Adrenal Activity

Question 1

What sort of response is mediated?

Answer 1

• Stress response, an adaptive response which involved adrenaline and noradrenaline (flight or fight)
• Involved increased sympathetic nervous activity and reduced parasympathetic to secrete these drugs.
• The hypothalamus releases corticotrophin releasing factor (CRF) which triggers the release of adrenocorticotrophic hormone (ACTH) from the anterior pituitary.
• Results in cortisol release.

Question 2

Cortisol

Answer 2

• A steroid hormone secreted from the adrenal cortex and regulated via the hypothalamus via negative feedback.
• Cortisol leads to an increase in heart rate, acts as an inflammatory, increases mobilisation of amino acids and the rate of lipolysis.
• Long term effects of cortisol include breakdown of proteins and fats, leading to weight loss or anxiety.

Question 3

Describe the effects of adrenaline and noradrenaline

Answer 3

• Mediate the short term stress response as they act within seconds or minutes.
• Cause an increase in blood pressure, breathing rate and metabolic rate.
• Stimulate the breakdown of glycogen to glucose to increase blood sugar, blood flow is decreased to digestive and excretory regions while increased to the muscles.