Organization of the Human Body – Organ Systems and Life-Span Changes Chapter 1 Organization of the Human Body – Organ Systems and Life-Span Changes

Organ Systems Integumentary System Includes the skin and accessory organs such as hair, nails, sweat glands, and sebaceous glands Protects underlying tissues Helps regulate body temperature Houses a variety of sensory receptors Synthesizes certain products

Organ Systems Skeletal System Includes, bones, ligaments, and cartilage Provides a framework Protects softer tissues Serves as a place of attachment for muscles Produces blood cells and stores inorganic salts in tissues within bones

Organ Systems Muscular System Includes muscles Provides forces that move body parts (through contracting) Helps maintain posture Provides main source of body heat

Organ Systems Nervous System Includes the brain, spinal cord, nerves, and sense organs How the system works: Nerve cells within the organs use electrochemical signals (called nerve impulses) to communicate with each other and with muscles and glands Some nerve cells act as specialized sensory receptors that detect changes occurring within and outside the body Other nerve cells receive impulses transmitted by the sensory nerve cells and act on the information Still other nerve cells carry impulses from the brain or spinal cord to the muscles or glands , stimulating them to contract or to secrete specific product The effect of the nerve impulse is relatively short-term

Organ Systems Endocrine System Includes all the glands that secrete hormones (chemical messengers), including the pituitary gland, thyroid gland, parathyroid gland, adrenal gland, pineal gland, pancreas, ovaries, testes, and thymus How the system works: Hormones travel away from the glands in body fluids (such as blood) or tissue fluids Usually the hormone will only affect a specific group of cells called target cells The hormone affects the metabolism of the target cells Effect of the hormone lasts for a long period of time

Organ Systems Cardiovascular System Includes the heart, arteries, capillaries, veins, and blood How it works: Heart pumps blood through blood vessels Blood transports gases, nutrients, hormones, and wastes Carries oxygen from the lungs to all body cells Carries nutrients from the digestive organs to all cells in the body Transports hormones from endocrine glands to target cells Carries wastes from body cells to the excretory organs

Organ Systems Lymphatic System Includes lymphatic vessels, lymph fluid, lymph nodes, thymus, and spleen Transports tissue fluid back into the blood stream Carries certain fatty substances away from the digestive organs Defends the body against infection by removing pathogens from tissue fluid (carried out by cells called lymphocytes)

Organ Systems Digestive System Includes the mouth, tongue, teeth, salivary glands, pharynx, esophagus, stomach, liver, gallbladder, pancreas, small intestine, and large intestine Breaks down food molecules into simpler forms that can pass through cell membranes and be absorbed into the internal environment Transports unabsorbed materials outside Some digestive organs can also produce hormones

Organ Systems Respiratory System Includes the nasal cavity, pharynx, larynx, trachea, bronchi, and lungs Takes air in and out Exchanges gases between the blood and the air Oxygen passes from air within the lungs into the blood Carbon dioxide leaves the blood and enters the air

Organ Systems Urinary System Includes the kidneys, ureters, urinary bladder, and urethra How it works: Kidneys remove wastes from the blood and assist in maintaining the water and electrolyte balance of the body, resulting in urine Urine is stored and transported out of the body

Organ Systems Reproductive System Male reproductive system includes the scrotum, testes, epididymides, ductus deferentia, seminal vesicles, prostate gland, bulbourethral glands, urethra, and penis These structures produce, maintain, and tranfer spermatozoa Female reproductive system includes the ovaries, uterine tubes, uterus, vagina, clitoris, and vulva. These structures: Produce, maintain, and transfer ova Supports the development of embryos Carry a fetus to term Function in the birth process