Physiology

Question 1

What are the compositions of CSF?

Answer 1

Glucose: 50-80mg/dl
Protein: 15-40mg/dl
Red blood cells: Nil
White blood cells: 0-3cells/mm3

Question 2

What are the stimulants of insulin release?

Answer 2

Glucose
Amino acid
Vagal cholinergic
Secretin/Gastrin/CCK
Fatty acids
Beta adrenergic drugs

Beta blockers inhibit the release of insulin

Question 3

At what site is dietary iron absorbed?

Answer 3

Duodenum

Iron is best absorbed from the proximal small bowel (duodenum and jejunum) in the Fe 2+ state. Iron is transported across the small bowel mucosa by a divalent membrane transporter protein (hence the improved absorption of Fe 2+). The intestinal cells typically store the bound iron as ferritin. Cells requiring iron will typically then absorb the complex as needed.

Question 4

Where is the main site of dehydroepiandrosterone release?

Answer 4

Zona reticularis of the adrenal gland.

Question 5

Secretions from which organ contain the highest levels of potassium?

Answer 5

Rectum
This is the rationale behind administration of resins for hyperkalaemia and the development of hypokalaemia in patients with villous adenoma of the rectum.

Question 6

What is the typical stroke volume in a resting 70kg man?

Answer 6

70mL.

Generally stroke volumes range from 55-100mL.

Question 7

What are the effects of the release of vasopression from the pituitary?

Answer 7

• Increase water permeability of the distal tubule and collecting ducts
• Increase arterial blood pressure by vasoconstriction

Question 8

What hormone is mainly responsible for sodium-potassium exchange in salivary ducts?

Answer 8

Aldosterone, which acts on sodium/potassium ion exchange pump.
It is a mineralocorticoid which derived from the zona glomerulosa of the adrenal gland.

Question 9

What nerve fibres is responsible for the transmission of mechanothermal stimuli?

Answer 9

C fibres.

A γ fibres transmit information relating to motor proprioception, A β fibres transmit touch and pressure and B fibres are autonomic fibres.

Question 10

What is the approximate volume of pancreatic secretion in 24 hour period?

Answer 10

1500mL

Question 11

What is the physiological effect of hypercapnia?

Answer 11

cerebral vasodilation, leading to raised intracranial pressure.

Question 12

What is the most likely electrolyte disturbance that occur post massive blood transfusion?

Answer 12

Hyperkalaemia