Vasculature Flashcards
In what direction to arteries travel? veins?
arteries go from the heart
veins go to the heart
What are the exceptions to the rule of arteries (largest->smallest) and veins (smallest->largest)?
hepatic portal vein: brings blood from intestine capilary bed to liver capilary bed
Renal efferent arteriole: between glomerulus capilary and vasa recta capilary
What are the three common layers of arteries and veins?
tunica interna, tunica media and tunica externa.
Tunica intima is made up of?
endothelial cells (simple squamous), subendothelial layer and interal elastic lamina (IEL)
Tunica media is made up of?
circular smooth muscle, external elastic lamina (EEL)
Tunica externa is made up of?
connective tissue and fibroblasts.
What differs between arteries and veins in terms of the three common layers?
the width of the middle layer tunica media is much thinner in veins.
which of the three layers in arteries and veins changes with the size of the artery or vein?
tunica media (larger artery, larger tunica media)
What type of artery is the largest?
Elastic
What is present in tunica media of elastic arteries? What is present in tunica externa?
collagen, elastic fibres and some smooth muscle (not very visible), thickest layer.
Blood vessels and nerves, some fibroblasts and it is loose connective tissue, this layer is thin compared to tunica media.
Muscular arteries are what sized arteries? what is unique about their tunica interna? tunica media is made up of? tunica externa?
medium/small.
dense wavy IEL (internal elastic lumina)
smooth muscle and collagen
collagen, elastin, fibroblasts, adipose, clear EEL (external ealstic lumina), thick layer.
EEL separates what two layers?
tunica media and tunica externa.
What are metamerioles?
bypass channels that allow for thermoregulation of blood.
Precapillary sphincters response to what?
temperature changes and internal signals i.e. vasomotor control allows for constriction if needed (for heat loss/retain)
The microvascular bed is made up of?
- arterioles
- capillaries (smallest and is the ONLY palce gas exchange can occur).
- postcapillary venules
Which are bigger generally arteries or veins?
arteries. due to reduced tunica media in veins
Small arteries normally only have how many layers of endothelium (tunica interna)? smooth muscle (tunica media)?
very few cells, usually not a full layer, can usually count.
usually only one layer of smooth muscle.
What are the three types of capillaries and where are they located?
- continuous capillary (most common, least leaky, has pericytes, has a BM, has tight junctions, 6-7 endothelial cells in tunica interna): located in retina and iris.
- fenestrated: has pores bridged by diaphragm, has few pericytes and sometimes has a BM, located in choroid
- discontinous: large pores, most leaky, no pericytes, no BM, found in liver, spleen and marrow (only three places in body)
opthalamic artery enters orbit where?
within dura (dense CT that covers optic nerve) of optic nerve thru optic canal.
What is usually the first branch off the opthalamic artery?
central retinal artery.
Central retinal artery enters the dura aprx how far behind the globe?
10 mm
Once the central retinal artery enters dura where does it go?
passes thru lamina cribosa (in sclera), enters disk nasal to center.
Macula is positioned how to the optic disk?
temporally.
The inner retina is supplied by?
central retinal artery
collateral branches supply what?
CT surrounding optic nerve