More on Chapter 1 A&P

Necessary Life Functions Maintain boundaries Move Respond to environmental changes Take in and digest nutrients Carry out metabolism Dispose of wastes Reproduce themselves Grow

Maintaining Boundaries The “inside” remains distinct from the outside. The integumentary system or skin is responsible for this function. Protects internal organs from: Drying out From bacteria and infection From the environment damaging effects of heat sun chemicals

Movement Propelling ourselves from one place to another by walking, swimming, etc.. Also by manipulating the external environment with our fingers All systems provide movement How do you think that is possible? Digestive Cardiac Urinary Respiratory

Responsiveness Ability to sense change or stimuli in the environment and react to them. Nervous system is the main system responsible for responsiveness Nerve cells are highly irritable Communicate with each other thru electrical impulses

Digestion Breaking down food into simple molecules that can be absorbed into the blood for delivery to all body cells. The digestive system is primarily responsible for this function.

Metabolism Chemical reactions that occur within the body cells Breaking down complex substances into simpler building blocks, makes larger structures from smaller ones, uses nutrients and oxygen to produce ATP (ATP powers cellular activities) Digestive System, Respiratory and Endocrine Systems primarily responsible. The hormones secreted by endocrine system are primarily responsible for metabolism

Excretion Removal of wastes from the body. Eliminates the non useful substances produced during digestion and metabolism. Digestive system & urinary system are primarily responsible for excretion

Reproduction Producing offspring. Can be cellular in nature, or organismal. Primarily organ system is the reproductive system.

Growth Increase in size. Cellular in nature. Cell construction must be faster then cell destruction.

Survival Needs Nutrients – energy and cell building Oxygen – needed for chemical reactions to occur Water – we are 60% - 80% water. Must abundant chemical in the body. Body temperature – necessary for metabolism to occur. Atmospheric pressure – force exerted on the surface o the body by the weight of air.

Homeostasis The ability of the body to maintain relatively stable internal conditions even though the outside world is always changing. It is the “balance” of the body. Most directly influenced by the endocrine and nervous systems. Receptors – sensor that monitors and responds to change Control center – determines the set point and response Effector – means for the controls center response to the stimuli