THE C

IRCULA

TORY

SYSTE

M

Y OU

R B

OD

Y’ S

“I N

TE

RN

AL T

RA

NS

PO

RT

SY

ST

EM

” !

WHAT THE CIRCULATORY SYSTEM DOES:

• The heart moves blood through blood vessels.

• Vessels move blood through the body to carry:• Oxygen• Carbon dioxide• Nutrients

WHAT IS BLOOD MADE OF?

• 55% = plasma • a clear liquid made up of 92% water•8 % is salts, nutrients, proteins and other chemicals

• The rest of the blood = 3 kinds of blood cells•Red = carry oxygen to the body •White = protect the body from disease• Platelets = cell fragments that cause blood to clot

WHAT

COLO

R IS B

LOOD??

?

• Hemoglobin = oxygen-carrying pigment in red blood cells• Is bright red when attached to oxygen• Is dark red when doesn’t have oxygen

• Veins appear blue b/c different colors of light reach different depths in the skin = the blue light is reflected back by the veins

HOW DOES THE HEART WORK?

• Beats constantly (no rest!)

• It pushes blood through the vessels

• Blood carrying carbon dioxide returns from the body and enters the right atrium of heart• Atrium = a chamber of the heart that RECEIVES blood

• Blood is pushed to the ventricle = pushes blood OUT of the heart toward the lungs and other parts of the body

WHAT

MAKES

THE H

EART

BEAT?

C O N T R A C T I O N O F T H E H E A R T !

1 . S I G N A L S AT T H E T O P O F T H E H E A R T C A U S E T H E H E A R T B E AT …

2 . A G R O U P O F C E L L S C A L L E D T H E “ C A R D I A C PA C E M A K E R ” O R S - A N O D E S TA R T A S I G N A L …

3 . T H E S I G N A L C A U S E S T H E AT R I A T O C O N T R A C T …

4 . T H E S I G N A L I S PA S S E D T O C E L L S I N T H E A - V N O D E A N D A L O N G T O V E N T R I C L E S …

5 . V E N T R I C L E S C O N T R A C T …

Y E A H = Y O U H A V E A H E A R T B E AT !

Arteries=

Blood vessels that carry blood AWAY from the heart

TYPES OF BLOOD VESSELS:

Veins=

Blood vessels that carry blood FROM all parts of body BACK to the heart

Capillaries=

Tiny blood vessels that connect arteries to veins