Overview
This lecture provides an overview of the 11 human organ systems, their main organs, functions, and uses a functional grouping approach for easier understanding.
System Groupings & Categories
- Organ systems are grouped by function: support/movement, integration/coordination, transport, absorption/excretion, and reproduction.
- There are 11 organ systems: integumentary, skeletal, muscular, nervous, endocrine, cardiovascular, lymphatic/immune, respiratory, digestive, urinary, and reproductive.
Support & Movement Systems
Integumentary System
- Main organs: skin (primary), hair, nails.
- Functions: Protection, Temperature regulation, Sensation, Vitamin D synthesis (PTSD acronym).
Skeletal System
- Main organs: bones, joints (fibrous, cartilaginous, synovial), ligaments.
- Functions: Structural support, Leverage for movement, Protection of organs, Blood cell production, Mineral storage.
Muscular System
- Main organs: skeletal muscles, tendons.
- Functions: Movement, Posture maintenance, Heat (thermal energy) production.
Integration & Coordination Systems
Nervous System
- Main organs: brain, spinal cord, nerves, sensory receptors/organs.
- Functions: Fast communication/control, Sensory processing, Coordination of body functions.
Endocrine System
- Main organs: hypothalamus, pituitary, pineal, thyroid, parathyroid, thymus, adrenal glands, pancreas, ovaries, testes.
- Functions: Long-term regulation via hormones, Metabolism, Calcium regulation, Stress response, Blood sugar control, Reproductive hormone production.
Transport Systems
Cardiovascular System
- Main organs: heart, blood vessels (arteries, veins, capillaries), blood.
- Functions: Transports oxygen, carbon dioxide, nutrients, hormones, waste, and immune cells.
Lymphatic/Immune System
- Main organs: lymph nodes, lymphatic vessels, spleen, thymus, bone marrow.
- Functions: Reduces tissue swelling (fluid drainage), Absorbs dietary lipids, Immune response (pathogen defense).
Absorption & Excretion Systems
Respiratory System
- Main organs: nasal/oral cavity, pharynx, larynx, trachea, bronchi, lungs, diaphragm.
- Functions: Gas exchange (oxygen in, carbon dioxide out).
Digestive System
- Main organs: mouth, esophagus, stomach, small/large intestines, rectum, anus; accessory: liver, gallbladder, pancreas.
- Functions: Digestion (breakdown of food), Nutrient absorption, Elimination of waste.
Urinary System
- Main organs: kidneys, ureters, bladder, urethra.
- Functions: Removes waste from blood, Regulates water/electrolytes/pH.
Reproductive System
- Main organs (male): testes, epididymis, vas deferens, seminal vesicles, prostate, bulbourethral gland, penis.
- Main organs (female): ovaries, fallopian tubes, uterus, vagina.
- Functions: Produces/transports gametes (sperm/egg), Nurtures developing fetus (female), Hormone production.
Key Terms & Definitions
- Organ system — a group of organs working together for a common function.
- PTSD (integumentary functions) — Protection, Temperature regulation, Sensation, Vitamin D synthesis.
- Homeostasis — maintaining stable internal conditions.
- Hormone — chemical messenger for body regulation.
- Gamete — reproductive cell (sperm or egg).
Action Items / Next Steps
- Download and review the free study guide for practice exercises.
- Engage in active recall: list organ systems and their functions from memory.
- Prepare for deeper study into individual systems as assigned.