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Chapter 15, Section 1
Body Organization and Homeostasis
Wednesday, January 27, 2010
Pages 472 -- 479
Objectives
Identify the levels of organization in the body.Identify and describe the four basic types of tissue in the human body.Define homeostasis and describe its importance to the body.
Vocabulary Words
CellCell membraneNucleusCytoplasmTissueMuscle tissueNerve tissue
Connective tissueEpithelial tissueOrganOrgan systemHomestasisStress
Levels of Organization
The levels of organization in the human body is made up of cells, tissues, organs, and organ systems.
Smallest is the cell.Largest is the organ system.
Cells
Basic unit of structure and function in a living thing.Carry on the processes that keep organisms alive.Inside the cells, molecules from digested food undergo chemical reaction that provide energy.Cells get rid of waste products, grow and reproduce.
Tissues
A group of similar cells that perform the same function.The human body contains four basic types of tissue.
Muscle tissueNerve tissueConnective tissueEpithelial tissue
Muscle Tissue
Muscle tissues can contract or shorten.
This makes parts of your body move.
Nerve Tissue
Carries messages back and forth between the brain and every other part of the body.
The brain is made up mostly of nerve tissues.
Connective Tissue
Provides support for your body and connects all its parts.Examples include:
Bone -- supports the body and protects the internal organs.Fat -- pads parts of the body, provides insulation, and stores energy.
Epithelial Tissue
Covers the surfaces of your body, inside and out.Serves as a layer of protection.Absorb or release substances such chemicals used in digestion.
Organs and Organ SystemsAn organ is a structure that is composed of different kinds of tissue.An organ performs a specific function.Its job is more complex than that of tissues.Each organ in the body is part of an organ system.An organ system is a group of organs that work together to perform a major function.
Circulatory System
Carries needed materials to the body cells.Carries wastes away from body cells.Helps fight disease.
Digestive System
Takes food into the body.Breaks food down.Absorbs digested materials.
Endocrine System
Controls many body processes -- such as the intake of sugar by cells -- by means of chemicals.
Excretory System
Removes wastes.
Immune System
Fights disease.
Muscular System
Enables the body to move.Moves food through the digestive system. Keeps the heart beating.
Nervous System
Detects and interprets information from the environment outside the body and from within the body.Controls most body functions.
Reproductive System
Produces sex cells that can unite with other sex cells to create offspring.Controls male and female characteristics.
Respiratory System
Takes oxygen into the body and eliminates carbon dioxide.
Skeletal System
Supports the body, protects it, and works with muscles to allow movement.Makes blood cells and stores some materials.
Skin
Protects the body.Keeps water inside the body.Helps regulate body temperature.
Homeostasis
Body’s tendency to keep an internal balance.
Systems of the body working together.
It is the process by which an organism’s internal environment is kept stable in spite of changes in the external environment.
Stress and Homeostasis
Stress is the reaction of your body and mind to threatening, challenging, or disturbing events.
Pupils of eyes widen totake in more light.
Heart rate increases.
Digestive Systemslows.
More blood goes to the brain.
Hearing ability increases.
Sweating increases.
Muscles tense. Blood receives more energy-producing substances. Body cells release energy faster.
Physical Responses to StressThe body will respond within seconds after experiencing stress.
This is called the alarm stage.
The body will release a chemical called adrenaline into the bloodstream.
Adrenaline
Adrenaline gives a boost of energy and causes changes in the body.Adrenaline prepares the body to take quick action.
Breathing quickens and sends more oxygen to the body cells to provide energy for the muscles.The heart will beat faster and increases the flow of blood.
Fight or Flight
This is the reaction caused by adrenaline.The body prepares you to either fight the stressor or to take flight and escape.The body system will work together to respond to the stressor
Homework
Workbook 15.1 (1/29)Vocabulary quiz 15.1 (1/29)