Microanatomy Muscle Weakness Motor And Sensory Endings

Front 1

three cells at NMJ

Back 1

motor neuron
schwann
muscle fiber

Front 2

Presynaptic features of NMJ

Back 2

AcH vesicles surround active zone(has Ca channels)

active zones above junctional folds(secondary synaptic cleft)

mito under the schwann cell(upper half)

Front 3

Presynaptic(perisynaptic) features of schwann cells

Back 3

attenuate synaptic transmission and help reinnervate muscle fibers

Front 4

Postsynaptic features

Back 4

primary junctional folds
secondary - crests have AcH R

nuclei and mito are underneath nn terminal

Front 5

Synaptic cleft features

Back 5

synaptic basal lamina passes through primary synaptic cleft and into secondary synaptic cleft, enriched in agrin neuregulin and acetylcholinesterase

Front 6

motor nn at smooth muscle

Back 6

less elaborate, NT released from boutons(varicosities)

beads on a string en passant

one varicosity can innervate MULTIPLE smooth muscle cells(skeletal = only one per terminus)

synaptic cleft is wider, NO JUNCTIONAL FOLDS
active zones not prominent

Front 7

CLINICAL CORRELATES

Back 7

kjsgf

Front 8

lambert eaton syndrome

cause
symptoms

Back 8

Ab against presynaptic Ca channels in active zone

muscle weakness and fatigability

Front 9

Myasthenia gravis

cause
symptoms

Back 9

Ab against postsynaptic ACh R

muscle weakness and fatigability

Front 10

Muscular dystrophies

Back 10

most by mutation in dystrophin, link b/w ECM and subsarcolemma cytoskeleton

Front 11

Where it comes from, cellular cause, symptoms

Botulinum

Bungarotoxin

Tick paralysis

Back 11

botulism - bacteria, blocks NT release, muscle paralysis

bungarotoxin - snake, irrev binds ACh R, muscle paralysis

Tick - tick, inhibits ACh release, flaccid paralysis

Front 12

Where it comes from, cellular cause, symptoms

latrotoxin

tetanus

Back 12

latrotoxin - black widow, stim synaptic vesicle fusion, muscle fatigue and PARALYSIS

Tetanus - bacterium, CNS inhibits NT release from INHIBITORY spinal motor neurons

Front 13

sense position of the entire body or body part

Back 13

proprioreceptor

a physiological classification

Front 14

sense pressure vibration touch sound

Back 14

mechanoreceptor
a physiological classification

Front 15

what type of nn ending?

loose all covering, end w/o specialization, majority of sensory receptors of skin
base of hair roots, sense pain, mechanical, warm, cold

Back 15

free nerve endings(peritricial)

Front 16

Type of anatomical nerve ending

slow adapting mechanoreceptors
basal layer of epidermis
unmyelinated cutaneous nn terminal form flattened discs that sits close to a modified epithelial cell attached to neighboring cells by desmosomes

Back 16

expanded tip endings

MERKLE's CORPUSCLE

Front 17

anatomical type of nn ending

CT sheath surrounding nerve terminal,

Back 17

encapsulated endings

Pascinian corpuscle
Ruffini endings
Meissners corpuscle
Muscle spindles
Golgi tendon endings

Front 18

Pacinian corpuscle

Location
Stimulus(function)
Structure

Back 18

location: glabrous and hairy subcutaneous layer

Stimuli - rapid adapting mechanoreceptors, high frequency touch/vibration

Structure: outercore of flattened fibroblasts, inner core of flattened schwann continuous with endoneurial sheath, nerve in middle ending in knoblike spray

Front 19

Ruffini ending

Location
Stimulus(function)
Structure

Back 19

Location - deep dermis of hairy and glabrous skin, joint capsules

Stimulus(function) - slow adapting mechanoreceptors, low freq vibration/pressure from stretching of collagen in skin

Structure - elongated fusiform, parallel to skin, callagen fibers running through

Front 20

Meissner's Corpuscle (not merkle cell)
Location
Stimulus(function)
Structure

Back 20

Location - dermis papilla

Stimulus(function)- rapid adapting , fires transient at onset to low freq irreg vib/pressure

Structure - small cylindrical perpendicular to skin, schwann cell horizontal flat inside fibrous CT, axonal ending spiral throughout

Front 21

Muscle spindle
Location
Stimulus(function)
Structure

Back 21

Location - skeletal muscle

Stimulus(function)- changes in muscle length causing contraction of extrafusal fibers (knee jerk reflex)

Structure - capsule of fibroblasts connected by desmosomes, surrounds CAPSULAR SPACE containing tissue fluid

Front 22

which two encapsulated endings have desmisomes

Back 22

merkle's corpuscle - between merkel cell and nighboring cell

muscle spindle - between fibroblasts of capsule

Front 23

Intrafusal fibers

Back 23

inside capsular space, non contractile middle, striated ends, smaller

nuclear bag fibers - cluster of nuclei

nuclear chain fiber - chain of nuclei

Front 24

innervation of spindles

Back 24

EFFERENT: gamma motor neurons on striated portion of intrafusal, contractions makes the fusal fibers more sensitive to muscle stretch

AFFERENT - each spindle recieves a primary sensory ending(myelinated afferent), also many smaller secondary sensory endings

Front 25

Golgi tendon

Location
Stimulus(function)
Structure

Back 25

Location - in tendons of muscle

Stimulus(function)- muscle contraction, monitors load, protective reflex

Structure - thin fibroblastic capsule filled with collagenous fibers(continuous with muscle tendon) and extrafusal muscle fibers

Front 26

how is golgi tendon innervated

Back 26

ONLY AFFERENT

large myelinated sensory looses myelin after encapsulation and ends in small sprays of free nerve endings

signal to spine through dorsal root ganglia, along inhibitory interneuron, and to alpha motor neuron which innervates the MUSCLE(not tendon)