nervous system Flashcards

1
Q

what is a stimulus?

A

change in the environment that causes a reaction

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2
Q

what is a response?

A

an organism’s reaction

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3
Q

what is the role of the nervous system?

A
  • allows us to detect change and respond to it

- enables coordination of diff body parts

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4
Q

define involuntary action?

A
  • automatic, not controlled
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5
Q

define voluntary action?

A

controlled conconsciously

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6
Q

what are the components of the nervous system?

A
  1. Central Nervous system (brain, spinal cord)

2. Peripheral nervous system (cranial nerve, spinal nerve)

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7
Q

what does nervous tissue consists of?

A

nerve cells called neurones

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8
Q

what is the function of the cell body?

A
  • nucleus, cytoplasm, cell surface membrane and organelles
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9
Q

what is the function of the dendron?

A
  • nerve fibre that trasnmits nerve impulses towards cell body
  • end branches, dendrites, receive nerve impulses
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10
Q

what is the function of the axon?

A
  • nerve fibres that transmit nerve impulses away from cell body
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11
Q

what is the function of the myeline sheath?

A
  • layer of fatty substances enclosing many nerve fibres

- insulates axon

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12
Q

what is the function of node of ranvier?

A
  • regions where myelin sheath are absent

- speeds up transmissions of impulses by allowing them to jump from node to node

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13
Q

what is the function of the axon terminal?

A
  • transmit nerve impulses to effector
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14
Q

what is the function of the motor end plate

A
  • junction between axon terminal and dendrite
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15
Q

what is the function of the motor neurone?

A

transmit nerve impulses from CNS to nerve effectors

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16
Q

what is the function of the sensory neurone?

A

transmit nerve impulses from the sense organs to CNS

17
Q

what is a synapse?

A
  • junction between 2 neurones, or a junction between a neurone and an effector
  • impulses transmitted from axon to dendron of another neurone
  • transmission of nerve impulses across a synapse by chemical means (neurotransmitters)
18
Q

what are nerves?

A
  • a bundle of nerve fibres enclosed in a sheath of connectivity tissue
  • from brain : cranial nerve
  • from spine : spinal nerve
  • they may contain :
  • sensory nerve fibres only, conduct nerve impulses from sense organs
  • motor nerve fibres only, conduct to effector
  • mixed fibres (spinal nerves)
19
Q

what is the function of grey matter?

A
  • mainly consists of cell body of neurones
  • outer layer of brain
  • central part of spinal cord
20
Q

what is the function of white matter?

A
  • mainly consists of nerve fibres of neurones
  • central part of brain
  • outer layer of spinal cord
21
Q

what is the function of the dorsal root ganglion?

A
  • contains cell bodies of sensory neurones
22
Q

what is the function of the dorsal root?

A
  • only contains sensory neurones
23
Q

what is the function of ventral root?

A
  • only contains motor neurones
24
Q

what is the function of the spinal nerve?

A
  • nerve fibres from dorsal root and ventral root

- both sensory and motor neurones

25
Q

what is the nervous system pathway of touching ice?

A

receptor in skin –> sensory neurone –> relay neurone in spinal cord –> forebrain
- impulses produced in forebrain and transmitted by a relay neurone from forebrain, down white matter of spinal cord, to grey matter. Impulses transmitted to motor neurone then to effector muscles. Muscle contracts
forebrain –> relay neurone in spinal cord –> motor neurone –> effector

26
Q

what is a reflex action?

A

immediate response to a specific stimulus without conscious control

27
Q

what is cranial reflex?

A

controlled by brain, usually in head region (pupil reflex)

28
Q

what is spinal reflex?

A

controlled by spinal cord (knee jerk)

29
Q

what are the similarities of reflexes?

A
  1. both involve transmission of nerve impulses
  2. both involve motor neurone
  3. both involve effectors to carry out desired response
30
Q

what are the differences between the reflexes?

A
  1. boluntary involves conscious control but reflex does not involve conscious control
  2. voluntary may not have an immediate response but reflex has immediate response
  3. voluntary does not heed stimulus but reflex occurs in response to stimulus
  4. voluntary is intiated by brain but reflex is not initiated by brain
31
Q

what happens when your hand touches an hot object?

A
  1. receptors in skin
    - heat on object stimulates nerve endings (receptors) in your skin and impulses are produced
  2. sensory neurone
    - neurone impulses are transmitted along sensory neurone to spinal cord
  3. spinal cord
    - in spinal cord, the nerve impulses are transmitted first across a synapse to relay neurone, and then across another synapse to motor neurone
    - at the same time, another set of nerve impulses are transmitted along relay neurone parallel to spinal cord, to brain
  4. motor neurone
    - transmits the impulses from the spinal cord to effector
  5. effector muscle contracts
    - muscle (effector) contracts then causes your hand to withdraw suddenly