Level of Organization Notes PDF

Level of Organization cells -> tissue -> organs -> organ system Cells - smallest unit of all living things Tissues - group of similar cells having the same function Organs - structure composed of tissue types that perform a specific function for the body Organ System - group of organs that work tog...

Level of Organization cells -> tissue -> organs -> organ system Cells - smallest unit of all living things Tissues - group of similar cells having the same function Organs - structure composed of tissue types that perform a specific function for the body Organ System - group of organs that work together to accomplish a common purpose Integumentary System: (Skin) - external covering of the body Function: - protects the body - waterproofs the body - cushions deeper tissues - excretes salt and urea in perspiration - cools down skin through perspiration Skeletal System: (bones) - consists of bones, cartilages, ligaments, and joints Function: - give structure to the body - supports the body - provides the framework that the skeletal muscles use to cause movement Muscular System: (muscles) - contains muscles Function: - contract or shorten to produce movement - mobility of the body as a whole reflects the activity of skeletal muscles Nervous System: (brain) - control center of the body Function: - for the body to be able to react to irritants/stimuli from outside the body and inside the body Endocrine System - contains body activities (organs releasing hormones) Function: - produces hormones, then releases them into the blood - include pituitary, thyroid, parathyroids, adrenals, thymus, pancreas, pineal, ovaries (female), testes (male) Release of Hormones: - for metabolism - growth - emotion and mood control - sleep - break down of food - get energy from nutrition Cardiovascular System (heart) Function: - using blood as the transporting fluid, the cardiovascular system carries oxygen, nutrients, hormones, and other substances Lymphatic System (lymph nodes) Function: - lymphatic vessels return fluid leaked from the blood back to the blood vessels so that blood can be kept continuously circulating through the body Respiratory System (lungs) Function: - keep the body constantly supplied with oxygen and remove carbon dioxide - gases are transported to and from the blood through the think walk of these air sacs Digestive System (stomach) Function: - break down food and deliver the products to the blood for dispersal to the body cells - undigested food that remains in the tract leaves the body through the anus as feces Urinary System (kidneys) Function: - maintain the body’s salt and water balance, regulate acid-base balance of the blood Reproductive System (female - ovaries, male - testes) Function: - exists primarily to produce offspring to ensure the survival of human species - female: to produce egg cells and to protect and nourish the offspring until birth - male: to produce and deposit sperm