Packet 14: Circulation and Respiration
14-2
Aim: How is blood transported through the body?
(A)
BLOOD VESSELS
 Blood circulates through the body through a series of vessels
1.
Arteries: ___________________________________________
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Except for the pulmonary arteries, all arteries carry
__________________________________________
With each contraction the heart forcefully ejects blood into
arteries
The artery’s wall expands and then returns to its original size
Blood passes from the arteries into a network of smaller arteries
called _________________________
2. Capillaries: ___________________________________________
_________________________________________________________
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______________________________
no cell in your body is more than a few cell diameters away from
a capillary
capillary walls are only one cell thick—gas and nutrient molecules
easily pass through their thin walls
capillaries are also very narrow with an internal diameter of
about 0.0003 in
**INTERESTING FACT: If all the capillaries of your body were laid end to end, they would
extend all the way across the US!!!!
3. Veins:
________________________________________________________________
____________________________________________
 The walls of veins consists of a much thinner layer of smooth
muscle than the walls of the arteries
 They are farther away from the heart pump so therefore are
exposed to less pressure
 Veins are also larger in diameter than arteries

(B)
The flow of blood in veins is helps by contractions of skeletal
muscles—
_________________________________________________________
BLOOD PRESSURE
 Blood moves through our system because it is under pressure
 This pressure is caused
_______________________________________________________________________
________________________________________________________________________
__________________________________
 Blood pressure:
________________________________________________________________________
________________________________________________________________________
_________________________________
 Blood pressure is always highest in the two main arteries that leave the heart
 Both high and low blood pressure can cause problems to our health
 High blood pressure is very common in Americans—
____________________________________________
 Blood pressure is measured with two numbers
 1—systolic:
_________________________________________________________
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_______________________________________
2—diastolic:
_________________________________________________________
_______________________________________
 blood pressure is given as the systolic number over the diastolic number
(C)
BLOOD
 “River of Life”
 blood:
________________________________________________________________________
________________________________________________________________________
____________________________________
 blood serves many functions:
1) collects ______________________ from the lungs
2) collects _______________________ from the digestive tract
3) collects _______________________________ from tissues
4) helps to ___________________________________________
5) helps fight ___________________________________________
6) helps repair damaged ________________________________
 Blood is made up of various components:
1) Blood Plasma
 Accounts for 60% of the blood
 Liquid portion of the blood—90% water and 10% solutes
 The other solutes include nutrients, gases, enzymes, hormones and waste
products
2) Red Blood Cells
 ______________________________________________________
 Each mL of blood contains 5 million RBCs
 RBCs have a biconcave shape—
________________________________________________________________
____________________________________________
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Also known as _________________________________
Carry hemoglobin—
________________________________________________________________

____________________________________________—it also gives RBCs
their color
Since mature RBCs carry so much hemoglobin, they do not have nuclei or
organelles
3) White Blood Cells
 Outnumbered by RBCs almost 500 to 1
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
Also known as ________________________________
The main function of the WBCs is to
________________________________________________________________
________________________________________________________________
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__________________________________
“army” of the body
larger than RBCs—do contain nuclei—almost colorless
there are different types of WBCs with different functions
4) Platelets
 Platelets are not cells—
________________________________________________________________
____________________________________________

Play an important role in _____________________________________—
they clump together and form a plug at the site of the wound
(D) BLOOD TYPES
 Blood type is determined by the type of antigen present on the surface of RBCs
 Antigen:
________________________________________________________________________
________________________________________________________________________
____________________________________
 If a person has A antigens—they are _________________
 if a person has B antigens—they are _________________
 if a person has both antigens—they are ____________________
 if a person has neither A nor B—they are ____________________
 Type AB is known as the universal receiver—
________________________________________________________________________
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________________________________________________
Type O is known as the universal Donor,
________________________________________________________________________
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