Responding to the Environment: Endocrine System & Homeostasis
Responding to the Environment: Endocrine System & Homeostasis is one of 10 topics in the Grade 12 Life Sciences CAPS syllabus, covered across 3 lessons on Study Vault. Below are real practice questions from this topic with full worked answers.
Sample practice questions
Easy
1. A hormone is best defined as a:
Chemical messenger produced by an endocrine gland and carried in the blood to target cells
Nerve impulse that travels along an axon
Structural protein found only in muscle tissue
Type of neurotransmitter released only at a synapse
Answer: Chemical messenger produced by an endocrine gland and carried in the blood to target cells — Hormones are chemical messengers secreted by endocrine glands directly into the blood, which then carries them to target cells or organs elsewhere in the body.
Easy
2. Which endocrine gland is often called the "master gland" because it regulates the activity of many other endocrine glands?
The pituitary gland
The thyroid gland
The pancreas
The adrenal gland
Answer: The pituitary gland — The pituitary gland, closely linked to the hypothalamus, produces hormones that regulate the activity of many other endocrine glands, earning it the name "master gland."
Medium
3. Why does a hormone circulating throughout the entire bloodstream only affect specific target tissues rather than every cell in the body?
Only cells with the correct receptor for that hormone will respond to it
Hormones physically cannot reach cells other than their target cells
All cells respond identically to every hormone
Hormones are destroyed before reaching non-target cells
Answer: Only cells with the correct receptor for that hormone will respond to it — A hormone can only trigger a response in cells bearing the specific receptor that recognises it; cells lacking that receptor are unaffected even though the hormone reaches them via the blood.
