Bell Ringer: 8.20.2012 Identify the directional term that corresponds with each phrase below a. towards the feet b. towards the outside c. closer to point of attachment d. towards the front

Orientation to the Body! Chapter 1 Notes Orientation to the Body!

Complementarity of Structure and Function Principle What a structure can do depends on its specific form. ex. Bones support and protect because they contain hard mineral deposits. ex. Blood flows in one direction because of valves in heart ex. Lungs are site of gas exchange because the walls of air sacs are extremely thin.

General Organization of Body Axial Portion - head, neck, trunk Appendicular Portion - arms & legs 1. Several body cavities 2. Layers of membranes within cavities 3. Variety of organs and organ systems within cavities (VISCERA = internal organs. "Visceral organs")

Levels of organization

Necessary Life Functions Maintain boundaries- internal environment is separate from external Movement- all activities by muscular system Responsiveness- ability to sense changes Digestion- breaking down food Metabolism- all chemical reactions in body Excretion- removing wastes from body Reproduction- growth and repair and reproduction of organism as a whole Growth- increase in size of body part or cell

Survival Needs Ultimate Goal: Maintaining life! Nutrients-macromolcules Oxygen-chemical reactions are oxidative Water- 60-80% of body weight Appropriate temperature-chemical reactions Atmospheric pressure-breathing depends on appropriate atmospheric pressure and in appropriate amounts Homeostasis-maintaining stable internal conditions

Homeostasis Ability to maintain relatively stable internal conditions even though the outside world changes continuously. Communication is essential for homeostasis. This is accomplished chiefly by the nervous and endocrine systems (electrical impulses or hormones).

Negative Feedback Mechanism The results of the response depress the stimulus. These mechanisms cause the variable to change in a direction opposite to that of initial change returning it to its “ideal” value. Example: body temperature

Positive Feedback Mechanism The result or response enhances the orginal stimulus so that the activity is accelerated. Likely to race out of control, and so they are rarely used to promote the moement-to moment well being of the body. Example: child birth (oxytocin)

Homeostasis Posters! Choose one of the following functions your body performs and draw the diagram describing how your body maintains homeostasis for the variable. * be sure to include : the variable, receptor, control center and effector body systems affected organs/glands involved chemicals signals /hormones involved positive or negative feedback mechanism Choose from: Labor contractions Hyperthermia Blood volume Blood glucose Blood clotting Ovulation Heart rate Withdrawal reflex