PBL1

1 Explain what the cauda equina is composed of?1 mark

It is the spinal nerve roots of the lumbar and sacral spinal cord

2 What type of joint is formed by the intervertebral discs?1 mark

Cartilaginous joint (symphysis)

3 What are the parts of a typical vertebrae?2 marks

Body, laminae, pedicle, processes (spinous and transverse), (neural arch (foramen))

4 Give four aims of a consultation and briefly explain what this aims to achieve?4 marks

Four from Define the reason for attendance. Include the history, the patient's ideas, concerns and expectations, and the effects of the problem. Why did the patient really come? Is there a false or unrealistic expectation? Are there fears that need to be allayed or other issues that need to be addressed? Is there a hidden agenda? Sometimes patients present with something grossly trivial and then proceed with 'By the way doctor, while I'm here ...' and proceed with the reason why they really came. Consider other problems. Include continuing problems and risk factors. This might include health promotion and addressing risks like smoking or obesity. It could include problems like social conditions. Choose an appropriate action. This includes clinical management. It may be prescription, reassurance or referral. It may involve follow-up. Analysis of the consultation is not simply about the psychosocial aspects but it also checks that good clinical practice is being observed. Appropriate action may also include a relevant and competently conducted physical examination. Achieve a shared understanding. It is important that the patient understand the disease, its etiology and its treatment as this may improve compliance, although the word compliance is regarded by some as derogatory and implying passive acquiescence and paternalism. The patient may need to know why it is important that certain lifestyles and habits be changed and the need to follow specific regimes of treatment. This puts a degree of responsibility on the patient. Involve the patient in management. This may also be part of getting the patient to take responsibility or it may be a valid discussion about alternative approaches. Use time and resources appropriately. This applies both during the consultation and long-term. Establish or maintain a relationship. The doctor-patient relationship remains crucial for successful medical practice. Always appear interested in the patient.

5

PBL21 Name three other types of common genetic inheritance patterns other than the autosomal recessive in the scenario and give one feature of each.3 marks

mark for the name of the genetic inheritance pattern and mark for the featureAutosomal dominantaffects both males and females, only need one copy of affected gene,X-linked recessiveonly affects boys usually, mothers are carriers, females are usually asymptomatic carriersX-linked dominantaffects both males and females (tending to affect more females). For an affected male all his daughters but none of his sons are affected. Each child of an affected mother has a 50% chance of being affected.mitochondrialaffects males and females, but maternally inherited (affected males will not pass on the condition)Y-linkedonly affects boys of affected fathers

2 What is the normal function of hexosaminidase A?1 mark

It hydrolyses GM2-gangliosides (breaks down glycolipids)

3 In which cell organelle is hexosaminidase A found?1 mark

Lysosome

5Sketch the Michaelis-Menten graphs of enzyme activity: rate of product production versus substrate concentration, and then with either a competitive and a noncompetitive inhibitor added. Show Vmax, and Km.5 marks

1 mark for non competitive with inh 1 mark competitive with inh 1 mark normal, 1 mark Vmax 1 mark KM

PBL31 Name the two monosaccharides that lactose is broken down to by lactase?1 mark

Glucose and galactose

2 Explain why one of the symptoms people with lactose intolerance have is flatulence and bloating?2 marks

If there is not enough lactase in the small intestine, the unabsorbed lactose moves through your digestive system to your colon (large intestine). (1 mark)Bacteria in the colon ferment (break down) the lactose, producing fatty acids and gases such as carbon dioxide, hydrogen and methane.

3 Explain why lactose intolerance is not an allergy and what the differences are between an allergy and food intolerance?2 marks

There is no activation of the immune system, lactose intolerance is a genetic trait that causes an unpleasant reaction. The effects are rarely immediate and people may still be able to eat small quantities of the food. A food allergy is relatively quick and will happen even with a small amount of the food.

4 What foods should Irmani be told to include to provide enough dietary calcium in a diet that excluded dairy products?2 marks

mark for each type.Green leafy vegetables, soya bean and or tofu, fortified cereals and or, fish.

5 Explain why primary lactose intolerance does not develop until after childhood?2 marks

Primary lactase deficiency develops when your lactase production decreases when your diet becomes less reliant on milk and dairy products. This is usually after the age of two, when breastfeeding or bottle-feeding has stopped, although the symptoms may not be noticeable until adulthood.

6 What is the name of the process that can alter gene expression without changing the structure of the DNA?1 mark

Epigenetics

PBL 4

1 What is methanol metabolised to in the body?2 marks

Methanol is metabolized rapidly to formaldehyde which is further converted into formic acid. The conversion of formic acid into CO2 by tetrahydrofolate synthetase is slow and therefore it accumulates causing metabolic acidosis.

2 What is the rationale for giving ethanol in cases of methanol intoxication?2 marks

It works by acting as a competitive inhibitor (1 mark); ethanol is metabolized by the same enzyme ADH, just as methanol is, but the enzyme has a higher affinity for ethanol than it does for methanol (1 mark). For example, the affinity of ADH for ethanol is 10-20 times greater than it is for methanol.

3 Briefly explain how metabolic acidosis is compensated for by both the lungs and the kidneys?2 marks

LungsLowering the PCO2 by hyperventilationKidneyadds more H+ (or NH+) to the urine

4 Outline the three necessary provisions for gaining valid consent. 3 marks

1. The patient must have capacity (Competence).2. The patient must be offered adequate information (Adequate Disclosure).3.The patient's decision must be non-coerced/voluntary (Non-Coercion/Voluntariness)

5 Define tachypnea.1 mark

Rapid breathing (usually over 20 breaths per min)

PBL51 What is the mode of action of cephalosprins?1 mark

Cephalosporins disrupt the synthesis of the peptidoglycan layer of bacterial cell walls.

2 Define hemarthrosis.1 mark

Bleeding into the joint

3 Draw a graph of time against plasma concentration following a single dose of a drug. Label the duration, peak concentration, therapeutic window, inactive range, and adverse effect range. 3 marks

4 What are the five pharmacokinetic phases that describe the handling of drugs by the body and explain which of these is affected by the co-administration of the antibiotic and alcohol that leads to the supratherapeutic levels of warfarin?3 marks

Liberation, Absorption, distribution, metabolism, elimination. (1/2 mark each)The antibiotic and alcohol inhibits the metabolism of warfarin so there is more warfarin in his system

5 What are the structures that compose the lower urinary tract?1 mark

Bladder and urethra

6 Warfarin is a racemic mixture, which enantiomer is the most biologically active?1 mark

s-warfarin

PBL 61 Normally when is the HPV vaccination given, and briefly explain why it is given at this age.2 marks

UK girls aged 12-13To be effective the vaccine has to be given before HPV exposure

2 What is the type of epithelia that are found in the ectocervix?1 mark

nonkeratinized stratified squamous epithelium

3 Name the two main classes of cancer genes and briefly describe their mode of action in cancer.2 marks

1) Proto-oncogenes can become an oncogene due to mutation or increased expression. Oncogenes can cause the cells that would undergo apoptosis to survive and proliferate. (1 mark)2) Tumour suppressor genes. These genes normally inhibit cell division and survival. When mutated to cause a loss or reduction in its function that protection is lost. (1 mark)

4 What are the cervical screening frequencies for the following age ranges?3 marks

25 49 yearsEvery 3 years

50 64 yearsEvery 5 years

65+ yearsOnly screen those who have not been screened since age 50 or have had recent abnormal tests

5 What are the differences between metaplasia and dysplasia?2 marks

Metaplasia: an initial change from normal cells to a different cell type (such as chronic irritation of cigarette smoke causing ciliated pseudostratified epithelium to be replaced by squamous epithelium more able to withstand the insult). Dysplasia: an increasing degree of disordered growth or maturation of the tissue (often thought to precede neoplasia) such as cervical dysplasia as a result of human papillomavirus infection. Dysplasia is still a reversible process

PBL71 From the family history of Ambrose what is the inheritance pattern and justify your answer.4 marks

x-linked recessive (1 mark mark for x-linked only)only boys affected (Ambrose and the uncle) (1 mark)Ambroses mother is a carrier she has 2 X chromosomes the affected chromosome is transferred to Ambrose(1 mark) but even if his sister has this affected chromosome she does not have the condition so its recessive (1 mark)

2 Explain why Ambrose was healthy for the first 8-9 months of his life?2 marks

The passive transfer of IgG across the placenta protected him (1 mark) plus the fact that he was breast fed again protected him for the 1st 8 months 91 mark)

3 Briefly explain how antibodies help prevent bacterial infections?4 marks

Antibody is critical for defence against pathogens, especially extracellular bacteria, it binds to them to increase their uptake by phagocytes (for example, macrophages or neutrophils), or to induce their killing by complement activation or by cellular components of the immune system (antibody dependent cellular cytotoxicity, ADCC). In addition, antibody can block infection by preventing the binding of pathogens to critical receptors on host cells and can neutralise the activity of toxins that cause disease.

PBL81 Label the diagram of the bronchial tree. 3 marks

2 Explain why people who are given the influenza vaccine could still be infected by the influenza virus?2 marks

1 Vaccine is against three strains if person is infected by a strain not covered by the vaccine they can still be infected.2 Takes around 10-14 days for full immunity to develop after the vaccine so they can still be infected and develop influenza if exposed in this period

3 Which class of antibodies are made 1st after the influenza vaccine is administered?1 mark

IgM

4 To what class of viruses does the influenza virus belong and what is the genetic material that it uses?2 marks

single-stranded ribonucleic acid (RNA)(1 mark) orthomyxovirus.(1 mark)

5 If Margery does get influenza what is the mode of action of the two antivirals tamiflu and relenza that could be prescribed?2 marks

They are both neuraminidase inhibitors. They prevent new viral particles being released and so stops these from infecting new cells.