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NS - Ascending Motor
n/a
28
Anatomy
Graduate
07/07/2009

Additional Anatomy Flashcards

 


 

Cards

Term
Name the five sensory receptors of the Ascending Motor Tracks
Definition
  1. Mechanoreceptors - tapping, touch, vibration, stretch, tactile & positional
  2. Thermoreceptors - temp change
  3. Nociceptors - pain
  4. Electromagnetic - light energy
  5. Chemoreceptors - glucose & oxygen uptake
Term
Sensory receptors are based on their adaptation speed
Definition

Slow adapting receptors = muscle spindle or pain receptors - more tonic

 

Rapidly adapting receptors = hair end organ - more phasic

Term

General classification of sensory receptors

name the 3

Definition
  1. Exteroreceptive = responds to external environment
  2. Proprioceptive = positions of the body in space
  3. Interoreceptive = responds to internal changes
Term

Mechanoreceptors

(tactile receptors - 2)

Definition
  1. Meissener's corpuscles = most superficial with elongated capsules lying in epidermis; finger pads, rapidly adapting, sensitive to light objects over skin and low frequency vibration; purpose-hand texture objects and adaptability fast and rapid.
  2. Merkel's cell disc = incapsulated endings and found in smooth skin; deep in epidermis sensitive to pressure, location - densely in distal phalanx; purpose - pressure- adaptability is slow - looks like a bullseye 
Term

Mechanoreceptors

(continued 2 more)

Definition
  1. Pacinian corpuscles = deep in dermis-onion slice, purpose HIGH frequency vibration; rapidly adaptable
  2. Ruffini endings = location - dermis, jt and nerve fiber; purpose - skin stretch or conscious touch/pressure; slow adaptability
Term

Mechanoreceptors

(continued 1 )

Definition
  1. Hair end organ/peritrichial plexi = deep dermis and epidermis; purpose - alerting body to environment; rapid adaptability
Term
Mechanoreceptors are responsible for:
Definition

Position (static and rate of mvmt)

Proprioception

Kinesthesia

- pacinian, ruffini, GTO = looking for sense of mvmt and vib

found in hand and larger jts

 

Term
Nociceptors (free nerve endings)
Definition

fast pain = A fibers

slow pain = C fibers

thermal, chemical and mechanical can stimulate

Term

Group I (IA and IB) = A alpha (A)-myelinated

 

Definition

diameter = 12 - 20

conduction velocity = 60 - 120 m/sec

location = muscle spindle and GTO

most amount of MYELIN

associated with spinocerebellar pathway = unconscious proprioception

Term
Group II = A beta (B)- myelinated
Definition

diameter = 6 - 12 microns

conduction velocity = 30 - 60 m/sec

location = mechanoreceptors and muscle spindle

associated = DCML

Term
Group III = A delta (smallest myelinated)
Definition

diameter = 2 - 6 microns

conduction velocity = 10 - 30 m/sec

location = nociceptors A pain

amnt of myelin = LEAST

associated with = Lat spinothalamic tract

Term
Group IV = C fibers unmyelinated
Definition

diameter = less than 1 micron

conduction velocity = 1 - 2 m/sec

location = nociceptors C fibers is pain

amnt of myelin = NONE

associated with = lat spinothalamic tract

Term

Ascending Pathway

dorsolateral systems

 

Definition
DCML and lat cervical system (spinocervical thalamic)
Term

Ascending pathway

 

antero lateral system

Definition

ant and lateral spinothalamic tracts

and spinoreticular and spinotectal tracts

Term

Ascending pathway

pathways to cerebellum

Definition

dorsal spinocerebellar

ventral spinocerebellar

cuneocerebellar

 

rostral spinocerebellar

Term

How many neurons does the ascending tract to take to get to the brain?

 

How many to the cerebellum?

Definition

 

2

afferent sensory fibers enter the SC through the dorsal root where brances can synapse in the SC or through a distinct pathway

Term
General org of sensory systems
Definition

Usually first order = psuedounipolar located at DRG

2nd order = spinal cord or medulla

3rd order = VPL or thalamus

 

Term
DCML
Definition

discriminative touch and proprioception

light touch, tactile discrimination

two pt discrimination and steregnosis

conscious proprioception

static position sense, kinesthetic sense and vibration

Term

DCML pathway

1st order

Definition
1st order = from DRG enter SC, fibers usually large and myelinated (group IA, IB, II) travel up fasiculus gracilis from all levels and from above T6 fasiculus cuneatus
Term
DCML 2nd order
Definition
2nd order = travel in fas gracilis and cuneatus until closed medulla terminate on nucleus gracilis and cuneatus where fibers travel as internal arcuate fibers immediately cross midline at point of decussation of medial leminiscus
Term
DCML 3rd order
Definition
3rd order = at VPL of thalamus fibers project to somatosensory (primary and sensory) cortex via posterior limb of internal capsule
Term

DCML

clinical lesions

Definition

below medulla = ispi

above closed medulla(decussation) = contra

direct effects of lesion = loss of light touch, tactile discrimination, vib and proprioception

Indirect = coordination, dexterity and motor control

 

Term
Spinothalamic system
Definition

pathway for pain and temperature

crude touch, itch, tickle and certain visceral sensations

pain and temp = lateral

crude touch = anterior

 

Term

Spinothalamic

1st order

Definition

1st order = neuron fibers enter SC in lateral bundles most are smaller, unmyelinated groups III and IV afferents cross in white matter (ant white commissure)

upon entering axons travel up two spinal seg ipsi via zone of lassiuer and terminate in substansia gelatinosa or nuclues propulsious

 

Term

Spinothalamic

2nd order

Definition
2nd order = cross via ant white commissure and ascend to brainstem as ant and lateral spinothalamic tracts; in brainstem ALS terminates on VPL of thalamus
Term

Spinothalamic

3rd order

Definition
3rd order = from VPL of thalamus via posterior limb of interal capsule to the primary sensory cortex
Term

Spinothalamic tract

clinical lesions

Definition

lesion in SC = loss of pain and temp on CONTRA side

lesion in brainstem, thalamus or internal capsule = CONTRA would have to be initial isolated area to be IPSI 1st order

Term

DCML

lesions

Definition

MCA = CONTRA if lesion of ant commissure = BILATERAL loss

PCA = thalamic pain syndrome

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