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Growth andDevelopment
“In my work
what I try to
say is that
as human beings
we are more
alike than we
are unalike.”
—Maya Angelou,American novelist
and poet
Talented TeensDiscuss Many children now have opportunities to
learn new skillsat an earlier age than ever before. But some argue
that pushing achild to excel can be harmful. Research two or three
talented teens(for example, Olympic athletes, musicians, or
actors). Were theiropportunities positive or negative, or a
combination of both? Discussyour findings with your class as part
of an oral report.
TEST YOUR GROWTH IQTrue or False?
1. Heart disease can begin todevelop during childhood.
TRUE: Although the symptoms ofheart disease do not usually
appearuntil middle age or older, one in sixteenagers has
well-developedplaque deposits in their arteries.
2. Shaking a baby is a good way to stop him or her from
crying.
FALSE: A baby’s neck and brain are fragile and damage
easily.Because neck muscles are weak,shaking a baby can result in
blind-ness, brain damage, or even death.
3. People with learning disabilitiescannot be successful.
FALSE: There have been many suc-cessful people who have had
learn-ing disabilities. For instance, ThomasEdison had dyslexia. He
and manyothers had significant accomplish-ments despite their
disabilities.
206 UNIT 4 • Growth and Development
LESSON 19Keeping Your Body Healthy
LESSON 20Learning About the
Reproductive Systems
LESSON 21Learning About Pregnancy
and Childbirth
Christopher Felver/CORBIS
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Visit www.glencoe.com to find regularly updated statistics on
U.S. lifeexpectancy. Using the information provided, determine the
answer to thisquestion: How has U.S. life expectancy changed in the
last 50 years?
Visit www.glencoe.com to use , an inter-active tool that helps
you determine your health status.
LESSON 22Caring for Infants and Children
LESSON 23Developing Learning and
Planning Styles
LESSON 24Aging Healthfully
UNIT 4 • Growth and Development 207
WHAT’S YOUR VERDICT?To evaluate this advertisement, use the
criteria for analyzing and evaluating healthmessages delivered
through media and technology that you learned in Unit 1.
EVALUATING MEDIA MESSAGES
CORBIS
http://www.glencoe.comhttp://www.glencoe.com
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Keeping Your Body Healthy
• I will keep my body systems healthy.
Your body is made of cells, tissues, and organs that form body
systems. A cell is the smallest living part of the body. An organ
is abody part consisting of several kinds of tissue that do
particularjobs. A body system is a group oforgans that work
together to performa main body function. This lessonwill help you
review informationabout body systems and whatyou can do to keep
thesebody systems healthy.
What You’ll Learn1. Identify behaviors to keep your
cardiovascular, nervous, andimmune systems healthy.(pp. 210,
213, 214)
2. List behaviors important to thehealth of your
respiratory,skeletal, and muscular systems.(pp. 215, 216, 217)
3. Identify behaviors important tothe health of your
endocrineand digestive systems. (pp. 219,221)
4. List behaviors important to thehealth of your
integumentaryand urinary systems. (pp. 223,224)
Why It’s ImportantThink about a car. Many partsneed to work
together to keep itrunning well. Your body also hasmany parts that
make up yourbody systems, which need towork together to keep you
well.
Key Terms• cardiovascular system• nervous system• immune system•
respiratory system• skeletal system• muscular system• endocrine
system• digestive system• integumentary system• urinary system
MAK 1
Writing About Stretching Suppose one of your friends says she
isnot going to warm up and stretch before the big track meet. She
saysthat warming up wastes valuable energy that she could use for
running.After you read the information on the muscular system on
page 217,write a response to this situation in your health
journal.
208 UNIT 4 • Growth and Development
19
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LESSON 19 • Keeping Your Body Healthy 209
Blood Your blood carries nutrients,oxygen, carbon dioxide, and
cellularwaste products to and from your bodycells. The
average-sized adult body hasabout ten pints of blood. Blood is
com-posed of plasma and blood cells.Plasma is the liquid component
ofblood that carries blood cells and dis-solved materials. It is
about 95 percentwater. Plasma contains two majortypes of blood
cells—red blood cellsand white blood cells. Plasma also con-sists
of particles called platelets. Aplatelet is a particle that helps
theblood clot. Blood clots stop the bleedingwhen blood vessels are
injured.
A red blood cell transports oxy-gen to body cells and removes
carbondioxide from body cells. Red bloodcells contain hemoglobin.
Hemoglo-bin is an iron-rich protein that helpstransport oxygen and
carbon dioxidein the blood. New red blood cells areconstantly
produced in bone marrow,which is the spongy material insidesome
bones.
A white blood cell is a blood cellthat attacks, surrounds, and
destroyspathogens that enter the body andprevents them from causing
infection.
A pathogen is a germ that causesdisease. The number of white
bloodcells in your blood increases whenyou have an infection.
Blood vessels There arethree major types of
bloodvessels—arteries, veins,and capillaries. An arteryis a blood
vessel that car-ries blood away from theheart. Arteries havethick
muscular wallsthat move blood be-tween heartbeats.A coronary
ar-tery supplies nu-trients and oxygento the heart mus-cle. A
pulmonaryartery carries bloodfrom the heart to thelungs, where it
absorbsoxygen and releases car-bon dioxide.
StudiOhio
The body system that transports nutrients, gases, hormones, and
cellular waste products
throughout the body is the The cardiovascular system
consists
of the blood, blood vessels, and the heart.
What to Know About theCardiovascular System
cardiovascular system.
The cardiovascularsystem consists of
blood, arteries, veins,and the heart.
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A vein is a blood vessel that returnsblood to the heart. Veins
have thinnerwalls than arteries. A capillary is atiny blood vessel
that connects arter-ies and veins. Capillaries have thinwalls that
allow the transfer of nutri-ents, oxygen, carbon dioxide, and
cel-lular waste between the blood andthe body cells.
Heart A four-chambered muscle thatcontinually pumps blood
throughoutthe body is called the heart. Thetwo upper chambers are
atria. The
two lower chambers are ventricles.The heart is divided into the
rightatrium and ventricle and the leftatrium and ventricle. Blood
that ispoor in oxygen, returning from thebody, flows constantly
into the rightatrium and ventricle.
From the right ventricle, blood ispumped through the
pulmonaryartery to the lungs. Carbon dioxide isreleased and oxygen
is absorbed asthe blood circulates in capillariesaround the air
sacs in the lungs. Thisoxygen-rich blood flows into the leftatrium
and ventricle. Contractions ofthe left ventricle pump the
bloodthrough the aorta to the body. Theaorta is the main artery in
the body.The aorta branches into smallerarteries through which
blood flows toall parts of the body.
Heart rate is the number of timesthe heart contracts each
minute.Pulse is the surge of blood thatresults from the
contractions of theheart. Blood pressure is the force ofblood
against the artery walls.
How to Keep Your Cardiovascular System Healthy The following are
some of the ways you can keep your cardiovascularsystem
healthy:
• Reduce the amount of fat inyour diet.
• Reduce the amount of salt inyour diet.
• Exercise regularly to strengthenyour heart muscles.
• Avoid using tobacco productsbecause they increase blood
pressure.
• Maintain a healthful weight.
• Practice stress-managementskills
210 UNIT 4 • Growth and Development
Blood is pumpedfrom the right
ventricle of theheart through thepulmonary artery
to the lungs.
Pulmonary artery
Left ventricle
Left atrium
Pulmonary veins
Right atrium
Right ventricle
Aorta
Vena cava
Coronary arteries
1. Name and describethe parts of thecardiovascularsystem.
2. What is bloodpressure?
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LESSON 19 • Keeping Your Body Healthy 211
The most common type of heart diseas
e is coronary
heart disease, also referred to as coron
ary artery dis-
ease (CAD). There are two coronary art
eries that
branch from either side of the ascendin
g aorta at the
top of the heart. The coronary arteries
are the vessels
that supply the heart muscle with oxyg
enated blood.
With age, these arteries, which are nor
mally elastic,
harden and lose their elasticity. This con
dition is
known as arteriosclerosis (ar TEER ee
o skluh ROH
suhs). A form of arteriosclerosis, called
atherosclerosis
(a thuh roh skluh ROH suhs), involves
the buildup of
deposits within the coronary arteries.
As these deposits accumulate on the in
terior
walls of these vessels, the diameter of t
he arteries
decreases, restricting and blocking the
flow of blood to
the heart muscle. The effects of atheros
clerosis on the
coronary arteries results in CAD.
Cholesterol Excess cholesterol, whic
h comes from
foods we ingest, also is deposited in a
rteries. Although
some cholesterol is needed by the bod
y to make cell
membranes and some hormones, it is
needed only in
small amounts.
As the flow of blood to the heart is res
tricted, the
heart’s ability to pump effectively is re
duced. This can
lead to a condition called angina (an J
I nuh), in which
a person may feel pain in the chest, lef
t shoulder, and
left arm. Angina also can result in a he
art attack, in
which some of the heart muscle tissue
actually dies
from a lack of proper blood supply.
Symptoms of CAD These can range
from not hav-
ing any symptoms or discomfort at all
to shortness of
breath and fatigue,or to mild or severe
chest pain.
Risk factors Can the development of
CAD be
avoided? The risk factors for CAD includ
e: age, family
history of heart disease, high blood cho
lesterol, smok-
ing, high blood pressure, diabetes, ove
rweight/obesity,
and physical inactivity. Some of these f
actors, such as
age and family history, are not in your
control. Many
of the others can be controlled throug
h diet, regular
exercise, and controlling diabetes or ot
her relevant
medical conditions.
CAD is the leading cause of death for
both men
and women in America today. More th
an 13 million
Americans suffer from CAD. Practicing
positive health
behaviors, such as following a well-ba
lanced diet and
exercising regularly, can help reduce yo
ur risk of devel-
oping CAD later in life.
HEARTDISEASE
An electrocardiogram (ECG) is a graph
ic
representation of electrical impulses t
hat
reflect the action of the heart.
Visit www.glencoe.com to resear
ch more
information about coronary artery d
isease.
• How can risk factors, such as bloo
d choles-
terol levels, blood pressure, and weig
ht, be
controlled?
• What effect does stress have on th
e develop-
ment of CAD?
• What role, if any, does gender pla
y in the risk
of developing CAD?
Create a presentation that outlines he
alth behav-
iors that everyone in your family can
follow to
reduce the risk of CAD. In your present
ation, be
sure to address risk factors such as sm
oking,
physical inactivity,and high blood pre
ssure.
Mehau Kulyk/Science Photo Library www.glencoe.com
http://www.glencoe.comhttp://www.glencoe.com
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212 UNIT 4 • Growth and Development
The body system that carries messages to and from the brain and
spinal cord and all
other parts of the body is the . The nervous system is composed
of two
divisions—the central nervous system and the peripheral nervous
system.
What to Know About the Nervous System
nervous system
The consistsof the brain and spinal cord. The
is made
up of nerves that branch out from thecentral nervous system to
muscles,skin, internal organs, and glands. Yoursense organs
continually send mes-sages, such as odors, sights, or tastes,to
your brain through the peripheralnervous system. Your central
nervoussystem, in turn, relays responses tothese messages to your
muscles andglands as your body responds tochanges in your
environment.
Brain The mass of nerve tissue thatacts as the control center of
the bodyis called the brain. The human brainweighs about three
pounds and canstore more information than all thelibraries in the
world put together.Your brain creates ideas and controlsthinking,
reasoning, movement, andemotions. The brain has three
majorparts—the cerebrum, the cerebellum,and the brain stem.
The cerebrum is the largest part ofthe brain and controls the
ability tomemorize, think, and learn. The cere-brum also determines
a person’s intel-ligence and personality. It consists oftwo halves,
called hemispheres. Theright hemisphere controls the left sideof
the body, and the left hemispherecontrols the right side of the
body. Thecerebellum is the part of the brainthat controls and
coordinates muscleactivity. It also helps you maintainyour
balance.
peripheral nervous system
central nervous system
Aaron Haupt
Spinal cord
Brain
Brain stem
Cerebrum
Cerebellum
Nerves
Concussion A braininjury that sometimesresults in a loss
ofconsciousness is aconcussion. An impactcreates a suddenmovement
of thebrain within the skull.
The nervous system ismade up of the central
nervous system (thebrain and spinal cord)
and the peripheralnervous system
(nerves).
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Your ability to catch a ball is a func-tion of your cerebellum.
The brainstem is the part of the brain that con-trols the functions
of the internalorgans.
Spinal cord The column of nerve cellsthat extends downward from
thebrain is the spinal cord. Your spinalcord carries messages to
and fromyour brain and all parts of your body.It keeps your brain
informed ofchanges in your body and in yourenvironment. Your spinal
cord is pro-tected by your vertebrae.
Nerve cells The nervous system iscomposed of cells called
neurons. Aneuron is a nerve cell that is the struc-tural and
functional unit of the nerv-ous system. Some neurons in the
spinalcord may be several feet long. A neuronconsists of a cell
body, an axon, anddendrites.A cell body is the main bodyof the
neuron. An axon is an elongatedfiber that carries impulses away
fromthe cell body to the dendrites ofanother neuron. Dendrites
arebranching fibers that receive impulsesand carry them to the cell
body.
Sensory and motor neurons worktogether to help you respond to
yourenvironment. Sensory neurons carryimpulses from the sense
organs to thespinal cord and brain. Motor neu-rons carry responding
impulses tomuscles and glands from the brainand spinal cord. Motor
neurons causeresponses in muscles and glands.
Reflex action Have you ever touchedsomething hot and quickly
pulledaway from it? You experienced a reflexaction. A reflex action
is an involun-tary action in which a message is sentto the spinal
cord, is interpreted, and isresponded to immediately.
Sensory neurons carry the mes-sage that you touched a hot
surfaceto your spinal cord and brain. Yourbrain interprets the
message. Motorneurons carry the message back toyour muscles. You
respond by movingyour hand. Reflex actions do notinvolve conscious
thought and takeonly a fraction of a second. Reflexactions help
keep you safe.
How to Keep Your Nervous System HealthyThe following suggestions
will protect your nervous system:
• Wear a protective helmet forsports.
• Avoid diving into shallowwater or water of unknowndepth.
• Use a safety belt.• Follow directions for taking
any medications that affectthe nervous system.
• Avoid drinking alcohol andusing other drugs that impairthe
functions of the brain.
• Follow directions for usinghousehold products that con-tain
chemicals that may affectthe nervous system.
LESSON 19 • Keeping Your Body Healthy 213
Sensoryneuron
Motor neuron
Spinal cord
Receptor in skin
Direction ofimpulse
Reaction –muscle contracts
This person’s sensoryneurons sense that abowl that has
beenheating in a microwaveis hot. The person’smotor neurons cause
theperson’s hand to pullaway from the bowl.
1. What is thedifference betweenthe central nervoussystem and
theperipheral nervoussystem?
2. What is a reflexaction?
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How to Keep Your Immune System HealthyThe following are ways to
keep your immune system healthy:
• Choose foods that are high inprotein and vitamin B.
• Keep accurate records of allimmunizations.
• Get plenty of rest and sleep.• Exercise to keep bones
dense
and to protect bone marrow.
The immune system protects yourbody from pathogens. A pathogen
is agerm that causes disease. When whiteblood cells attack
pathogens, thepathogens are filtered into the lymph.Lymph is a
clear liquid that surroundsbody cells and circulates in lymph
ves-sels. Lymph carries harmful pathogensand other small particles
to lymphnodes. A lymph node is a structurethat filters and destroys
pathogens.The spleen is an organ on the left sideof the abdomen
that filters foreignmatter from the blood and lymph.
Immunity is the body’s resistance todisease-causing agents.
White bloodcells are formed in bone marrow andcirculate in the
blood. These whiteblood cells are changed to T cells withinthe
thymus gland. A T cell is a whiteblood cell that destroys
pathogens. A Bcell is another kind of specializedwhite blood cell
that produces antibod-ies. An antibody is a special proteinthat
helps fight infection.
The body system that removes harmful organisms from the blood
and combats
pathogens is the The immune system is composed of lymph,
lymph
nodes, lymph vessels, tonsils, the thymus gland, and the
spleen.
What to Know About the Immune System
immune system.
Make theConnection
Immune System Formore information onthe immune system,see page
485 inLesson 44.
214 UNIT 4 • Growth and Development(tt)Photodisc/Getty Images;
(cr)Aaron Haupt
Thymus gland
Lymph vessel
Lymph node
Spleen
The immune system protectsyour body from pathogens.
1. What is apathogen?
2. What is immunity?
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The body system that provides body cells with oxygen and removes
carbon
dioxide that cells produce as waste is the Air enters through
your nose or mouth when you
inhale. Mucus in the nasal passages and sinuses warms and
moistens the air and traps dust particles and
pathogens. Mucus is a thick secretion that moistens, lubricates,
and protects mucous membranes. A mucous membrane
is a type of tissue that lines body cavities and secretes
mucus.
What to Know About the Respiratory System
respiratory system.
Air moves from your nose or mouththrough your pharynx to your
trachea.The epiglottis is a flap that covers theentrance to the
trachea when you swal-low. When you inhale, the epiglottisopens and
air flows into the trachea.The trachea is a tube through whichair
moves to the bronchi and lungs.Thetrachea is lined with cilia.
Cilia arehairlike structures that remove dustand other particles
from the air.
The bronchi are two tubesthrough which air moves to the
lungs.The lungs are the main organs of therespiratory system. As
the bronchienter each lung, they branch to formbronchioles. The
bronchioles aresmall tubes that branch to form alve-oli. Alveoli
are microscopic air sacs.The walls of the alveoli are so thinthat
oxygen and carbon dioxide easilypass through them.
Two exchanges take place in thealveoli. Oxygen passes from the
alve-oli into your capillaries and carbondioxide passes from your
capillariesinto the alveoli. You exhale carbondioxide. Blood rich
in oxygen flowsfrom your lungs to your heart.
How to Keep Your Respiratory System HealthyThe following are
ways to keep your respiratory system healthy:
• Do not smoke.• Avoid breathing secondhand
smoke.• Do not inhale harmful drugs.• Avoid breathing polluted
air.
• Exercise regularly.• Avoid inhaling harmful
chemicals.• Seek medical help for respira-
tory infections.
LESSON 19 • Keeping Your Body Healthy 215(tt)CORBIS
Nasal cavity
Mouth
PharynxTrachea
Lungs
Larynx
Bronchiole
Alveoli
Epiglottis
The respiratory system providesbody cells with oxygen andremoves
carbon dioxide thatcells produce as waste.
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Bone is the structural material ofthe skeletal system.
Periosteum (peree AHS tee um) is a thin tissue thatcovers bone and
contains nerves andblood vessels. Bone marrow is softtissue in the
center of most boneswhere both red and white blood cellsare
formed.
Cartilage is soft, connective tis-sue on the ends of some bones.
It alsoacts as a cushion where bones meet,such as in the knee and
hip joint.Cartilage disks between vertebraeserve as shock
absorbers. A liga-ment is a tough fiber that connectsbones
together. A joint is the pointwhere two bones meet. There are
sev-eral types of joints in your body.
The body system that serves as a support framework, protects
vital organs, works with muscles to produce movement, and
produces blood cells is the
What to Know About the Skeletal System
skeletal system.
How to Keep Your Skeletal System HealthyThe following are ways
to keep your skeletal system healthy:
• Choose foods rich in calcium,phosphorus and vitamin D.
• Exercise to strengthen joints.• Wear protective equipment
and well-cushioned, properly
fitting shoes and warm upbefore exercising.
• Sit, stand and walk with cor-rect posture. Participate
inscreening for scoliosis.
216 UNIT 4 • Growth and Development(tt)Photodisc/Getty Images;
(cr)Yoav Levy/Phototake
The skeletalsystem servesas a supportframework foryour body.
1. List three functionsof the skeletalsystem.
2. What connectsbones?
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Muscles are divided into two majorgroups: voluntary and
involuntary. Avoluntary muscle is a muscle a per-son can control.
Muscles in your arms
and legs that help you move are vol-untary muscles. An
involuntarymuscle is a muscle that functionswithout a person’s
control. Muscles inyour stomach and other internalorgans are
involuntary muscles.
There are three types of muscle tis-sue in your body. Smooth
muscle isinvoluntary muscle tissue found inmany internal organs.
Skeletal mus-cle is voluntary muscle tissue that isattached to
bone. Cardiac muscle isspecialized muscle tissue found onlyin the
heart. It is unique from othermuscle tissue because of its
struc-ture. Contractions in cardiac musclesare generated by nerve
stimulation.
A tendon is tough tissue fiber thatattaches muscles to bones.
Skeletalmuscles work in pairs to move yourbody. One muscle in the
pair con-tracts and shortens, while the otherrelaxes and
lengthens.
How to Keep Your Muscular System HealthyThe following are ways
to keep your muscular system healthy:
• Discontinue exercise if youhave a muscle injury.
• Warm up and stretch beforeexercise.
• Exercise different musclegroups regularly.
• Maintain your desirableweight.
• Bend at the knees and keepyour back straight when lift-ing
heavy objects.
• Select foods and beveragescontaining carbohydrates andproteins
for energy and mus-cle development.
• Sleep on a firm mattress.
Frontalis
Pectoralis(chest muscle)
Sternocleidomastoid(neck)
Rectus abdominis(abdominal muscles)
Rectus femoris
Biceps femoris(back of thigh)
Biceps brachiiTriceps brachii
Sartorius
Quadriceps(front ofthe thigh)
Gastrocnemius(calf muscle)
Gluteus maximus
Latissimus dorsi
Deltoid
(The dotted lines are used for musclesthat are on the back side
of the figure
and can't be seen from the front.)
Muscles Musclesshorten and lengthenbecause of elasticityin
muscle fibers. Thisallows movement atthe joints.
The body system that consists of muscles that provide
motion and maintain posture is the
There are more than 600 muscles in your body.
What to Know About the Muscular System
muscular system.
LESSON 19 • Keeping Your Body Healthy 217(tt)CORBIS; (cl)Lori
Adamski Peek/Getty Images
The muscularsystem consistsof muscles thatprovide motionand
maintainposture.
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Pituitary gland The endocrine glandthat produces hormones, which
controlgrowth and other glands is the pitu-itary gland. The
pituitary gland islocated below the hypothalamus in thebrain and is
about the size of a pea.
Hormones from the pituitary glandinfluence growth, metabolism,
devel-opment of the reproductive organs,uterine contractions during
child-birth, and many other body functions.
The pituitary gland often is calledthe master gland because it
releaseshormones that affect the function ofother glands.
Thyroid gland The endocrine glandthat produces thyroxin is the
thy-roid gland. A hormone that controlsmetabolism and calcium
balance inthe body is thyroxin. The rate atwhich food is converted
into energyin body cells is metabolism. The thy-roid gland is
located near the upperportion of the trachea.
Parathyroid glands The endocrineglands that secrete hormones,
which control the amount of calcium andphosphorus in the body are
theparathyroid glands. There are four parathyroid glands that
arelocated on the thyroid gland. Each parathyroid gland is about
the size ofa grain of rice.
Parathyroid glands
Thymus
Thyroid gland
Ovaries
Pancreas
Adrenal glands
Pituitary gland
The body system that consists of glands that produce hormones is
the
A group of cells that secretes hormones is a gland. A chemical
messenger
released into the bloodstream is a hormone. Hormones control
many body activities.
What to Know About the Endocrine System
system.
endocrine
Hormones Hormonescirculate throughoutthe body in thebloodstream.
However,each hormone targetsonly certain organs or tissues.
218 UNIT 4 • Growth and Development
Testes
The endocrinesystem consists of
glands that producehoromones.
Aaron Haupt
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Pancreas The gland that producesboth digestive enzymes and
insulin isthe pancreas. The digestiveenzymes produced by the
pancreasare essential to the digestion of food.
Insulin is a hormone that regu-lates blood sugar level. If the
pan-creas fails to produce enough insulin,a person develops
diabetes mellitus.Diabetes mellitus is a disease inwhich the body
produces little or noinsulin. Diabetes will be discussedfurther in
Lesson 48.
Adrenal glands The endocrine glandsthat secrete several
hormones,including adrenaline, are the adre-nal glands. A hormone
that pre-pares the body to react during timesof stress, danger, or
in an emergencyis adrenaline. When adrenaline issecreted into the
bloodstream, bothheart rate and blood pressureincrease.
The adrenal glands also secretehormones that affect the body’s
metab-olism. There are two adrenal glands inthe body, located on
each kidney.
Ovaries There are two ovaries in thefemale body. The ovaries are
femalereproductive glands that produce ovaand estrogen. Ova are egg
cells, orfemale reproductive cells.
Estrogen is a hormone producedby the ovaries that stimulates
thedevelopment of female secondary sexcharacteristics and affects
the men-strual cycle.
Testes There are two testes in themale body. The testes are male
repro-ductive glands that produce spermand testosterone.
Testosterone is ahormone that produces the male sec-ondary sex
characteristics.
How to Keep Your Endocrine System HealthyThe following are
important ways to keep your endocrine system healthy:
• Have regular medical checkups.• Perform testicular
self-examinations each month.• Keep track of the length and dates
of your menstrual cycles.
TestesOvaries
UterusThyroid gland
Kidneys
Adrenal glands
Bones
Pituitary hormones have many functions. They regulate the
development of bones andmuscles; affect the reproductive organs;
affect the functioning of the kidneys, the adrenalgland and the
thyroid glands; and stimulate the uterus to contract during
childbirth.
LESSON 19 • Keeping Your Body Healthy 219(l)Aaron Haupt;
(r)Aaron Haupt
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The body system that breaks down food into nutrients that can be
used by the body is the
The digestive system also allows nutrients to be absorbed by
body
cells and waste materials to be eliminated from the body.
Digestion is the process by
which food is changed so that it can be absorbed by body
cells.
What to Know About the Digestive System
digestive system.
Mouth When food is chewed in themouth, teeth break it into
smallerpieces. The salivary glands areglands in the mouth that
releasesaliva, which contains a chemicalthat begins the digestion
of carbohy-drates. Saliva is a fluid that helpssoften food so that
it can be swal-lowed more easily.
Approximately 10,000 microscopictaste buds are on the tongue.
Eachtaste bud contains 50–100 receptorcells. A tiny hair extends
from eachreceptor cell. When the hairs arestimulated by food, they
send nerveimpulses to the brain that registerone of four basic
flavor sensations:sweet, salty, sour, or bitter.
Esophagus When you swallow food, itmoves into the esophagus.
Theesophagus is a tube that connectsthe mouth and the stomach.
Foodpasses to your stomach by theprocess of peristalsis.
Peristalsis(per uh STAHL suhs) is a series ofinvoluntary muscle
contractions.Peristalsis can move food to yourstomach even if you
are standing onyour head.
220 UNIT 4 • Growth and Development(tt)Photodisc/Getty Images;
Aaron Haupt
The digestive systembreaks down food into
nutrients that can beused by the body.
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Stomach The organ that releasesacids and juices that mix with
foodand produce a thick paste calledchyme (KIM) is the stomach.
Thestomach produces a layer of mucus toprotect its lining from the
strongacids released in digestion. Afterabout four hours of
churning thefood, muscle contractions force thefood into the small
intestine.
Small intestine The coiled tube inwhich the greatest amount of
diges-tion and absorption take place is thesmall intestine. The
small intestineis about 21 feet long and is lined withvilli. Villi
are small folds in the liningof the small intestine that
increasethe surface area and allow more foodto be absorbed. Several
enzymes areproduced in the lining of the smallintestine. An enzyme
is a protein thatregulates chemical reactions.
Liver The gland that secretes bile tohelp break down fats,
maintain bloodsugar level, and filter poisonouswastes is the liver.
Bile flows to the
small intestine to help in the diges-tion of fats. Bile is
stored in the gallbladder, which is a small sac-likeorgan located
under the liver.
Pancreas The gland that producesboth digestive enzymes and
insulin isthe pancreas. Enzymes from the pancreas break down
proteins,starches, and fats from food in thesmall intestine.
Large intestine After food passesthrough the small intestine, it
entersthe large intestine, also called thecolon. The large
intestine is a tubeextending from the small intestine inwhich
undigested food is prepared forelimination from the body. When
thelarge intestine is full, it contracts,and solid wastes leave the
bodythrough the rectum and anus. Therectum is the lower end of the
largeintestine that stores wastes tem-porarily. The anus is the
opening tothe outside of the body at the end ofthe rectum.
(t to b)Tony Freeman/PhotoEdit, David Young-Wolff/Getty Images,
Terry Sutherland
LESSON 19 • Keeping Your Body Healthy 221
Make theConnectionHealth BehaviorContracts For moreinformation
onmaking a healthbehavior contract to keep your bodysystems
healthy, seepage 32 in Lesson 3.
TABLE 19.1 Keep Your Digestive System Healthy
Fiber-rich foods Choose a variety of foods every day and eat
plenty of foods that containfiber. Whole-grain breads and cereals,
as well as fruits and vegetables, aregood sources of fiber. Fiber
stimulates digestive tract muscles.
Enjoyment Chew slowly and enjoy your food. Do not rush to finish
a meal. Chew foodwell and avoid indigestion. Avoid arguments when
eating.
Drink at least six to eight glasses of water each day. Water is
involved inmany body functions, including digestion and maintaining
normal bodytemperature.
Fluids
Healthful Behavior Description of Healthful Behavior
1. What is digestion?
2. What are the four basic flavorsensationsdetected by taste
buds?
-
222 UNIT 4 • Growth and Development(tt)Photodisc/Getty
Images
The body system that covers and protects the body and consists
of skin, glands
associated with the skin, hair, and nails is the (in TEG yuh
MEN
tuh ree) The skin performs several functions that are essential
for survival.
What to Know About theIntegumentary System
system.
integumentary
The largest organ in the body is skin.It contains nerve cells
that help youdetect pain, pressure, touch, heat,and cold. Skin
protects some bodyparts against injury, serves as a pro-tective
layer that keeps microorgan-isms from entering the body, andhelps
maintain a healthful body tem-perature.
Skin helps with the removal ofwastes from the body and helps
yousense the environment. It also helps
protect you from ultraviolet radiationbecause of the presence of
melanin.Melanin is a pigment that gives theskin its color.
Two layers Skin is made up of two lay-ers. The epidermis is the
outer layerof skin cells. These cells are constantlyshed and
replaced. The epidermis doesnot contain blood vessels or nerve
end-ings. New skin cells are produced inthe deepest layer of the
epidermis.The dermis is a thick layer of cellsbelow the epidermis
that containssweat glands, hair follicles, sebaceous(oil) glands,
blood vessels, and nerves.
Glands A gland that aids the body ingetting rid of wastes, such
as salt, isa sweat gland. Sweat glands alsohelp cool the body by
releasing sweatthrough pores to evaporate on thesurface of your
skin.
A sebaceous gland is a small oil-producing gland that helps
protectthe skin. Sebum is the oil producedby sebaceous glands.
Sebaceousglands are usually found togetherwith hair follicles,
though some existin hairless areas. Below the dermis isthe
subcutaneous layer. The subcu-taneous layer is a layer of fatty
Dermis
Epidermis
Nerves
ArteryVeinHair follicle
Hair
Sweat gland
Sebaceous gland
The integumentarysystem consists of skin,glands associated
withthe skin, hair, and nails.
-
tissue located below the dermis. Alarge portion of the body’s
fat is storedin this layer.
Birthmarks and Scars Because skin isthe largest organ in the
body, it also isthe most vulnerable organ. There areseveral types
of conditions that affectthe skin. Common skin conditionsinclude
birthmarks and scars. A birth-mark is an area of discolored skin
thatis present at birth. Birthmarks includedifferent types of
freckles and molesand may be removed by a physician. Ascar is a
mark left on damaged tissueafter the tissue has healed. If a
personis cut or has a severe burn, a scar maydevelop. Some people
are more likelythan others to develop scars.
Warts Warts and acne are other com-mon skin conditions. A wart
is a con-tagious growth that forms on the toplayer of the skin.
Warts are caused bya viral infection. They usually grow ingroups
and can be spread by contact.Warts can be treated with
over-the-counter drugs. However, if wartsspread, they should be
treated by aphysician.
Acne A skin disorder in which hair fol-licles or pores in the
skin becomeplugged with sebum is acne. Acnemay be prevalent during
adolescencebecause hormonal changes stimulatethe sebaceous glands
to producesebum. A pustule is a dome-shapedlesion that contains pus
consisting ofwhite blood cells, dead skin cells and bacteria. The
plug may close thepore, causing it to swell, creating awhitehead.
If the pore is open,it is commonly called a blackheadbecause the
surface of the plug has a dark appearance. Blackheads are notcaused
or colored by dirt.
Acne can last through early adult-hood. Acne may be aggravated
byapplication of oil-based makeup, sun-tan oil, or hair
products.
Ringworm A skin condition thatcauses small, red, ring-shaped
markson the skin is ringworm. Ringwormis caused by a fungal
infection and can be spread by physical contact.Physicians usually
treat ringwormwith ointments or creams. However,severe cases of
ringworm may requiretreatment with antifungal tablets.
Nails and hair Nails and hair also arepart of the integumentary
system.Nails are made up of dead cells andkeratin, a tough protein.
Hair is athreadlike structure consisting of deadcells filled with
keratin. Hair protectsskin from harmful sun rays and helpsmaintain
body temperature. Hairvaries in color, texture, and amount foreach
person. From 100,000 to 200,000hairs may be on your head. Each
hairgrows from a follicle. A hair follicle isa depression on the
surface of the der-mis that contains nutrients a hairneeds to grow.
The roots of hairs aremade up of living cells.
How to Keep Your Integumentary System HealthyThe following tips
will help you keep this body system healthy:
• Wear sunscreen with an SPFof at least 15 when you areexposed
to the sun.
• Examine skin monthly for anychanges in moles, warts,
orfreckles.
• Follow directions when usingmakeup.
• Shower or bathe each day.• Eat foods containing
vitamin A.• Seek proper medical care for
skin rashes.• Wash hair regularly.• Treat dandruff with
appropri-
ate products.
LESSON 19 • Keeping Your Body Healthy 223
Blisters Blisters arecaused by pressure or friction that causes
fluid to collectbetween the layers of the skin.
1. How does skin aidthe body in gettingrid of wastes?
2. What causeswarts?
-
The body system that removes liquid wastes from the body and
maintains the body’s
water balance is the The organs of the urinary system are the
kidneys,
ureters, bladder, and urethra.
What to Know About the Urinary System
urinary system.
Kidneys An organ that filters theblood and excretes waste
productsand excess water in the form of urineis a kidney. A pale
yellow liquid com-posed of water, salts, and other wasteproducts is
urine. The body has twokidneys. They lie on either side of
thespinal column just above the waist.
Ureters A narrow tube that connectsa kidney to the urinary
bladder is aureter (YUR uh tur). Two ureterscarry urine from the
kidneys to theurinary bladder.
Urinary bladder The muscular sacthat stores urine is the
urinarybladder. As the urinary bladder fillswith urine, it expands.
During urina-tion, urine is forced out of the bladderinto the
urethra.
Urethra The narrow tube extendingfrom the urinary bladder to the
out-side of the body, through which urinepasses out of the body is
the urethra(yu REE thruh).
Urinarybladder
UreterArtery
Urethra
Kidney
Vein
How to Keep Your Urinary System HealthyThese two tips will help
you keep this body system healthy:
• Drink plenty of water a day,especially in hot weather orwhen
doing physical activity.
• Maintain a healthful bloodpressure, as high blood pres-sure
damages the kidneys.
224 UNIT 4 • Growth and Development(l)Aaron Haupt, (r)Gen
Nishino/Photodisc/Getty Images
The urinary systemconsists of the kidneys,
the ureters, thebladder, and the
urethra.
To keep your urinary system healthy, make sure youstay
hydrated.
1. Name twofunctions of theurinary system.
2. How can highblood pressureaffect the urinarysystem?
-
19STUD
Y
GUIDE
Key Terms ReviewMatch the following definitions with the lesson
Key Terms on the left. Do not write in this book.
Recalling the Facts
1. produces a hormone that controls growth
2. includes ligaments and joints
3. contains cells that transmit messages tobody parts
4. includes plasma and hemoglobin
5. helps the body remove liquid wastes
6. the main organs are the lungs
7. helps provide motion and maintain posture
8. covers and protects the body
9. includes antibodies that fight infection
10. produces enzymes that break down proteins and
starchescardiovascular
systemcentral nervous
systemdigestive systemendocrine systemimmune
systemintegumentary
systemmuscular systemnervous systemperipheral nervous
systemrespiratory systemskeletal systemurinary system
11. What is the function of white blood cells?
12. List three ways to keep your integumentarysystem
healthy.
13. What is the difference between pulse andblood pressure?
14. What are three types of muscle? How arethey different?
15. Describe the exchange that occurs in thealveoli.
16. What is the function of the urinary system?
17. Why is it important to eat foods that con-tain fiber?
18. Name and describe the five functions ofthe brain.
Critical Thinking
LESSON 19 • Study Guide 225MAK 1
ActivitiesSharpen Your Life Skills28. Analyze Influences on
Health Set
up six or eight stations. Choose an activity(such as push-ups or
jumping jacks) for eachstation. Circulate through the
stations.Record your heart rate before and after eachactivity.
Allow two minutes at each station.A rest station is last. Evaluate
your results.Did your heart rate differ? Discuss how theheart
reacts to activity and then recovers.
Responsible Decision Making27. Journaling You are going to a
midday
baseball game with a friend. The weatheris going to be hot and
sunny. Your friendtells you that you should protect yourselffrom
the sun so that you don’t get sun-burned. What should you do? Write
aresponse to this situation in your journal.Refer to the
Responsible Decision-MakingModel on page 61 for help.
19. How are sensory and motor neurons simi-lar? How are they
different? How do theywork together?
20. How are the cardiovascular and immunesystems related?
21. Explain the relationship between the mus-cular and the
skeletal systems in the waythey function.
22. Explain how the integumentary and urinarysystems have a
common function.
Real-Life Applications23. Why would having a hyperventilating
per-
son breathe into a paper bag be helpful?
24. Investigate what options are available to youif you injure
the cartilage in your knee joint.
25. How might eating too fast affect yourdigestive system?
26. Explain why physical activity might be beneficial to a
person recovering fromcoronary artery disease.
Visit www.glencoe.com for more Health & Wellness
quizzes.
http://www.glencoe.com
Health & WellnessTable of ContentsUNIT 1 Health SkillsLesson
1 Taking Responsibility for HealthLesson 2 Accessing Valid Health
Information, Products, and ServicesLesson 3 Practicing Healthful
BehaviorsLesson 4 Analyzing Influences on HealthLesson 5 Using
Communication SkillsLesson 6 Setting Health Goals and Making
Responsible DecisionsLesson 7 Being a Health Advocate
UNIT 2 Mental and Emotional HealthLesson 8 Developing Good
CharacterLesson 9 Developing a Healthy MindLesson 10 Expressing
Emotions and Managing StressLesson 11 Dealing with DepressionLesson
12 Dealing with Loss and Grief
UNIT 3 Family and Social HealthLesson 13 Developing Healthful
Family RelationshipsLesson 14 Adjusting to Family ChangesLesson 15
Examining Dating and FriendshipsLesson 16 Practicing Abstinence
From SexLesson 17 Recognizing Harmful RelationshipsLesson 18
Preparing for Marriage and Parenthood
UNIT 4 Growth and DevelopmentLesson 19 Keeping Your Body
HealthyLesson 20 Learning About the Reproductive SystemsLesson 21
Learning About Pregnancy and ChildbirthLesson 22 Caring for Infants
and ChildrenLesson 23 Developing Learning and Planning StylesLesson
24 Aging Healthfully
UNIT 5 NutritionLesson 25 Choosing Healthful FoodsLesson 26
Following Dietary GuidelinesLesson 27 Using Diet to Guard Against
DiseaseLesson 28 Developing Healthful Eating HabitsLesson 29
Maintaining a Healthful Weight
UNIT 6 Personal Health and Physical ActivityLesson 30 Having
Regular Physical ExamsLesson 31 Being Well-GroomedLesson 32 Getting
Adequate Rest and SleepLesson 33 Participating in Physical
ActivityLesson 34 Practicing FitnessLesson 35 Exercising Safely
UNIT 7 Alcohol, Tobacco, and Other DrugsLesson 36 Using
Prescription and OTC Drugs SafelyLesson 37 Choosing an Alcohol-Free
LifestyleLesson 38 Choosing a Tobacco-Free LifestyleLesson 39
Avoiding Illegal Drug UseLesson 40 Avoiding Drug DependenceLesson
41 Resisting Pressure to Abuse DrugsLesson 42 Reducing Risk by
Being Drug FreeLesson 43 Assessing Treatment Options
UNIT 8 Communicable and Chronic DiseasesLesson 44 Avoiding
Communicable Diseases.Lesson 45 Dealing with Respiratory Diseases,
Asthma, and AllergiesLesson 46 Reducing the Risk of STDs and
HIVLesson 47 Reducing the Risk of Cardiovascular DiseasesLesson 48
Managing Chronic Health ConditionsLesson 49 Reducing the Risk of
Cancer
UNIT 9 Consumer and Community HealthLesson 50 Acquiring
Knowledge of Health LawsLesson 51 Managing Time and MoneyLesson 52
Analyzing Media MessagesLesson 53 Accessing Reliable Health
CareLesson 54 Investigating Health CareersLesson 55 Learning About
Public Health
UNIT 10 Environmental HealthLesson 56 Learning About
Environmental IssuesLesson 57 Preventing Air and Water
PollutionLesson 58 Preventing Noise and Visual PollutionLesson 59
Practicing Recycling and ConservationLesson 60 Protecting the
Environment
UNIT 11 Injury Prevention and Personal SafetyLesson 61 Reducing
Unintentional InjuriesLesson 62 Staying Safe During Severe Weather
and Natural DisastersLesson 63 Reducing the Risk of ViolenceLesson
64 Respecting Authority and Obeying LawsLesson 65 Protecting
Yourself From Physical ViolenceLesson 66 Protecting Yourself From
Sexual ViolenceLesson 67 Staying Away From GangsLesson 68 Reducing
Weapon InjuriesLesson 69 Performing Common First Aid
ProceduresLesson 70 Performing Emergency First Aid Procedures
Health ResourcesEnglish/Spanish GlossaryIndexCredits
Feature ContentsActivity: Using Life SkillsSpeaking OutHealth
NewsFacts AboutJust the Facts
Student WorkbooksReading EssentialsTo the StudentUnit 1: Health
SkillsLesson 1: Taking Responsibility for HealthLesson 2: Accessing
Valid Health Information, Products, and ServicesLesson 3:
Practicing Healthful BehaviorsLesson 4: Analyzing Influences on
HealthLesson 5: Using Communication SkillsLesson 6: Setting Health
Goals and Making Responsible DecisionsLesson 7: Being a Health
Advocate
Unit 2: Mental and Emotional HealthLesson 8: Developing Good
CharacterLesson 9: Developing a Healthy MindLesson 10: Expressing
Emotions and Managing StressLesson 11: Dealing with
DepressionLesson 12: Dealing with Loss and Grief
Unit 3: Family and Social HealthLesson 13: Developing Healthful
Family RelationshipsLesson 14: Adjusting to Family ChangesLesson
15: Examining Dating and FriendshipsLesson 16: Practicing
Abstinence From SexLesson 17: Recognizing Harmful
RelationshipsLesson 18: Preparing for Marriage and Parenthood
Unit 4: Growth and DevelopmentLesson 19: Keeping Your Body
HealthyLesson 20: Learning About the Reproductive SystemsLesson 21:
Learning About Pregnancy and ChildbirthLesson 22: Caring for
Infants and ChildrenLesson 23: Developing Learning and Planning
StylesLesson 24: Aging Healthfully
Unit 5: NutritionLesson 25: Choosing Healthful FoodsLesson 26:
Following Dietary GuidelinesLesson 27: Using Diet to Guard Against
DiseaseLesson 28: Developing Healthful Eating HabitsLesson 29:
Maintaining a Healthful Weight
Unit 6: Personal Health and Physical ActivityLesson 30: Having
Regular Physical ExamsLesson 31: Being Well-GroomedLesson 32:
Getting Adequate Rest and SleepLesson 33: Participating in Physical
ActivityLesson 34: Practicing FitnessLesson 35: Exercising
Safely
Unit 7: Alcohol, Tobacco, and Other DrugsLesson 36: Using
Prescription and OTC Drugs SafelyLesson 37: Choosing an
Alcohol-Free LifestyleLesson 38: Choosing a Tobacco-Free
LifestyleLesson 39: Avoiding Illegal Drug UseLesson 40: Avoiding
Drug DependenceLesson 41: Resisting Pressure to Abuse DrugsLesson
42: Reducing Risk by Being Drug FreeLesson 43: Assessing Treatment
Options
Unit 8: Communicable and Chronic DiseasesLesson 44: Avoiding
Communicable DiseasesLesson 45: Dealing with Respiratory Diseases,
Asthma, and AllergiesLesson 46: Reducing the Risk of STDs and
HIVLesson 47: Reducing the Risk of Cardiovascular DiseasesLesson
48: Managing Chronic Health ConditionsLesson 49: Reducing the Risk
of Cancer
Unit 9: Consumer and Community HealthLesson 50: Acquiring
Knowledge of Health LawsLesson 51: Managing Time and MoneyLesson
52: Analyzing Media MessagesLesson 53: Accessing Reliable Health
CareLesson 54: Investigating Health CareersLesson 55: Learning
About Public Health
Unit 10: Environmental HealthLesson 56: Learning About
Environmental IssuesLesson 57: Preventing Air and Water
PollutionLesson 58: Preventing Noise and Visual PollutionLesson 59:
Practicing Recycling and ConservationLesson 60: Protecting the
Environment
Unit 11: Injury Prevention and Personal SafetyLesson 61:
Reducing Unintentional InjuriesLesson 62: Staying Safe During
Severe Weather and Natural DisastersLesson 63: Reducing the Risk of
ViolenceLesson 64: Respecting Authority and Obeying LawsLesson 65:
Protecting Yourself From Physical ViolenceLesson 66: Protecting
Yourself From Sexual ViolenceLesson 67: Staying Away From
GangsLesson 68: Reducing Weapon InjuriesLesson 69: Performing
Common First Aid ProceduresLesson 70: Performing Emergency First
Aid Procedures
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