Science Module
th
7
Grade
Circulatory System
Structures
• Heart
• Blood Vessels
– Arteries
– Veins
– Capillaries
• Blood
Circulatory System
Function
• The overall function of the circulatory system is
to transport materials throughout the body
toward and away from particular target organs
and tissues.
Two Pathways
• Pulmonary Circulation
– Carries blood to lungs and back to the heart
• Systemic Circulation
– Carries blood to body and back to the heart
Capillaries of head and arms
Superior vena
cava
Aorta
Pulmonary artery
Pulmonary vein
Capillaries of right
lung
Capillaries of left
lung
Inferior vena cava
Capillaries of abdominal
organs and legs
Your Blood Vessels:
Pathway of Circulation

3 types of vessels
– Arteries
– Capillaries
– Veins
Arteries:
carries blood Away from heart
–
–
–
–
Large
Thick-walled, Muscular
Elastic
Oxygenated blood

Exception Pulmonary Artery
– Carried under great pressure
– Steady pulsating
Arterioles: smaller vessels, enter tissue
Capillaries
–
–
–
–
Smallest vessel
Microscopic
Walls one cell thick
Nutrients and gases diffuse here
Veins:
Carries blood to heart
–
Carries blood that contains
waste and CO2

–
–
Exception pulmonary vein
Blood not under much
pressure
Valves to prevent much
gravity pull
Venules: larger than capillaries
Varicose Veins
Damaged Valves in Veins
Artery vs. Vein
Your Heart: The Vital Pump
At REST, the heart
pumps about 5
QUARTS of blood a
minute.
 During EXTREME
EXERTION (exercise)
it can pump 40 quarts
a minute.

Structure of Heart

Four chambers
– Two upper (Atria)
 Right Atria
 Left Atria
– Two lower
(Ventricles)
 Right Ventricle
 Left Ventricle
Heart Pumping
http://library.med.utah.edu/kw/pharm/hyper
_heart1.html
Lyrics
Pump, pump, pumps your Blood.
 The right atrium’s where the process begins, where the
CO2 Blood enters the heart.
 Through the tricuspid valve, to the right ventricle, the
pulmonary artery, and lungs.
 Once inside the lungs, it dumps its carbon dioxide and
picks up its oxygen supply.
 Then it’s back to the heart through the pulmonary vein,
through the atrium and left ventricle.
 Pump, pump, pumps your Blood.

Blood Flow Through Heart
Label the Following Structures
Right ventricle
Left ventricle
Right atrium
Left atrium
Pulmonary arteries
Pulmonary veins
Aorta
Superior vena cava
Inferior vena cava
Semi-lunar valves
Bicuspid valve
Tricuspid valve
Cardiac muscle
Pericardium
Septum
Color in oxygenated blood red
& de-oxygenated blood blue
Draw arrows showing blood flow
Through the heart & adjacent
Blood vessels
Indicate the location of the lungs
Heart Sounds

First heart sound or “lubb”
– Atrioventricular valves and surrounding fluid vibrations as
valves close at beginning of ventricular systole

Second heart sound or “dupp”
– Results from closure of aortic and pulmonary semilunar
valves at beginning of ventricular diastole, lasts longer

Third heart sound (occasional)
– Caused by turbulent blood flow into ventricles and detected
near end of first one-third of diastole
The Blood
Body contains 4-6 L
 Consists of

–
–
–
–
Water
Red Blood Cells
Plasma
White blood cells and
platelets
Erythrocytes (RBC)

Transporters of
– Oxygen
– Carbon Dioxide

RBC are produced in red bone
marrow of
–
–
–
–
ribs,
humerus,
femur,
sternum, and other long bones
Leukocytes (WBC)

WBC fight infection
–


Attack foreign
substances
Less abundant
Large cells
Platelets
PLATELETS are for CLOTTING blood
 Cell fragments
 Produced in bone marrow
 Fibrin (sticky network of protein
fibers)

– Form a web trapping blood cells
Blood Clotting
Section 37-2
Break in Capillary Wall
Clumping of Platelets
Clot Forms
Blood vessels injured.
Platelets clump at the site
and release thromboplastin.
Thromboplastin converts
prothrombin into thrombin..
Thrombin converts
fibrinogen into fibrin, which
causes a clot. The clot
prevents further loss of
blood..
Blood Types
Massive loss of blood requires a transfusion
 Four Types

–A
–B
– AB
–O

Inherited from your parents
Blood Types
What happens when you mix blood
types?
 Plasma
contains proteins that
correspond to the shape of the
different antigens
 If you mix one type with the
wrong one, you get CLUMPING
Type O is the universal donor
 Type AB is the universal acceptor

What Makes Our Blood Type?
Blood Transfusions
Blood Type
of Donor
Blood Type of Recipient
A
B
AB
O
A
B
AB
O
Unsuccessful transfusion
Successful transfusion
Rh Factor

Rhesus factor (Rh), also inherited
– Rh+ (have antigen)
– Rh- (NO antigen)

Can cause complications in pregnancies
– mother Rh- 1st baby Rh+ : blood mixes with
mother; mother’s body makes anti-Rh+
antibodies
– 2nd Rh + body attacks baby
– Now have medicine to prevent antibody
formation