

When we are too cold nerve impulses are sent to the hair erector muscles which contract raising the skin hairs.

145
Q

Osmoregulation

A

is the control of water levels and mineral salts in the blood.

146
Q

Why are water and mineral salts controlled in the blood

A

To protect cells by stopping too much water from entering or leaving them, as the concentrations of water and salts is the same inside and outside the cells. If body cells lose or gain too much water by osmosis, they do not function efficiently.

147
Q

Hypotonic

A

More dilute solution outside the cell

cells will swell and may burst

148
Q

Hypertonic

A

More concentrated solution outside the cell

Cells will shrivel

149
Q

What happens to a plant cell when they undergo osmosis and are hypotonic

A

cells become turgid when they are full of water

150
Q

What happens to a plant cell if they undergo osmosis and are hypertonic

A

Cytoplasm shrinks from cell wall.

151
Q

e.gs of water loss from body

A

urine from kidneys

sweat from skin

water vapour, from lungs when we exhale

152
Q

how does the skin lose water, ions and urea

A

they produce sweat which contain water ions and urea

153
Q

How do the lungs release water

A

When you exhale as well as an excess of carbon dioxide

154
Q

How does the body deal with an excess of amino acids

A

they 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

155
Q

Can the body store amino acids or proteins

A

no

Biology paper 2 (5 decks)

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