Paper 1 Flashcards
(22 cards)
Name the different meningeal layers from innermost to outermost that form a covering of the CNS
Pia, Arachnoid and Dura mater
Name the folds of meninges that form compartments within the cranial cavity and describe the specific
areas where they are located.
a. Falx cerebri and tentorium cerebelli (1)
b. The falx cerebri lies in the sagittal plane between the two cerebral hemispheres. (1)
c. Its free border lies above the corpus callosum. (1)
d. The tentorium cerebelli is oriented horizontally, (1) lying beneath the occipital lobes of the
cerebral hemispheres and above the cerebellum. (1)
Name the main subdivisions of the dural venous sinuses and briefly describe each according to its
location.
along the lines of attachment of the falx cerebri and tentorium cerebelli to the interior of the skull (1)
(superior sagittal sinus (1), transverse sinus (1)
along the line of attachment of the falx cerebri and tentorium cerebelli to one another (1) (straight sinus)
(1)
Describe the blood supply to the brain. Indicate which vessels form the anterior and posterior cerebral
circulation. You may use a well labelled diagram if you wish.
The brain receives blood from two sources: the internal carotid arteries, which arise at the point in the
neck where the common carotid arteries bifurcate, and the vertebral arteries. This is the so-called anterior
and posterior cerebral circulation. The internal carotid arteries branch to form two major cerebral
arteries, the anterior and middle cerebral arteries.
Vertebral arteries join to form the basilar artery and supply cerebellum and the brainstem, ending as the
posterior cerebral arteries (left and right).
The neural portion of the eyeball is considered to be an outgrowth of the brain. Justify this statement by
giving an overview of the embryological development of the eyeball. You may use a set of well labelled
diagrams as your answer.
Day 22. Formation of optic grooves –> bulges out forming vesicles –> grow toward ectoderm –> touch –> ectoderm thickens –> lens placed –> vesicle invaginated forming optic cup (retina and pigment epithelium) –> lens placed invaginated and pinches off forming lens
List four (4) biochemical features of primary hyperaldosteronism.
Hypokalaemia
Metabolic alkalosis
Increased aldosterone
Decreased renin
Mild hypernatreamia
Urine potassium > 30 mmol/day
State which single biochemical test is most useful for distinguishing primary hyperaldosteronism from
apparent mineralocorticoid excess
Plasma aldosterone
Explain the mechanism whereby Cushing’s Syndrome can cause secondary hypertension.
Capacity of the enzyme 11-β hydroxysteroid dehydrogense to convert cortisol to inactive cortisone is
overwhelmed by excessive cortisol production [2].
Cortisol is able to bind to and activate the mineralocorticoid receptor [1].
Mineralocorticoid receptor stimulates excessive uptake of sodium and therefore water leading to
hypertension [1].
- Complete the table below which compares and contrasts an epidural, subdural and subarachnoid
haemorrhage. For each, specify :
a) The vessel type (artery/vein/capillary) that is bleeding and where typical, the usual vessel
involved (3 marks)
b) The likely time interval between breech of the vessel/s and clinical presentation (3 marks)
c) The severity of the onset of clinical symptoms (3 marks)
d) The prognosis (good/intermediate/poor) if treated after onset of established symptoms
(3 marks)
e) For each give a TYPICAL clinical history that is obtained (3 marks)
EPIDURAL
Vessel: Artery (middle meningeal)
Time Interval: Within hours (typically 8 hours)
Onset Severity: Severe: profound rapid neurological loss
Prognosis: Poor: rapid depressurization of vessels → onset of oedema
Clinical History: Always able to elicit a history of severe head injury, with fracture of skull, typically over pterion
SUBDURAL
Vessel: Vein (penetrating between surface of brain and sinuses)
Time Interval: Very variable: may be days to months
Onset Severity: Minimal: slow deterioration usually
Prognosis: Good
Clinical History: May not elicit a history of trauma. Often underlying cause for cerebral atrophy (alcohol/chronic head injury)
SUB-ARACHNOID
Vessel: Artery in Circle of Willis
Time Interval: Acute and immediate
Onset Severity: Severe
Prognosis: Intermediate
Clinical History: Sudden exquisite blinding headache and often with collapse
- Using an ecological framework, outline the risk factors for violence in South Africa.
Individual - psychological disorder, alcohol abuse
Relationship - material discord, poor parenting, Leo SES
Community - poverty, crime, drug trade
Societal - gender norms, poor law, poverty
- Draw the pedigree.
1/2 symbols correct; 1/2 relationship lines correct; 1/2 each for Bob, his nephew and his son in law
indicated as affected; 1/2 each for his mother , sister and daughter indicated as obligate carriers and ½ if
correct symbol for X- linked carrier used.
Do you think that Mitchel (Bob’s father) has haemophilia A? Explain your answer.
No. X linked disorder and he got Y from his father and it would be very unlikely for his father to have had
inherited it form his mother and only present at this stage of life.
What is the chance of Bob’s grandchildren (expected twins) having haemophilia A? Explain your
answer.
Boy - 50% chance – their mother an obligate carrier
Girl 50% chance of being affected and 50% chance of being just a carrier – must inherit a mutated X from
her father and 50% chance from mother - if mutated x form mom will have haemophilia B, if not will be a
carrier.
Sally bleeds more heavily than expected and has also needed factor VIII replacement sometimes. Give
the most likely genetic reason for why this may occur.
Skewed X inactivation
Describe the positional changes of the spinal cord in the embryo, fetus, neonate and adult. You
may use a set of well labelled diagrams as your answer.
Positional Changes of Spinal Cord
The spinal cord in the embryo extends the entire length of the vertebral canal. The spinal nerves
pass through the intervertebral foramina opposite their levels of origin. Because the vertebral
column and dura mater grow more rapidly than the spinal cord, this positional relationship of the
spinal nerves does not persist. The caudal end of the spinal cord in fetuses gradually comes to lie at
relatively higher levels. In a 24-week-old fetus, it lies at the level of the first sacral vertebra.The
spinal cord in neonates terminates at the level of the second or third lumbar vertebra. In adults, the
cord usually terminates at the inferior border of the first lumbar vertebra. The spinal nerve roots,
especially those of the lumbar and sacral segments, run obliquely from the spinal cord to the
corresponding level of the vertebral column. The nerve roots inferior to the end of the cord
(medullary cone) form a bundle of spinal nerve roots called the cauda equina.
Name two (2) fetal conditions in which maternal plasma alpha-fetoprotein (AFP) levels are decreased.
Down syndrome
Trisomy 18
Name two (2) other glycoprotein hormones that share an α-subunit with human chorionic
gonadotrophin (hCG ).
TSH
LH
FSH
List four (4) counter-regulatory hormones that increase blood glucose levels.
Cortisol
Glucagon
Catecholamines
Growth hormone
Briefly explain why an uncontrolled type 2 diabetic patient with hyperosmotic non-ketotic (HONK)
coma does not develop ketoacidosis despite very high levels of blood glucose.
Insulin levels are still high enough to prevent hepatic ketone synthesis [1] but not high enough to supress
hepatic gluconeogenesis and increase peripheral glucose uptake [1].
Briefly explain why blood glucose control improves before significant weight loss occurs in an obese
type 2 diabetic after a Roux Y gastric bypass procedure.
Increased delivery of nutrients into the distal small intestine stimulates the release of glucagon like peptide 1
(GLP-1) [1] that in turn causes increased insulin production and insulin sensitivity [1].
State how the body mass index (BMI) is calculated and state what is considered an ideal BMI for adults.
BMI Is defined as body mass (in kg) divided by the square of the height (in metres) [1], an ideal BMI is
between 20 and 25 [1]. Range for males and females. [1]
When you see Gwen she tells you she has epilepsy. She is on sodium valproate but doesn’t take it
regularly when she drinks. She asks if there will be any risks for her next pregnancy if she is thinking of
stopping drinking. A friend of hers with epilepsy recently had a baby with spina bifida. She wasn’t
worried about that in this pregnancy as the nurse gave her medicines to prevent it.
34. Describe the advice that you would give Ms de Waal about future pregnancies.
There is an increased risk of NTD with sodium valproate and with alcohol abuse (~5%)
Her risk of another child with FASD would be high if she continues drinking
She should stop drinking and you should offer support to help
She should see her doctor to optimise her antiepileptic treatment before she is pregnant again
She should have a good diet
She should take high dose folic acid (5mg daily) a month before and 3 months after conception
She should be offered ultrasound monitoring and if available maternal serum AFP to screen for NTD in
future pregnancies
