The photo shown below is taken from the skin of a human patient with Shingles. E

Question

The photo shown below is taken from the skin of a human patient with Shingles. Explain the pathophysiological mechanism by which this occurs in the skin. The answer should be based around neuroscience not virology. You need to explain briefly and clearly:

(a) What are major symptoms and the cause of Shingles? (1 mark)

(b) What is a dermatome? (1 mark)

(c) Why is a dermatome relevant to Shingles? (1 mark)

(d) What are dorsal root ganglia (DRG)? (1 mark)

(e) Do DRG neurons receive synaptic inputs from other neurons, and if so, what types of inputs are they? (1 mark)

(f) Regarding the pain sensation underlying shingles, where does this sensory information enter the spinal cord? (1 mark)

(g) What major types of nerve fibres make up the ventral thoracic nerve roots? (1 mark)

(h) What would it mean if a patient with Shingles had skin lesions over many body regions compared with a patient who had lesions only over a small part of the body (e.g. as is shown in the image)? (1 mark)

(i) What is postherpetic neuralgia? (1 mark)

(j) What types of nerve fibres transmit inflammatory (slow pain) from skin? (1 mark)

Chronic Obstructive Pulmonary Disease (COPD) is a debilitating lung condition that limits airflow in the lungs. The two most common conditions are emphysema and chronic bronchitis. This question is focussed on emphysema. You may use diagrams to help explain your answer.

(a) What is emphysema and what is the cause? (1 mark)

(b) What are the effects of smoking on the ability of the lung to protect itself and the major pathophysiological consequences of the loss of this protective ability? (2 marks)

(c) What is a major hallmark of emphysema? (1 mark)

(d) What limits flow rate when you forcible breathe out? (1 mark)

(e) Why is the down slope on a flow volume loop is always the same no matter how intense the effort during a forced expiration? (1 mark)

(f) What happens with a flow volume loop in patients with emphysema when they breathe out? (1 mark)

(g) Why do people with emphysema have low arterial oxygen (hypoxia)? (2 marks) (h) What can be done to help people with emphysema? (1 mark)

Robbie Jenkins is a four year old boy growing up in Blackwood. He is small for his age and seems to be growing slowly compared to his friends. Recently, he has been complaining of abdominal pain and he sometimes has diarrhoea. The stool that he passes is watery and floats in the toilet bowl. It smells particularly bad. His parents take him to the doctor. The doctor takes a blood sample and has it analysed for "antibodies to tissue transglutaminase" (tTG or TG2). The results are positive. Robbie then undergoes an endoscopy in Flinders Medical Centre. He is sedated and a fibre-optic endoscope is passed down his oesophagus, through his stomach and into his small intestine. It is noted that the villi in his small intestine do not have the normal finger-like shape; they have very little depth so that the mucosa looks almost flat. These are all typical signs and symptoms of coeliac disease. His parents are told to change his diet to avoid gluten. They talk to a nutritionist and make the appropriate changes and his symptoms and signs improve over the next 2 months.

(a) What is gluten? (1 mark)

(b) Where does tissue transglutaminase come from? (1 mark)

(c) What does a "transglutaminse" enzyme do (it's primary role)? (1 mark)

(d) Which 3 cereal grains that are most common in the Australia diet contain sufficient gluten to trigger exacerbations of coeliac disease? (1 mark)

(e) What is gliadin? (1 mark)

(f) Why is Robbie failing to grow at a normal rate? (1 mark)

(g) Why do his stools float in the toilet bowl and smell so bad? (1 mark)

(h) Why does Robbie have frequent bouts of abdominal pain? (1 mark)

(i) Why does Robbie have diarrhoea? (1 mark)

(j) Most of us eat lots of gluten and have lots of tissue transglutaminase, yet we don't have celiac disease. There are two specific serotype of an antigen presenting protein (an HLA) that greatly increase someone's risk of developing Coeliac Disease. Which HLA form are they? (1 mark)

A patient experiences a sudden rupture of the chordae tendineae that results in the mitral valve not closing properly. In this patient:

(a) Describe the filling of the left ventricle during diastole. (0.5 mark)

(b) Describe the movement of the left ventricular blood during systole. (1 mark)

(c) Describe what may happen to blood pressure in the pulmonary vein and why. (2 marks)

(d) Describe what might be happening in the lungs and the symptoms that may result. (2 marks)

(e) Describe what might be happening to cardiac output and arterial blood pressure both in the short-term and in the long-term

The photo shown below is a human kidney cut in half. In the center of the image is a large kidney stone. Explain:

(a) Why kidney stones form; and what sort of conditions may lead to kidney stone formation? (2 marks)

(b) What are kidney stones made of? (2 marks)

(c) Why patients with kidney stones experience pain? (2 marks)

(d) How are kidney stones treated? (2 marks)

(e) How can kidney stones be prevented? (2 marks)

Explanation / Answer

Answer

The virus varicella zoster or Herpes zoster cause chickenpox in humans. It stays dormant for many years without showing any symptoms. They reside in the sensory nerves. It suddenly reactivates by reduced immunity with age or other factors, any surgeries or other diseases. It reactivates and migrates to the skin surface through the nerve fibers, resulting in a painful rash with red blisters. This is known as Shingles. These blisters are fluid filled and appears anywhere on the body. Mostly found in the region of waist, forehead and near the eyes.

It is transmitted through air. The virus from skin rashes spread through air. Direct contact also spreads the disease.

When the virus reactivates, it moves down the axon and replicates there producing vesicles which are painful. These vesicles damage the sensory nerves. This condition is referred as postherpetic neuralgia.

It causes itching, pain, irritation, fever, headache, back pain and nausea.

a. Shingles is caused by varicella zoster or Herpes zoster virus. Its symptoms are

Fluid-filled blisters on the skin

Itching, pain, redness, burning and tingling.

b. The region of the skin where the spinal nerve specifically innervates into it, is referred as a dermatome.

c. The dormant virus resides in the dermatome and moves down the axon upon activation, replicates, reaches the surface and forms painful blisters. The pain in the region of the nerve ganglia.

d. A group of neurons is a ganglion. The spinal nerves have posterior and anterior roots. The posterior root ganglia of the spinal nerve are the dorsal root ganglia.

e. Yes, DRG receive synaptic input from other neurons. They transmit the sensory stimulus (pain or touch), towards the sensory root of the spinal nerve. This is afferent sensory input.

f.  It enters at the dorsal sensory root of the spinal cord.

g. The dorsal root consists of sensory fibers and the ventral root consists of motor fibers. The ventral thoracic nerve roots are efferent somatic motor fibers and they are unmyelinated.

h. The image is not provided.

Assumed answer General shingles affects some regions of the body. But there is wide spread of the disease all over the body or large area of the body in condition of weak immune system.

i. When the virus reactivates, it moves down the axon and replicates there producing vesicles which are painful. These vesicles damage the sensory nerves. This condition is referred as postherpetic neuralgia.

j. The unmyelinated nerve fibers that have low conduction velocity are C-nerve fibers. They are associated with the dorsal root ganglia. They transmit slow pain from skin.

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