38
Body Systems
T
Human Body Systems
he human body consists of nine major body systems. Each carries out a different activity, and
consists of a number of parts, or organs. Only the major parts of the systems are shown in the
illustrations in this section. The urinary, endocrine and reproductive systems are not shown.
Skeletal System
The skeletal system consists of all the bones in the body.
The skeleton gives the body shape, protects and supports vital
organs, and, together with the muscles, allows the body to
move.
The adult human skeleton has about 206 bones. They are
joined to each other by joints. Joints may be immovable, such
as the joints in the skull, or movable, such as the hinge joint of
the elbow or the ball and socket joint of the shoulder.
Muscular System
The muscular system consists of all the muscles in the
body. Skeletal muscles are voluntary muscles. They move
the bones of the skeleton and are controlled by thought. The
heart muscle is an involuntary muscle that pumps blood
through the body. Smooth muscles are also involuntary, not
controlled by thought. They move food through the digestive
system and help blood circulate.
An adult’s body has about 656 skeletal muscles, which
make up between one-third and one-half of a person’s weight.
70
Time Line of History
3000 B.C. Recorded history began
Kings ruled in Ancient Egypt
(later called Pharaohs)
2000 B.C.
B.C. means “before
Christ.” In the Gregorian
calendar, the years before
Christ’s birth are counted
backwards. 3000 B.C. is
almost 5000 years ago.
B.C.E. “before common
era” may also be used.
1900 B.C.
2900 B.C.
1800 B.C.
2700 B.C. First books, papyrus scrolls
(c.2700 B.C.)
1700 B.C. Jewish religion began with
Abraham
2600 B.C.
1600 B.C.
The Great Pyramids of Giza
and the Sphinx built along
the Nile River in Egypt
2500 B.C. Earliest written music
(c.2500 B.C.)
2400 B.C.
Ancient Egyptian Civilization
Ancient Egyptian Civilization
2800 B.C.
Time Line
of
Recorded
History
1500 B.C. Hindu religion began
in India
1400 B.C.
King Tutankhamen ruled in
Egypt (1347–1339 B.C.)
2300 B.C.
2200 B.C.
2100 B.C.
2000 B.C.
The Chinese have the
world’s oldest living
civilization, with a
written history dating
back to about 1500 B.C.
Many great ideas and
inventions, such as paper,
silk cloth, gunpowder,
eyeglasses and the
compass, originated in
China. Western people
knew nothing about this
rich eastern civilization
until Marco Polo’s visit
in the 1200s.
1300 B.C.
1200 B.C.
1100 B.C.
1000 B.C.
The bars to the left of the
time line show major eras,
events and civilizations
that lasted for a long time.
Although ancient Egyptian
civilization ended in about
715 B.C., people have lived
in Egypt throughout history
to this day.
134
South America
South America
80
HONDURAS
Caribbean Sea
Tegucigalpa
NICARAGUA
Managua
San José
COSTA RICA
Maracaibo
Valencia
Barquisimeto
Panama
Cúcuta
PANAMA
BARBADOS
Port-of-Spain
Caracas
Barranquilla
Cartagena
Ciudad
Guayana
Georgetown
Paramaribo
Cayenne
VENEZUELA
GUYANA
E
D
N
A
Cali
0
Equator
North
Atlantic
Ocean
TRINIDAD AND
TOBAGO
San Cristóbal
S
Medellín
40
60
ST. LUCIA
ST. VINCENT AND
THE GRENADINES
GRENADA
Bogotá
SURINAME
COLOMBIA
Boa Vista
French
Guiana
(FRANCE)
Macapá
Quito
Amazon
ECUADOR
Guayaquil
River
Manaus
0
Belém
São Luís
Santarém
Iquitos
Fortaleza
Teresina
Piura
Natal
Trujillo
Rio
Branco
Huánuco
Pôrto
Velho
South
Pacific
Ocean
Maceió
Lima
A
N
D
Cusco
E
Trinidad
S
Antofagasta
AMA DESERT
AT A C
rn
Caprico
Brasília
Goiânia
BOLIVIA
Arica
20
Salvador
Cuiabá
La Paz
Arequipa
Iquique
f
Tropic o
Recife
BRAZIL
PERU
Cochabamba Santa Cruz
Sucre
Potosí
Salta
Vitória
20
PARAGUAY
Asunción
San Miguel
de Tucumán
Rio de Janeiro
São Paulo
Santos
Curitiba
Florianópolis
Resistencia
CHILE
Aconcagua
(highest point in
South America)
Valparaíso
Pôrto Alegre
Córdoba
Mendoza
Santiago
Puerto Montt
ANDES
Concepción
Belo
Horizonte
Uberlândia
Campo
Grande
Santa Fe
Salto
South
Atlantic
Ocean
URUGUAY
Rosario
Buenos Aires
La Plata
Montevideo
ARGENTINA
Mar del Plata
Bahía Blanca
San Carlos de
Bariloche
40
40
Comodoro Rivadavia
(lowest point in South America and
the Western Hemisphere)
Scale 1:35,000,000
Río
Gallegos
Azimuthal Equal-Area Projection
0
0
Stanley
Falkland Islands
500 Kilometers
Punta Arenas
500 Miles
Boundary representation is
not necessarily authoritative.
100
Strait of
Magellan
80
Ushuaia
Cape
Horn
South Georgia and the
South Sandwich Islands
60
40
20
163
Special Alphabets
Special Alphabets
Braille is a coded alphabet of raised dots
that can be read by touch. It was
developed in 1824 by Louis Braille,
a 15-year-old blind Frenchman, and
is the alphabet used most often by
the blind. Numerals are formed by
using a special number sign with the
first ten letters. An A preceded by
this sign is 1, B is 2, C is 3, and so
on. J is used for the numeral 0.
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
ch
gh
sh
th
wh
ed
er
ou
ow and for
of
the with
The phonetic alphabet is used by the military and by airplane pilots around
the world to stand for letters of the alphabet. A pilot whose airplane
number is N6837E would say November 6837 Echo.
Sign language is a system of
communicating with hand gestures.
The American manual alphabet below
can be used to spell out words and is
generally understood by deaf persons.
B
A
C
D
H
G
L
Q
V
M
O
N
R
W
J
I
S
X
F
E
K
P
T
Y
U
Z
Alpha
Bravo
Charlie
Delta
Echo
Foxtrot
Golf
Hotel
India
Juliet
Kilo
Lima
Mike
November
Oscar
Papa
Quebec
Romeo
Sierra
Tango
Uniform
Victor
Whiskey
X Ray
Yankee
Zulu
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
V
S
W
Z
T
X
Y
Period
?
Error
Start
4
8
Comma
Wait
Understand
1
U
2
5
End
SOS
3
6
9
7
0
International Morse code was
developed by the inventor of
the telegraph, Samuel Morse.
It was used extensively in
the past to transmit telegraph
messages and news.