Adrenal Glands

What are adrenal glands?

-Pair of endocrine glands that sit just above the kidneys and secrete hormones (epinephrine and norepinephrine) that help arouse the body in times of stress.

What are the two main regions of the adrenal gland?

• The adrenal cortex (outer region) and the adrenal medulla (inner region).

What hormones are released by the Adrenal Cortex?

• Steroid hormones.

Name the three classes of steroid hormones produced by the adrenal cortex.

• Glucocorticoids, Mineralocorticoids, and Androgens.

What is the primary function of glucocorticoids like cortisol?

-To regulate metabolism, control blood pressure and stress responses, and suppress inflammation.

What is the primary function of mineralocorticoids like aldosterone?

• To maintain blood pressure by balancing salt and water levels in the blood.

What type of hormones does the adrenal medulla produce, and what triggers their release?

• It produces catecholamines(adrenaline, noradrenaline) . Their release is triggered by stimulation of the sympathetic nervous system.

State three effects of adrenaline on the body.

• (Any three) Increases heart rate, increases blood pressure, increases blood glucose levels, increases breathing rate, dilates bronchioles.
  

How does noradrenaline help redirect blood flow during the 'fight-or-flight' response?

• It narrows (constricts) blood vessels in non-essential organs (like the gut), diverting blood to more critical areas like the muscles and brain.

Compare adrenal cortex and medulla hormones. (4 marks)

• Adrenal Cortex: Produces steroid hormones (glucocorticoids, mineralocorticoids, androgens). Roles are long-term, including metabolic regulation, salt/water balance, and sexual characteristics.

• Adrenal Medulla: Produces catecholamines (adrenaline, noradrenaline). Roles are short-term, involved in the immediate 'fight-or-flight' response (e.g., increasing heart rate, blood glucose).

Explain how adrenaline prepares the body for 'fight-or-flight'. (3 marks)

1. Increases heart rate and blood pressure to enhance blood flow to muscles and brain.

2. Increases blood glucose levels to provide more energy for respiration in muscles.

3. Increases breathing rate and dilates bronchioles to maximise oxygen intake and carbon dioxide removal.

Predict the effect of aldosterone underproduction. (3 marks)

• The patient would likely have low blood pressure and may suffer from dehydration or electrolyte imbalance.

• Justification: Aldosterone regulates salt and water balance. Without it, the kidneys cannot reabsorb sufficient sodium and water, leading to excessive loss in urine, a drop in blood volume, and consequently, low blood pressure.

Difference in triggers for adrenal cortex vs. medulla. (2 marks)

• The adrenal medulla is triggered directly by the sympathetic nervous system for a rapid, short-term response.

• The adrenal cortex is triggered by chemical signals (e.g., hormones from the hypothalamus/pituitary gland, like ACTH) for slower, longer-term regulation.