test 3 - CV system pt 3 Flashcards
where does the pulmonary circuit begin and end?
- starts at pulmonary trunk
- ends at left atrium receiving blood from pulmonary vein
where does the systemic circuit begin and end?
- begins at aorta
- ends at right atrium
what are the 3 layers of a blood vessel wall from superficial to deep?
1) adventitia
2) media
3) intima
blood vessel wall layer: adventitia
- superficial
- thick CT (mostly collagen, some elastin) that binds vessels to surrounding tissues
- thickest layer in veins
blood vessel wall layer: media
- middle
- smooth muscle and loose CT
- alters vessel diameter and BP (vasoconstriction and dilation)
- external elastic membrane
blood vessel wall layer: intima
- deepest
- endothelial lining and dilation of CT
- internal elastic membrane
what are the 3 types of arteries?
1) elastic
2) muscular (aka distribution)
3) arterioles
what are examples of elastic arteries?
- aorta
- pulmonary trunk and arteries
- brachiocephalic trunk
- subclavian artery
- common carotid and iliac arteries
elastic arteries - characteristics
- large lumen
- thick intima
- media has a lot of elastic fibres (high pressure)
- few myocytes (do not respond to SNS or local factors)
what are examples of muscular (aka distribution) arteries
- radial
- ulnar
- basilar
- popliteal
- brachial
- vertebral
- splenic
- renal
muscular arteries - characteristics
- moderate lumen
- media is thicker with many more myocytes (under SNS and local factor control)
- prominent internal elastic membrane
arterioles - characteristics
- small lumen
- only visible with a microscope
- thin adventitia
- media is 1-2 layers of myocytes
- control BF between arteries and capillaries
atherosclerosis - def
- build up of plaque in artery
- can cause angina or myocardial infarction if in coronary artery
what are the 3 types of capillaries?
1) continuous
2) fenestrated
3) sinusoids
which are our most common capillaries?
-continuous - found everywhere except epithelia and cartilage (need blood flow)
continuous capillaries
- found everywhere except in epithelia and cartilage
- endothelium forms a complete lining, and endothelial cells connected by tight junctions and desmosomes
- single endothelial cell wraps all the way around the lumen
-only small molecules (e.g. ions) can pass
fenestrated capillaries
- contain windows, or pores, in their walls, due to incomplete or perforated endothelial lining
- far more permeable - allows molecules as large as peptides and small proteins to pass
- e.g. choroid plexus of brain, small intestine, endocrine glands, kidneys
sinusoids
- discontinuous capillaries
- resemble fenestrated capillaries that are flattened and irregularly shaped
- sinusoids are larger, and have gaps between endothelial cells
- sinusoids have thin basement membrane (sometimes absent)
- e.g. liver, bone marrow, spleen, adrenal glands
what is a capillary bed?
network of capillaries supplying blood to a specific organ or area of the body
what happens in a capillary bed?
-facilitates the exchange of nutrients, gases, wastes, and hormones between the blood and tissue cells
is the rate of blood flow constant in capillary beds?
- no
- blood flow can vary considerably
- BF occurs in series or pulses
- BF also changes due to anastomoses, metarterioles (precapillary sphincters)
what are the 3 types of veins?
1) large veins
2) medium sized veins
3) venules
give examples of large veins
- superior and inferior vena cava
- subclavian vein
- renal vein
- portal veins
large veins - characteristics
- intima and media are thin and difficult to distinguish
- adventitia is thick (collagen, elastin, and some myocytes)
examples of medium sized veins
- radial
- tibial
- popliteal (deep veins)
medium sized veins - characteristics
- usually found within the same CT sheath as muscular artery, three layers most distinguishable
- contain valves
venules - characteristics
smallest vein
-media is not complete or 1-2 layers of myocytes (mostly CT)
large veins have valves
true or false?
false, only medium sized veins have valves
which layer of medium sized veins creates the valves?
thickening of the intima
which type of vein do not have all 3 BV layers?
venules only have adventitia (and endothelial lining)
- do not have media
- (sometimes media is present, but very thin)
why do we only have a brachiocephalic trunk on the right side of the body?
-because heart is on the left, need a brachiocephalic trunk on the right because there is an increased distance to go
which vein do we use to donate blood?
medial cubital
look at whole body diagrams
lab 6 last pages
