Lecture Test 3 Part 1 Flashcards
Blood vessels form a network of tubes that carry blood away from the heart, delivering
oxygen to the tissues through the capillaries and then returning it deoxygenated to the heart
What is the pathway to the cardiovascular system?
heart arteries arterioles metarteriole capillary venules veins heart
A 150 lb person has roughly
60,000 miles of vessels in the body
What is significant of the arteries?
vesssels carry blood away from the heart
blood is usually oxygenated
has a large diameter
has 3 layers of tissue that make up the artery wall
What are the three layers of the artery wall?
tunica intima
tunica media
tunica externa
what is the tunica intima of an artery?
deepest tunica consisting of endothelium and an internal elastic membrane
what is endothelium?
single layer of epithelial cells lining the heart and vessels
what is the tunica media of an artery?
usually the thickest layer consisting of smooth muscle and in some vessels an external elastic membrane
what is the tunica externa of an artery?
elastic and collagen fibers
Due to the presence of elastic fibers, arteries will
expand during systole and recoil during diastole. A pulse can also be detected
A pulse can be detected in
a superficial artery that lies over a bone or other firm tissue
What are arterioles and metarterioles?
small arteries
connect arteries with capillaries
important in the regulation of flow of blood to the capillaries
what are capillaries composed of?
a single layer of epithelium
where are capillaries found?
throughout the body except the lens, cornea, epithelium and cartilage
What is the size of the lumen of the capillaries?
large enough to allow one RBC to flow per unit of time
What is significant of the size of the lumen of the capillaries?
allows for diffusion of gases in and out of the RBC; decreased velocity
capillaries exist in
capillary beds
When tissue needs are low, blood will
flow only through a small portion of the capillary bed.
When tissue needs are high,
the entire capillary bed is full of blood
Capillaries are the
site of material moving in and out of the circulatory system.
What is the bulk flow in the capillaries?
ions, proteins, other nutrients and water
The bulk flow out of the capillary happens
at the arteriole end
What happens at the venule end of the capillary?
the fluid moves into the capillary from the tissues spaces
In health, majority of the fluid at the arteriole end of the capillary is
reabsorbed at the venule end