Transcript PowerPoint - Bio12.com

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Blood vessels
Basis of
Contrast
Artery
Structure
Thick, elastic
walls
Very thin
walls
Thin walls;
Contain
valves
Function
Transport
blood away
from heart
Connect
arteries to
veins
Transport
blood back to
heart
Location
Capillary
Usually deep, Everywhere
along bones
Vein
Often near
surface
Arteries are defined as
blood vessels that carry
blood away from the heart.
In most cases they are
delivering oxygenated
blood to the body tissues.
This is the SYSTEMIC CIRCULATION
(since it is going to the systems)
The pulmonary artery
transports
deoxygenated blood
from the heart to the
lungs.
This is part of the PULMONARY CIRCUIT
Veins are defined as blood
vessels that transport
blood back to the heart.
In the systemic circuit, they
transport deoxygenated blood;
In the pulmonary circuit, they
transport oxygenated blood;
Arteries and veins have
structural differences as well.
The arterial wall are able to expand
and receive a quantity of blood
every time the heart pumps.
Approximately 70 ml is pumped into
the aorta with each contraction of
the left ventricle. The resulting
expansion of the walls of the arteries
is detected as the pulse.
Arteries and veins have
structural differences as well.
The veins are relatively thinwalled. They do not receive any
large volumes of blood or
pressures from blood flow.
Veins also contain valves to assist
with the upward movement of blood
back to the heart. The valves
prevent back flow.
The third type of blood vessels
are capillaries. These blood
vessels are so tiny that they will
only allow blood cells through
them one at a time.
They are also very thin-walled…
thus helping with the delivery of
materials to and from cells in a
process of capillary fluid exchange
Two other types of blood vessels are often
described. They are arterioles and venules
(small arteries and small veins). All the features
of arteries and veins apply to arterioles and
venules (respectively), but on a smaller scale.
In addition, arterioles leading into a particular
organ or region are equipped with sphincter
muscles. When triggered, these can dilate or
constrict to regulate blood pressure and flow to
the intended
capillary beds.
AORTA
This is the major blood vessel carrying
oxygenated blood out of the heart.
It leaves the left ventricle, loops over the top
of the heart creating the structure known as
the aortic arch before descending along the
inside of the backbone (= dorsal blood
vessel). Branches from this blood vessel feed
all the body systems except the lungs.
Coronary arteries and veins
The very first branches off the aorta are the
coronary arteries. These relatively small
blood vessels can be seen on the surface of
the heart. They feed the heart muscle. The
heart does not receive its nutrients from the
blood that travels through it. The muscle
tissue is too dense and thick and the blood is
travelling though it too hard and fast. The
coronary veins take the "spent blood" back
to the vena cava.
Carotid arteries
These branches of the aortic arch take the blood to the
head (including the brain). They are highly specialized
in that they contain a number of different types of
nerve endings:
chemoreceptors that detect oxygen content, and
pressure receptors that detect blood pressure changes.
These features are essential for homeostasis. The
carotid arteries run reasonably close to the surface,
and the pulse in the carotids can usually be easily
found along the sides of the neck.
Jugular veins
Unlike most arteries, which are paired with
veins having a corresponding name, the jugular
veins are the match for the carotid arteries. As
such, they conduct blood out of the head region
to the anterior vena cava. The jugular veins do
not contain valves. The blood flowing through
them is under the influence of gravity. (When
you stand on your head, the blood stays in your
head!)
Subclavian arteries and veins
The subclavian arteries also branch from the
aorta (see diagram). The subclavians, as their
name suggests travel under the clavicle
(collarbone) and branch to feed the arms
(brachial artery) and the chest wall etc. An
interesting feature of the subclavian veins is that
just before they join the anterior vena cava to
return the blood to the heart, they meet up with
the major lymphatic ducts.
Mesentaric arteries
These arteries branch off the aorta as it
travels posteriorly. They go to the intestines
where they subdivide to form the capillaries
that can be identified in the villi. In addition
to feeding the organs of the digestive system,
they pick up the newly digested nutrients and
carry them away. The mesentaric vein is
reduced in structure and function because of
the hepatic portal vein.
Hepatic portal vein
This vein transports blood rich with nutrients
directly from the intestines to the liver. Hepatic
means liver;portal indicates that there is a
capillary bed on both ends of it. The liver
detoxifies blood, destroys aged red blood cells,
and regulates the glucose concentration in the
blood
Hepatic vein
When the blood leaves the liver it returns
to the venous system. The hepatic vein
carries the blood to the
posterior vena cava.
Renal arteries and veins
The renal arteries branch off the dorsal
aorta as it passes through the lumbar
region of the body. They take blood to the
kidneys while the renal veins take blood
away from the kidneys and back to the
posterior vena cava.
Iliac arteries and veins
When the dorsal aorta gets to the pelvic
region, it branches into two iliac
arteries, one goes down each leg. The
femoral artery is a major branch of the
iliac artery . The femoral artery
services the large quadriceps
muscle of the leg.
Anterior and Posterior Vena Cava
The vena cavae collect up all the blood from
the various veins of the systemic circuit and
conduct it back into the right atrium. The
anterior vena cava services the anterior part
of the body, while the posterior services the
posterior part.
Note: anterior = superior
posterior = inferior
Pulmonary veins and arteries
Reflecting back on the difference between
systemic and pulmonary circuits, all of the blood
vessels listed so far are part of the systemic
circuit.
The pulmonary circuit is comprised of the
pulmonary trunk and arteries that take
deoxygenated blood from the right ventricle to
the lungs while the pulmonary veins take
oxygenated blood from the lungs
to the left atrium.
For the rest …
Blood, Antigens and Antibodies as
well as Capillary Fluid Exchange,
Fetal Circulation and the
Lymphatic System see the handout.
Once you’ve had a good read
attempt the Vocabulary exercise for
Unit J.