Human Structure and Function Chapter 1.3

8 Necessary functions of life

Maintaining boundaries, movement, responsiveness, digestion, metabolism, excretion, reproduction, growth

Maintaining boundries

Internal environment stays separated from external by plasma membrane separating the intracellular and extracellular fluid, Integumentary system(skin) encloses body as a whole

Movement

Activities promoted by the muscular system, the skeletal system provides the framework muscles must work with, all systems involved must move substances through each other, contractility: cells shortening to allow movement

Resposiveness

ability to sense changes and respond, the nervous system is most involved with highly excitable nerve cells

Digestion

Breaking down of ingested foodstuffs into molecules that can be absorbed into the blood, nutrients distributed by the cardiovascular system to body cells

Metabolism

Chemical reactions in body cells(catabolism, anabolism, cellular respiration), the digestive and respiratory systems provide nutrients to blood, cardiovascular distribute to body

Excretion

Removing waste, must get rid of useless substances after digestion/metabolism, digestive system rids indigestible food, urinary system disposes of metabolic waste

Reprodcution

cellular and organismal level, cellular reproduction: cells divide, reproductive system's main job, eggs and sperm division of labor

Growth

Increase in size of a body part or organism as a whole, through an increase in cell amount or cell size, constructive activities must happen more than destructive ones

5 Survival needs required for life

Nutrients, Oxygen, Water, Normal Body temperature, Appropriate atmospheric pressure

Nutrients

gathered by eating, have chemical substances used for energy and cell building(carbohydrates, vitamins, minerals, fat)

Oxygen

Chemical reactions that release energy are oxidative(needs oxygen), respiratory and cardiovascular systems make oxygen available for blood and body cells

Water

Most abundant chemical substance in the body, provides watery element for chemical reactions and fluid base for body secretions and excretions

Normal Body Tempature

Needs to be maintained to have chemical reactions, as temp drops below 37°C metabolic reactions slow then stop, temp too high chemical reactions happen frantically

Appropriate Atmospheric Pressure

Force that air exerts on the surface of the body, breathing and gas exchange in the lungs depend on appropriate atmospheric pressure