Anatomy and Physiology / Unit 7: The Endocrine System
7.5 Other Endocrine Glands
Notes
- Pineal gland: melatonin regulates the sleep-wake cycle.
- Thymus: thymosin; T-cell maturation; large in children and shrinks in adults.
- Gonads: ovaries make estrogen and progesterone; testes make testosterone. Controlled by FSH and LH.
- Other hormone sources: the kidneys (erythropoietin, EPO, stimulates red blood cell production when oxygen is low), the heart (atrial natriuretic peptide lowers blood pressure), the stomach and small intestine (gastrin, secretin, cholecystokinin), and adipose tissue (leptin).
- Example: a person moves to a high altitude, blood oxygen falls, kidneys release more EPO, and red blood cell count rises.
Practice
Which hormone from the pineal gland helps regulate the sleep cycle?
Melatonin levels rise in darkness.
A person moves to a high altitude and, after some weeks, has a higher red blood cell count. Which hormone made this happen?
Low oxygen stimulates the kidneys to release EPO, which stimulates red marrow.
Which gland is largest in children and shrinks with age and is important for T-cell maturation?
The thymus gland supports the immune system, especially in childhood.
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