Endocrine system

How do cells communicate with each other?

Endocrine gland
Hormone
Target cells
- One hormone, many effects
Receptors
- Membrane receptors: signal transduction (Peptide hormones)
- Nuclear receptors: activate transcription (Steroid hormone)
Different hormone, different effect
- Steroid & thyroid hormones: slower but longer-lasting
- Peptide & amine hormones: faster but shorter-lasting

Hypothalamus: Brain control
1. Releasing hormones for anterior pituitary
2. Oxytocin: milk letdown; uterine contraction
  - Inducing labor: pitocin
3. Vasopressin (ADH): water reabsorption by kidney
  - Alcohol effect
Pituitary gland: Master gland
1. Regulatory hormones
  - ACTH: regulates adrenal gland
  - LH: stimulates release of sex hormones
  - FSH: stimulates sperm & egg production
  - TSH: regulates thyroid gland
2. Growth Hormone: bone, muscle, fat
3. Prolactin: milk production
Adrenal gland: Stress
1. Glucocorticoids (Cortisol): raise blood sugar
2. Mineralocorticoids (Aldosterone): Sodium retention
  - blood pressure control
3. Androgens (steroids)
4. Adrenaline: speeds up heart/respiration
  - Controlled by nervous system
Thyroid gland
1. Thyroid hormones (T3, T4)
2. Calcitonin (lowers blood calcium)
Parathyroid gland
1. Parathyroid hormone: raises blood calcium
  - essential for life
Pancreas
1. Insulin: lowers blood glucose
  - Diabetes mellitus
2. Glucagon: raises blood glucose
Testes
1. Testosterone: male secondary sex characteristics, spermatogenesis
Ovaries
1. Estrogen: female secondary sex characteristics, oogenesis
  - HRT
2. Progesterone: maintain uterine lining
Pineal gland
1. Melatonin: circadian rhythms