Brainscape's Knowledge GenomeTM

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


See full index

ANAT 242 > L8 > Flashcards

L8 Flashcards

1
Q

what is sensation

A

detection of sensory stimulus

stimulus is a change in the external or internal environments

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

list some sensory stimuli

A

sight, sound, smell,
touch, pressure, taste, temperature, gravity,
position, pain etc.

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

what is perception

A

interpretation of the meanings of the

sensory stimuli

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

where do sensation and perception occur

A

in the brain

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

what are the special sensors

A

Taste, smell, vision, hearing & balance

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

where does each specialised sense organ project to in the brain

A

primary sensory cortex

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

where are the neurons for taste located

A

taste - lower end of postcentral gyrus

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

where are the neurons for smell located

A

smell - medial temporal (uncus) and orbitofrontal lobes

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

where are the neurons for vision located

A

vision - occipital lobe

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

where are the neurons for hearing located

A

hearing - superior temporal lobe

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

where are the neurons for equilibrium/balance located

A

equilibrium - mainly to the cerebellum

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

what nerves are involved in the special sensors

A

all of the cranial nerves

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

what are sensory receptors

A

are specialized receptors that respond to changes in their

environment

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

how are sensory receptors classified

A

the type of stimulus they detect

their body location

their structural complexity

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

what are mechanoreceptors

A

are sensitive to a mechanical force

e.g. touch, pressure, vibration, stretch & itch

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

what are thermoreceptors

A

are sensitive to temperature changes

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

what are photoreceptors

A

respond to light energy (the retina of the eye)

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

what are chemoreceptors

A

respond to chemicals in solution (molecules smelt or tasted, or changes in blood chemistry)

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

what are nociceptors

A

respond to potentially damaging stimuli that result
in pain eg burn or sting

noci = harm

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

what are exteroceptors

A

are sensitive to stimuli arising outside the body therefore they are located near or at the body surface

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

what are some examples of exteroceptors

A

touch, pressure, pain & temperature receptors (skin)

receptors of special senses (vision, hearing etc.)

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

what are interceptors/visceroceptors

A

are sensitive to stimuli within the body therefore they are located in the visceral organs & blood vessels

they monitor a variety of stimuli (eg. chemical changes, tissue stretch, temperature)

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

what are proprioceptors

A

are sensitive to internal stimuli

these are the receptors located in skeletal muscles, tendons, joints,
ligaments & in connective tissue coverings
of bones & muscles (located in the musculoskeletal system) (eg. joint kinesthetic receptors)

equilibrium receptors of the inner ear are
sometimes included in this class

their job is to constantly advise the brain of the body’s movement and location in space

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

where are complex receptors found

A

in the special sense organs

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

what is the somatosensory system

A

the part of the sensory system serving the

body wall & limbs

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

where does the somatosensory system receive inputs from

A

receiving inputs from exteroceptors &

proprioceptors

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

what are the 3 levels of the somatosensory system

A

the sensory receptors, ascending pathways and the cerebral neuronal circuits

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

describe processing at the receptor level

A

the receptors detect the stimuli –> then transduction happens (converting stimulus energy into changes in membrane potential in sensory axons) –> Propagation (generating nerve impulses)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

describe processing at the circuit level

A

impulses are delivered to the appropriate regions of the cerebral cortex for
stimulus localization &
perception

or

impulses delivered to
the cerebellum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what is discriminative and non discriminative sensation

A

discriminative = fine touch/vibration and conscious proprioception

precise localization; only a few receptor types

non-discriminative = pain, temp, crude touch and pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what pathway does discriminative sensation take

A

dorsal column pathway

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what pathway does non-discriminative sensation take

A

spinothalamic pathways

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what is dissaspcated sensory loss

A

discriminative and non-discriminative sensation travel in different pathways therefore if you were to damage one pathway you would still have the other type of sensation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

where is the first order neuron of the dorsal column pathway located

A

dorsal root ganglion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

where is the second order neuron of the dorsal column pathway located

A

the nuclei gracilis and cuneatus

36
Q

where is the 3rd order neuron of the dorsal column pathway located

A

the internal capsule (thalamus)

37
Q

where does the dorsal column pathway decussate

A

the medulla

38
Q

what is the role of the dorsal column medial lemniscus pathway

A

Transmits sensory impulses from general sensory
receptors of skin & proprioceptors (interpreted as discriminative touch &
conscious proprioception) to opposite somatosensory cortex

39
Q

where does the gracile tract carry impulses from

A

Gracile tract carries impulses from lower limbs

& inferior body trunk

40
Q

what information does the cuneate tract transmit

A

Cuneate tract transmits afferent impulses from

upper limbs, trunk & neck (not present in spinal cord below T6)

41
Q

what do the gracile and cuneate tract form

A

the dorsal column pathway

42
Q

what is a lemniscus

A

a bundle of axons

43
Q

what is the role of the dorsal column medial lemniscus pathway

A

Transmits sensory impulses from general sensory receptors of skin & proprioceptors (interpreted as discriminative touch &
conscious proprioception) to opposite somatosensory cortex

44
Q

what information does the gracile tract carry

A

impulses from lower limbs

& inferior body trunk

45
Q

what information does the cuneate tract carry

A

transmits afferent impulses from upper limbs, trunk & neck (not present in
spinal cord below T6)

46
Q

what does the lateral spinothalamic pathway detect

A

pain and temp

47
Q

describe the lateral spinothalamic pathway

A

the first order neuron is in the dorsal root ganglion

synappes in the spinal cord

second order neuron is the dorsal horn neuron

crosses laterally in the spinal cord and then goes up to the thalamus. this is the location of the 3rd order neuron

from here the 3rd order neuron goes up though the internal capsule to the postcentral gyrus

48
Q

where is the lateral tract located

A

lateral to the anterior horn (after it crosses over)

49
Q

what kind of information does the anterior spinothalamic pathway transmit

A

Transmits impulses concerned with crude
touch & pressure to opposite somatosensory
cortex

50
Q

what are spinocerebellar pathways

A

from the spinal cord to the cerebellum

these are NOT for conscious sensation

51
Q

what information do the spinocerebellar tracts transmit

A

Transmit information about muscle or tendon
stretch to the cerebellum, which use this
information to coordinate skeletal muscle
activity

therefore they are responsible for unconscious proprioception

52
Q

describe the pathway of the spinocerebellar tract

A

start in proprioceptor. the first order neuron is in the dorsal root ganglion

the 2nd order neuron is in the dorsal horn nucleus which then goes into the cerebellum

NOTE there is no 3rd order neuron because this tract does NOT decussate

this travels up the posterior lateral side of the spinal cord

53
Q

how does the brain process perceptual information

A

Interpretation of sensory
input (stimulus location
and/or type) depends on the locations of the target neurons in the sensory cortex

Each sensory axon -
“labeled phone line”
telling brain “who” is
calling & from “where”

54
Q

what would be the result of a dorsal column injury

A

Loss of fine touch and conscious proprioception on same side below the site of injury

55
Q

what would be the result of an injury on the left anterolateral side

A

Loss of pain and temperature on right

side

56
Q

what would be the result of an injury on the right posterolateral side

A

Loss of unconscious proprioception to the cerebellum from the right side of the body.

Because this one never crossed over

57
Q

describe the general organisation of the motor systems

A

the premotor cortex is always planning movement. this signal goes to the cerebellum which works out the best way to do the movement and sends it to the thalamus

the signal waits in the thalamus until a signal from the premotor cortex removes the brake from the basal ganglia

from the thalamus it goes back up to the primary motor cortex

from here it goes to the brain stem via the dirrect pathway and then from the brainstem to the spinal cord via the indirect pathway

it then goes through the spinal cord to the skeletal muscles

58
Q

what is the hierarchy of motor control

A

the highest level contains the premotor cortex, basal ganglia and the cerebellum

the middle level is the primary motor cortex

the lowest level is the spinal cord

59
Q

what is the name of the highest level of hierarchy of motor control

(theres 2 names)

A

precommand level

or pre action level

60
Q

what is the name of the middle level of hierarchy of motor control

A

projection level

61
Q

what is the name of the lowest level of hierarchy of motor control

A

segmental level

62
Q

what is the orientation of neurons at the segmental level

A

there are interneurons in the dorsal horns of the spinal cord

ventral horns contain motor and inter neurons

63
Q

what are central pattern generators

A

the segmental circuits in the spinal cord that control
locomotion (eg. walking)
& other specific & oft-repeated motor activity

64
Q

what do central pattern generators consist of

A

consists of a network of local interneuron and motor neurons, on both sides of the spinal cord, that work together to generate
a rhythmic pattern of motor activity

65
Q

what initiates and modulates central pattern generators

A

a “switch” consisting of the brainstem command neurons, particularly reticulospinal neurons

66
Q

Upper Motor Neurons in the primary cortical motor areas & brainstem directly control what

A

the spinal cord

The cortical motor areas produce the direct
(pyramidal) system

Brainstem motor areas oversee the indirect
(multineuronal, extrapyramidal) system

67
Q

describe the pathway of the pyramidal tract (direct pathway)

A

the primary motor cortex transmits its signal through the posterior limb of the internal capsule to the cerebral peduncle in the medulla. from here it goes through the pons to the pryimid (medulla)

it crosses over at the pyramidal decussation (at the level of the medulla spinal cord junction) into the lateral corticospinal tract where it descends in the lateral column to the lateral intermediate zone and the lateral motor nuclei

68
Q

what are the 3 parts of the internal capsule

A

the anterior limb, genu and the posterior limb

69
Q

what tract runs through the posterior limb of the internal capsule

A

the corticospinal tract

70
Q

there are body regions sitting within the internal capsule. what are these

A

most anteriorly is the face

then upper extremity –> trunk –> and lower extremity most posteriorly

71
Q

the corticospinal tract breaks into 3 parts at the decussation. what are these

A

90% goes into the lateral corticospinal tract

8% becomes the anterior corticospinal tract

2% never crosses over and becomes the uncrossed lateral corticospinal tract

72
Q

what does the corticospinal tract regulate

A

fast and skilled movements

73
Q

what does the corticospinal tract control

A

reflex motor output and modifying sensory input

74
Q

what does damage to the corticospinal tract cause

A

damage at any level leads to paralysis of target muscles

eg If lesion above pyramidal decussation on right –> paralysis of left upper limb and lower limb muscles

If lesion below the pyramidal decussation in the left lateral T10 spinal cord paralysis of left
lower limb muscles.

75
Q

what are the corticobulbar tracts

A

they go from the cortex to the bulb (brainstem). these have bilateral synappes and are mainly on the contralateral side

these then go into the crainial nerve

76
Q

what is the indirect (extrapyramidal) system

A

Motor axons arise from several brainstem nuclei

77
Q

what are the 4 major nuclei/regions of the extrapyramidal system

A

Superior colliculus, located in tectum or roof of midbrain

Red nucleus in the midbrain

Reticular formation in pons & medulla

Vestibular nuclei in medulla

78
Q

what are the 4 major pathways of the extrapyramidal system

A

Tectospinal tracts – move head & neck, visual input

Rubrospinal tracts – maintain muscle tone

Reticulospinal tracts – initiates CPG in spinal cord

Vestibulospinal tracts – maintain balance

79
Q

what are the Tectospinal tracts responsible for

A

move head & neck, visual input

80
Q

what are the Rubrospinal tracts responsible for

A

maintain muscle tone

81
Q

what are the Reticulospinal tracts responsible for

A

initiates CPG in spinal cord

82
Q

what are the Vestibulospinal tracts responsible for

A

maintain balance

83
Q

summery

what is the projection level

A

The pyramidal tracts
- originate from the primary motor cortex
- synapse either with interneurons or with
ventral horn motor neurons in spinal cord
- concerned with voluntary, discrete, skilled
movements

The command neurons in the brainstem nuclei can function to start, stop or modify the basic rhythm of CPGs of the spinal cord
through the indirect pathways

The command neurons in the brainstem nuclei also
regulate muscle tone (posture) and balance

84
Q

summery

what is the precommand level

A

Includes the premotor cortex, cerebellum & basal
ganglia

Premotor cortex responsible for initiating plan for next intended movement

innervates Basal ganglia to
release brake to start a specific movement

innervates Cerebellum which precisely calculates the best way to achieve
coordinated synergistic movements across multiple
limb joints = sends this “blueprint” to the primary
motor cortex, which then starts the intended
movement. also monitors muscle tone and balance

85
Q

what is the effect of a stroke in the internal capsule

A

the function of the face, upper extremity, truck, and lower extremity would be effected

ANAT 242 (17 decks)

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