Melatonin regulation is directly through the amount of light that strikes the retina. More melatonin is released during darkness. Light inhibits melatonin release.
Hormones from Other Endocrine Tissues and Organs
GIT - Gastrin
Placenta – chorionic gonadotropin, relaxin, estrogen & progesterone
Kidneys – renin, erythropoietin, calcitrol
Heart – Atrial natriuretic peptide, erythropoietin
Adipose Tissue – leptin
Thymus - Thymosin, Thymic Humeral Factor (THF), Thymic Factor (TF), Thymopoietin
The Stress Response
Not all stress is bad, and it is impossible to remove stress entirely from our lives. The helpful stress is called Eustress and prepares us to meet certain challenges. Other stress is called Distress and is harmful. Any stimulus that produces a stress response is called a Stressor . Homeostasis attempts to counteract stress and when successful, your body’s internal environment returns to within physiological normal limits. However, our bodies are often overcome by extreme stress or prolonged stress.
The stress response occurs in 3 stages:
1) Fight-or-Flight Response
This response is initiated by nerve impulses from the hypothalamus to the sympathetic division of the ANS, including the Adrenal Medulla. It then quickly mobilizes the body’s resources for immediate physical activity.
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