Hormones and the Endocrine System

Definition and Function

• Hormones are chemical messengers produced by glands in the endocrine system that regulate various bodily functions.
• They are transported through the bloodstream to reach their target cells, tissues, or organs.

Types of Hormones

• Steroid hormones: derived from cholesterol, lipophilic, and can diffuse through cell membranes. Examples: estrogen, testosterone, aldosterone.
• Peptide hormones: composed of amino acids, hydrophilic, and require a receptor on the cell surface. Examples: insulin, growth hormone, thyrotropin-releasing hormone.
• Amine hormones: derived from amino acids, hydrophilic, and require a receptor on the cell surface. Examples: epinephrine, norepinephrine, dopamine.

Hormone Regulation

• Negative feedback loop: a self-regulating mechanism where the hormone inhibits its own production when levels are high.
• Positive feedback loop: a self-reinforcing mechanism where the hormone stimulates its own production when levels are low.

Major Hormone-Producing Glands

• Pituitary gland: regulates growth and development, and stimulates other endocrine glands.
• Thyroid gland: regulates metabolism, growth, and development.
• Adrenal glands: regulates stress response, electrolyte balance, and blood pressure.
• Pancreas: regulates blood sugar levels.
• Ovaries (in females): regulates reproductive cycles and puberty.
• Testes (in males): regulates reproductive cycles and puberty.

Hormone Imbalance and Disorders

• Hypothyroidism: underactive thyroid gland, leading to slowed metabolism and growth.
• Hyperthyroidism: overactive thyroid gland, leading to rapid metabolism and growth.
• Diabetes: insufficient insulin production, leading to high blood sugar levels.
• Hypogonadism: insufficient sex hormone production, leading to reproductive issues.

Hormones and Endocrine System

• Hormones are chemical messengers produced by glands in the endocrine system that regulate various bodily functions.
• They are transported through the bloodstream to reach their target cells, tissues, or organs.

Classification of Hormones

• Steroid hormones: derived from cholesterol, lipophilic, can diffuse through cell membranes, and include estrogen, testosterone, and aldosterone.
• Peptide hormones: composed of amino acids, hydrophilic, require a receptor on the cell surface, and include insulin, growth hormone, and thyrotropin-releasing hormone.
• Amine hormones: derived from amino acids, hydrophilic, require a receptor on the cell surface, and include epinephrine, norepinephrine, and dopamine.

Hormone Regulation Mechanisms

• Negative feedback loop: a self-regulating mechanism where the hormone inhibits its own production when levels are high.
• Positive feedback loop: a self-reinforcing mechanism where the hormone stimulates its own production when levels are low.

Major Hormone-Producing Glands and Their Functions

• Pituitary gland: regulates growth and development, stimulates other endocrine glands.
• Thyroid gland: regulates metabolism, growth, and development.
• Adrenal glands: regulates stress response, electrolyte balance, and blood pressure.
• Pancreas: regulates blood sugar levels.
• Ovaries (in females): regulates reproductive cycles and puberty.
• Testes (in males): regulates reproductive cycles and puberty.

Hormone Imbalance and Disorders

• Hypothyroidism: underactive thyroid gland, leading to slowed metabolism and growth.
• Hyperthyroidism: overactive thyroid gland, leading to rapid metabolism and growth.
• Diabetes: insufficient insulin production, leading to high blood sugar levels.
• Hypogonadism: insufficient sex hormone production, leading to reproductive issues.