This definitions covers Key Definitions within Human Endocrine System for GCSE Biology. Topic 4: Human Endocrine System It is section 6 of 11 in this topic. Make sure you can use the exact wording confidently, because definition marks are often lost through vague language.
Key Definitions
Endocrine system: The system of glands that produce and secrete hormones directly into the bloodstream to regulate body functions.
Hormone: A chemical messenger produced by an endocrine gland, secreted into the blood, and transported to target organs where it produces a specific effect.
Endocrine gland: A ductless gland that secretes hormones directly into the bloodstream (e.g. pituitary, thyroid, adrenal glands, pancreas).
Pituitary gland: The "master gland" located at the base of the brain that secretes multiple hormones, many of which control the activity of other endocrine glands.
Target organ: An organ that responds to a specific hormone because its cells possess the complementary receptor proteins that bind to that hormone.
Adrenaline: A hormone produced by the adrenal glands (above the kidneys) in response to stress or danger; prepares the body for "fight or flight" by increasing heart rate and blood glucose.
Thyroxine: A hormone produced by the thyroid gland that regulates the body's metabolic rate (how quickly cells carry out chemical reactions).
Practice questions for Human Endocrine System
Which gland is known as the 'master gland' because it controls other endocrine glands?
Compare how the nervous system and the endocrine system coordinate responses in the body. [3 marks]
Quick recall flashcards
What is the endocrine system?
The endocrine system is a network of glands that produce and release hormones directly into the bloodstream. Hormones travel to target organs to trigger a response.
What is a hormone?
A hormone is a chemical messenger produced by a gland, released into the blood, and carried to a target organ where it causes a response.