Summary
Hormones are chemical substances produced by glands and carried by the blood to alter the activity of specific target organs. They play a crucial role in coordinating and regulating various body functions.
- Hormone — a chemical substance produced by a gland and carried by the blood to alter the activity of specific target organs. Example: Adrenaline is a hormone that prepares the body for 'fight or flight' by increasing heart rate and blood glucose levels.
- Endocrine System — a collection of glands that produce hormones. Example: The pancreas is part of the endocrine system and produces insulin.
- Adrenaline — a hormone produced in response to stress, increasing heart rate and energy availability. Example: Adrenaline increases blood glucose concentration for increased respiration in muscle cells.
Exam Tips
Key Definitions to Remember
- Hormone: A chemical substance produced by a gland and carried by the blood to alter the activity of specific target organs.
- Endocrine System: A collection of glands that produce hormones.
Common Confusions
- Confusing hormones with nerve impulses, which are electrical signals.
- Mixing up the roles of different hormones, such as insulin and glucagon.
Typical Exam Questions
- What is a hormone? A chemical substance produced by a gland and carried by the blood to alter the activity of specific target organs.
- How does adrenaline affect the body? It increases heart rate and blood glucose levels to prepare the body for 'fight or flight'.
- What is the role of the endocrine system? It produces hormones that regulate various body functions.
What Examiners Usually Test
- Understanding the role of hormones in the body.
- Differences between hormonal and nervous control.
- Effects of specific hormones like adrenaline on the body.