Zoology Notes: 008 Unit 2

Unit 2 An organ is composed of tissues integrated to perform common functions. An organ system is a group of organs that work together to provide the organism with some necessity for survival. The system is the basis for the general structural plan of the body. The integumentary system is made up of the skin and, as a system, includes the hair, nails, and glands. Its primary functions are temperature and water regulation, insulation of the body from various environmental hazards, and sensation. The skeletal system is composed of bones and the cartilaginous and membranous structures associated with them. This system primarily protects and supports the soft parts of the body and supplies leverage for body movement. The muscular system is composed of muscles, with fasciae, tendon sheaths, and bursae. The chief function of the muscular system is to contract and facilitate movement of the organism. The digestive system includes the alimentary tract, with its associated glands. It extends from the lips to the anus. This system converts food into absorbable substances and eliminates waste products from the body. The respiratory system is composed of the air passages from the nose to the lungs. It is involved in gaseous exchange allowing the absorption of oxygen into the body and the elimination of carbon dioxide from the blood. The heart, the blood vessels and the blood make up the circulatory system. This system circulates nutrients to the different parts of the body and is also involved in bringing waste products to the appropriate organs for elimination. The urinary system is composed of the kidneys, the ureters, the urinary bladder, and the urethra. Its chief function is the formation and elimination of urine. The reproductive system consists of the gonads (the testes and the ovaries), the different glands, and structures involved in the production of progeny. Its main purpose is to ensure the perpetuation of the species. The nervous system consists of the brain, the spinal cord, cranial nerves, pripheral nerves, and sensory and motor terminals. It is the coordinating and controlling system of the body, intimately connected with other systems and with the outside world. The endocrine system includes the different glands that secrete hormones. It is primarily involved in the chemical regulation of body functions.

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