Chapter 14: Bones, Muscles and Skin

Section 1: Body Organization and Homeostasisp. 468 – p.473

Body Organization

• How the body systems work together to keep you alive

Levels of Organization in the Body

• The levels of organization in the human body consist of:

– Cells – the basic unit of structure and function in living things

– Tissues – a group of similar cells that work together to perform the same function

– Organ – A structure in the body that processes materials necessary for the body to survive

– Organ system – A group of organs that work together to perform a major function in the body

– Organism – A complete, living thing

homeostasis

• Our internal environment stays the same in spite of changes on the outside

• Keeping things in balance

Homeostasis

• The maintenance of stable internal condition in an organism even when the outside environment changes

• Like body temperature• Sugar • Iron• Calcium

Cell

• The basic unit of structure and function in a living things.

• A human being contains 100 trillion cells.

Cell Membrane

• The cell membrane forms the outside boundary of the cell.

• It is picky about what it allows into and out of the cell.

• One could say, “It is selectively permeable.”

Nucleus

• It is the control center of the cell.

• It directs all the cell’s activities.

• It contains the information that determines the cell’s form and function.

Cytoplasm

• The material within the cell apart from the nucleus. The clear, jellylike substance containing the cell’s structures and organelles.

Tissue

• A group of similar cells that perform the same function. The human body contains four basic types of tissue:– Muscle Tissue– Nervous Tissue– Connective Tissue– Epithelial Tissue

Muscle Tissue

• Muscle tissue can contract or shorten.

• By doing this, muscle tissue makes parts of your body move.

Nervous Tissue

• Nervous tissue carries electrical messages back and forth between the brain and other parts of the body.

• It controls the brain messages and responses from the brain.

Connective Tissue

• Connective tissue provides support for your body and connects all its parts.

• Bone tissue and fat are connective tissues.

Epithelial Tissue

• The surfaces of your body, inside and out are covered by epithelial tissue.

• Some epithelial tissue, such as your skin, protects the delicate structures that lie beneath it.

• The lining of your digestive system consists of epithelial tissue that allows you to absorb the nutrients in your food.

Organ

• An organ is a structure that is composed of different kinds of tissue.

• Your stomach, heart, brain and lungs are all organs.

• An organ performs a specific job.

Organ System

• Each part of your body is part of an organ system.

• An organ system is a group of organs that work together to perform a major function to sustain the body.

• Check page 471 in your textbook

Stress

• The reaction of your body to potentially threatening, challenging, or disturbing events.

Summary

• What information was helpful to me?• Is there something interesting that I

may look back at in this section?