Week 2 Flashcards
Describe nociceptive pain
normal pain only elected when intense/noxious stimuli threaten to damage tissue adaptive/ biologically useful high threshold limited duration
Describe chronic pain
sustained sensory abnormality / ongoing peripheral pathology
maladaptive pain
either evoked or spontaneous
Ab AD or C fibres
What is allodynia?
pain elicited by a normally innocuous sensation
What are Meissner’s corpuscles used in?
light touch
what are merkel disks used in?
mechanical deflection
What are hair follicles afferents used in?
gentle brushing
What are pacinian corpuscles used in
gross pressure changes
vibration
What are ruffini endings used in?
stretching of skin (slippage)
What are the three aspects of the triple response?
red reaction
wheal
flare
What chemicals activate nociceptors?
K+
prostaglandins
bradykinin
5-HT
What are released from nociceptors that cause positive feedback?
CGRP and substance P
What does CGRP do?
dilates blood vessels
What does substance P do?
plasma extravasation
oedema
release of bradykinin
What pathway is used for discriminative tactile sensation?
dorsal column (medial lemnical)
What pathway is involved in pain?
spinothalamic
when do the eyes begin to appear?
day 22
how do the eyes appear?
a pair of shallow grooves
What do the grooves from?
outgrowths from the diencephalon of the forebrain called the optic vesicle
what do the optic vesicles do?
they are in contact with surface ectoderm and induce changes necessary for lens formation
What happens to the placodes?
they become columnar and invagination
“double walled” cup
optic stalk forms
describe the blood supply to the developing eye
grooves arise on the ventral surface of the optic cup forming the choroidal fissure
a branch of the ophthalmic artery - the hyaloid artery - passes along the choroidal fissure to supply the lens and developing retina
what is the lens of the eye derived from?
surface ectoderm
what is special about fibres of the lens?
they contain no organelles or neclei
Describe the structure of the optic cup
bilaminar structure
outer layer forms the pigmented later of the retina
inner later forms the nervous layer of the retina
WHat give rise to the iris and the ciliary body?
the rim of the optic cup
what does the ciliary produce?
the aqueous humour
what is in the centre of the optic nerve
central artery and veins of the retina
what does the mesenchyme around the optic cup condense into?
layers of the eyeball
the choroid and the sclera
what develops between the cornea and the lens?
the anterior chamber of the eye
where is gelatinous substance found in the eye?
the gap between the lens and the retina
what is the posterior chamber of the eye also called?
the vitreous body
When do the eyelids reopen?
between the 5th and 7th month in utero
WHat is the key regulatory molecule in eye development?
PAX6
where is PAX6 expressed?
the anterior neural plate before neurulation begins
What molecule is involved in eye field separation?
SHH
What is microphtalmia?
eyeball is too small
What is anophtalmia?
absence of the eye
WHat is cyclopia?
one eye
What is the function of the blood brain barrier?
maintain constant environment
protect brain from foreign substances
protect brain from peripheral transmitters
What drugs can be used to transiently disrupt the BBB?
manitol
What type of drug is L-DOPA?
pro molecule
give an example of an inhaled anaesthetic
desflurane
give an example of an injected anaesthetic
propofol
what is the definition of anxiolytics and sedatives?
drugs that cause sleep and reduce anxiety
what is the definition of antipsychotic drugs?
drugs that are effective in receiving symptoms of schizophrenic illness
what is the definition of antidepressant drugs?
drugs that alleviate the symptoms of depressive illness
What are affective disorders?
disorders of mood rather than though or cognition
What is the definition of analgesic drugs?
drugs used clinically for controlling
what is the definition of a psychomotor stimulant?
drugs that cause wakefulness and euphoria
WHat is the definition of psychotomimetic drugs?
drugs that cause disturbance of perception and of behaviour that can be simply characterised as sedative or stimulant
What is the definition of cognition enhancers?
drugs that improve memory and cognitive performance
WHat pathway is involved in parkinson’s disease?
nirgostriatal
what pathway is involved in schizophrenia?
mesolithic / cortical
WHat are the symptoms of parkinsons disease?
tremor, hypokinesia and rigidity
What are the positive symptoms of schizophrenia?
delusions
hallucinations
thought disorders
What are the negative symptoms of schizophrenia?
social withdrawals. emotional flattening
reduced drive
poverty of speech
inability to feel pleasure
What are some mechanical causes of back pain?
trauma muscular and ligaments pain postural back pain lumbar spondylosis facet joint syndrome lumbar disc prolapse spinal and root canal stenosis
Give some examples of inflammatory causes of back pain
infective lesions of the spine
ankylosing spondylitis
Describe some metabolic causes of back pain
osteoporotic spinal fractures
osteomalacia
paget’s disease
What are the parts of the IV disc?
annulus fibrosis and nucleus pulposis
What nerve is involved in sciatica?
S3
What are some features and signs of serious spinal disease?
previous malignancy younger than 16 or older that 50 with new pain unexplained weight loss recent serious illness or infection saddle anaesthetsia reduced anal tone hip or knee weakness generalised neurologcal deficit spinal deformities urinary retention
What are some of the yellow flags in chronic pain?
belief pain is harmful and activity is harmful fear-avoidance behaviours and inactivity social withdrawal emotional problems dissatisfaction at work financial problems overprotective family or lack of support
How is chronic pain prevented?
managing symptoms with analgesics
early detection of risk factors
advise and education to patient
discharge of patient as early as possible
What nerve innervates the muscles of facial expression?
the facial nerve (CNVII)
WHat are the muscles of mastication?
massseter
temporalis
medial pterygoid
lateral pterygoid
What are the main vessels of the face?
facial artery, superficial temporal artery
What is the consequence of severing the parotid duct?
salivary mucocoele
What are the five branches of the facial nerve?
temporal zygomatic buccal marginal mandibular cervical
