#4: Adrenaline and Secondary Messengers

These flashcards cover the key concepts related to the function of adrenaline and its interaction with secondary messengers in enzyme activation and glucose regulation.

What is adrenaline and what role does it play in the body?

Adrenaline is a hormone produced by the adrenal glands in times of stress that prepares the body for emergency situations.

What is the secondary messenger model in relation to non-lipid-soluble hormones?

It is the process by which non-lipid-soluble hormones, like glucagon or adrenaline, activate production of a second messenger, such as cyclic AMP, through receptors on target cells.

How does glucagon facilitate glycogenolysis in liver cells?

Glucagon binds to liver cell membrane receptors, activating a G protein, which in turn activates adenylyl cyclase, converting ATP to cyclic AMP, leading to breakdown of glycogen to glucose.

What steps are involved in adrenaline's action on liver cells?

1. Adrenaline binds to liver cell receptors. 2. This activates adenylyl cyclase. 3. Adenylyl cyclase converts ATP to cyclic AMP. 4. Cyclic AMP initiates protein kinases which activate glycogenolysis.

In addition to activating glycogenolysis, what other effects does adrenaline have related to blood glucose levels?

Adrenaline inhibits glycogenesis, stimulates glucagon secretion, inhibits insulin secretion, and promotes breakdown of glycogen stores in muscles during exercise.

When is adrenaline secreted?

Adrenaline is secreted during times of low blood glucose concentration, stress, or physical exercise.

What is the ultimate role of adrenaline during the fight or flight response?

Adrenaline prepares the body for the fight or flight response by increasing glucose availability to muscles for respiration.

What is cyclic AMP and what role does it play in hormone action?

Cyclic AMP (cAMP) acts as a second messenger that amplifies the signal from the hormone, activating various enzymes such as protein kinases.