Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

PHOL1001 > The Nervous system - Introduction to CNS and reflexes (lecture 1) > Flashcards

The Nervous system - Introduction to CNS and reflexes (lecture 1) Flashcards

1
Q

What is the central nervous system comprised of ?

A

brain and spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What two types of cells are found in the nervous system ?

A

neurons and neuroglia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the four types of neuroglia cells in the CNS ?

A

Illustration of the four different types of glial cells found in the central nervous system: ependymal cells (light pink), astrocytes (green), microglial cells (red), and oligodendrocytes (light blue).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the two types of neuroglia cells in the peripheral nervous system ?

A

schwann cells and satillite cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How many neurones are in the CNS ?

A

10 to the power of 12 - millions !!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

whats makes up the grey matter of a spinal cord cross section ?

A

dendrites, cell bodies, axon terminals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What happens in the grey matter of the spinal cord ?

A

Synapses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Whats the white matter composed of ? why white ?

A

axons - because myelin is white

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what are the two types of wings in the spinal cord ?

A

posterior (dorsal horns) and the anterior (ventral horns)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are propriospinal neurons?

A

i have no idea?

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are ascending tracts ?

A

organised axons that pass information from the spinal cord to higher centres in the brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are descending tracts ?

A

axons that relay commands from the brain and the spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Where does the term nuclei refer to ?

A

within the brain, neurones which work together functionally are found in groups known as nuclei.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How do bundles of axons in the brain run ?

A

longitudinally as well as transversely and thus divides the grey matter into discrete lumps

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does the forebrain, cerebellum and the centrally located grey matter have in common ?

A

they have a peripheral layer of neurons known as the cortex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What do afferent neurons do ?

A

sensory fibres relay information to the CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What do efferent neurons do ?

A

motor fibres leave the CNS relaying commands to effectors such as muscle (skeletal, smooth or cardiac )

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What do sensory receptors do ?

A

monitor the external and internal environments for example the visual field or blood pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What does the term reflex describe ?

A

Automatic, reproducible and goal directed responses of an organism to stimuli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are reflexes involved in ?

A

homestasis, postural stability others are protective in function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Give me two examples of reflexes ?

A

cardiovascular reflexes, stretch reflex, the flexor withdrawal reflex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Describe short-loop reflexes refer to ?

A

reflexes that only require spinal circuitry for example stretch and cutaneous reflexes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Describe long-loop reflexes do ?

A

reflexes that involve higher centres (i.e. centres in the brain)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How central modulation of reflex arcs occur ?

A

via descending pathways from higher centres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What does a reflex arc involve ?

A

sensory receptors, afferent (sensory) neurons, central neurons and efferent (or motor neurons)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What do motor neurons do ?

A

Excite effectors (skeletal muscle, smooth muscle, cardiac muscle or a gland)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

How is the stretch reflex unique ?

A

it is monosynaptic - i.e one synapse no central neurones involved. The afferents synapse directly onto motoneurons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What does the stretch reflex act to maintain ?

A

muscle length and is important in the control of posture

29
Q

What are the stretch receptors ?

A

muscle spindles which lie to parallel to the muscle fibres (known as extrafusal fibres)

30
Q

What are intrafusal fibres ?

A

muscle fibres contained within the muscle spindle s ?

31
Q

Tell me a characteristic of intrafusal fibres ?

A

they are thinner than extrafusal fibres

32
Q

What do muscle spindles contain ?

A

intrafusal muscle fibres and stretch receptors

33
Q

How many types of sensory endings do spindles have

?

A

two, primary and secondary

34
Q

What are the primary endings associated with ?

A

large diameter afferent axons and are sensitive to both the length of the muscle and the rate of the change of length

35
Q

What are secondary endings sensitive to ?

A

only muscle length

36
Q

What do the primary afferents synapse directly with ?

A

motoneurons of the homonomous (same) muscle (and to a lesser extent onto motoneurons of synergistic muscles) and bring about reflex contraction .
the same afferents also synapse with inhibitory interneurones which inhibit those motoneurons which innervate antagonistic muscles (reciprocal inhibition)

37
Q

what happens to antagonistic muscles ?

A

they are relaxed

38
Q

What can occur during a slow stretch ?

A

the firing of secondary endings may also contribute to the reflex excitation

39
Q

what occurs during a withdrawal reflex ? where do the afferent fibres arise from ?

A

from cutaneous nociceptors

40
Q

what do the small diameter afferent fibres synapse with during withdrawal reflex ?

A

The small diameter afferent fibres synapse with a number of interneurons( much divergence) within the dorsal horn of the spinal cord which then synapse with and excite motoneurons of flexor muscles.

41
Q

Is reciprocal inhibition seen during the withdrawal reflex ?

A

yes; the afferents synapse with a second group of interneurons which in turn synapse with and inhibit the firing of motoneurons of extensor muscles( i.e muscles which are antagonistic in action to flexor muscles).

42
Q

What does the excitation of flexor muscles produce ?

A

A reflex withdrawal of the stimulated limb away from the offending stimulus, so this reflex is protective in function

43
Q

What are the three protective structures of the CNS ?

A

Bone, Meninges and cerebrospinal fluid, glial cells, bone, connective tissue

44
Q

What are meninges ?

A

the three membranes that line the skull and vertebral canal and enclose the brain and spinal cord.

45
Q

What are the three meninges ?

A

(the dura mater, arachnoid, and pia mater)

46
Q

What is the cranium? function ?

A

the skull, protects the CNS, i.e protects the brain

47
Q

What is the vertebrae ?

A

each of the series of small bones forming the backbone, having several projections for articulation and muscle attachment, and a hole through which the spinal cord passes. the needle is inserted between two of the vertebrae.

48
Q

What is the cerebrospinal fluid ?

A

clear, colourless fluid found in the brain and spine. Protects the brain

49
Q

properties of a unipolar neuron have ? Are they motor neurons ?

A

one process, one dendrite that splits and one axon.

no they are sensory neurons

50
Q

properties of a bipolar neuron ? where are they found ?

A

two processes, one dendrite, and one axon.

In the retina of the eye

51
Q

properties of pseudo-unipolar cell ? where is it found ?

A

two processes, one dendrite, and one axon.

Ganglion cell of dorsal root

52
Q

What are the the three types of multipolar cells ?

A

normal motor neuron of spinal cord.
Pyramidal cell of hippocampus
purkinje cell of cerebellum

53
Q

Which matter are the cell bodies and dendrites grouped in ?

A

gray matter

54
Q

Which matter are the axons grouped in ?

A

white matter

55
Q

What do you call cell bodies in the CNS?

A

Nuclei

56
Q

What do you call cell bodies in the PNS ?

A

Ganglia

57
Q

What are axons in the CNS referred to as?

A

pathway projections, tracts , commissures

58
Q

Axons in the PNS?

A

Nerves: sensory. motor, mixed

59
Q

What cell produces myelin in in the CNS ?

A

oligodendrocytes

60
Q

give me three examples of involuntary/ automatic motor activity ?

A

reflexes not under direct control of the brain
postural activity
learnt, skilled activity

61
Q

Give me two examples of voluntary motor activity ?

A

Well learnt movements due to practice e.g drinking, driving, sports
Goal directed activity with a degree of conscious attention to the take

62
Q

Properties of reflexes ?

A

Simplest motor act
Fast , automatic, stereotyped (reproducible)
involuntary - not under direct control of brain, but often modulated by activity in the CNS
Short loop and long loop ( short/ long latency)
response to specific stimulus

63
Q

Function of reflexes ?

A

involved in homeostasis
involved in control of movement
can be protective

64
Q

after a painful encounter of your toe with a needle what contracts and is inhibited ?

A

Flexors contract moving painful stimulus away. Extensors on same leg inhibited. on other leg: flexors inhibited.
extensors contract as weight shifts to left leg

65
Q

What are the components of a reflex arc ?

A

Receptor: sensor (requires an adequate, specific stimulus)
Afferent neurons: sensory
Interneurons - spinal cord: depends on the type of reflex. monosynaptic = no interneurone
efferent neurons: motor
effector:
muscle: skeletal, cardiac, smooth
Gland

66
Q

Give me an example of a monosynaptic reflex ?

A

Stretch reflex

67
Q

Describe the stretch reflex ?

A

has both a monosynaptic (no interneurone) and disynaptic component ( 1 interneurone ). This is called reciprocal innervation.

68
Q

What is the function of the stretch reflex ?

A

The stretch reflex (myotatic reflex) is a muscle contraction in response to stretching within the muscle. It is a monosynaptic reflex which provides automatic regulation of skeletal muscle length. When a muscle lengthens, the muscle spindle is stretched and its nerve activity increases.

PHOL1001 (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions