Physiology neuro Book Flashcards
Major neural pathways in spinal cord
Corticospinal- motor - desiccate at medulla
Dorsal- touch, vibration, proprioception - desecrate at medulla
Spinothalamic- crude touch, pain and temp desiccate at level where leaves
Best clinical sign of compartment syndrome
Extreme pain on passive stretch
Ulcer forming from head trauma
Cushing ulcer - can form from operations or strokes too
Afferent limb to cranial reflexes
Cough- vagus
Clink- V1
Sneeze- V2
Jaw- V3
Gag- IX
Primary aim after major head injury
To prevent hypoxia, hypercapnia and hypotension
Cells on SA node
B1
M2
Calculating Cerebral perfusion pressure
MAP- ICP
Effects of raised ICP
Hypertension
Low HR
Irregular breathing
Eventually- pupillary constriction due to compression of 3rd CN
MAP calculation
1/3 (systolic-diastolic) + diastolic
When does auto regulation of CPP become impaired and when is there a bad outcome
In head injury
Occurs at 60-150
Volume of CSF
150ml
Order of CSF flow
Lateral
Foreamen on monro
3rd
Aqueduct of slyvius
4th
Lateral foreman of Luschka
SAS
Resting membrane potential, threshold and depolarisation potential
-70- -95mv
-55
To +40mv
Conduction speed of myelinated and unmyelinated
Myelinated 50-100m/s
Unmyelinated 1m/s
Brainstem death criteria
Pupils fixed
No corneal
Absent vestibule ocular reflex
No motor
Absent gag
Absent resp disconnected from ventilator
No sedation, muscle relaxants, electrolyte distubrances, normothermic
CO2 effect on cerebral blood vessels
High- vasodialtion
Timeline of spinal shock
Usually above T6
Happens instantly
Recovers after a few days/months
Types of nervous cells
Microglia- scavenger- phagocytosis
Schwann- myelin peripheral
Oligo- myelin CNS
Astrocytes- most common, supportive, maintaining environment and BBB
Neurotransmitters for autonomic system
Ach- pre ganglionic on nicotinic
Post- noradrenaline for symp
Ach para- Muscarinic
Adrenal medulla- noradrenalin from pre ganglionic symp directly
Location of pre ganglionic autonomic fibres
Symp- T1-L2 Lateral horns
Para- BS and sacral
Definition of motor unit
All the motor fibre a motor neurone innervates
What determines finer muscle control
The lower the innervation ratio
I.e less motor units to nerve
Different tissue around and within nerves
Endoneurium - surrounds peripheral nerves with capillaries and lymphatics
Perineurium- strong mechanical- surround bundles of fascicles
Epineurium- joins fascicles together- biggest
Types of nerve fibres
A and C
A- subtypes- a,b, y, d
Typically large and medium
a- motor
b- sensory
y-muscle
d- pain, temp
C umyeliainted- pain
