Spinal tracts/ Muscle fibres

Question 1

what type of info do ascending pathways carry?

Answer 1

sensory

Question 2

how many orders does the ascending pathway have

Answer 2

4

Question 3

what does DCML carry

Answer 3

fine touch, vibration, proprioception

Question 4

what r the two parts of the DCML and what do they relate sensory info for

Answer 4

fasciculus cuneate- upper limb

fasciculus gracilis- lower limb

Question 5

what r the two parts of the spinothalamic tract and what type of sensory information do they carry

Answer 5

anterior= crude touch and pressure
lateral= pain and temp

Question 6

what does spinocerebellar carry

Answer 6

unconscious proprioceptive information from muscle to cerebellum

Question 7

what type of info do descending pathways carry?

Answer 7

motor

Question 8

how many orders of neurons does the descending pathway have

Answer 8

2

Question 9

what r the 2 classification of descending tracts

Answer 9

pyramidal and extrapyramidal

Question 10

what do pyramidal tracts carry

Answer 10

voluntary control of muscle

Question 11

what do extrapyramidal tracts carry

Answer 11

involuntary/ autonomic control of musculature

Question 12

what re the two pyramidal tracts and what do they carry

Answer 12

corticospinal- results of body muscles

corticobulbar- head and neck muscles

Question 13

what r the 4 extrapyramidal tracts

Answer 13

vestibulospinal
reticulospinal
rubrospinal
tectospinal

Question 14

what is the path fo the DCML

Answer 14

1. respective fasciculus bring info up to reach the dorsal root ganglia and ascend ipsilaterally
2. decussate at medulla
3. ascends to contralateral thalamus to go to contralateral somatosensory cortex

Question 15

what is the path fo the spinothalamic

Answer 15

1. reaches dorsal root ganglion from receptors in periphery
2. decussation 1/2 levels above ventral horn
3. ascends to contralateral thalamus to go to contralateral somatosensory cortex

Question 16

what does vestibulospinal tract carry and where does it come from

Answer 16

balance and posture

vestibular (8th) nucleus

Question 17

what does reticulospinal tract carry and where does it originate from

Answer 17

muscle tone and voluntary movement

pons

Question 18

what does tectospinal tract carry and where does it originate from

Answer 18

movment of head in relation to vision

superior colliculus

Question 19

what does rubrospinal tract carry and where does it originate from

Answer 19

fine control of hand movement

red nucleus

Question 20

what r the 2 extrapyramidal tracts that decussate

Answer 20

rubrospinal and tectospinal

Question 21

path of corticospinal tract

Answer 21

1. ascends though corona radiata to the internal capsule
2. 85% decussates at medulla and goes contralateral and 15% remains ipsilateral
3. terminates at the ventrolateral horn of the spinal cord and synapses onto 2 order neurons

Question 22

path of corticobulbar tract

Answer 22

1. corona radiata to internal capsule to crus cerebri, pons and medulla
2. synapse at cranial nerve nuclei to supply head and neck muscles

Question 23

5 stages of neurotransmitter cycle at NM junction

Answer 23

1. manufacture
2. storage
3. release
4. interaction (NT with post synaptic receptors)
5. inactivation (of NT)

Question 24

compare bells palsy to stroke (UMN/LMN, what order neurone, where is teh lesion)

Answer 24

bells= LMN affected, 2nd order neurones, CN 7 lesion
stroke= UMN affected, 1st order neuorons, UMN lesion

Question 25

what is a motor unit

Answer 25

alpha motor neurone and the extrafusal skeletal muscle it innervates

Question 26

function of alpha motor neurons

Answer 26

voluntary muscle contraction

Question 27

function of gamma motor neurons

Answer 27

controls muscle contraction in response to external forces acting on muscles

Question 28

what does a smaller motor unit mean

Answer 28

fine regulation/ control

Question 29

what muscle is controlled by lateral and medial alpha motor neurones

Answer 29

lateral- distal muscle | medial- proximal

Question 30

what r the two things intrafusal muscles fibres sense and for what reason

Answer 30

sense stretch and monitors muscle length and rate of change to prevent overstretching of muscles

Question 31

types of intrafusal muscle fibres and functions (2)

Answer 31

1a- excites alpha motor neurones | 2- inhibits alpha motor neurones

Question 32

what do golgi tendons detect and what type of sensory fibres do they have and what is its function

Answer 32

tension 1B if too much tension, golgi tendon inhibits muscle from contracting

Question 33

what is a muscle spindle made of and what does it detect

Answer 33

intrafusal fibres and stretch receptors | stretch

Question 34

efferent and afferent supply of muscle spindle

Answer 34

``` efferent= gamma afferent= 1a (fast), 2 (slow) ```

Question 35

types of pain and what tract carries them and what fibres is this

Answer 35

slow pain- anterior spinothalamic C fibres | fast pain- lateral spinothalamic alpha fibres

Question 36

what is the neurotransmitter for fast acting pain, where does it act and what fibre is this

Answer 36

glutamate at 1st and 2nd order neurones alpha fibres

Question 37

what is the neurotransmitter for slow acting pain and what fibre is this

Answer 37

glutamate AND substance p | C fibres

Question 38

what does substance p do and how

Answer 38

gives nociception (dull achy pain) by binding for longer

Question 39

analgesic vs anaesthetics

Answer 39

analgesic- selective pain suppression, consciousness not affected anaesthetics- total pain suppression, consciousness can be affected

Question 40

ascending pathway for PAIN

Answer 40

1. nociceptors sense pain 2. trasnmit impulse to DRG via alpha or c fibres 3. decussation 1-2 spinal levels above where alpha becomes lateral and c fibres become anterior 4. go to thalamus to the somatosensory cortex

Question 41

compare alpha and c fibres

Answer 41

``` alpha= unmyelinated c= myelinated ```

Question 42

what is pain gate and what is the effect of this

Answer 42

small descending pathways that inhibit interneurones of the spinothalamic tract prevent impulses reaching the somatosensory cortex

Question 43

which 3 tracts decussate at the medulla

Answer 43

DCML corticobulbar corticospinal

Question 44

what is end plate potential adn how is the AP propagated

Answer 44

like at a NM junction but stronger depolorisation | propagated to all adjacent fibres in an alpha motor unit

Question 45

compare UMN and LMN lesion location

Answer 45

``` UMN= between motor cortex and the spinal cord LMN= between spinal cord and muscle ```

Question 46

compare UMN and LMN lesion damage symtoms

Answer 46

``` UMN= hypertonia, spasticity (hyperactive kid) LMN= hypotonia, muscle atrophy (slow grandad) ```

Question 47

what is conus medularis and what level does this occur

Answer 47

where the spinal cord becomes tapered | L1/2

Question 48

what is cauda equina

Answer 48

nerves from lumbar and sacral nerves handing obliquely downwards

Question 49

what is the filum terminale and what does it contain

Answer 49

fibrous strand extending from conus medullaris to coccyx

Question 50

curves of the vertebral column name and direction

Answer 50

cervical and lumbar curve anterior | thoracic and sacral curve posterior