Transcript O: You will be able to explain the difference between blood vessels.

O: You will be able to explain the
difference between blood
vessels.
Do Now: What transports the
blood and oxygen around our
body?
The circulatory system
• The heart, lungs, and
blood vessels work
together to form the
circulatory system.
• They form a a circle
of blood around the
body.
Blood Vessels
• A blood vessel is a hollow structures for
carrying blood that are located throughout
your body.
• There are three main types of blood
vessels.
• Arteries
• Capillaries
• Veins
Arteries
• Arteries carry blood AWAY from the heart.
• One main artery carries the oxygen rich
blood out of the heart but then divides into
smaller arteries that transport the blood all
over your body.
• The arteries transport the “renewed blood”
to the body.
About the Artery
• The artery has muscles in it.
• It works with the heart to expand and
contract to pump your blood.
• When you touch an artery you can take
your pulse.
Veins
• Veins transport the blood back to the heart
and lungs.
• The blood flow is not as strong in the veins
as it is in the arteries.
• The veins bring the blood with carbon
dioxide and the muscle waste back to the
lungs and heart.
Veins continued
• Once the carbon dioxide or “waste rich”
blood reaches the lungs the carbon
dioxide is released and the oxygen is
reabsorbed.
• The blood is then pumped back out
through the artery.
• Veins have special valves so that the
blood only pumps in one direction.
Home work
• 1. What is the difference between veins
and arteries?
• 2. Why is it important that the blood in
veins can only flow n one direction?
• 3.Why do you think it is called the
circulatory system?
O: You will be able to explain
the role of capillaries.
Do Now: What would happen if
you only had arteries?
Capillaries
• The capillaries are the blood vessels that
connect arteries and veins.
• They are like little webs that pass all
through the body’s tissue and connect the
veins and arteries.
• The capillaries are so thin that the blood
has to go through single file.
• It is in the capillaries that the exchange of
oxygen for carbon dioxide happens.
• The blood releases the oxygen and takes
the carbon dioxide from the tissue and the
tissue releases the carbon dioxide and
takes the oxygen.
• Capillaries are very thin and fragile.
• Capillaries are also involved in the body's
release of excess heat. During exercise, for
example, your body and blood temperature
rises. To help release this excess heat, the blood
delivers the heat to the capillaries which then
rapidly release it to the tissue. The result is that
your skin takes on a flushed, red appearance. If
you hold your hand, for example, under hot
water, your hand will quickly turn red for the
same reason. Your arm, however, is not likely to
change color because it is not actually feeling an
increase in temperature.
Fun Facts
• If you took all of the blood vessels out of
an average child, and laid them out in one
line, the line would be over 60,000 miles
long! An adult's vessels would be closer to
100,000 miles long!
• You have 5 liters of blood that circulates
around your body.
Homework
• 1. What is the main job of capillaries?
• 2. What do you think is the most important
blood vessel? Why do you think that?
• 3. What would happen if you broke all of
your capillaries?