Trigger 1 - spina bifida Flashcards
when does spina bifida occur
when the neural tube fails to close during the first month of embryonic development
spinal cord and meningeal membranes protrude
common symptoms of spina bifida
urinary/faecal incontinence
muscle weakness
how many spinal/somatic nerves
31 pairs
5 locations of spinal nerves
cervical thoracic lumbar sacral coccygeal
2 types of spinal nerves
sensory
motor
sensory nerves/neurones
deliver information from muscles/joints to spinal cord about body position
transmit sensations such as temperature, pressure, pain and touch from skin’s surface
information enters spinal cord via grey posterior horn
dermatome chart
maps areas of skin that relate to particular spinal nerves
motor nerves/neurones
pass info from brain to skeletal muscles through spinal tracts
direct precise voluntary movements
spinal nerves are linked to specific…
muscles
cervical spinal nerves
supply muscles of the neck, shoulders, arms, hands and diaphragm
e.g. extending elbow/fingers
thoracic spinal nerves
supply truck muscles and muscles involved with breathing
intercostal and abdominal muscles
lumbar and sacral spinal nerves
supply hip, leg, foot muscles
sacral nerves supply anal/urethral sphincters
major breathing muscles
diaphragm and intercostal muscles
abdominal muscles
help you cough and expel matter from your air passages
important in balance and posture.
divisions of autonomic nervous system
parasympathetic
sympathetic
what is the ANS responsible for
bodily functions such as digestion, urination, changing the size of blood vessels in order to regulate blood pressure, regulating body temperature and keeping your heart beating.
parasympathetic nervous system is responsible for…
slowing your heart rate
bronchial or air passage constriction
increasing gastric secretions
bladder function (e.g. bladder muscle contraction, release of urine)
bowel function
sexual function (e.g. erectile function and lubrication)
sympathetic nervous system
increasing your heart rate increasing blood pressure increasing respiratory or breathing rate regulating your temperature pupil dilation (enlargement) bronchial or air passage dilation decreasing gastric secretions bladder function (e.g. bladder muscle relaxation, storage of urine) sexual function
reflex activity
fast and automatic responses
occur via spinal nerves
overview of the study design pyramid
case-control makes up the base
as we progress upwards, studies becomes more evidence based and less numerous
meta-analysis is at the top
why is meta-analysis at the top of the study design pyramid
can only be written after much other research has been done on a topic
fewer of them but offer strong evidence
case reports
An article that describes and interprets an individual case, often written in the form of a detailed story
lowest level/first line of evidence
can help identification of a new drug/disease/trend
case-control
compares a group of patients who have the disease (cases) with a group of patients who don’t (controls)
purely observational - study carried out after disease has occurred
no intervention
retrospective
advantages and disadvantages of case-control studies
good for studying rare diseases
can look at multiple risk factors
take less time to complete- disease already occurred
useful to initially establish an association between a risk factor and a disease
problems with data quality - rely on memory/recall bias
difficult to find suitable control group
cohort study
where one or more samples (cohort) are followed and evaluations with respect to the disease and conducted to determine which risk factors are associated with it
outcome from participants in each cohort is measured and relationships with specific characteristics determined
cohorts need to be chosen from separate but similar populations
risk factor
initial participants exposure characteristics
advantages of a cohort study
subjects in cohorts can be matched
standardisation of outcome/criteria is possible
easier/cheaper than RCT
disadvantages of a cohort study
cohorts difficult to identify due to confounding variables
no randomisation - imbalances in patient characteristics could exist
blinding is difficult
outcome of interest could take time to occur
randomised control trial
randomly assigns participants into an experimental/control group
the difference between the two groups should be the variable being studied
should be a study of one population only
advantages of RCT
randomisation washes out population bias
easier to blind
well known stats tools easily used for analysis
populations of participating individuals easily identified
disadvantages of RCT
time/money consuming
volunteering population may not be representative
does not reveal causation
practice guidlines
a statement outlining best practice to inform health care professionals and patients in making clinical decisions
should be updated frequently
created by panel of experts
known as ‘evidence-based’ or ‘clinical’ guidlines
systematic review
document reviewing/summarising all relevant studies on a particular clinical or health-related topic/question
advantages of systematic review
evidence based
reliable
less time consuming than making a new study
however may not be easy to combine studies into one
meta-analysis
subset of systematic reviews
combines quantitative and qualitative study data
develops single conclusion with great statistical power due to increased number/diversity of subjects
studies for review should all be of a similar type e.g. all RCT so they are comparable
when would you use a meta-analysis study
To establish statistical significance with studies that have conflicting results
To develop a more correct estimate of effect magnitude
To provide a more complex analysis of harms, safety data, and benefits
To examine subgroups with individual numbers that are not statistically significant
advantages of meta-analysis
Greater statistical power
Confirmatory data analysis
Greater ability to extrapolate to general population affected
Considered an evidence-based resource
disadvantages of meta-analysis
Difficult and time consuming to identify appropriate studies
Not all studies provide adequate data for inclusion and analysis
Requires advanced statistical techniques
Heterogeneity of study populations
when would you carry out csf analysis
to diagnose a condition involved with CNS
e. g. bleeding within brain/skull, autoimmune disorder or cancer
e. g. meningitis, encephalitis (determining if it fungal, viral or bacterial)
how do you collect a csf sample
lumbar puncture or spinal tap from lower back
multiple tubes may be used to improve quality of testing
where is csf formed continually
choroid plexus tisssue
(has many blood vessels lining the ventricles of the brain)
500mL produced a day
what characteristics of csf are measured
pressure
colour - should be clear
turbidity - cloudy/turbid could mean presence of WBC/RBC
viscosity- should be same as water
biomarker definition
“a characteristic that is objectively measured and evaluated as an indicator of normal biological processes, pathogenic processes or pharmacological responses to a therapeutic intervention
characteristics of a good biomarker
Safe and easy to measure
Cost efficient to follow up
Modifiable with treatment
Consistent across gender and ethnic groups
anticholinergic medicines
used to treat urinary incontinence
relax the overreactive detrusor muscle in the bladder wall
bladder capacity increases and urinary urge decreases
features of sympathetic ganglionic neurons
short pre-ganglionic
- releases ACh to nicotinic receptor
long post-ganglionic
- releases noradrenaline to muscarinic adrenoreceptor
which nerve regulates gastric acid secretion
vagus nerve
which autonomic nervous system has a long pre-ganglionic neuron
parasympathetic
where does reflex signal travel through
spinal cord
not brain
why does myelination increase speed of conduction
Na+ can only depolarise at nodes of ranvier
saltatory conduction
jump from node to node
myotomes
the group of muscles that a singler spinal nerve innervates
clinical significance of myotomes
can identify where spinal lesions might be
Na+ influx via ligand-gated channels on post-synaptic membrane
causes end-plate potential
propagates across muscle
calcium storage in SR
uptake via ATP exchange - SERCA pump
calsequestrin
important to reduce calcium conc to relax muscles
thin filaments in sarcomeres
actin
tropomyosin
troponin
thick filament
myosin
H band
just mysoin
I band
just actin
A band
length of myosin with some actin overlap
Z line
vertical line between adjacent sarcomeres
what makes up limbic system
thalamus
hypothalamus
normal CSF composition
no RBC few WBC water few small proteins some glucose
hydrocephalsu
build up of CSF in the brain
icnreases intracranial pressure
chairi malformation
cerebellum too larger
blocks ventricles in brain
CSF builds up
intracranial pressure increases
if CSF is cloudy
WBC or RBC present
microorganisms or proteins present
proteins in CSF
disease
reciprocal innervation
when contraction of muscles is accompanied by simulatous inhibition of antagonistic muscles
when do stretch receptors in the bladder signal to sacral nerves (parasympathetic NS)
when it fills to 400ml
which sacral nerves are involved in micturition
S2-S4
receptor and signalling causing contraction of bladder detrusor muscle
M3
Gaq
effect of cAMP on smooth muscle contraction
G alpha s increases cAMP which inhibits MLCK so inihbits smooth muscle contraction
opening of external sphincter
voluntary
somatic
allows you to wee
sympathetic control of bladder
filling
B3 adrenoreceptor stimulated
relaxation of bladder detrusor muscle
contraction of internal sphincter
closes sphincter
alpha 1 adrenoreceptor
most rigorous study design
meta-analysis
major regions found in temporal lobe
primary auditory cortex
wernickes area
lateral fissure
between temporal and frontal lobe
wernickes area
responsible for comprehension of speech
temporal loebe
middle cerebral artery (MCA)
largest branch on internal carotid artery
common stroke site
lenticulostriate arteries branch off
difference between cerebral arteries and systemic arteries
cerebral arteries have no external lamina
and fewer elastic fibres
anterior cerebral artery
supplies frontal lobes
posterior cerebral artery
supplies temporal/occipital lobes
common carotid arteries
external and internal
cause of haemorrhagic stroke
when a weakened blood vessel ruptures in the brain
blood spills causing swelling and pressure
tissue damage
why are strokes on left side of brain worse
effects seen on right side of body
e..g speech and language problms
2 types of haemorrhagic stroke
intracerebral - blood leaks to surrounding brain
subarachnoid - blood leaks into subarachnoid space
circle of willis
arterial loop at the base of the brain
carotid and vertebrobasilar arteries
collateral circulation
circle of willis ensures that if blood flow is obstructed to one vessel, blood can still be delivered to all regions of the rbain
methods to avoid aschaemia
stents are used to treat
narrow or weak arteries
percutaneous coronary intervention (PCI)
stent implantation method
- insertion of catheter with collapsed balloon inserted into bronchial artery
- balloon inflated to compress plaque against artery wall and expand stent
- balloon deflated, catheter removed
- cells grow over to cover stent
drug-eluting stent
coated with medicine which releases slowly over time
often immunosuppressants
reason for drug-eluting stent
prevent re-stenosis
re-stenosis
too much tissue growth around stent can lead to more blockage
