Rucete ✏ Biology In a Nutshell
1. Hypothalamus
- Produces ADH and oxytocin, stored and secreted by the posterior pituitary
- Acts as a major neuroendocrine center
2. Posterior Pituitary (Stores & Releases)
- ADH (Antidiuretic Hormone) → kidneys: increases water reabsorption
- Oxytocin → mammary glands: stimulates milk release
3. Anterior Pituitary (Produces Hormones)
- TSH (Thyroid-Stimulating Hormone) → thyroid: secretion of T3 and T4
- ACTH (Adrenocorticotropic Hormone) → adrenal cortex: secretion of glucocorticoids
- FSH (Follicle-Stimulating Hormone) → ovaries/testes: oogenesis and spermatogenesis
- LH (Luteinizing Hormone) → ovaries/testes: ovulation and testosterone production
- PRL (Prolactin) → mammary glands: milk production
- GH (Growth Hormone) → bones, muscles: stimulates growth
4. Pancreas (Islets of Langerhans)
- Alpha cells: secrete glucagon → liver: increases blood glucose
- Beta cells: secrete insulin → liver, muscles, fat: lowers blood glucose
5. Adrenal Glands
a) Adrenal Medulla
- Epinephrine (adrenaline) and norepinephrine (noradrenaline)
- Target: blood vessels, liver, heart
- Action: increases blood glucose, constricts vessels
b) Adrenal Cortex
- Glucocorticoids → general: increases blood glucose
- Mineralocorticoids → kidneys: increases Na⁺ reabsorption, K⁺ excretion
6. Thyroid Gland
- T4 (thyroxine) and T3 (triiodothyronine) → general: increases metabolic rate
- Calcitonin → bones: lowers blood Ca²⁺
7. Parathyroid Glands
- PTH (Parathyroid Hormone) → bones: increases blood Ca²⁺
8. Testes
- Testosterone → testes, general: promotes spermatogenesis and secondary sex characteristics
9. Ovaries
- Estrogen → uterus: regulates menstrual cycle, secondary sex characteristics
- Progesterone → uterus: regulates menstrual cycle and supports pregnancy
10. Pineal Gland
- Melatonin → body: regulates circadian rhythms
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Biology in a nutshell