Organ Systems - Quick Reference

Definitions and Concepts

Organ: a structure made up of two or more kinds of tissue organized to perform a more complex function than any tissue alone.
Organ system: a group of organs arranged to perform a more complex function together.

Structure: Skin (the only organ); appendages include hair, nails; sense receptors; sweat and oil glands.
Functions: Protection; regulation of body temperature; synthesis of chemicals; sense organ.

Structure: Bones; joints.
Functions: Support; movement (with joints and muscles); storage of minerals; blood cell formation.

Structure: Muscles; types include voluntary/striated; involuntary/smooth; cardiac.
Functions: Movement; maintenance of body posture; production of heat.

Structure: Brain; spinal cord; nerves; sense organs.
Functions: Communication to and from organs; integration of body functions; control; recognition of sensory stimuli.
Characteristics: Nerve impulses; fast-acting and of short duration.

Structure: Pituitary gland; pineal gland; hypothalamus; thyroid; parathyroid; thymus; adrenal glands; pancreas; ovaries (female); testes (male).
Functions: Secretion of hormones into the blood (ductless); slower but longer-lasting control; communication, integration, control.

Structure: Heart; blood vessels (arteries, veins, capillaries).
Functions: Transportation of blood (oxygen, carbon dioxide, nutrients, hormones) around a closed circuit; regulation of body temperature; immunity.

Structure: Lymphatic vessels; lymph nodes; tonsils; thymus; spleen; red bone marrow.
Functions: Transportation; immunity (body defense).

Structure: All of the body’s defense systems.
Functions: Protects from disease-causing microorganisms and toxins; helps respond to irritants and injuries.

Structure: Nose; pharynx; larynx; trachea; bronchi; lungs; alveoli.
Functions: Inhalation of oxygen; gas exchange (CO₂ and O₂) in alveoli; warming and humidifying incoming air; filtration of irritants; regulation of acid-base balance.

Structure:
- Primary organs: Mouth; pharynx; esophagus; stomach; small intestine; large intestine; rectum; anal canal.
- Secondary (accessory) organs: Teeth; salivary glands; tongue; liver; gallbladder; pancreas; appendix.
Functions: Mechanical and chemical breakdown of food; absorption of nutrients; elimination of waste (feces).
Notes: Appendix is a structural but not a functional part of the digestive system; appendicitis is inflammation of the appendix.

Structure: Kidneys; ureters; urinary bladder; urethra.
Functions: Cleansing of blood; excretion of waste as urine; electrolyte balance; water balance; acid-base balance.
Note: In males, the urethra also has reproductive functions.

Structure:
- Male: Testes; vas deferens; urethra; prostate; scrotum; penis.
- Female: Ovaries; uterus; uterine (fallopian) tubes; vagina; vulva; mammary glands.
Functions: Survival of genes; production of sex cells (sperm/ova); transfer and fertilization of sex cells; development and birth of offspring; nourishment of offspring; production of sex hormones.

Focus: How each system and its organs relate to the body as a whole.
Homeostasis: Relative constancy of the internal environment; no single system operates completely independently of others.
Note: Refer to framework of holistic physiological integration (Table 5-1).