What to study as part of the Molecular Medicine MRCP 1 course. These are slideshows only. The demonstration with video presentation and explanation that goes along with these slides, as well as free example exam questions and the paid full e-lecture can be viewed at https://www.123doc.com/electures/molecular-medicine/

1. Molecular Medicine for MRCP
Part 1
Alistair Lindsay
BSc (Hons), MBChB, MRCP (UK)

2. What does that mean?
The MRCP (UK) website states that 25/200 marks will be on
questions on “Clinical Science”
Topic include:-
Cell, Molecular & membrane biology
Clinical Anatomy
Clinical Biochemistry & Metabolism
Clinical Physiology
Genetics
Immunology
Statistics, Epidemiology, EBM

3. What to study?
• Obviously covering these topics in detail would be an
enormous task; you can not know it all.
• It is important to be selective; this is certainly an area
where you must focus on “hot topics”
• The one exception to this is Clinical Anatomy, where
seemingly any anatomical area can come up
(Although not to FRCS level!) e.g. blood supply to the
liver.

4. Topics Covered
• The cell membrane & ion channels
• Second messenger & G proteins
• Steroid receptors
• Cancer
• Genetic inheritance
• Trinucleotide repeats
• Genetic mutations
• Imprinting
• Non-disjunction
• Mitochondrial DNA disorders
• BNP
• Electrolytes

5. The cell membrane
• This is an important place to start
• You need to be aware of the basic structure of
the cell membrane to understand many of the
other “hot topics” in molecular medicine.
• Questions in the exam are most likely to be on
ion channels or gap junction.

6. Cell fluid mosaic membrane
Remember the fluid mosaic model?

7. Cell Membrane

8. Cell membrane components
• Phospholipid bilayer
• Proteins: Integral and peripheral
• Intracellular junctions: Tight junctions, gap
junctions
• Ion channels are integral proteins, that means
they span the membrane and permit the
passage of certain ions.
• Gas junctions current flow and electrical flow
between myocardial cells

9. Ion channel
• The most important ion channel for MRCP purposes is
the sodium/potassium ATPase
• Remember Na+ is transported FROM the intracellular to
extracellular fluid against the electrochemical gradient.
• Specific inhibitor of the pump ouabain ouabain and
digoxin- as a result sodium leaks back into the cell and a
sodium/calcium pump is upregulated. This increased
calcium makes contraction more forceful. This makes
digoxin a positive inotrope.

10. Digoxin toxicity can be caused by
which of the following electrolyte
abnormalities?

11. Digoxin toxicity can be caused by which of the
following electrolyte abnormalities?
Answer A
Hypermagnesaemia
HYPOmagnesaemia can predispose to arrhythmias,
whether digoxin is present or not.

12. Digoxin toxicity can be caused by which of the
following electrolyte abnormalities?
Answer B
Hyperkalaemia
Although it certainly can caused malignant arrhythmia,
hyperK decreases digoxin binding site and hance is
arrhythmogenic potential.

13. Digoxin toxicity can be caused by which of the
following electrolyte abnormalities?
Answer C
Hyponatramia
Potassium and digoxin bind to the same site on the
sodium/potassium pump. A low potassium level means
excress digoxin can bind and have a toxic effect

14. Digoxin toxicity can be caused by which of the
following electrolyte abnormalities?
Answer D
Hypokalaemia

15. Digoxin toxicity can be caused by which of the
following electrolyte abnormalities?
Answer E
Hypercalaemia
Hypercalcaemia causes a shortened QTc, making
arrhythmia less likely.