Endocrine System Lecture Notes

Introduction

Robert Wadlow: Tallest modern-day man (8 feet 11.5 inches) due to a pituitary tumor causing excess growth hormone production.
Importance of the endocrine system and its contrast with the nervous system.

Composed of neurons with dendrites, cell body, and axon.
Neurons connect via synapses, where neurotransmitter chemicals control communication.
Analogy: Nervous system as Gmail (fast, direct communication).

Analogy: Endocrine system as Facebook (broadcast communication, slower response).
Uses glands to secrete hormones, which target specific or multiple cells.

Water Soluble Hormones: e.g., epinephrine, dock on cell surface.
Lipid Soluble Hormones: e.g., testosterone, pass through cell membrane into the nucleus.

Pineal Gland
- Hormone: Melatonin (regulates circadian rhythms, secreted at night).
Hypothalamus
- Connects brain to the endocrine system.
Pituitary Gland
- Anterior Pituitary: Secretes growth hormone, endorphins, etc.
- Posterior Pituitary: Secretes antidiuretic hormone (ADH) for water retention, oxytocin.
Thyroid Gland
- Hormones: T3 and T4 (regulate metabolism), Calcitonin (lowers blood calcium).
Parathyroid Glands
- Hormone: Parathyroid hormone (raises blood calcium).
Pancreas
- Hormones: Insulin (lowers blood sugar), Glucagon (raises blood sugar).
Adrenal Glands
- Adrenal Cortex: Secretes glucocorticoids (anti-inflammatory).
- Adrenal Medulla: Secretes epinephrine (triggers fight-or-flight response).
Ovaries
- Hormone: Estrogen (female sex characteristics).
Testes
- Hormone: Testosterone (male sex characteristics).

Reviewed hormone sources and functions for each gland.
Importance of endocrine feedback loops, e.g., insulin/glucagon, calcium regulation.

Understanding the endocrine system is crucial for comprehending how the body communicates internally through hormones.
Endocrine system's slower, widespread effects contrast with the targeted, rapid effects of the nervous system.