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Endocrine Glands & Hormones Cheat Sheet
A printable reference covering endocrine glands, major hormones, feedback loops, homeostasis, and hormone effects for grades 9-12.
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The endocrine system uses glands and hormones to control body processes such as growth, metabolism, stress response, reproduction, and blood sugar balance. This cheat sheet helps students connect each major gland to the hormones it releases and the body effects those hormones produce. It is useful for reviewing anatomy, physiology, health science, and medical science topics in grades 9 to 12. The core idea is that endocrine glands release hormones into the bloodstream, where they travel to target cells with matching receptors. Many hormone levels are controlled by negative feedback, which helps keep internal conditions stable. Important examples include insulin and glucagon for blood glucose, thyroid hormones for metabolism, and ADH for water balance.
Key Facts
- Endocrine glands secrete hormones directly into the bloodstream, while exocrine glands release substances through ducts.
- A hormone affects only target cells that have the correct receptor for that hormone.
- The hypothalamus controls the pituitary gland using releasing and inhibiting hormones, forming a major control center for the endocrine system.
- Negative feedback means a change triggers responses that reverse the change, such as high blood glucose causing insulin release.
- Blood glucose control can be summarized as high glucose -> insulin -> cells take in glucose -> blood glucose decreases.
- Low blood glucose control can be summarized as low glucose -> glucagon -> liver releases glucose -> blood glucose increases.
- The thyroid gland releases T3 and T4, which increase metabolic rate, and calcitonin, which helps lower blood calcium.
- The adrenal medulla releases epinephrine and norepinephrine, which increase heart rate, breathing rate, and blood glucose during the fight or flight response.
Vocabulary
- Endocrine gland
- An organ that releases hormones directly into the bloodstream to regulate body functions.
- Hormone
- A chemical messenger that travels through the blood and changes the activity of target cells.
- Target cell
- A cell that has receptors for a specific hormone and can respond to that hormone.
- Negative feedback
- A control process in which the body detects a change and activates responses that bring the condition back toward normal.
- Homeostasis
- The maintenance of stable internal conditions such as temperature, blood glucose, water balance, and calcium levels.
- Pituitary gland
- A small gland at the base of the brain that releases hormones controlling growth, reproduction, water balance, and other endocrine glands.
Common Mistakes to Avoid
- Confusing endocrine and exocrine glands is wrong because endocrine glands release hormones into blood, while exocrine glands use ducts to release substances onto surfaces or into cavities.
- Thinking every cell responds to every hormone is wrong because hormones act only on target cells with matching receptors.
- Mixing up insulin and glucagon is wrong because insulin lowers blood glucose, while glucagon raises blood glucose.
- Assuming negative feedback makes a condition keep increasing is wrong because negative feedback reduces the original change and helps restore homeostasis.
- Forgetting the hypothalamus-pituitary connection is wrong because many endocrine pathways begin in the brain and use the pituitary to control other glands.
Practice Questions
- 1 A student's blood glucose rises after eating a meal. Which hormone should increase, which gland releases it, and what effect does it have on blood glucose?
- 2 A patient has low blood glucose at 62 mg/dL. Explain how glucagon helps bring blood glucose back toward a normal range.
- 3 During a stress response, heart rate increases from 72 beats per minute to 108 beats per minute. Which adrenal hormones are mainly responsible for this change?
- 4 Explain why hormone receptors are necessary for endocrine signaling even though hormones travel throughout the entire bloodstream.