An
artery
is a
blood vessel
that carries
blood
away from the
heart
to other parts of the body. Almost all arteries carry blood with a lot of
oxygen
in it. The only arteries that do not carry oxygen-rich blood are the
pulmonary artery
, and (in a
fetus
) the
umbilical
artery.
[1]
Every artery has three layers. The outer layer is a thick covering made of stretchy
tissue
. The middle layer is made of
muscle
, so the artery can
get wider
or
get smaller
when the body needs it to. The inner lining is made of the same
cells
that line the heart.
[2]
Arteries are deep under the
skin
. They do not have valves to prevent blood from flowing backwards. Instead, every time the heart beats, the arteries stretch out so the blood has room to go through. Once the walls have completely stretched out, the muscles in the arteries make them shrink back to their normal size. This pushes the blood through.
[1]
Arteries split down into small vessels called
arterioles
.
![](//upload.wikimedia.org/wikipedia/commons/thumb/1/10/Arterial_System_en.svg/220px-Arterial_System_en.svg.png)
The body's major arteries. Notice how they all branch off of the aorta.
The aorta is the main artery in the
human body
. It starts in the left ventricle of the heart, which is full of blood that just picked up oxygen in the lungs. (This is called
oxygenated
blood - meaning it has a lot of oxygen in it.) The left ventricle pumps this oxygen-rich blood out through the aorta. The aorta brings this blood to every
organ
in the body.
[2]
The aorta runs all the way from the heart to the bottom of the
abdomen
. Along the way, smaller arteries split off the aorta, like branches on a tree, to bring blood to different parts of the body. The aorta finally ends by splitting off into the two arteries that bring blood to the legs.
[2]
Except for the pulmonary artery, every artery in the body is connected to the aorta.
[2]
Some other important arteries include:
- The
carotid arteries
, which bring blood to the brain, head, and face
- The
femoral arteries
, which bring blood to the legs
- The coronary arteries, which bring blood to the heart
The pulmonary artery is the only artery in the adult body that:
[3]
- Does not connect to the aorta; and
- Carries blood that does not have much oxygen in it. (This is called
deoxygenated blood.
)
The body uses the oxygen carried in the other arteries
to make energy
. The blood in these arteries becomes
deoxygenated
- it does not have much oxygen left in it. This blood then travels through
capillaries
to get from the arteries to the
veins
. The veins' job is to carry the
deoxygenated
blood back to the right side of the heart. The pulmonary artery carries this blood from the heart's right ventricle to the lungs. In the lungs, the blood can pick up more oxygen.
[3]
After picking up more oxygen, the blood travels back to the left side of the heart and is pumped out to the body by the aorta. This cycle continues, over and over again.
[3]
Because the heart pumps blood right into the arteries, the arteries are under a lot of
pressure
.
[1]
Unlike the veins, the arteries are always stretching and then squeezing to push blood through them to the body. Because of this, an
arterial bleed
-
bleeding
from an artery - can be a
medical emergency
, especially if the artery is big. Arterial bleeding can happen very quickly. For example, if a person's
femoral artery
is cut, they can
bleed to death
.
[4]
If an artery in the brain starts bleeding, the bleeding can cause a
stroke
.
Arteriosclerosis and atherosclerosis
[
change
|
change source
]
When a person has
arteriosclerosis
, the walls of their arteries get harder, stiffer, and less stretchy. This makes it more difficult for blood and oxygen to get through the arteries to the body's important
organs
.
[5]
One type of arteriosclerosis is
atherosclerosis
. Atherosclerosis is a
disease
where the arteries get narrower because they are clogged up with things like
cholesterol
and
fat
. Like a clog in sink pipes makes it harder for water to get through the pipes, clogs in arteries make it more difficult for blood to get through. This makes the heart have to work harder to push blood through the arteries. Atherosclerosis is a big risk factor for
high blood pressure
and
heart disease
.
[5]
When atherosclerosis happens in the coronary arteries, it can cause
coronary heart disease
. If these arteries get too clogged, the heart will not get the blood and oxygen it needs to survive. This can cause
angina
,
a heart attack
,
heart failure
, or even
sudden death
.
[5]
When atherosclerosis happens in one of the arteries in the brain, it can cause a stroke.
An
aneurysm
is a bulge in the wall of an artery. It is like a little balloon, filled with blood, coming off the artery.
[6]
As the aneurysm gets bigger, it is more likely to break. If the aneurysm breaks ("ruptures"), the artery will start bleeding. If the artery is big, a person could bleed to death. Also, if an artery is bleeding, blood cannot get through it. The part of the body that the artery is supposed to feed will not get the blood and oxygen it needs. A ruptured aneurysm is a medical emergency.
[6]
- ↑
1.0
1.1
1.2
"Artery: Anatomy"
.
Britannica.com
. Encyclopædia Britannica. January 14, 2016
. Retrieved
January 29,
2016
.
- ↑
2.0
2.1
2.2
2.3
"Anatomy of the Aorta and Heart"
.
Cedars-Sinai Heart Institute ? Aortic Program
. Cedars-Sinai. 2016. Archived from
the original
on February 11, 2016
. Retrieved
January 29,
2016
.
- ↑
3.0
3.1
3.2
Human Biology and Health
. New Jersey: Prentice Hall. 1999.
ISBN
0-13-981176-1
.
- ↑
"U.S. Navy Standard First Aid Manual, Chapter 3: Bleeding"
.
United States Navy
. Retrieved
January 29,
2016
.
- ↑
5.0
5.1
5.2
Mendis, Shanthi; Puska, Pekka; Norrving, Bo (2011).
Global atlas on cardiovascular disease prevention and control
(PDF)
(1st ed.). Geneva: The World Health Organization, the World Heart Federation, and the World Stroke Organization. pp. 3?18.
ISBN
9789241564373
.
- ↑
6.0
6.1
DeBakey, Michael E. (September 12, 2014).
"Aneurysm: Pathology"
.
Britannica.com
. Encyclopædia Britannica
. Retrieved
January 29,
2016
.