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Eddie's Biology > Co-ordination and response > Flashcards

Co-ordination and response Flashcards

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1
Q

What is a voluntary action

A

A voluntary action involves a conscious decision made within the cerebral hemispheres of the brain Relatively slow response The same stimulus can provide a variety of different responses Many voluntary actions are learnt

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2
Q

What does the nervous system allow us to do

A

It allows us to make sense of our surroundings and respond to them and to co-ordinate and regulate body functions

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3
Q

What are neurones

A

Nerve cells found in the nervous system

Hundreds of neurones make up one nerve

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4
Q

What are receptors

A

They are found in sense organs

They respond to changes in the environment (stimuli)

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5
Q

What is an effector

A

Parts of the body that respond to a stimulus

e.g. muscles and glands

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6
Q

What are the three different types of neurone and what are their functions

A

Sensory - Carry nerve impulses from sense organs to the central nervous system

Relay - Found in the central nervous system and connect sensory and motor neurones

Motor - Carry nerve impulses from the central nervous system to effectors

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7
Q

Why can a nerve impulse only travel in one direction along the reflex arc?

A

Because the neurotransmitter is present on the only one side of the synapse Drugs act as synapses

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8
Q

What does the human nervous system contain

A

Central nervous system - brain and spinal cord

Peripheral nervous system - all of the nerves in the body

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9
Q

What is an involuntary action

A

An involuntary action only involves the spinal cord and other parts of the brain Faster response The same stimulus produces the same response; it is automatic Many involuntary actions are instinctive

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10
Q

What is a synapse?

A

A tiny gap between two neurones

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11
Q

Describe what happens when a nerve impulse arrives at the end of a sensory neurone

A

Vesicles containing neurotransmitters move to the cell membrane of the sensory neurone The vesicles burst open and empty the neurotransmitter into the synaptic cleft The neurotransmitter diffuses across the cleft The neurotransmitter molecules slot into their receptors on the membrane of the relay neurone This sets off a nerve impulse in the relay neurone

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12
Q

How are neurones adapted

A

They have a long axon to carry impulses over long distances

The axon is insulated by a fatty (myelin) sheath, increases the speed of nerve impulse

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13
Q

What do dendrites do

A

Dendrons are tiny branches at the end of neurones which break up in dendrites which recieve incoming nerve impulses

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14
Q

What is a nerve impulse

A

An electrical signal that passes along a nerve impulse

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15
Q

What is a sense organs

A

Groups of receptor cells responding to specific stimuli; light, touch, sound, tempurature and chemicals

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16
Q
A
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17
Q

What does the iris do

A

Controls how much light enters the pupil

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18
Q

What does the lens do

A

Focuses light on the retina

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19
Q

What do the pupil do

A

A hole in the iris that allows light to pass through to the lens

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20
Q

What does the cornea do

A

Refracts light

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21
Q

What does the retina do

A

Contains light receptors, some sensitive to light of different colours

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22
Q

What does the fovea do

A

Where light is focused when you look directly on an object; geatest concentration of receptors is here

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23
Q

What does the blind spot do

A

No receptors here; so light falling onto this area is not seen

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24
Q

What does the optic nerve do

A

Carries nerve impulses to the brain

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25
Q

What happens when light enters the eye

A

Light enters the eye through the cornea

Light is refracted as it passes through the cornea and the lens

Light is focused onto the recpetor cells in the retina

This sets off nerve impulses that travel along the optic nerve to the brain

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26
Q

Why do the muscles in the iris contract making the diameter of the pupil smaller in bright light

A

The bright light may damage the retina

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27
Q

What happens when bright light falls on the retina

A

Impulses pass alomng sensory neurones to the brain, and then along motor neurones to the muscles in the iris

Circular muscles in the iris contract, the diameter of the pupil is decreased, reduces amount of light able to pass through the pupil

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28
Q
A
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29
Q

What happens when dim light falls on the retina

A

Radial muscles in the iris contract, this widens the pupil allowing more light to pass through

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30
Q

What are the radial and circular muscles in the eyes

A

Antagnostic, they have opposite effects

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31
Q

What do the suspensory ligaments do

A

They hold the lens in place

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32
Q

How does an eye focus on a close object

A

The lens needs to be wide and thick, so it refracts more strognly

To achieve this, the suspensory ligaments must be loose

the ciliary muscles must contract

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33
Q

How does an eye focus on a distant object

A

The lens must be narrow and thin, to refract light less strongly

The suspensory ligaments must be pulled tight

The ciliary muscles need to relax

34
Q

What two types of light sensitive cell does the retina contain

A

Rods - sensitive to dim light

cones - sensitive to bright light

35
Q

Where are rods and cones found

A

Cones - In the fovea

Rods - in most other parts of the retina

36
Q

What is a hormone

A

A chemical substance, produced by a gland and carried by blood which alters the activity of one of more specific target organs

37
Q

What gland secretes adrenaline

When is it secreted

what is its function

A

The adrenal glands; it is secreted when the person is excited or freightened; it increases heart rate, breathing rate, pupils dilate, causes concentration of glucose in blood to increase

38
Q

What gland secretes insulin

when is it secreted

what is insulins function

A

The pancreas; when the concentration of glucose in the blood is too high, causes the liver to reduce concentration of glucose in the blood

39
Q

Where is testosterone secreted

when is it secreted

what is its function

A
  • Secreted from the testes
  • it is secreted from puberty onwards
  • its function is to produce male secondary sexual characteristics
40
Q
  • Where is oestrogen secreted
  • When is it secreted
  • what is its function
A
  • Secreted from the ovaries
  • from puberty onwards
  • secreted to produce female secondary sexual characteristics and to regulate menstrual cycle
41
Q

What are the difference between nervous and hormonal control

A

Hormonal control acts slower than nervous control as it must travel in the blood rather than along neurones as electrical signals

Hormones take a longer time to break down as they remain in the blood for a while whereas nerve impulses happen at an instant in time

42
Q

What is the general type of gland that produces hormones

A

An endocrine gland

43
Q

Define “homeostasis”

A

The maintenance of a constant internal environment

44
Q

What happens if the internal body tempurature rises too high

A
  • Blood tempurature receptors in the brain detect the rise in tempurature
  • This causes the brain to send nerve impulses to the sweat glands
  • this makes the sweat glands secrete more sweat, which evaporates and cools the skin
  • the erector muscles relax so the hairs lie flat
45
Q

What happens if the internal body tempurature falls too low

A
  • Blood tempurature receptors in the brain detect the fall in tempurature
  • This makes the brain send nerve impulses to the erector muscles and skeletal muscles
  • This makes the erector muscles contract so hairs are pulled erect, trapping an insulating layer of hair
  • the skeletal muscles contract and relax quickly (shivering), releasing heat that helps warm the blood
46
Q

What can happen to arterioles (homeostasis)

A

They can become narrower (vasoconstriction) or wider (vasodilation)

47
Q

What happens if vasoconstriction occurs

A

Arterioles become narrower

  • less blood is delivered to the surface capillaries, and blood is diverted beneath the fat layer
  • this reduces heat loss from the blood to the air
48
Q

What happens if vasodilation occurs

A

The arterioles become wider

  • more blood flows through the surface capillaries
  • more heat can therefore be lost from blood to the air
49
Q

What happens when blood glucose concentration rises too high

A
  • The pancreas secretes insulin into the blood
  • Insulin is carried into the blood from the liver
  • insulin stimulates the liver to take up glucose from the blood
  • the liver changes glucose into the polysaccharide glycogen, and stores it
50
Q

What happens when blood glucose levels fall too low

A
  • The pancreas secretes glucagon into the blood
  • glucagon is carried in the blood to the liver
  • glucagon stimulates the liver to break down glycogen into glucose
  • the liver reduces glucose into the blood
51
Q

What is type 1 diabetes

A

The type where the person’s own immune system attacks and destroys cells in the pancreas which secrete insulin

52
Q

Why after a meal does a diabetes patient have very high glucose levels in his blood

A

Because there is no insulin to stimulate the liver to convert the extra glucose in the blood into glycogen

53
Q

Between meals, what is happening to a diabetes patient’s glucose levels and why

A

The glucose levels are falling much lower than usual

This is because the body gradually uses up the glucose in respiration

But there is no glycagon in the liver to be converted to glucose to top up the glucose concentration in the blood

54
Q

What are some symptoms of diabetes

A
  • Thirst - because a high concentration of glucose in the blood decreases its water potential; the brain percieves this as the body needs more water
  • Having glucose in urine - happens when the blood glucose concentration rises so high that the kidneys are unable to absorb all the glucose back into the blood
  • Blurred vision - happens because the change of water potential of the blood cause osmosis to occur, which changes the shape of the lens of the eye
  • feeling very tired between meals - betwee meals blood sugar levels drop very low, as there is not enough glucose for respiration to occur
55
Q

How is type 1 diabetes cured

A

A combination of diet and insulin injections

  • eat regular small meals, to even out the intake of carbohydrates throughout the day
  • Injecting insulin after a meal to reduce any spikes in the blood glucose concentration
56
Q

Definition of gravitropism

A

A response in which parts of the plant grow towards or away from gravity

57
Q

Definition of phototropism

A

A response in which parts of a plant grow towards or away from the direction which light is coming from

58
Q

How does a plant grow in even light

A

The shoot grows straight upwards

59
Q

How does a plant grow in light from one side

A

A shoot grows towards the light

This is phototropism

60
Q

How does a plant grow in no light

A

In darkness, a shoot grows very tall and spindly, and looses its green colour

61
Q

What are auxins and what do they do

A

Auxins are plant hormones which stimulate cells to get longer by making plants take up extra water

62
Q

What happens to auxins when light shines on one side of the plant

A

active transport causes auxin to accumulate on the shady side

  • This means that the shady side elongates more causing it to curve
63
Q

What happens to the auxin on the shaded side of the plant

A

They elongate more than the cells on the bright side

The shoot curves towards the light

64
Q

What happens to auxins on a horizontally growing shoot when light is shone on the up side

  • What does it cause
A

Auxins accumulate on the lower side

  • This causes elongation of auxins on the dark side which causes the shoot to curve upwards
65
Q

Defintion of a drug

A

A substance taken into the body that modifies or affects chemical reactions in the body

66
Q

What is a medicinal drug

A

A drug used to prevent or cure disease

67
Q

What are antibiotics

A

Drugs that kill bacteria inside the body.

  • Used to cure infections that are caused by pathogenic bacteria
68
Q

How do certain types of bacteria become reistant to antibiotics

A
  • Within a population of bacteria, there are some bacterium that have alleles that make them resistant to antibiotics
  • these bacteria survive and reproduce to create the next generation in which all of them have the allele
69
Q

How can we reduce the risk of bacteria developing resistance

A

By reucing the use of antibiotics

e.g. don’t give people antibiotics who have viral infections, which antibiotics are ineffective against

70
Q

What is alchahol

A
  • A depressant drug
  • people become addicted to alchahol and cannot function without it
  • They experience withdrawal symptoms like nausea and tremors
  • causes agression and anti social habits
71
Q

What is a depressant drug

A

A drug which slows reaction times and reduces self-control

72
Q

What is heroin

A
  • Heroin is a depressant
  • It reduces pain and slows breathing rate
  • injection of heroin carries risks of transmitting pathogens into the blood, such as HIV
    *
73
Q

What does heroin affect?

A

Synapses

  • It fits into receptors that normally accept neurotransmitters called endorphins which make us feel good
  • heroin reduces the production of endorphins
  • if a person takes heroin, they have fewer endorphins when sober creating awful withdrawals
74
Q

What does cigarette smoke contain

A

Carbon monoxide - binds to haemoglobin and prevents transfer of oxygen

Nicotine - a highly addictive stimulant drug

Tar - mixture of different substances some of these are carcinogens which carry the risk of cancer

75
Q

What does tobacco smoke also cause

A
  • Chronic obstructive pulmonary disease -
  • happens when delicate walls of alveoli break down, so that gas exchange cannot occur
  • their cells cannot recieve oxygen so they cannot respire
  • eventually they dont have enough energy to walk around and need to sit all day, breathing from an oxygen cylinder
76
Q

Why does smoking cause cancer

A

The chemicals in cigarette smoke cause changes in the DNA which lead to the cells dividing uncontrollably and forming cancerous tumors

77
Q

What chemicals are steroids

A
  • Testosterone
  • Osetrogen
  • Progestorone
78
Q

What is testosterone

A

An anabolic steroid

79
Q

What does an anabolic steroid cause

A

It stimulates metabolic reactions that result in muscle developemtn and increased strength

80
Q

What is a correlation

A

One thing causes another

Eddie's Biology (15 decks)

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