Do all veins carry oxygen poor blood?

Week 7, Day Three
HW # 27- Review your notes from the human body
unit (skeletal, muscular, circulatory systems) –
Check your Have a Heart answers online.
Extra Credit- Blood Pressure Worksheet
Warm up
Do veins always carry blood with no oxygen? Do
arteries always carry blood with oxygen? Give
examples to support your answer.
Warm up Response
No, the pulmonary veins carry oxygen rich blood and the
pulmonary arteries carry oxygen poor blood.
Homework Response/Check
Collect Heart Beat, Health Beat lab report.
Have a Heart
Question: Explain why oxygen-poor blood and oxygen-rich
blood never mix in the human body.
• Two sides of the heart are separated by the septum.
• Each side has an upper chamber and a lower chamber.
• Oxygen rich blood is carried in arteries, and oxygen poor
blood is carried in vein; they never meet.
The oxygen in oxygen-rich blood diffuses through cell
walls and powers the metabolism of cells, leaving oxygen
poor blood behind to be collected by veins and
transported to the heart and lungs for re-oxygenation.
Question: Do all arteries carry oxygen-rich blood? Do
all veins carry oxygen poor blood?
No, the pulmonary veins carry oxygen rich blood and the
pulmonary arteries carry oxygen poor blood.
Question: Starting at the right atrium, describe the path
that blood takes through the heart and body, ending
again in the right atrium.
• Blood circulates in two loops.
• First, it travels from the heart to the lungs and then back
to the heart.
• Second, it is pumped from the heart to the body and
then it returns to the heart.
Blood enters the heart through the superior and inferior vena cava. These two paths dump deoxygenated
blood into the right atrium. Blood passes from the right atrium through the tricuspid valve into the right
ventricle. The right ventricle contracts and forces the blood through the pulmonary semilunar valve into
the pulmonary arteries. The blood moves into the lungs and gas exchange occurs, oxygenating the blood.
The blood then moves through the pulmonary vein, emptying into the left atrium. The oxygenated blood
then passes through the bicuspid valve into the left ventricle. The left ventricle contracts and forces the
blood out through the aortic semilunar valve and into the aorta. The aorta is the bodies largest artery and
blood is distributed to smaller arteries and out to the entire body (except the lungs).
Question: how are the structures of an artery, vein, and
capillary able to help each do the specific function that they
do for the body?
• Arteries carry blood from the heart, so their walls have
to withstand high blood pressure.
• They also have to maintain blood pressure to ensure a
continuous blood flow.
• Therefore, their three-layered walls are strong, elastic,
have smooth muscle cells and collagen fibers.
• Capillaries exchange material (oxygen, carbon
dioxide, nutrients etc.) between the blood and
interstitial fluid.
• To be able to carry out this function, they have to
have very thin, permeable walls.
• Arteries and veins are the parts of the circulatory
system which carry blood between the heart, lungs,
and all other areas of the body.
• While they both carry blood, they do not have much
else in common. Arteries and veins are made of
somewhat different tissue, each performing certain
functions in a specialized way.
• The first and most important difference between the
two is that all arteries carry blood away from the
heart, and all veins carry blood to the heart from
outlying areas.
• Most arteries carry oxygenated blood, and most veins
carry deoxygenated blood; the pulmonary arteries
and veins are the exceptions to this rule.
• Arterial tissue is designed and specialized in a way to
make it particularly suited to the quick and efficient
delivery of blood, which carries the oxygen essential
for the functioning of every bodily cell.
• The outer layer of an artery is made of connective
tissue, which covers the muscular middle layer.
• These muscles contract between heartbeats in such a
reliable way that when we take our pulse, we are not
actually feeling our heartbeat per se, but arterial
muscle contraction instead.
Beyond the arterial muscle is the innermost layer, made of
smooth endothelial cells. These cells are specialized to provide
a smooth pathway for blood to flow through.
This area of cells is also what can become damaged and
compromised over a person's lifetime, leading to two common
causes of death, namely heart attack and stroke.
Veins have a different structure and function from arteries.
They are very flexible, and collapse when they are not filled
with blood. They usually carry deoxygenated blood, rich in
carbon dioxide, to the heart so that it can be sent to the lungs
for oxygenation.
The layers of vein tissue are similar in some ways to those of
arteries, although the muscle does not contract like arterial
muscle does.
• Unlike other arteries, the pulmonary artery carries
deoxygenated blood. Once the veins have brought this blood
from the body to the heart, it is pumped to the lungs.
• The pulmonary vein moves the oxygenated blood from the
lungs back to the heart.
• While the location of arteries is very similar from person to
person, this is not so much the case with veins, which have
greater variability.
• Veins, unlike arteries, are used as access points to the
bloodstream in the medical field, such as when a person
receives medicine or fluids directly into the bloodstream, or
when blood is drawn. Because veins do not contract as arteries
do, there are valves present in veins which keep blood flow
going in one direction only. Without these valves, gravity
would quickly cause blood to pool in the extremities, causing
injury or at the very least impairing the system's efficiency.
Question: An artificial heart actually replaces only
the ventricles of a human heart. Suggest a reason
why replacing the atria is not necessary?
Because the atria only collect blood. The ventricles are
needed to pump the blood to the lungs (right) and to the
body (left). Thus, they need to be stronger.
Question: Explain why chronic heart disorders such as
hypertension and atherosclerosis are more of a
problem today then they were 200 years ago. Predict
how great of a problem it will be in the future.
Hypertension- high blood pressure
Atherosclerosis- Atherosclerosis (ath-er-o-skler-O-sis) is a disease in which plaque
(plak) builds up inside your arteries. Arteries are blood vessels that carry oxygenrich blood to your heart and other parts of your body.
Plaque is made up of fat, cholesterol, calcium, and other substances found in the
blood. Over time, plaque hardens and narrows your arteries. This limits the flow
of oxygen-rich blood to your organs and other parts of your body.
Atherosclerosis can lead to serious problems, including heart attack, stroke, or
even death.
They are more common now, because we are living longer and because we lead
more sedentary lifestyles.

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