MRCS Part B Revision · Applied surgical science and critical care
Adrenal Function — MRCS Part B Applied surgical science and critical care
By Dr Richard Miller, MBChB FRCS · Reviewed
Adrenal Function is an applied surgical science and critical care station. Three of the seventeen examined stations in the MRCS Part B OSCE fall in this area. These stations ask you to interpret data and manage a sick surgical patient: a chart, a blood gas, an imaging study or a deteriorating patient on the ward, and the physiology underneath the decision.
What you need to know for the Adrenal Function station
Adrenal Shock
The adrenal glands are endocrine glands that produce a wide variety of hormones.They are found on the top of the kidneys and consist of a number of different layers that directly influence the structure and function of the glands.
Each gland has an outer cortex made of steroid-producing cells surrounding a core of medulla, formed by chromaffin cells in direct relationship with the sympathetic nervous system. The adrenal cortex is divided into three zones according to their functions and microscopic appearance.
Hormones
The adrenal cortex produces a class of steroid hormones, the corticosteroids, which are classified according to their effects. Mineralocorticoids, produced in the zona glomerulosa, help in the regulation of blood pressure and electrolyte balance. Glucocorticoids such as cortisol, are synthesized in the zona fasciculata and their functions include regulation of glycogen and lipid metabolism and immune system suppression. The innermost layer of the cortex, the zona reticularis produces androgens (steroid hormones) that are converted to fully functional sex hormones in the gonads and other target organs.
The medulla produces the catecholamines, adrenaline and noradrenaline which function to provoke a quick response on diverse organs in stress situations.
Regulation and Feedback
Mineralocorticoid production is mainly under influence of the renin–angiotensin–aldosterone system, in which specialized juxtaglomerular cells of the kidneys monitor blood volume and start a cascade of reactions that leads to the stimulation of aldosterone synthesis in the zona glomerulosa.
Cortisol and androgen synthesis are under control of the hypothalamic-pituitary-adrenal (HPA) axis in a classic example of a negative feedback loop, in which the hypothalamus and pituitary gland release stimulating hormones whenever cortisol levels are low. In contrast, release of medullary catecholamines is regulated by direct innervation from the sympathetic nervous system.
Diseases
There are a number of endocrine diseases and disorders that can affect the normal functioning of the adrenal gland. Overproduction of corticosteroid hormones leads to Cushing's syndrome, whereas insufficiency is commonly associated with Addison's disease. Congenital adrenal hyperplasia is a genetic disease produced by a disregulation of endocrine control mechanisms. A variety of tumours can arise from adrenal tissue, and are commonly found in medical imaging when searching for other diseases.
What are you asked at the Adrenal Function station?
The station runs to 17 questions over nine minutes. A prompt the station repeats — against each marker on a specimen, for instance — is listed once here; the model answers are in the question bank.
- What hormones does the adrenal cortex produce and from which layers?
- Describe the effects of Aldosterone
- What causes an increase in Aldosterone release?
- What is Cushing's Disease/Syndrome?
- What reduces Aldosterone secretion?
- What are the causes of Cushing's Disease/Syndrome?
- What are the signs and symptoms of Cushing's Disease/Syndrome?
- What are the causes of excess Aldosterone production?
- What are the signs and symptoms of Conn's syndrome?
- What would the urine of a Conn's syndrome patient show?
- What are the causes of Addison's Disease?
- What are the signs and symptoms of Addison's Disease?
And 4 more at this station.
How is the applied surgical science and critical care station marked in MRCS Part B?
Each of these three stations is marked out of 20, split 12 marks for clinical knowledge and its application, 4 for clinical and technical skill and 4 for professionalism. No communication marks are available. The three cover critical care management, interpretation of clinical data, and interpretation of visual information.
FAQ
What does the Adrenal Function station ask?
It opens with "What hormones does the adrenal cortex produce and from which layers?" and runs to 17 questions over nine minutes. Each of these three stations is marked out of 20, split 12 marks for clinical knowledge and its application, 4 for clinical and technical skill and 4 for professionalism. No communication marks are available. The three cover critical care management, interpretation of clinical data, and interpretation of visual information.
What counts as applied surgical science in MRCS Part B?
Three of the seventeen examined stations: critical care management, interpretation of clinical data such as blood results and charts, and interpretation of visual information such as imaging and traces.
How is an applied science station marked?
Out of 20, with 12 marks for clinical knowledge and its application, 4 for clinical and technical skill and 4 for professionalism. Unlike the communication stations, none of the marks are for how you say it.
How much physiology do I need?
Enough to explain the decision you are making. The station rewards applying physiology to the patient in front of you rather than reciting it, so practise talking through why a number changes your management.
How many stations are in the MRCS Part B OSCE?
Seventeen examined stations of nine minutes each, with a minute to read the task before each one. Two preparation stations and at least one rest station bring the circuit to about twenty, and the exam takes about three and a half hours.
What is the pass mark for MRCS Part B?
There is no published pass mark. The cut score is set separately for Applied Knowledge and Applied Skills, for each circuit, by borderline regression. Published pass rates across the 2024/25 diets ranged from 51% to 66%.
Can I fail a station and still pass?
Yes. There is no rule about how many stations you may fail: the cut score applies to your total mark in each component, so a weak station costs the marks you lost on it and strong stations elsewhere can make them back. Applied Knowledge and Applied Skills are passed separately and must both be passed at the same sitting, so a strong anatomy performance cannot rescue a weak communication one.
Dr Richard Miller, MBChB FRCS
Station summaries are reviewed against the current intercollegiate MRCS syllabus and the published marking blueprint. Guidance changes between diets: check the royal colleges' own pages before relying on a date, a fee or a threshold.
Practise this station
The question bank carries the model answer to every question above, with the rest of the applied surgical science and critical care stations.
More applied surgical science and critical care stations