B I G I D E A S

3.0B I G I D E A

Your health depends on the effective functioningof your interdependent organ systems.

If you have ever experienced any kind of stress, youwould know from your natural response to it that yourorgan systems work together as a whole. In other words,your organ systems are interdependent. For example, oneof the immediate effects of stress is that your musclesbecome tense. This can trigger the heart, part of yourcirculatory system, to beat faster, so it pumps blood morequickly to the surface of the skin. As a result, you feelwarmer or even flushed. Tense muscles over a period of time can also lead to aches, pains, and exhaustion.

Scientists have collected much experimental evidencethat your reaction to stress affects your health in manyways. Some forms of stress, such as doing somethingexciting or trying out a new game, can be fun andthrilling. This stress can help prepare your body toperform at its best. Other forms of stress can be unpleasant, such as being nervous in new surroundings or situations. Your reaction to stress can cause nausea or stomach pain, or result in emotional problems.

Interdependence of systems is viewed in a broader way in Indigenous Knowledge. Good health is when your mind, heart, body, and spirit are in balance (mental, emotional, physical, and spiritual harmony). See Elder Velma Goodfeather’s message on page 58.

3.1 A Look Inside

How do you feel when you are tense? What about when you arerelaxed? What are the physical, mental, emotional, and spiritualeffects when you feel tense or relaxed? Try the exercises on thenext page to find out.

43Unit 1 Cells, Tissues, Organs, and Systems©P

Do you think these people are experiencing stress?

physical

mental

spiritual

emot

iona

l

The medicine wheel indicates theconnections and interactionsbetween mental, emotional, physical,and spiritual aspects of a person’sbeing. There are many ways ofrepresenting the medicine wheel.

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44 3.0 Your health depends on the effective functioning of your interdependent organ systems. ©P

A

B

C

D

E

Sit so that you feelcomfortable. Close youreyes and breathe slowlyand rhythmically. Focusyour attention on thesound of your breathing.Now, curl the toes of yourleft foot as tightly as you can. Hold for 3 s, then slowly let them relax.Slowly draw your footupward, hold for threeseconds, and then let itdown to the floor again.Keep breathing slowly.Now, repeat this with your right foot.

Tighten the muscles in your left leg and hold for 3 s. Then, relax your leg. Keep breathing slowly. Repeat this with your right leg.

Push your belly out asfar as you can, and holdfor 3 s. Pull it in as faras you can, hold for 3 s,then relax. Take slow,rhythmical breaths. Pullyour shoulders up towardyour ears as if you wereshrugging. Hold for 3 s, then relax. Keepbreathing slowly.

Push your lips out and squeezeyour eyes shut as tightly as youcan. Hold for 3 s, then relax.Open your eyes and mouth aswide as you can—as if you were screaming silently. Hold for 3 s, then relax.

Clench your left hand in a tight fist, hold for 3 s, then relax.Stretch your fingers apart as far as you can, hold for 3 s,then relax. Repeat with your right hand.

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D E V E L O P

How Your Body Is OrganizedMany parts of your body were involved in the exercises you justcompleted. These included your skin, your bones, your heart,your lungs, your mouth, and your stomach. What other examplescan you think of? Think back to Health Education and Scienceclasses that you did in earlier years. When scientists investigatehow your body works, they find that none of your body partsfunctions on its own. Each part is an organ, a particulararrangement of tissues that has a special function. A group oforgans form a body system, called an organ system. The organsthat make up each organ system work together to perform acertain task or function.

Scientific studies allow a complex function to be brokendown into the simpler workings of its parts. Each part must work well for the function to work well. For example, when youeat an apple, the organs of your digestive system work together to break down the food to supply your body with the energy and nutrients you need to survive. Afterward, your digestivesystem helps your body remove any unused material as waste.The digestive process allows the cells in your body to get theenergy they need and eliminates harmful waste materials. Thefollowing tables describe some of your body’s organ systems.

Circulatory System

Circulatory System

45Unit 1 Cells, Tissues, Organs, and Systems©P

Structures Function Factors That Help Functioning

heart, blood, arteries, veins

• transport oxygen, food, andother substances throughout the body

• transport some wastes to otherorgans for elimination

• defend the body againstdiseases

• connect all other organ systems

• arteries that are clear ofcholesterol

• exercise

arteries = redveins = blueRed blood cells

heart

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46 3.0 Your health depends on the effective functioning of your interdependent organ systems.

The digestion of food begins in your mouth.

Respiratory System

Digestive System

Structures Function Factors That Help Functioning

nose, mouth,trachea,bronchi,lungs

• transport oxygen from theoutside air to the blood

• transport carbon dioxide fromthe blood to the outside air

• keep structures clear of harmfulpollutants (such as tar from cigarette smoke)

• keep free from colds

Structures Function Factors That Help Functioning

mouth, esophagus, stomach, liver, intestines

• break down food pieces intomuch smaller pieces (particles)so they can be absorbed andtransported throughout the body

• remove unused materials fromfood out of the body as waste

• balanced diet

• water

nose

mouth

trachea

lungs

bronchi

mouth

esophagus

liver

stomach

intestines

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47Unit 1 Cells, Tissues, Organs, and Systems

The brain controls your nervous system.

Structures Function Factors That Help Functioning

brain, spinal cord,eyes, ears, and othersense organs(hand, nose, etc.)

• co-ordinate and control theactions of all organs and organ systems

• detect, process, and respond to changes in external andinternal environment

• enough rest

• no stimulants or depressants

Nervous System

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Structures Function Factors That Help Functioning

kidneys, bladder,lungs, skin

• remove chemical and gaseouswastes from the blood

• water

• balanced diet

Excretory System

brain

spinal cord

nerve

kidney

kidney

bladder

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Working Together for HealthAll your organ systems work together as a single unit for a commonpurpose: to support and maintain your life. This idea of workingtogether as a unified, purposeful unit goes even deeper thansystems. Each of your body’s systems contains organs. The organsthat make up each system work together to perform a certain taskor function. For example, the organs that make up your respiratorysystem work together to provide your body with the oxygen itneeds, while ridding it of carbon dioxide. All of your organs supportand maintain the healthy functioning of the system of which theyare a part. The organs work in harmony for a healthy system.

As you already learned, there are four types of tissues inhumans and each human organ is made up of a group of tissuesthat work together. For example, your heart is made up ofconnective tissue (to hold its shape together), muscle tissue (tohelp it to move), and nerve tissue (to co-ordinate its movement).Different organs are composed of different kinds and amounts oftissues. It all depends on the role (or function) that the organ serves.

48 3.0 Your health depends on the effective functioning of your interdependent organ systems. ©P

A Close Association

Most people know that drinkingalcohol when you are pregnantcan harm your baby. But do youknow why this happens? Whena pregnant woman has analcoholic drink, the alcoholpasses from the mother into the unborn baby’s (fetus’s)bloodstream. Once inside thefetus, the alcohol can damageor destroy developing cells,including brain and spinal cord cells. The effects of thisdamage can include birthdefects such as odd facialfeatures, growth problems, andlearning and behaviour problems.

i n f oBIT

Cells are the buildingblocks of all organisms.

Examples in plantsExamples in animals

nerves

shoot system

rootsystem

brain

nervoussystem

Tissues are clumps ofsimilar cells working

together in the same way.

Organs are groups oftissues working together.

Systems are groups oforgans working together.

Every tissue in your body is made up of a group of smaller units,the cells. These cells work together for a particular function andeach kind of cell suits its role in the body. For instance, musclecells can stretch and snap back into shape. Cells are the smallestknown functioning units of life. That is why scientists say thatthe cell is the most fundamental or basic unit of all living things.

Cells form tissues, which form organs.

cell = an individualunit of life

tissue = a group of specialized

cells

organ = a group of

tissues thatperform a

special function

Body systems are made up of thesethree types of structures.

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1 a) Which of your organ systems were you aware of duringthe stress-relieving exercises you did at the beginning ofthis section?

b) Which of your organ systems do you think were actuallyinvolved during the exercises? Provide details to supportyour answer.

2 Demonstrate understanding of the relationship among theseterms: organ system, organ, tissue, and cell. Use words,diagrams, flow charts, or a combination of these tocommunicate your ideas.

3 Re-examine the organ system diagrams on pages 45–47.a) Does any one system seem to be more important than

any of the others? Explain your answer.b) Do you think you could stay healthy if any of these systems

were damaged, diseased, or missing? Why or why not?c) For one of the systems, suggest another factor that might

affect the way it functions.d) What does the title “Working Together for Health” mean

to you?

3.2 Close-up of the Circulatory System

Following are some early ideas about the circulatory system and itsmain organ, the heart. Today, after about 350 years of investigation,we know that only one of these early ideas is accurate. One ispartially accurate. The rest have been shown to be incorrect. Do you know, or can you figure out, which is which?

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