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Anatomy Chapter 19


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how many miles of vessels?
60,000 miles
What are

Arteries- large and carry blood away from heart

Arterioles- small and carry blood away from the heart

Veins- large and carry blood To the heart.

Venules- small and carry blood to the heart

Cappilaries- small structures in between Veins and arteries.
From the last chapter we know that the lumen is the space in the vessel. Is the lumen smaller in arteries or veins?
Despite having thinner lumen the veins have (more/less) blood than arteries. Therefore we know...
Veins have less lumen and more blood (65%), thus we know it has higher pressure.
Where should blood pressure be taken? why?
On the left side of the body. Because it is closest to the heart to get the most accurate measurement.
The STRUCTURE of blood vessels allows for what 2 processes?
1. Blood flow

2. molecular exchange between blood and tissue.
Tunica externa
Tunica media
Tunica interna
Tunica Externa

-found where
- made of what tissue
- purpose
outside (external)

Connective tissue

protects, strengthens and anchors the vessel.
Tunica media

-found where
-made up of

Smooth muscle

allows for changes in diameter (vasodilation & constriction?)
Tunica interna

-found where
-made up of
Inside (internally)

Simple squamous epithelial tissue

allows for gas exchange
Artery structure
Arteries are more CIRCULAR, RIGID AND CANNOT collapse.
The largest arteries are

-which allows them to
more elastic

change diameters more so than smaller arteries.
How can large arteries change shape?
they are made up of elastic fibers in the tunica media which can change shape.
Medium sized arteries are more _________________ and less _____________ than large arteries.
Muscular; Elastic
Because they have more smooth muscle in the tunica media than do large veins (which have elastic fibers)
Medium sized arteries are full of smooth muscles giving them the ability to
Change their shape.

How do medium arteries change thier shape?
by smooth muscle contraction
Arterioles are the __________ of all arteries. There is less of ____________ and so the arteriole is only made up of _____________ allowing ______________.
smallest; tunica media and externa; tunica interna; diffusion of gases
Veins structurally are
NOT rigid and can collapse
Large veins contain
All tunica and have thickest layers (???)
Middle sized veins contain
ALL TURNICA but less turnica media (less smooth muscle)
Venules contain
NO TURNICA MEDIA (No smooth muscle)
What is the purpose of VENOUS valves?
The blood pressure is too low to get blood back to the heart and so the valves prevent blood from flowing away from the heart in the veins.
What is the skeletal muscle pump?
contracting skeletal muscles press agains the thin-walled veins, forcing valve proximal to the area of contraction open and propelling blood toward the heart.
What are vericose veins? AKA? caused by?
Dilated, swollen, painful, veins.

Caused by malfunctioning valves or long period of standing or inactivity.
Recall capillaries connect areteries and veins. What are the two classes of capillaries?
Continous capillary- made of complete endothelial tissue with NO HOLES.

Fenestrated capillary- "windowed" endothelial lining.
What is the purpose of having fenestrated "windowed" capilaries?
In places where exchange needs to be verry rapid, fenestrated capillaries allow for the speed of movement.
Which class of capillary is more COMMON?
Continuous capillaries.
The blood brain barrier is made up of what class of capillaries?
Continuous capillaries. we cannot have leaking in to the brain.
The Aorta is the
LARGEST ARTERY in the body.
What is the longest VEIN in the bodY?
The GReat Saphenous vein.
The hepatic portal system.

Hepatic= liver

Portal= connects two capillary beds.
What two capillary beds does the hepatic portal system connect?
Digestive organs (mostly small intestine)

Sinusoids of the Liver
hepatic portal system
Nutrient rich oxygen rich blood arrives in the intestines where the inferior and superior messenteric remove all nutrients and toxins and deposit them into the capillary bed of the digestive system.

The nutrients and toxins travel through the hepatic portal vein to the capillary bed in the sinus of the liver.

Here the nutrients and toxins are removed from the capillary bed.

Deoxygenated blood is then returned to the circulatory system via the hepatic vein.

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