Blood vessels Flashcards
What are the different types of blood vessels?
Arteries
Veins
Capillaries
Where do arteries carry blood?
What do they branch into?
Carry blood away from the heart
Branch to form arterioles
Where to veins carry blood?
What are the smallest veins called?
Carry blood towards the heart.
Smallest veins are called venules.
What are capillaries?
Smallest blood vessels.
Site of exchange between blood and tissue fluid
Provide a schematic of blood flow.
SVC/IVC/CS –> RA –> T –> RV – PSLV –> PT –> LPA, RPA –> Lungs –> 4 PV –> LA –> BV/MV –> RV –> ASLV –> Aorta, CA –> Body
What are the three layers of blood vessels>
Tunica intima/interna
Tunica media
Tunica externa
What is the tunica intima?
Simple squamous epithelium
Intimate contact with blood
What is the tunica media?
Sheets of smooth muscle, elastic CT, collagen
What layer allows for vasoconstriction/dilation? How?
Tunica media
Contract - constrict
Relax - dilate
What is the tunica externa composed of?
CT
What is the lumen of the blood vessels?
Central, blood-filled space of a vessel
What are the differences between the arteries and veins?
Arteries are more elastic - external elastic membrane
- arteries have a larger smooth muscle layer
- lumen of artery is circular (Even without blood)
Veins have valves
- veins have a thinner tunica media (less smooth muscle)
- lumen of vein is more floppy (especially without blood)
What are the different types of arteries?
Elastic
Muscular
(Arterioles)
What are elastic arteries?
Conducting arteries
The largest arteries - aorta and its major branches
high elastic content (dampens surge of blood pressure)
Thick tunica media, lots of elastic fibres
What are muscular arteries?
Distributing Lie distal to elastic arteries Thick tunica media Unique structures: - internal and external elastic laminae Can contract or relax to change the amount of blood going to certain organs
Describe arterioles.
Smallest arteries
Larger arterioles have all three tunics
Close to capillary beds
Describe the control of arteriole diameter.
Due to local factors in the tissues and the sympathetic nervous system
What are capillaries?
Smallest blood vessels
Renew and refresh surrounding tissue fluid
RBCs pass in a single file
What are the site-specific functions of capillaries at the: lungs SI endocrine glands kidneys
Lungs - oxygen enters blood, carbon dioxide leaves
SI - receives digestive nutrients
Endocrine glands - picks up hormones
Kidneys - removal of nitrogenous wastes
What are capillary beds?
Network of capillaries running through tissues.
What are metarterioles?
Intermediate between capillary and an arteriole
What is a thoroughfare channel?
Intermediate between capillary and venule
What are precapillary sphincters?
Regulate blood flow through capillaries.