Chapter 13- Nervous System Flashcards

Components of nervous system; job ; fucyions of different neurones; relation between receptors,the cns,the spinal nerves and effectors; reflex action

1
Q

Role of nervous system

A

Controls the Activities of the body and how it reacts to the surrounding

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2
Q

Stimulus

A

Any change in the environment that causes an organism to react is called a stimulus.

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3
Q

Response

A

An organisms reaction to a stimulus

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4
Q

Nervous system consists

A
  • brain
  • spinal cord
  • spinal nerves
  • hughly soecialosrd sense organs
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5
Q

What do sense organs d⁷o

A

. Help body to adjust to stimulus

. Enable various parts of body to coordinate with one another quickly

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6
Q

Involuntary actions

A

Automatic and not controlled
. Heart beat
. Breathung
. Peristalisis

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7
Q

Voluntary actions

A

Controlled consciously

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8
Q

Components of nervous system

A

CNS: brain nd spinal cord

PNS peripheral cranial :(nerves from brain) spinal nerves( from spinal cord) and sense organs

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9
Q

How nervous system works

A
  1. Sense organs receive stimulus: receptors
  2. Through electrical impulses: nerve impulses, receptors inform CNS of any change in surroundings
  3. Nerve impulses are transmitted to CNS by nerves
  4. Muslces: Effectors rsspond to the processed stimulus
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10
Q

Things by
•brain
•spinal cord

A

°voluntary action by geneeating nerve inpulses
°controls cranialreflexes e.g. salivation

° transmits nerve impulses to nd from the brain
°controls spinal reflexes e.g. knee jerk reflex

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11
Q

Cranial nerves

A

Sensory nerves transmit impulses ftom receptors to brain

Motor nerves transmit impulses from brain to effectors

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12
Q

Spinal nerves

A
  • Sensory nerves transmit impulses from receptor to spinal cord
  • Motor nerves transmit impulses from spinal cord to effectors
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13
Q

Nervous tissue

A

It makes the nervous system. Consists of nerve cells called NEURONES.

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14
Q

Sensory neurone

A

Receptor neurone

Transmits nerve impulses from the sense organs or receptors to the cns

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15
Q

Motor neurones

A

Effectors neurones

Transmits nerve impulses from CNS to the effectors

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16
Q

Relay neurone

A

Intermediate neurone

Transmits nerve impusles from sesnsory neurone to motor neurone. Found with in CNS

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17
Q

Nerve fibre

A

Strand of cytoplasm extending from cell body

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18
Q

Dendron

A

A nerve fibre that transmits impulses towars the cell bodyof a neurone

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19
Q

Axon

A

Nerve fibre that transmits nerve impulse away from cell body

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20
Q

Dendrites

A

Terminal branches: receive nerve impulses from other neurons

21
Q

Axon terminal

A

Terminal branches: transmit nerve impulses to another neuron

22
Q

Cell body

A

Nucleus adn cytoplasm

23
Q

Mylein Sheath

A

Fatty substancs->enclose many nerve fibres -> insulation for fast transmission of nerve impulses

24
Q

Neurilemma

A

Thun membrane arojnd myelin sheath

25
Q

Nodes of ranveir

A

Gaps in myelin sheThspeeds up rate of transmission of nerve inoulses along the fibres

26
Q

Motor end plate

A

Small gap between dendrite and nuscle fibres

27
Q

Synapse

A

Gap between rn and mn

28
Q

SN structure

A

Long dendron
Short a on
Cell body is round
Transmit Nerve imoulse to rscepto to RN

29
Q

Mptor neuron structure

A

Short dendron
Long axon
Cell body is irregular
Transmit nerve imoulses to releay neurone ro effector

30
Q

Dorsal root

A

SN only

31
Q

Dorsal root hanglion

A

A swellkng in dorsal root where cell bodirs of SN are locatdd

32
Q

Spinal nerves

A

Nerve fibres fron both axon and dendron

33
Q

Ventral root

A

Motor neurones only

34
Q

Cental canal

A

Carebrispinal fluid -> bribg nutients to spinal cords

35
Q

Grey matter

A

Comsistes of cell bodies of neurones

Forms outer layefd of brain dn centrak oarts of spinal cord

36
Q

Whiye matter

A

Consits of nerve fibres mainly

Forms central parts of brajn and outer layers of spinal cords

37
Q

Spinal cords transmits impulses from

A

Sensory neurone ip to brain

Brain down to motor neurone.

38
Q

Pthways of imoulses during senssation

A

Receptor to SN to RN in spinal cord to forebrain

39
Q

Pathway of impilses dyring voluntary actions

A

Forebrain to RN in spinal cord to motor neurone to effector

40
Q

Reflex action

A

An immmediate response to a specific stimulus without concious control

41
Q

Two classifciayions of reflex actions

A

■ cranial reflex – contoled by brain but not concious will and usually occur in the head region e.g. pupil reflex,blinking and salivation
■ spinal reflex– controlled by the spinal cords e.g. knee herk reflexand sudden withdrawal of hands on touching hot objects

42
Q

Reflex arc

A

Shortest pathwat by which N.I. trvel from receptor to effector in reflex action

43
Q

Parts of reflex arc

A
Receptor 
SN
RN jn reflex cenyre
MN
Effector
44
Q

Hand withdrawal reflex

A
  1. Receptors in skkn
  2. SN
  3. Spinal cord
  4. MN
  5. effecyor muscles contract
45
Q

Knee jerk reflex

A
  1. Tap allied stretched upper thugh muscles
  2. stretch recepto which is sensitive to stetchjng of thugh muscles
  3. Recptor neurone leading to CNS
  4. effector neurone leading back to CNS
  5. Upper thigh muscles which is effdctor
46
Q

Cerebrum

A

Forebrain,cerebrum
.interlligwnce,memory,learning,sensations and overall control of all voluntary actions jn humans
.concerned with refulwayion og body temp a d water potential of blood,apperite,sleep and emotions
Produces and releases i.t. hormones including ADH

47
Q

Mid brain

A

.concerned witi sight and visual reflexes e.g. movement of the eyeballd

48
Q

Hind brajn

A

.control mascular coordinatikn especially in maintaing balance
.contols involuntary actions e.g heartbeat, peristalisis,rate of respiratory movemnets and contraction and dilation of blood vessels

49
Q

Parts of brain names

A

Forebeain cerbrum
Mid brajn medulla oblongata
Hind brain cerebellum