Lecture 7 - Cardio microanatomy Flashcards
what are the 4 structures of the cardiovascular system?
- arteries
- capillaries
- veins
- heart
as the distance from the heart increases, what happens to the diameter of the arteries
decreases
what property allows arteries to accommodate large pressures
elasticity
smaller arteries can restrict and limit blood flow based on what property
contractility
what are the 3 categories of arteries
- conducting
- muscular
- arterioles
what is an example of a conducting artery
aorta
what is the primary job of conducting arteries
maintain even flow and constant blood pressure
summarize the properties of conducting arteries
- large volume
- tunica media contains elastic fibers
- tunica externa contains vessel supply
what are the 3 layers of blood vessels innermost to outermost
- tunica intima
- tunica media
- tunica externa
tunica intima
endothelium and basement membrane; internal elastic membrane
tunica media
smooth muscle; collagen and elastic fibers
tunica externa
external elastic membrane; loose irregular CT; nerves and small arteries present
summarize the properties of muscular arteries
- distributing (to limbs)
- tunica media contain >5 layers of smooth muscle
- regulates volume
summarize the properties of arterioles
- <5 layers of smooth muscle
- last branches before capillaries
- regulate blood volume
what two things can influence vasodilation or constriction
neurotransmitters and hormones
arterioles are described as ____ without ____
contractility; elasticity
capillaries consist of
basement membrane and endothelium
what are the three types of capillaries
- continuous
- fenestrated
- sinusoidal
what is an example of continuous capillaries
blood-brain barrier
gap junctions
what is an example of fenestrated capillaries
kidneys
what is an example of sinusoidal capillaries
liver
large holes
why are veins considered poorly developed relatives of arteries
same layers but more flimsy
T/F: veins contain valves to prevent retrograde flow
TRUE
venules have~____ times the diameter of capillaries
20
summarize the properties of medium veins
- valves
- increased collagen and elastic fibers
- more smooth muscle
- thin internal tunic, thick external
valves are extensions of
the tunica intima
summarize the properties of large veins
- thick subendothelium in the tunica intima
- poorly developed tunica media
- increased contractility
what are the four layers of the heart outermost to innermost
- pericardium
- epicardium
- myocardium
- endocardium
pericardium
- forms a sac around the heart with the epicardium
- fibrous pericardium and parietal pericardium
epicardium
- serosal surface (visceral pericardium)
- nerves, vessels, fat
myocardium
- same as tunica media
- cardiac muscle fibers
endocardium
- endothelial lining
- subendothelial region contains impulse-conducting fibers
what are the impulse-conducting fibers
Purkinje fibers
T/F: the heart is a voluntary muscle
FALSE
what allows for the quick transmittance of electrical impulses between muscle fibers
intercalated discs
what is considered the pacemaker cells
sinoatrial (SA) node
describe the SA node
- the medial wall of the right atrium
- spontaneously depolarizes
what transmits electrical signals to the atrioventricular bundle
atrioventricular (AV) node
where is the AV node
between atria, cranial edge of the interventricular septum
