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MEDSCI 142 > Section 1: Nervous System > Flashcards

Section 1: Nervous System Flashcards

1
Q

Brain: Frontal association cortex - functions

A 
Intelligence
Personality
Behaviour
Mood
Cognitive function
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2
Q

Brain: Parietal association cortex - functions

A

Spatial skills

3D recognition, e.g. shapes, faces, concepts, abstract perception

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3
Q

Brain: Temporal association cortex - functions

A

Memory
Mood
Aggression
Intelligence

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4
Q

Brain: Non-dominant hemisphere (right) - functions and effects of injury

A 
Non-verbal language (e.g. body language)
Emotional expression (tone of language)
Spatial skills (3D)
Conceptual understanding
Artistic/musical skills (can sing when they can't speak)
Loss of non-verbal language
Speech - lacks emotion
Spatial disorientation
Inability to recognise familiar objects
Loss of musical appreciation
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5
Q

Tracts vs nerves

A

Tracts: bundles of axons in the CNS
Nerves: bundles of axons in the PNS

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6
Q

Brain: Auditory cortex - function

A

Primary:
Puts time and tone together
Simply take the sounds in its individual tones - in a tonotopic fashion

Secondary:
Interprets and understands these tones

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7
Q

Brain: Visual cortex - functions

A

Primary visual cortex:
Conscious processing of visual stimuli
Dives right into the brain medially

Secondary visual cortex:
Interpretation
Illusions affect secondary, not primary

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8
Q

Brain: Wernicke’s area

A

Analyses/understands the spoken word via time/tone relationship
2° language area

Sensory/Wernicke’s/Fluent aphasia - problem with ability to interpret language/instructions

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9
Q

Brain: Broca’s area

A

Controls the motor act of speech
Smooth vocalisation

Motor/Broca’s/Non-fluent aphasia - can still read and write properly, but struggles to get words out

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10
Q

Brain: Arcuate fasciulus

A

Responsible for taking information from Wernicke’s area to Broca’s area
White matter tract

Connectional aphasia - can understand and read, but difficulty linking tgt

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11
Q

Brain: Gray matter

A

Where cell bodies live

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12
Q

Brain: White matter

A

Made up of bundles of axons, many of which are myelinated

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13
Q

Brain: Hypothalamus - function

A

Deals with endocrine functions

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14
Q

Mid-brain

A 
Gateway to (higher order) cerebrum
Can cause Parkinson's disease
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15
Q

Frontal and temporal lobes - tissue

A

Have 3 strips of tissue; superior, middle and inferior

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16
Q

Brain: Occipital lobe

A

Gyri and sulci are more densely packed

To do with processing of vision

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17
Q

Brain: Cerebellum

A

Extra wrinkly
Sense of balance
Processing and planning of movement

Assists motor cortex and basal ganglia by making body movements smooth and co-ordinated
Helps maintain normal posture and balance

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18
Q

Brain: Parts of the brainstem

A

Midbrain
Pons
Medulla

All contain sensory (ascending) and motor (descending) neurons

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19
Q

Brain: Parts of the hindbrain

A

Cerebellum
Pons
Medulla

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20
Q

Brain: Primary motor cortex

A

Decides what action to take
Intricate planning
Relates to what is in the homunculus

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21
Q

Brain: Exener’s area

A

Controls hand movements

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22
Q

What is a homonculus

A

Representation of entire body (body map)
Areas with higher sensitivity have greater area / larger no of neurons
Houses large cells that will product down from the motor cortex to the spinal cord

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23
Q

Brain: Left hemisphere is dominant for ____

A

Language

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24
Q

Brain: Medulla - function

A

Regulates heartbeat (CV system)

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25
Q

Brain: Primary cortices

A

1° motor cortex: pre-central gyrus
1° sensory cortex: post-central gyrus
1° auditory cortex: superior temporal gyrus
1° visual cortex: occipital lobe

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26
Q

Brain: SMAGLA

A

Supramarginal and angular gyri
Language areas

Interpretation of what is being read/written
Control eye movements responsible for reading

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27
Q

Spinal cord: Sensory input

A

Afferent pathway; to bring / carry towards

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28
Q

Spinal cord: Motor output

A

Efferent pathway; carry away

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29
Q

Spinal cord: Enlargements on vertabrae

A

Need more SA to accommodate nerves in arms and legs
Cervical enlargement - superior enlargement (upper limbs)
Lumbar enlargement - inferior enlargement (lower limbs)

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30
Q

Spinal cord: Types of nerves

A 
Cervical nerves (1-8)
Thoracic nerves (1-12) - come out directly under each rib
Lumbar nerves (1-5) - spinal cord ends around lungs
Sacral nerves (1-5) - fused vertebrae
Coccygeal nerve
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31
Q

Spinal cord: Meninges

A

Protection for spinal cord
From superficial to deep:
Dura mater - durable; protects outside of spinal cord, composed of dense irregular CT

Arachnoid mater - thin and avascular, contains collagen and elastic fibres

Pia mater - tightly adhered, thin and transparent, many blood vessels

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32
Q

Spinal cord: Cauda equina

A

Fibres that exit at the lumbar levels to supply nerves to and from legs

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33
Q

Spinal cord: Filum terminale externum

A

Anchors spinal cord onto bottom of coccyx

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34
Q

Spinal cord: What to do if meninges are inflammed

A

Take CSF fluid and determine if there are pathogens there

CSF is nutrient-rich

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35
Q

Spinal cord: Somatic nervous system - types of periphery sensory

A

Discriminative sensory: touch and pressure

Non-discriminative sensory: pain and temperature

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36
Q

Spinal cord: Somatic nervous system - encapsulated receptors

A

Meisner’s corpuscle: touch

Pacinian corpuscle: pressure

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37
Q

Spinal cord: Somatic nervous system - types of nerves

A

Pseudo uni-polar neuron:
Has myelin sheath - more effective conduction of info and energy
~50ms^-1
Can go to either 1. up to brain stem or 2. into gray matter
Has an encapsulated receptor

Free nerve-ending:
Unmyelinated as doesn’t need to fire very often
Only responds to the extreme, i.e. pain and temp
~1ms^-1
Goes only to gray matter

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38
Q

Spinal cord: Ganglion

A

A gang of cell bodies

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39
Q

Spinal cord: Dorsal root

A

Where cell bodies live

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40
Q

Where does the spinal cord begin

A

Medulla oblongta

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41
Q

Spinal cord: Ventral and dorsal

A

Ventral: motor functions
Dorsal: sensory functions

Autonomic functions: housed in between

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42
Q

Brain: Lateral fissure

A

Primarily separates the frontal lobe from the temporal lobe

Partially separates parietal lobe from temporal lobe

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43
Q

Dermatomes and myotomes

A

Dermatomes: Cluster of nerve fibres in the skin that will go towards a particular area in the spinal cord
Myotomes: Cluster of nerve fibres in the muscle that will go towards a particular area in the spinal cord

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44
Q

Brain vs spinal cord: Grey and white matter

A

Brain: Gray matter goes around outside and white matter inside
Spinal cord: Central gray matter at its core and insulating white matter on the outside

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45
Q

Motor vs sensory input - how is carried

A

Motor info tends to be carried forward

Sensory info carried back in the brain

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46
Q

Funiculi

A

Big grouping of fasciulus

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47
Q

Columns

A

White matter

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48
Q

Gracile vs Cuneate fasciculus

A

Gracile: lower limb info
Cuneate: upper limb info

Mid-upper region of spine = both
Lower region = gracile only

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49
Q

Spinal cord: Thalamus

A

Decides which sensation is important

Deals with motor sensory info input

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50
Q

Spinal cord: Cuneate nucleus

A

A ganglion

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51
Q

Spinal cord: Discriminative pathway - Where do nerves cross over

A

Medulla

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52
Q

Spinothalamic tract

A

Pain and temperature pathway

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53
Q

Dorsal Column - Medial Leminiscal System

A

Pathway of discriminative sensation

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54
Q

Spinothalamic tract: Medial lemniscus

A

Where all pain, temp, and discriminative info comes together

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55
Q

Associative vs dissociative sensory loss

A 
Associative:
If nerves (sensory and free nerve endings) on right side are affected, the left side loses pain, temp and discriminative info

Dissociative:
If free nerve ending on right side is affected, left side loses pain and temp (but right side loses discriminative info?)

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56
Q

Spinal cord: Pain and temp pathway - where do nerves cross over (decussate)

A

Anterior white commissure

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57
Q

Brain: Motor region of cerebral cortex

A

Initiates and controls precise, discrete muscular movements

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58
Q

Brain: Basal ganglia - functions

A

Receives input from cerebral cortex and provides output to motor parts of cortex via the medial and ventral group nuclei of thalamus
Establishes muscle tone
Integrate semi-voluntary, automatic movements
Picks up practice and learned movements
Smooth and precise movement control
Regulates initiation and termination of movements - may be linked to Parkinson’s disease

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59
Q

Parkinson’s disease - symptoms

A

Mood (emotionally flat)
Wooden face and rigidity
Bradykinesia (hypokinesia - difficulty initiating movement)
Tremor at rest

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60
Q

Homunculus: Neurons at hand

A

~160 microns wide

Very wide

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61
Q

Pyramidal tract AKA…

A

Corticospinal tract

i.e. from cortex to spine

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62
Q

Brain: Internal capsule

A

Thick band of white matter
Contains ascending and descending axons
Has a homuncular representation

63
Q

Corticospinal tract: Where do pyramidal fibres cross over

A

85% cross over at pyramidal decussation (deals with precise movement)
15% crosses over at anterior corticospinal tract (spinal segmental level - deals with coarse movement)

64
Q

Corticospinal tract: What happens if there’s a lesion at the lower motor neuron

A

Since LMN activates muscles for contraction, it results in flaccid paralysis (floppy)

65
Q

Brain: Basal ganglia/nuclei - structure

A

Group of grey matter in forebrain

  1. Caudate nucleus
  2. Putamen
  3. Globus pallidus (much paler, has internal and external)
  4. Subthalamic nucleus
  5. Substantia nigra

1+2 = striatum
2+3 = lentiform nucleus
1 + lentiform = corpus striatum

66
Q

Hypoactivity and hypoexcitability

A

Output from hypoexcitability in brain is hypoactivity in the body

67
Q

Define hypoexcitability

A

Uncontrolled firing of inhibitory neurons

68
Q

When does Parkinson’s disease occur

A

When 60-80% of nigrostriatal pathways die (cup half full)

Results in lots of glutamate firing –> toxic (spasticity)

69
Q

Dopamine

A

Itself is not excitatory or inhibitory, depends on what type of receptor it binds to
Holds neurons ready (cup full)

70
Q

How is Parkinson’s disease treated

A 
With levodopa (precursor of dopamine, as dopamine itself is not digested well in stomach), which is then converted to dopamine (increases dopamine, decreases ACh)
Levodopa crosses gut --> crosses blood-brain barrier --> converted to dopamine by cells in substantia nigra
Causes fluctuation of dopamine levels, thus symptoms range from hallucinations/depression (too much dopamine) to rigidity (not enough dopamine)
Taken 6 times a day
71
Q

Schizophenia

A

Treated with anti-dopamine
Patients start off with hallucinations and depression, and take anti-dopamine which makes them rigid (i.e. polar opposite of Parkinson’s)

72
Q

Basal ganglia vs cerebellum

A

Basal ganglia = initiation of movement

Cerebellum = termination of movement

73
Q

Lesion in corticospinal tract: Damage to UMNs and LMNs

A

Upper motor neurons: lose all control over LMNs –> spastic paralysis, but can still activate themselves

Lower motor neurons: totally no input to muscles –> flaccid paralysis (muscles limp and floppy)

74
Q

When do lower motor neurons (LMNs) act independently

A

Reflexes

75
Q

Brain: Cerebrum

A

Consists of an outer cerebral cortex, internal region of cerebral white matter, and gray matter nuclei deep within the white matter

76
Q

Brain: Cerebral cortex - structure

A

Region of grey matter that forms the outer rim of the cerebrum
Contains billions of neurons arranged in layers

77
Q

Brain: During embryonic development, does grey or white matter develop faster

A

Gray matter of cortex enlarges much faster than the deeper white matter
Causes cortical region to roll and fold on itself

78
Q

Brain: Gyri, fissures and sulci

A

Gyri - folds
Fissures - deepest grooves between folds
Sulci - shallower grooves between folds

79
Q

Brain: Longitudinal fissure

A

Separates cerebrum into right and left halves, called hemispheres

80
Q

Brain: Corpus callosum

A

Broad band of white matter

Contains axons that extend between cerebral hemispheres to connect them

81
Q

Brain: Central sulcus

A

Separates frontal lobe from parietal lobe

82
Q

Brain: Cerebral white matter - tracts

A

Association tracts - conduct nerves impulses between gyri in same hemisphere
Commissural tracts - conduct nerve impulses from gyri in one cerebral hemisphere to corresponding gyri in other hemisphere
Projection tracts - conduct nerves impulses from cerebrum to lower parts of CNS (thalamus, brain stem, spinal cord) or vice versa

83
Q

Brain: Basal ganglia/nuclei - Axons from the substantia nigra terminate in the…

A

Caudate nucleus and putamen

84
Q

Brain: Sensory, motor, and association areas

A

Sensory areas: receive sensory info and involved in perception (conscious awareness of a sensation)
Motor areas: control execution of voluntary movements
Association areas: deal with more complex integrative functions, e.g. memory and emotions

85
Q

Brain: Where do sensory impulses mainly arrive

A

In the posterior half of both cerebral hemispheres, in regions behind the central sulci

86
Q

Brain: Primary sensory areas

A

Receive sensory info that has been relayed from peripheral sensory receptors through lower regions of the brain

87
Q

Brain: Sensory association areas

A

Often adjacent to primary areas

Integrate sensory experiences to generate meaningful patterns of recognition and awareness

88
Q

Brain: Somatosensory association area

A

Receives input from primary somatosensory area, thalamus and other parts of brain
Allows you to determine the exact shape and texture of an object by feeling it, determine orientation of object, sense relationship of one body part to another
Storage of memories of past somatic experiences - can compare

89
Q

Brain: Visual association area

A

Receives sensory impulses from primary visual area and thalamus
Essential for recognising and evaluating what is seen

90
Q

Brain: Facial recognition area

A

Receives nerve impulses from visual association area
Stores info about faces –> allows recognition of them
Often more dominant in the right hemisphere

91
Q

Brain: Auditory association area

A

Recognises a particular sound as speech, music or noise

92
Q

Brain: Common integrative area

A

Bordered by somatosensory, visual and auditory association areas
Integrates sensory interpretations –> allows formation of thoughts based on a variety of sensory inputs

93
Q

Brain: Pre-motor area

A

Motor association area
Deals with learned motor activities of a complex and sequential nature
Generates nerve impulses that cause specific groups of muscles to contract in a specific sequence

94
Q

Brain: Hemisphere lateralisation

A

Functional asymmetry of left and right hemispheres of brain

95
Q

CNS: Layers of protection

A

1st layer: Hard bony skull and vertebral column
2nd layer: Meninges
3rd layer: Space between two of the minengeal membranes containing CSF

96
Q

Cerebrospinal fluid (CSF)

A

A buoyant liquid that suspects the central nervous tissue in a weightless environment while surrounding it with a shock-absorbing, hydrauilc cushion

97
Q

Spinal cord: Epidural space

A

Space between the dura mater and wall of vertebral canal

98
Q

Where does spinal cord extend to and from

A

Adults: From medulla to border of second lumbar vertebra
Newborn: From medulla to third or fourth lumbar vertebra

99
Q

Spinal cord: Anterior median fissure and posterior median sulcus

A

Anterior: wide groove on anterior (ventral) side
Posterior: narrow furrow on posterior (dorsal) side

100
Q

Spinal cord: Gray commissure

A

Forms crossbar of ‘H’

Contains central canal, which extends the entire length of the spinal cord and is filled with CSF

101
Q

Spinal cord: Posterior, anterior and lateral grey horns

A

Posterior: contains cell bodies and axons of interneurons and axons of incoming sensory neurons
Anterior: contain somatic motor nuclei (clusters of cell bodies of somatic motor neurons)
Lateral: contain autonomic motor nuclei (clusters of cell bodies of autonomic motor neurons)

102
Q

Spinal cord: White matter in cervical to sacral segments

A

Since more sensory and motor tracts are present in upper segments of spinal cord than lower segments, amount of white matter decreases from cervical to sacral segments

103
Q

Define sensation

A

The conscious or subconscious awareness of changes in the external or internal environment

104
Q

Define perception

A

The conscious interpretation of sensations

Primarily a function of the cerebral cortex

105
Q

General vs special senses

A

General: refers to both somatic and visceral senses

Special senses: include sensory modalities of smell, taste, vision, hearing and equilibrium/balance

106
Q

Somatic senses

A

Arise from skin

Tactile sensations, thermal sensations, pain sensations, proprioceptive sensations

107
Q

Proprioceptive sensations

A

Allow perception of static position of limbs and body parts and movements of limbs and head
Allow us to recognise that parts of our body belong to us (self)
Weight discrimination - ability to assess weight of an object

108
Q

Visceral senses

A

Provide info about conditions within internal organs, e.g. pressure, stretch, hunger, temp

109
Q

Sensory receptors - selectivity

A

Only responds vigorously to one particular kind of stimulus - responds only weakly or not at all to other stimuli

110
Q

For a sensation to arise, these four events typically occur…

A
  1. Stimulation of sensory receptor
  2. Transduction of stimulus
  3. Generation of nerve impulses
  4. Integration of sensory input
111
Q

Exteroceptors, interoceptors and proprioceptors

A

Exteroceptors: located at or near the external surface of body (external environment)
Interoceptors: located in blood vessels, visceral organs, muscles and nervous systems (internal environment)
Proprioceptors: located in muscles, tendons, joints and inner ear (body position, muscle length and tension, joint position and movement)

112
Q

Tactile sensations

A

Touch, pressure, vibration, itch, tickle

113
Q

Thermoreceptors

A

Free nerve endings that have receptive fields on skin surface

114
Q

Nociceptors

A

Receptors for pain
Free nerve endings found in every tissue except brain
Can be activated by intense thermal, mechanical or chemical stimuli

115
Q

Fast pain

A

Nerve impulses propagate along medium-diameter, myelinated fibres
Not felt in deeper tissues of body

116
Q

Slow pain

A

Begins a second or more after a stimulus is applied
Gradually increases in intensity over a period of several seconds/mins
Conduct along small-diameter, unmyelinated fibres
Can occur in both skin and deeper tissues

117
Q

Superficial somatic pain, deep somatic pain and visceral pain

A

Superficial: arises from stimulation of receptors in skin
Deep: arises from stimulation of receptors in skeletal muscles, joints, tendons, fascia
Visceral: arises from stimulation of nociceptors in visceral organs

118
Q

Localisation of pain

A

Fast pain: very precisely localised to stimulated area

Slow pain: well localised, but more diffuse (involves large areas)

119
Q

Kinesthesia

A

Perception of body movements

120
Q

Direct vs indirect motor pathways

A

Direct: provide input to LMNs via axons that extend directly from cerebral cortex
Indirect: provide input to LMNs from motor centres in basal nuclei, cerebellum and cerebral cortex

121
Q

Lateral vs anterior corticospinal tract

A

Lateral:
Corticospinal axons that decussate in medulla
Synapse with local circuit neurons or LMNs in anterior grey horn
Anterior:
Corticospinal axons that don’t decussate in medulla
Anterior white column of spinal cord

122
Q

Somatic sensory pathways: Types of neurons

A

First-order neuron
Second-order neuron
Third-order neuron

123
Q

First-order neurons

A

Conduct impulses from somatic receptors into brain stem or spinal cord
From the face, somatic sensory impulses propagate along cranial nerves into brain stem
From the neck, trunk, limbs and posterior of head, somatic sensory impulses propagate along spinal nerves into spinal cord

124
Q

Somatic sensory pathways: Second-order neurons

A

Conduct impulses from brain stem and spinal cord to thalamus
Decussate in brain stem or spinal cord before ascending to ventral posterior nucleus of thalamus
i.e. all somatic sensory info from one side of body reaches thalamus on other side

125
Q

Somatic sensory pathways: Third-order neurons

A

Conduct impulses from thalamus to primary somatosensory area of cortex on the same side

126
Q

Somatic sensory pathways: Relay stations

A

Regions within CNS where neurons synapse with other neurons that are part of a particular sensory or motor pathway
e.g. thalamus, spinal cord, brain stem

127
Q

Somatic sensory impulses ascend to the cerebral cortex via which general pathways?

A
  1. The dorsal column-medial lemniscus pathway

2. The anterolateral (spinothalamic) pathway

128
Q

Where do LMNs have their cell bodies

A

In brain stem and spinal cord
From brain stem, axons of LMNs extend through cranial nerves to innervate skeletal muscles of face and head
From spinal cord, axons of LMNs extend through spinal nerves to innervate skeletal muscles of limbs and trunk

129
Q

Why are LMNs also called the ‘final common pathway’

A

Only LMNs provide output from CNS to skeletal muscle fibres

130
Q

Somatic motor pathways: Types of neurons

A

Local circuit neurons
Upper motor neurons (UMNs)
Basal nuclei neurons
Cerebellar neurons

131
Q

Somatic motor pathways: Upper motor neurons

A

Both local circuit neurons and LMNs receive input from UMNs
Most synapse with local circuit neurons, which in turn synapse with LMNs
UMNs from cerebral cortex essential for execution of voluntary movements
Other UMNs originate in motor centres of brain stem - regulate muscle tone, postural muscles, balance
Basal nuclei and cerebellum exert influence on UMNs

132
Q

Pyramidal cells

A

UMNs with pyramid-shaped cell bodies located in primary motor area and premotor area of cerebral cortex

133
Q

UMNs: Example of a direct motor pathway

A

Corticospinal pathway

134
Q

UMNs: Corticospinal tracts - types

A

Lateral corticospinal tract

Anterior corticospinal tract

135
Q

Third-order sensory neurons in the posterior column-medial lemniscus pathway extend from the…

A

Thalamus to the somatosensory area of the cerebral cortex

136
Q

Which structure involved in the production of CBF or its flow through the brain, is closest to the midbrain

A

Cerebral aqueduct

137
Q

Where are cell bodies of motor neurons to skeletal muscles are located

A

Anterior grey horns

138
Q

Where are cell bodies of first-order neurons in the posterior column-medial lemniscus pathway to the cortex located

A

Dorsal root ganglia of spinal nerves

139
Q

Lesion in cerebellum

A

Unlike the rest of the brain, a lesion in the cerebellum affects the same side of the body

140
Q

Brain: Hemisphere lateralisation - dominant hemisphere

A

Exner’s, Broca’s, Wernicke’s area and the SMAGLA regions only occur in the dominant hemisphere (usually left)

141
Q

Spinal cord transection at level of the neck would result in…

A

Loss of sympathetic control over SV

Parasympathetic nerves don’t travel through brainstem

142
Q

Where does the medial lemniscus convey info to and from

A

From gracile and cuneate nucleus (medulla) to thalamus, therefore is located in brainstem

143
Q

Lesion in brainstem

A

Brainstem = UMN = spastic

Already decussated = other side of body

144
Q

Pulmonary valve is ____ to the aortic valve

A

Ventral

145
Q

Where are the heart sounds best heard

A

1st: best heard near apex of heart
2nd: best heard near base of heart

146
Q

Where is the basal ganglia located

A

In cerebrum

147
Q

The basal ganglia is rich in..

A

Dopamine

148
Q

What is the main relay system for conducting info between the spinal cord and cerebrum

A

Thalamus

149
Q

Where does precise location and identification of sensation occur

A

Cerebral cortex

Contains somatosensory cortex, where sensory info goes

150
Q

Where do first order sensory neurons conduct impulses to and from

A

From a (encapsulated) receptor to CNS

151
Q

Where do UMNs terminate and synapse with LMNs

A

In ventral horn of spinal cord

152
Q

Corticospinal/pyramidal tract - types of neurons

A

Only involves UMNs - only spasticity can occur

153
Q

Where are cell bodies of UMNs located

A

In motor cortex

MEDSCI 142 (9 decks)

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