PBL2

Question 1

what happens when you bleed

Answer 1

HR goes up to compensate for drop in BP in order to maintain cardiac output. CO=HRxSV

Question 2

how do we know that Cody is not bleeding

Answer 2

• we know he is not bleeding because his heart rate decreases from 82 to 64

Question 3

why is Cody still breathing but has shallow breathing

Answer 3

• he has a C5/C6 fracture, but c3 c4 c5 phrenic nerve innervation keeps the diaphragm alive, therefore he has breathing but restricted breathing

Question 4

what is the babinski sign a sign of

Answer 4

Positive babinski sign is a sign of upper motor neurone damage in the corticospinal tract

Question 5

what is spinal cord shock

Answer 5

A state of temporary loss of function in the spinal cord

All functions below lesion are depressed or absent due to removal of all descending motor pathways

Gives impression of flaccid paralysis and loss of sensation

Question 6

how long does spinal cord shock last for

Answer 6

• often only lasts 1 day

- can last months

Question 7

what happens after spinal cord shock

Answer 7

Neurones gradually regain their excitability and the flaccid paralysis gives way to spastic paralysis

Oedema and inflammation reduced

Question 8

what happens when you have upper motor neurone lesions

Answer 8

Damage to the CNS

Spastic paresis

Hypertonia

Clonus

• Distributed to groups of muscles, never individual muscles. Stretch reflexes hyperactive

Question 9

what happens when you have lower motor neurone lesions

Answer 9

Damage to PNS

Flaccid paralysis

Limited to muscles innervated by damaged motor neurones or axons

Pronounced atrophy

hypoactive stretch reflexes

Question 10

where does the corticospinal tract decussates

Answer 10

Corticospinal tract – decussates at the medulla, damage leads to ipsilateral motor deficits

Question 11

where does the spinothalmic tract decussate

Answer 11

Spinothalamic tract – decussates in spinal cord – lesions lead to a contralateral deficit at the level of lesion

Question 12

where does the DCML decussate

Answer 12

DCML – gracile and cuneate fasciculi. Decussates at medulla. Damage leads to ipsilateral loss of proprioception

Question 13

what are the pyramidal tracts

Answer 13

• lateral and anterior corticopsinal tracts

Question 14

what are the extrapyramidal tracts

Answer 14

rubrospinal
reticulospinal
vestibulospainl tract

Question 15

what is the prognosis of Cody

Answer 15

Further functional recovery is poor. CNS regeneration is poor, lost neurons won’t be replaced

Question 16

why can’t Cody maintain his blood pressure and why does he have warm peripheries

Answer 16

In spinal cord injury, lose the inability to vasoconstrict. Vasodilation causes warm peripheries and low BP.

Question 17

why is the heart rate low

Answer 17

Also because of the feedback mechanism to the heart, HR does not increase to compensate

Question 18

what is shock

Answer 18

Shock is inadequate perfusion to tissue, sufficient to cause end organ damage

Question 19

what are the 2 main sensory tracts in the spinal cord

Answer 19

spinothalamic and dorsal columns

Question 20

describe input into spinothalamic tract

Answer 20

• smal diameter sensory neurones which are unmyelianted or thinly myelinated

Question 21

what information does the spinothalmic tract relay

Answer 21

• crude touch, pain, temperature

Question 22

where is the spinothalamic tract in the spinal cord

Answer 22

ventrolateral spinal tract

Question 23

what are the inputs into the DCML

Answer 23

• carry information from larger diameter myelinatedneurones

Question 24

What information is in the DCML

Answer 24

• vibration
• proprioception
• discriminatory touch

Question 25

what is the babinskin response to

Answer 25

• it is in response to a polysyantpic reflex
• it is evoked to by stimulation to the sole of the foot
• this normally produces a flexion withdraws reflex

Question 26

what is the normal response to the babinski when the corticospainl tract is normals

Answer 26

• toes curl down and adduct together

Question 27

what is the abnormal baninskin sign when the corticospainl tract is damaged

Answer 27

• big toe dorsiflexes and the other toes fan out

- this is normal in a baby

Question 28

what does the babinski sign due to

Answer 28

upper motor neurone damage

Question 29

Define the term spasticity and state its clinical significance

Answer 29

Increased muscle tone and exaggerated tendon reflexes; Sign of upper motoneuron damag

Question 30

State two reasons for weakness in Cody’s breathing.

Answer 30

Damage to the motoneurons of C5 innervating the diaphragm.
Complete injury at C5 level results in loss of control on lower motoneurons innervating external intercostal and abdominal muscles