Bones, Muscles and Skin Chapter 14-1 Human Body Bones, Muscles and Skin Chapter 14-1

Body Organization and Homeostasis Key Concepts: What are the levels of organization in the body What is homeostasis

Vocabulary Cell Cell Membrane Nucleus Cytoplasm Tissue Muscle Tissue Nervous Tissue Connective Tissue Epithelial tissue Organ Organ System Homeostasis Stress

Lunch in the cafeteria The bell rings you hurry down the hall to the cafeteria You smell hot pizza, and nachos this makes your mouth water You get your food and balance your tray After you pay you look around for your friends You walk over, sit down, and eat Think about how many body parts were involved in this simple act of getting and eating your lunch

Organization The levels of organization in the human body consist of cells, tissues, organs and organ systems Smallest unit of organization-CELL Next largest unit-TISSUE, then Organs Largest unit of organization-ORGAN SYSTEM

Cells Basic unit of structure and function in a living thing is a cell The structure of most animal cells/including the human body are cell membrane, nucleus and cytoplasm The human body is made up of trillions of tiny cells

Function of Cells Cells carry on the processes that keep organisms alive They release energy for the bodies activities Grow and reproduce They get rid of waste products that result from these activities

Tissues Group of similar cells that perform the same function Four basic types of tissue Muscle Nervous Connective Epithelial

Muscle tissue Every movement you make depends on muscle tissue Muscle tissue can contract

Nervous tissue Enables you to see, hear and think Directs and controls, it carries electrical messages back and forth between the brain and other parts of the body

Connective Tissue Connects and supports parts of your body Bone tissue and fat are connective tissues

Epithelial Tissue Covers the surfaces of your body and lines your internal organs Some epithelial tissue such as your skin protects the delicate structures that lie beneath it Digestive system is lined with epithelial tissue which allows you to digest and absorb the nutrients in your food

Organs and Organ Systems What is an example of an organ? Stomach, heart, brain lungs An organ is composed of different kinds of tissue and performs a specific job Each organ is part of an organ system a group of organs that work together to perform a major function

Homeostasis When all the systems work together such as respiratory, digestive and circulatory they are maintaining a process called homeostasis The process by which an organisms internal environment is kept stable in spite of changes in the external environment

Maintaining Homeostasis Your body has various ways of maintaining homeostasis When you are too warm you sweat which helps to cool your body When you are cold you shiver-shivering occurs when your muscles contract and relax rapidly These processes help maintain homeostasis