week 2 Flashcards
activation of c fibres gives off what pain?
dull aching pain
what pain is characterised by a high threshold and limited duration?
nociceptive pain - mediated by A delta and C fibres
what is chronic (maladadaptive pain)?
either evoked or spontaneous
A sustained sensory abnormality
comes with hyperalagesia and allodynia
after ebing scratched , what appears?
red reaction, wheal (white area) and flare
when u damage the skin what happens
free nerve endings activated by release of K ions and prostagandins . bRradykinin and 5 -HT is released and activates themand
Substance P and CGRP are also released and they activate mast cells that release histamine.
what does CGRP do?
dilation of blood vessels , more blood flowing to blood vessels and that makes the skin appear red.
consequence of substance P?
can result in oedema , tissue fluid buildup plasma extravasation and release of bradykinin
into the dorsal roots and bifurcate to where
one bracnch goes to dorsal columngracile nucleus-> internal acuate ….
and the little branch into dorsal horn
in the spinothalamic pathway , wherdoes the nerve cross over to from dorsal horn?
anterolateral funiculus
supraspinal system does what?
in build system to help modulate pain input.
gate control theory of pain ?
c fibres activated - projecting into dorsal horn of spinal cord, release glutamate to send of 2nd neuron.
when you rub your hand u activate the A beta pathways sends action potwntials to sensory cortex via DC -ML .
An inhibitory neuron is activated to decrease pain.
What happens when the BBB breaks down ?
Hypertension …
Agonist?
Activates a receptor , toproduces a functional response
Binds to receptor without activating it - blocking the action of the agonists ?
Antagonist
Examples of anaesthesia
Halothane isoflurane (gases - inhalation)
Propofol(IV)
Act on neurotransmitter receptors especially gaba a receptor
Drugs that cause sleep and reduce anxiety?
Sedatives
Anxiolytics
- Barbiturates
- Benzodiazepines
Examples of antipsychotic drugs ?
Typical - chloromazine
Atypical - Clozapine
Examples of anti depressants
Phenelzine - monoamine oxidase inhib
SSRIs - fluoxetine
Tricyclic antidepress - imipramine
Ketamine - rapid onset
Example of analgesic drugs
Opiates
Baclofen - gaba b receptor agonist
NSAIDs
Cognition enhancers
Galantamine - ACh E inhibitors
Improve memory
dopamine synthesising cells are located where and what makes it black?
Melanin
Substantia nigra
Diminished substantia nigra is seen in what disease?
Parkinson’s
Causes of Parkinson’s
Degeneration of the Nigrostriatal DA pathway
Aging
Genetic factors
- synuclein
Environmental factors
- herbicides , pesticides
Therapies aimed to enhance dopaminergic pathways ?
Boosts d
what does dura contain?
large blood vessels, have to consider with trauma to the head
what does the pia mater fuse with
fuses with the ependyma to form choroid plexus
what mater develops first?
pia mater - dy24
dura develops when?
day 45
arachnoid mater develops?
day 57
where does the CSF go?
4 ventricles and subarachnoid space , cisterns , sulci and central canal of SC
what does CSF do?
brain wont compress on the cranial nerves as it allows the brain to float
what is a ependyma ?
roof plate of the myelencephalon consists of a single layer of ependymal cells covered by pia mater .
it is the thin epithelium like lining of the brain and the central canal of the SC .
Ependyma is involved in the production of CSF .
why is there obstruction of the foramen magnum by the cerebellum in SB cystica?
A chiari maformation , is where the cerrebellum pushes down in the spinal canal. range of severity 1 to 4.
1 -headache , neck pain
2 - hydrocephalus and SBC (bag of cyst with nerves protruding out)
defect in mesoderm in type 1
defect in neuroectoderm in type 2
characteristics of chiari malformation type 2
a small post fossa and cranial vault
due to failure of fusion at the craniocervical junction
results in enlargement of the foramen magnum , stretching the fourth ventricle and aqueduct
also have lumbar myelomeningocoele and associated issues with this.
treatment includes decompression
what is insensate skin?
This condition, called insensate skin, means that you may not feel pain, touch, or respond to heat or cold on the area of skin below the level of your lesion.
when does alar and basal plate form?
week 5-6
when do dorsal and ventral horns form?
week 8-9
how and where do the primary brain vesicles form?
the brain vesicles arise from the neural tube . once the tube has formed and closed , the anterior portion expands quicker than the posterior forming the brain vesicles
then they differentiate to give secondary brain vesicles
the remainder of the neural tube becomes the spinal cord.