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OCR A GCSE Biology (B1-B3) > B3.1 - Nervous system > Flashcards

B3.1 - Nervous system Flashcards

1
Q

What does the nervous system do

A
  • detects change in external environment and sends it to the brain
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2
Q

what are the three stages of a nervous response?

A

1) stimulus (change in environment)
2) sensory detector (detects stimulus)
3) effector (responds to an impulse)

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3
Q

how to glands respond to a stimuli?

A

release hormones

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4
Q

where are receptor cells found?

A

sense organs (eyes, ears, nose, tongue, skin)

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5
Q

what do receptor cells do?

A

change the stimuli to electric impulses to travel along neurone to CNS

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6
Q

what is the CNS made of?

A

brain and spinal cord

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7
Q

how is the spinal cord protected?

A

by the vertebrae column (backbone)

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8
Q

what is the stimulus for skin?

A

pressure, heat

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9
Q

what is the role of sensory neurones?

A

carry electric impulses from receptor cells to CNS

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10
Q

what is the role of motor neurones?

A

carry electric impulses from CNS to effectors

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11
Q

what is the nervous system made of?

A
  • brain
  • -spinal cord
  • neurones
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12
Q

what are effectors?

A

muscles or glands that respond to the change in environment

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13
Q

what are synapses?

A

gaps between neurones which allows nerve impulses to travel

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14
Q

how do synapses work? (5)

A
  • electrical impulse reaches the end of neurone
  • triggers the release of chemicals called neurotransmitters from vesicles
  • neurotransmitters diffuse (move down a concentration gradient) across the synapse.
  • neurotransmitters bind to receptors on the next neurone.
  • presence of the neurotransmitter causes the production of an electrical impulse in the next neurone.
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15
Q

how do reflex actions help?

A

allow us to respond to dangerous situations rapidly and automatically

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16
Q

give three examples of reflex actions

A

blinking, sneezing, flinching from a hot pan

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17
Q

what is a stimulus?

A

change in the environment to which the body needs to respond

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18
Q

describe the response arc

A
  • stimulus detected by a receptor
  • sensory neurone carries signal (through impulse) to CNS
  • motor neurone carries electrical impulse from the CNS to an effector.
  • effector (a muscle or gland) produces the response to the stimulus
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19
Q

what can effect human reaction time?

A

caffeine, exercise

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20
Q

what is the role of the brain?

A

processes all the information collected by body and produces a co-ordinated response

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21
Q

medulla

A

unconscious activities (breathing, heart rate)

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22
Q

cerebellum

A

muscle coordination (posture, balance, speech)

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23
Q

cerebral cortex

A

conscious thought (memory, language)

24
Q

Why is it hard to treat brain damage or problems in the brain?

A

we don’t understand it enough, easy to make mistake and cause irreversible damage

25
Q

name some of the techniques used in neuroscience (3)

A
  • fMRI
  • CT scans/electrical stimulation
  • MRI scanners
26
Q

what are the 4 different ways you can damage your PNS or CNS?

A
  • injury
  • disease
  • genetic condition
  • ingesting a toxic substance (lead)
27
Q

what does damaging the nervous system cause?

A

prevents impulse being passed through nervous system effectively

28
Q

effects of peripheral nervous system damage? (3)

A
  • inability to detect pain
  • numbness
  • lack of co-ordination
29
Q

how can PNS damage be fixed? (2)

A
  • limited ability to regenerate (minor nerve damage reveals), and symptoms gradually decrease
  • severe nerve damage treated through surgery
30
Q

how can nerve damage be treated through surgery?

A

sections of nervous tissue can be drafted over damaged tissue (restoring electric conduction path for impulse)

31
Q

can the CNS regenerate

A

no, unless corrected by surgery

32
Q

why is it difficult to repair the spinal cord?

A
  • 1.5 cm in diameter

- so identifying and repairing damage to an individual nerve fibre without damaging others is difficult

33
Q

why is damage to the interior of the brain difficult to repair?

A

it is difficult to diagnose, not many different treatments available as hard to test, as may kill person

34
Q

optic nerve

A

Transmits visual information, in the form of electrical impulses, from the retina to the brain

35
Q

cornea

A

The transparent frontal portion of the eye responsible for refracting light

36
Q

sclera

A

The white of the eye; the opaque protective outer layer (all around the eye)

  • even in a cross-sectional diagram, would see it on outer edge
37
Q

retina

A
  • Packed with receptor cells
  • sensitive to both the brightness
  • colour of light
38
Q

pupil

A

A hole in the centre of the iris through which light passes to get to the retina

39
Q

iris

A

controls pupil dilation and therefore quantity of light reaching retina

40
Q

ciliary muscles

A
  • ring of smooth muscle

- change shape of lens (to focus light)

41
Q

suspensory ligaments

A
  • ring of fibres, connect ciliary muscle to lens
42
Q

what is the process of changing lens shape in order to focus on an object at its distance from the eye changes?

A

accommodation

43
Q

What happens when our eyes focus on a distant object?

A
  • minor refraction of light rays
  • ciliary muscles relax
  • lens become flatter and thinner
  • suspensory ligaments tighten
44
Q

what controls how our eyes adapt to different light levels?

A

iris

45
Q

what is hyperopia, and treatment?

A
  • longsightedness
  • lens too thin
  • eyeball too short
  • light ends up behind retina
  • convex lens (fat one)
46
Q

what is myopia and treatment?

A
  • short sightedness
  • lens too thick
  • eyeball too long
  • light in front of retina
  • concave lens (inwards),
47
Q

what causes colour blindness?

A
  • defects in the photoreceptors
48
Q

focusing on a close object?

A

contraction of the ciliary muscles and loosening of the suspensory ligaments.

49
Q

focusing on a far object?

A

loosening of the ciliary muscles and contraction of the suspensory ligaments.

50
Q

as people get older, the lens in the eye becomes less flexible and cannot change shape easily.
This means they cannot focus clearly on near objects.
Explain why.

A
  • lens cannot become fat

- light is focused behind retina

51
Q

what is a CT scan and what does it show?

A
  • computed tomography
  • uses X-rays to create 3D images of inside of body
  • but cannot be used regularly (X-rays can cause cancers)
  • only show still images
52
Q

what is MRI scanning and how does it work? (3)

A
  • magnetic resonance imaging
  • use powerful magnets to identify brain abnormalities
  • see which areas of brain are active
53
Q

what is fMRI scanning and how does it work?

A
  • functional magnetic resonance imaging
  • produces images in real time by sending magnetic radiation
  • radiation bounces back and can see the properties/density of tissue ie. whether it is oxygenated or not
  • areas are active when increased blood flow during a specific activity
54
Q

how does electrical stimulation work?

A
  • electrodes places inside animal/human brains

- electrodes transmit electrical impulses + result in movement

55
Q

draw a neurone out

label with - nucleus, cell body, axon, dendrites

A

nucleus - little circle
cell body - area around little circle
axon - the body - long bit
dendrites - sticky out bits around cell body

55
Q

what does the cerebrum control?

A

complex behaviour (memory/learning/personality/conscious thought)

OCR A GCSE Biology (B1-B3) (12 decks)

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