Endocrine System Hormones

Endocrine System

• Regulates various body functions, including metabolism, growth, reproduction, and stress responses.
• Consists of a network of glands that produce and release hormones.

Pituitary Gland

• Regulates reproductive processes.
• Produces hormones, including:
  • Follicle-Stimulating Hormone (FSH) and Luteinizing Hormone (LH)
  • Prolactin (PRL), which stimulates milk production
  • Regulates various endocrine glands

Posterior Pituitary

• Produces hormones, including:
  • Antidiuretic Hormone (ADH), which promotes water reabsorption in kidneys
  • Oxytocin, which stimulates uterine contractions and milk ejection

Thyroid Gland

• Regulates metabolism, growth, and development.
• Produces hormones, including:
  • Thyroxine (T4) and Triiodothyronine (T3), which increase metabolic rate
  • Calcitonin, which lowers blood calcium levels

Parathyroid Glands

• Regulates calcium levels in the blood.
• Produces Parathyroid Hormone (PTH), which increases blood calcium levels.

Adrenal Glands

• Adrenal Cortex:
  • Produces hormones, including:
    • Cortisol, which regulates metabolism, immune response, and stress
    • Aldosterone, which regulates sodium and potassium balance
    • Androgens, which contribute to sex characteristics
• Adrenal Medulla:
  • Produces hormones, including:
    • Epinephrine (Adrenaline) and Norepinephrine, which mediate the fight-or-flight response

Pancreas

• Regulates blood glucose levels.
• Produces hormones, including:
  • Insulin, which lowers blood glucose levels
  • Glucagon, which raises blood glucose levels

Gonads (Ovaries and Testes)

• Regulates reproduction and secondary sex characteristics.
• Produces hormones, including:
  • Estrogens and Progesterone in ovaries
  • Testosterone in testes

Pineal Gland

• Regulates sleep-wake cycles.
• Produces Melatonin, which regulates sleep-wake cycles.

Hormonal Regulation and Feedback Mechanisms

• Negative Feedback: Maintains homeostasis.
• Positive Feedback: Amplifies responses.

Immune System

• Defends the body against infectious organisms and other invaders through a series of steps called the immune response.
• Consists of various organs, cells, and proteins.

Innate Immunity (Non-specific)

• First Line of Defense: Skin, mucous membranes, and secretions.
• Second Line of Defense: Phagocytic cells, natural killer cells, inflammation, and fever.
• Phagocytes: Neutrophils and macrophages (engulf and digest pathogens).
• Natural Killer Cells: Destroy infected or cancerous cells.
• Inflammatory Response: Redness, heat, swelling, and pain; involves histamines and cytokines.

Adaptive Immunity (Specific)

• Lymphocytes: B cells and T cells.
• B Cells: Produce antibodies (humoral immunity).
• Plasma Cells: Secrete antibodies.
• Memory B Cells: Provide long-term immunity.
• T Cells: Attack infected cells (cell-mediated immunity).
• Helper T Cells: Activate B cells and cytotoxic T cells.
• Cytotoxic T Cells: Destroy virus-infected cells and cancer cells.
• Regulatory T Cells: Suppress immune response to maintain tolerance.

Organs and Tissues

• Primary Lymphoid Organs: Bone marrow and thymus.
• Secondary Lymphoid Organs: Lymph nodes, spleen, tonsils, and Peyer's patches.
• Lymphatic System: Network of vessels and nodes that return interstitial fluid to the blood and provide sites for immune cell activation.

Digestive System

• Produces digestive enzymes (amylase, lipase, proteases) and bicarbonate.
• Key Structures: Pancreatic ducts (secrete into duodenum).
• Key Processes:
  • Ingestion: Taking in food via the mouth.
  • Propulsion: Moving food through the GI tract (swallowing and peristalsis).
  • Mechanical Digestion: Physical breakdown of food (chewing, churning in stomach).
  • Chemical Digestion: Enzymatic breakdown of macromolecules into absorbable units.
  • Absorption: Transfer of nutrients from the GI tract to the blood or lymph.
  • Defecation: Elimination of indigestible substances and waste.

Digestive Enzymes and Hormones

• Salivary Amylase: Breaks down starch into maltose in the mouth.
• Pepsin: Breaks down proteins into peptides in the stomach.
• Pancreatic Enzymes: Include trypsin (proteins), pancreatic amylase (carbohydrates), and pancreatic lipase (fats).

Common Disorders

• Gastroesophageal Reflux Disease (GERD): Acid from the stomach flows back into the esophagus, causing heartburn.
• Peptic Ulcers: Sores in the stomach lining due to HCl and pepsin.