Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Year 2: Neurobiology II > Lecture 2: Somatosensory system > Flashcards

Lecture 2: Somatosensory system Flashcards

1
Q

what are receptors and the 2 subgroups

A

things that detect stimuli

can be a cell or a nerve ending

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

difference between microscopic and macroscopic receptors

A

macro = a STRUCTURE that detects a stimuli (like a hair cell or ORN)

micro = a MOLECULE that interacts with the stimulus

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

cells that acts as receptors

A

can be a neuron (i.e. olfactory receptor neuron)

or can be other cell type (hair cell, rods, cones, etc)

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

how does a free nerve ending act as a receptors

A

specialized capsules

can function as a mechanoreceptor, chemoreceptor, thermoreceptor, or nociceptor

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

what is a mechanoreceptor

A

detects touch, vibration, stretch

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

what is a chemoreceptor

A

detects taste, smell, pH, O2, etc

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

what is a thermoreceptor

A

detects hot/cold and FLAVOR OF FOOD

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

what is a nociceptor

A

detects pain and noxious stimuli

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

what are special sensory receptors

A

special receptors that pick up various types of signals

i.e. like rods and cones that pick up electromagnetic waves

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

what organelle are receptors rich in

A

mitochondria

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

what are the special sensations

A

taste
smell
vision
hearing
vestibular

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

describe the localization of sensations; unconsious vs conscious and where these signals project to in brain

A

conscious maintains somatotopy and signals project to S1

unconscious project to subcortical structures like the RF or cerebellum

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

describe how a receptor graded potential works

A

potential stops when the stimuli stops

can have a lag effect like with vision (persistence of vision = you continue to see an image for a split second even after the object is no longer in line of sight)

intensity depends on AMPLITUDE (stronger/longer stimuli produce greater graded potential)

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

describe how an action potential works

A

frequency of a stimulus determines the intensity of the AP

AP changes with the receptor graded potential

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

explain how stimuli act on receptors similarly to how neurotransmitters act on postsynaptic membrane

A

when the stimuli act on the receptive area it has the same effect as a neurotransmitter binding to the post synaptic membrane

ionotropic receptors = ligand/modality gated ion channels

metabotropic receptors = G protein coupled receptor

when stimuli interact with receptor, it is either excitatory (depolarization) or inhibitory (hyperpolarization)

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

what are slow adapting receptors

A

good for static stimuli/telling static position

respond constantly to stimuli; continues to fire AP as long as it is stimulated

i.e. a mm spindle; signals are continually sent saying that the muscle is being stretched until it is no longer occurring

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

what are rapid adapting receptors

A

good for dynamic stimuli; good indicator of movement or change in stimulus

adapt greatly and quickly

some only signal at the beginning and end of stimulus, whereas some signal throughout just at a very diminished level

i.e. like when a hair is pulled; you get the signal quick but as soon as it happens you do not feel it anymore

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

5 types of cutaneous mechanoreceptors

A

meissner corpuscles

merkel cells

hair follicles

ruffini endings

pacinian corpuscles

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

what are meissner corpuscles

A

found on hairless skin (i.e. palms, lips)

detect flutter/vibration

rapid adapting

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

what are merkel cells

A

detect complex/fine touch

allow us to perceive object edges

slow adapting

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

what are hair follicles

A

on hairy skin only

detect fine touch and movement

can be rapid or slow adapting

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

what are ruffini endings

A

somatic

detect stretch in skin

slow adapting

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

what are pacinian corpuscles

A

in the whole body; have various functions

detect vibration in skin

rapid adapting

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

where are cutaneous mechanoreceptors most abundantly found

A

in fingertips and on lips

they have small receptive fields which allows for great details/signals to be sent back to the brain about what is being felt = allow for fine/discriminative touch

sparse in the trunk where there is an increased size of the receptive field

25
what are intrafusal vs extrafusal muscle fibers
extrafusals = main movers/contractors - alpha motor neuron -generate most of the tension/cause contractions - make up bulk of skeletal muscle intrafusals = found in mm spindle; detect proprioception and motor info - gamma motor neurons (not as much force) - type Ia and II sensory fibers innervate to detect proprioception and motor info -nuclear chain and bag cells are 2 structural types
26
nuclear chain vs bag cells
intrafusal fiber types chain = nuclei are in a line bag = nuclei are clustered in a "bag"
27
where do you find GTOs and what is their innervation
at muscle tendon junction type Ib sensory fibers innervate ruffini like sensory endings
28
what fibers innervate the joint capsules
type Ib sensory fibers ruffini like endings pacinian type endings
29
cutaneous mechanoreceptors have what type of neuronal axon
A beta (aka type II) myelinated, large diameter, fast conduction
30
A alpha senseory neurons types
type Ia = for muscle spindles type Ib = for GTO detect stretch
31
A beta sensory neurons are also called what type/what is their function
type II secondary receptors for mm spindles and contribute to cutaneous mechanoreceptors
32
clinical test for vibration should be conducted at what frequency and why
128Hz only frequency picked up by pacinian type endings
33
fasciculus gracilis processes what type of information
sensory info below T6
34
fasciculus cuneatus processes what type of information
sensory info above T6
35
fasciculus interfascicularis and the septomarginal fasciculus contain what type of pathways
visceral and some somatic pain pathways
36
describe the DCML pathway
1st order neuron in dorsal root ganglion 2nd order neuron = both the gracile nucleus and the cuneate nucleus (both located in the caudal medulla) the post synaptic axons form the internal arcuate fibers and cross at the caudal medulla fibers continue on to the contralateral VPL nucleus of the thalamus
37
in the DCML path, once signals reach the ventral posterior lateral nucleus of the thalamus, what information is relayed at the shell vs core portion
shell = information about proprioception core = information about vibration and fine touch
38
the trigeminothalamic pathway interprets information about what areas of the body
face and anterior scalp
39
describe the path of the trigeminothalamic pathway
1st order neuronal cell bodies: - trigeminal ganglion -mesencephalic nucleus 2nd order = these axons mentioned above project to the motor nucleus (for myotatic reflex) or the main sensory nucleus axons decussate at caudal pons 3rd order = synapse at ventral posterior medial nucleus of thalamus VPM projects to S1; somatotopy maintained
40
in the trigeminothalamic pathway, what information is given from the trigeminal ganglion vs the mesencephalic nucleus
trigeminal ganglion = fine touch, vibration, and limited proprioception mesencephalic nucleus = proprioception of mm/joints/periodontal ligaments
41
which CNs follow the spinal trigeminal nucleus pathway with limited info
CNs VII/IX/X (7, 9, 10)
42
what is the blood supply to the DCML before the decussation as well as the somatotopy of the tract at this time
before decussation = dorsal column blood supply = posterior spinal artery Somatotopy of Neck to LE = LATERAL TO MEDIAL
43
what is the blood supply to the DCML after the decussation in the medial lemniscus, rostral medulla as well as the somatotopy of the tract at this time
blood supply = anterior spinal artery somatotopy from neck to LE = POSTERIOR TO ANTERIOR
44
what is the blood supply to the DCML after the decussation in the medial lemniscus, pons as well as the somatotopy of the tract at this time
blood supply = basilar branches/PICA/AICA somatotopy from neck to LE = MEDIAL TO LATERAL + INVERTED
45
somatotopy of S1
From medial to lateral +interior (makes a C shape) = lower limb to face
46
the thalamogeniculate aa branch from
posterior cerebral artery (PCA)
47
the anterior cerebral artery supplies what
medial and superior portions of both the frontal and parietal lobes
48
the middle cerebral artery supplies what
the lateral portions of the frontal and parietal lobes + superior temporal lobes
49
what is the somatotopy of the medial lemniscus tract (after decussation) toward the thalamus
anterior to posterior = neck to LE Head = deep to medial
50
what info is encoded at the different sections of Brodmanns areas that correspond to S1 ( 3ab, 1, 2)
Proprioception information: 3a = info from mm spindles and GTO 2 = joint capsule info conscious sensations: 3b + 1 = fine touch, crude touch, sharp P!, temp
51
posterior spinocerebellar tracts relay what type of information
unconscious proprioception
52
describe the path of the posterior spinocerebellar tract/cuneocerebellar tract for unconscious proprioception
1. proprioceptive axons synapse at clarke's nucleus 2. post synaptic axons ascend ipsilaterally - posterior spinocerebellar tract = info about LE and body - cuneocerebellar tract (only from C2-T4) = neck info 3. travel through ipsilateral inferior cerebellar peduncle to the spinocerebellum
53
anterior spinocerebellum relays what type of info
motor info
54
describe the path of the anterior spinocerebellum
1. proprioceptive axons synapse at clarkes nucleus 2. post synaptic axons decussate at the anterior funiculus 3. axons then ascend contralaterally to the spinocerebellum - anterior spinocerebellum tract enters cerebellum through bilateral superior cerebellar peduncles - rostral spinocerebellar tract (C2-T4 only) enter through superior/inferior cerebellar peduncles
55
describe the trigeminocerebellar pathway
proprioceptive info for face Mesencephalic nucleus travels through superior cerebellar peduncle to ipsilateral cerebellum other info from trigeminal nuclei (mainly) and main sensory nucleus (minorly) travels through inferior cerebellar peduncle to the ipsilateral cerebellum
56
Tabes dorsalis: what is it, what causes it, and what are the S&S
what = progressive locomotor/sensory ataxia; degeneration of DCML causes functional loss why = infection via treponema pallidum or STD that causes neurosyphilis S&S = wide stance/feet grasping for floor/steppage gait
57
differential dx for tabes dorsalis
peripheral neuropathy with proprioceptive loss guillan barre syndrome
58

Year 2: Neurobiology II (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions