Brainscape's Knowledge GenomeTM

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


See full index

Organ Systems III > Exam 3 > Flashcards

Exam 3 Flashcards

0
Q

What are the 4 attributes of somatic sensation?

A

Intensity - increased stimulus reflects increased AP
Sensory adaptation - decreased neural activity with sustained stimulation
Modality - tactile sensation (touch, pain, temperature) or proprioception
Localization - receptor fields varying in size/acuity

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

What are thee 3 levels of integration associated with primary/association somatosensory cortices?

A

Somatic sensation
Somatic perception
Somatic representation

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

What is meant by compound action potential?

A

Summed action potentials representing the groupings of various sensory/motor neurons that propagate signals at different speeds depending on size/myelination

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

What are the different classifications of nerve fibers?

A

Roman numerals correspond to motor nerves while letters correspond to sensory nerves
I or A are fastest
IV or C are slowest

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

What are the 5 different types of sensory neurons involved in discriminatory touch?

A 
Merkel cells - form/texture
Ruffini corpuscles - hand shape/position
Meissner corpuscles - skin movement
Pascinian corpuscles - vibratory stimuli
Hair follicles - motion/direction of tactile stimuli
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the difference between the slow vs fast adapting receptors in terms of messages sent to the brain?

A

Slow (Merkels & Ruffini) send info of form and hand shape in relation to an object
Fast (Meissner, Pascinian, hair follicles) send info related to movement/vibration

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

Which mechanoreceptors are localized in smaller RFs and which are in larger RFs?

A

Meissner and merkels are in smaller RFs (finger tips)

Pascinian and ruffini are in larger RFs

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

Are proprioceptive receptors fast or slow conducting? Large or small fibers?

A

Fast conducting (ruffini and pascinian) with large, myelinated axons (Aalpha/B)

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

How are sensory modalities distinguished by peripheral nerves?

A

Distinguished by ascending pathways
Dorsal column - quantitative localization of stimulus
Anterolateral system - qualitative experience

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

What information do slow vs fast adapting exteroreceptors mediate?

A

SLOW - non-discriminative touch, pain, temperature via Adelta and C fibers through the anterolateral system of spinal cord
FAST - proprioception (position, location, orientation, movement) via large, Aalpha and B fibers through dorsal column-lemniscal system of spinal cord

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

Where are 1st, 2nd, and 3rd order neurons located in the dorsal column-lemniscal system?

A

1st order neurons form the dorsal column (cuneate and gracile fasciculi) of spinal cord
2nd order neurons travel from dorsal column to decussate at the medulla and synapse in the thalamus
3rd order neurons travel thalamus to primary somatosensory cortex of the parietal lobe

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

Where are 1st, 2nd, and 3rd order neurons located in the anterolateral system?

A

1st order sensory neurons synapse onto 2nd order neurons in dorsal horn (substance P, glutamate, NO)
2nd order neurons decussate at level of spinal cord to the anterolateral system to take one of two main pathways (neospinalthalamic or paleospinal thalamic)
3rd order neurons from thalamus project to primary somatosensory cortex or cingulate gyrus/insula for integration

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

Distinguish between the two anterolateral pathways (neospinothalamic and paleospinothalamic) involved with propagating sensory information.

A

Neospinothalamic - projects to lateral thalamic neurons and then to the primary somatosensory cortex of parietal lobe to provide sensory localization
Paleospinothalamic - projects to medial thalamic neurons and then to cingulate gyrus/insula to provide qualitative aspects of sensation (pain, temperature, and non-discriminatory touch)

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

What is the reticular formation?

A

Involved with paleospinothalamic tract of anterolateral system - projects from medulla to cortex for somatosensory association

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

What are the symptoms and causes of syringomyelia?

A

Cysts in anterolateral system interrupt decussation of signals leading to bilateral loss of pain/temperature sensation but NOT discriminatory touch

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

What are the symptoms and causes of Brown-Sequard syndrome?

A

Loss off ipsilateral discriminative touch/motor and contralateral pain/temp sensation due to lesion of dorsal and anterolateral systems

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

Describe the anatomy and sensory projections of the trigeminal nerve. What are the different nuclei that mediate the different modalities?

A

CN V has 3 branches - opthalmic, maxillary, and mandibular
Principal sensory nucleus - discriminative touch from face
Spinal trigeminal nucleus - pain/temp from face
Mesencephalic nucleus - proprioception from masticators
Motor nucleus - motor to mastication muscles

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

What are dermatomes? How do the body and face dermatomes compare?

A

Dermatome - area of skin innervated by cutaneous branch of single spinal nerve
pain/temp dermatomes of face are represented in an ‘onion skin’ fashion

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

How many layers are there in neocortex? Which layers contain the major input receiving cell and the output cells? What are those cells called?

A

6 cell layers (I - VI)
Stellate cells are found in layer IV and receive sensory info from thalamus
Pyramidal cells are found in layer V and project info to other regions of the CNS

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

What are brodman’s areas?

A

Numbered areas of cerebral cortex that are histologically distinguishable, used for anatomical identification of functional areas

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

What does an fMRI show/measure?

A

Enables visual of brain activity in response to mental/physical stimulus due to magnetic induction of proton spin

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

What is the antatomical organization of the thalamus?

A

Pair of grouped nuclei on either side of the 3rd ventricle within the diencephalon that project axons to all areas of the cortex

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

Which nuclei of the thalamus project to the somatosensory cortex?

A

VPL and VPM

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

Where is the somatosensory cortex? How is it organized?

A

Within postcentral gyrus of parietal lobe, organized into cortical columns that are somatotopically organized with different RFs/modalities

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

What is the homunculus?

A

Somatotopic organization of sensory information that shows density of sensory receptors associated with different body parts - high density in face (mouth/tongue/lips) and extremities

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

What is cortical plasticity?

A

Ability of cortex to functionally adapt by recruiting neighboring regions of ‘latent’ cortex

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

What is the significance of lateral inhibition in somatosensation?

A

Cortex, thalamus, and DCN are able to enhance differences between somatosensory RFs through the action of surrounding inhibitory interneurons

27
Q

How do the sensory and motor cortices affect lateral inhibition and information processing in the ascending somatosensory system?

A

Motor cortex sends info to muscles for movement and also to DCN to facilitate sensory stimuli related to the movement
*Motor cortex enhances lateral inhibition to allow greater tactile resolution and manipulation skills

28
Q

What is two-point discrimination? What part of the somatosensory system is responsible for this?

A

Ability to discriminate 2 separate, simultaneous pin pricks
Tests the integrity of the dorsal column lemniscal system
- can be reduced with dorsal column degeneration associated with syphilis

29
Q

What is the ventral stream of somatosensory information? What conscious information does this provide?

A

S1 projects to S2 (limbic system) bilaterally to answer the question “What is it?” while developing a 3D image and responding based on behavioral context or motivational state

30
Q

What is the dorsal stream of somatosensory information? What conscious information does this provide?

A

Dorsal stream takes info to the posterior parietal association cortex (PPC) to answer the question “Where?” and “How?” through integration of touch, proprioception, audition, and vision to create body schema or ‘ego-centric space’

31
Q

What gives rise to ‘somatosensory attention?’

A

Convergence of bottom up and top-down input shape perception/awareness of somatic stimuli giving rise to consciousness

32
Q

What are the characteristics and cortical issues associated with phantom limb phenomena?

A

Reorganization of somatosensory cortex after denervation of limb cortex which unmasks latent sensory pathways

33
Q

What is astereognosis? neglect syndrome? What part of the brain is usually involved in neglect?

A

Astereognosis - inability to identify an object by touch
Neglect syndrome - loss of sensation/consciousness of (left) side of the body, often due to lesion of (right) inferior parietal lobe

34
Q

What is the difference between illusion and delusion?

A

Delusion = tactile hallucination

35
Q

What is the difference between upper and lower motor neurons?

A

Lower motor neurons consist of alpha and gamma motor neurons from brain stem and spinal cord that make up the common pathway for motor commands
Upper motor neurons reside in cortex, reticular formation, and vestibular system and project to lower motor neurons

36
Q

What is the difference between a superficial and a deep reflex?

A

Superficial reflexes involve flexor withdrawal, and require an inhibitory interneuron within spinal cord
Deep reflexes are simpler stretch or tension induced reflexes that are monosynaptic within spinal cord

37
Q

What is a muscle spindle and how does it respond to changing muscle length?

A

Muscle spindles are intrafusal fusel receptors that serve to provide feedback of muscle length via Ia and II afferent activation through the opening of physically gated channels

38
Q

Describe the myotatic reflex. What motor neurons are involved?

A

The myotatic reflex serves to maintain muscle length when muscles are stretched
Stretch -> Spindle receptor activation -> Ia/II afferent -> alpha motor neuron -> contract muscle to maintain length and inhibit antagonists via recipricol inhibition
Jendrassik maneuver enhances DTRs

39
Q

How does gamma motor neurons activity affect myotatic reflexes?

A

Gamma motor neuron activity enhances myotatic reflexes by increasing sensitivity of muscle spindle receptors - Jendrassik maneuver

40
Q

Describe the flexor withdrawal/crossed extension reflex.

A

Pain afferent activity stimulates ipsilateral contraction/withdrawal coupled with contralateral extension

41
Q

What is a Golgi tendon organ and how does it respond to muscle tension? Is it regulated by gamma motor neurons?

A

GTOs are receptors located in muscle tendons that work to maintain muscle tension in response to stretch by inhibiting antagonist
*not innervated by gamma motor neurons

42
Q

Describe propriospinal neurons and their action on spinal reflexes.

A

Propriospinal neurons located in intermediate spinal gray matter interconnect spinal levels for complex actions and regulating reflexes

  • medial propriospinal neurons project over who spinal cord to regulate posture
  • lateral propriospinal neurons project over few spinal segments to regulate finer movements
43
Q

What are some general functions of upper motor neurons?

A

Balance, posture, fine movements of extremities

44
Q

Describe the motor control functions of the vestibulospinal and reticulospinal tracts. What is the antigravity posture and what produces it?

A

Vestibulospinal tract - Vestibular nuclei of medulla relay head positional information from saccule/utricle/semi circular ducts to maintain posture and balance
Reticulospinal tract - Reticular nuclei from pons/medulla project to proximal muscles of trunk to regulate complex structure
Antigravity is extension of lower limbs and flexion of upper limbs, resulting from lesion

45
Q

Describe the three parts of the corticospinal tract system (corticospinal, corticonuclear corticoreticular) and what they do.

A

Corticopsinal - lateral provides fine control of movement and medial provides posture of head and trunk
Corticonuclear - controls muscles of the face, head, and neck projecting to motor neurons of cranial nerves
Corticoreticular - smooths out general movement through projection from reticular formation

46
Q

What is the significance of the internal capsule? What is the significance of the medullary decussation?

A

The internal capsule protects a bundle of axons within the cerebral hemispheres that is a common site of stroke
The medullar decussation is where descending motor neurons cross - a lesion/stroke above this level will result in hemiplegia

49
Q

Compare lower motor neuron and upper motor neuron disease. What are the aspects of spasticity?

A

Lower - flaccid paralysis - due to lesions of alpha motor neurons to muscles
Upper - spastic paralysis - due to disrupted cortical projection to reticular formation

51
Q

How do the anterior and lateral corticospinal tracts differ in structure and function?

A

Anterior corticospinal tract in ventral funiculus controls posture of head/neck/trunk
Lateral corticospinal tract descends from cortical, homuncual regions, providing fine control of motor function

52
Q

What are the 3 extrapyramidal tracts of descending motor info?

A

Vestibulospinal
Reticulospinal
Corticoreticular

53
Q

What is the function of the primary motor cortex?

A

Precentral gyrus arranged somatotopically as homunculus encodes force, direction, extent, and speed of movements to activate small groups of muscles to carry out actions

54
Q

What is the function of the supplementary motor cortex?

A

Ensures correct motor sequences independent of external circumstances by generating sequences of movements and rehearsal to transform kinematic info to dynamic info

55
Q

What is the function of the premotor cortex?

A

Integration of spatial/sensory info in the preparation and planning of movement - intention
- Broca’s area is part of premotor cortex involved in motor preparation of speech

56
Q

What is efference copy? How does it play a role in self awareness?

A

Motor cortex sends copies of motor programs directly to somatosensory cortex to integrate with incoming sensory info to predict expected sensations (‘feed-forward anticipation’)
The integration of feed forward and feedback info is what provides self-agency, self-ownership, and self-awareness

57
Q

What are mirror neurons and where are they located?

A

Mirror neurons unify action perception and action execution - represent intention of action as opposed to specific movements

  • when we observe someone performing an action, motor pathways are triggered in the observers brain
  • evidence of this is seen in the inferior premotor cortex and inferior parietal cortex
58
Q

What are the 3 lobes of the cerebellum and the 3 cellular layers?

A

Anterior, posterior, flocculonodular lobes

Granular, purkinje, and molecular cell layers of gray matter

59
Q

Describe the pathway from cerebellar cortex to motor cortex and back.

A

Granule cells receive sensory input > purkinje cells transmit output to deep cerebellar nuclei > nuclei transmit info to thalamus and cortex

60
Q

How does the vestibulocerebellum connect with the motor cortex and spinal cord to participate with motor function?

A

Vestibulocerebellum (flocculonodular lobe) receives sensory input from vestibular system and projects to vestibular nuclei of medulla to control posture, balance, and eye movements (VOR)

61
Q

How does the spinocerebellum connect with the motor cortex and spinal cord to participate with motor function?

A

Receives input from spinal cord (spinocerebellar tracts) and cortex (pontine nuclei) to provide feedback control of ongoing movements (efference copy) in order to smooth movements and dampen unwanted oscillations

62
Q

How does the cerebrocerebellum connect with the motor cortex and spinal cord to participate with motor function?

A

Cerebellar hemispheres > dentate nuclei > thalamus/cortex > pontine nuclei > cerebellar cortex —- closed circuit
cerebrocerebellum plans and programs voluntary, learned, skillful movements - continued communication allows movements to become rapid and precise with practice

63
Q

What is dysmetria and decomposition of movement?

A

Dysmetria is inability to control range of movement - finger to nose test
Decomposition is the inability to sequence fine coordinated acts

64
Q

What is ataxia?

A

Lack of smoothly coordinated movements resulting from dysmetria combined with decomposition

65
Q

What is dysarthria?

A

Inability to articulate words - slurring speech

66
Q

What is dysdiadochokinesia?

A

Inability to perform rapid, alternating movements

67
Q

What is an intention tremor?

A

Rhythmic, alternating, oscillatory movements of a limb as it approaches a target - gets worse with increased intention

68
Q

What roles does the cerebellum play in cognition?

A

Cerebellum serves in timing and temporal recognition in cognitive processes - dampening oscillations and smoothing out movements - as well as mental flexibility, multi-tasking, and problem solving to obtain a certain goal

69
Q

What are the somato-visceral functions of the cerebellum?

A

Cerebellar connections to hypothalamus and brainstem are involved in GI, cardio, respiratory, micturition, and immune function

Organ Systems III (5 decks)

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