blood vessels Flashcards
what are the parts of the artery
-Lumen
-Endothelium
-Smooth muscle and elastic tissue
-Connective tissue
what is the role of the lumen in the artery
-relatively narrow to maintain a high blood presssure
what is the role of the endothelium in the artery
-forms the inner layer (known as tunica interna) of an artery wall
-consists mainly of endothelial (same as epithelial except in blood cells) cells to form a lining
what is the inner layer of an artery wall or vein wall known as
tunica interna
what is the outer medium layer of an artery or vein known as
tunica media
what is the role of the smooth muscle and elastic tissue in the artery
-forms middle, thickest layer of an artery wall (tunica media)
-enable artery to flex (muscle contracts) and stretch (elastic tissue)
-overall role to maintain a high blood pressure
what is the role of the connective tissue in an artery
-form the outer layer of an artery wall (tunica externa)
-consists of tough collagen fibres which provide strength and durability
-overall role to withstand a high pressure
what is the outer layer of a artery and vein known as
tunica externa
what do veins contain that is unlike capillaries and artery’s and what is the role
-valves
-prevent backflow and pooling of blood in lower parts of body due to gravity
what is the role of the lumen in the vein
-is relatively larger as there is no need to maintain a high prerssure
what is the role of the endothelium in the vein
-form the inner layer (tunica interna) of a veins wall
-forms lining from endothelial cells
what is the role of the smooth muscle and elastic tissue in the vein
-forms the tunica media like artery
-however is much thinner as it does constrict but much less
what is the role of the connective tissue in a vein
-same as an artery however much less of it as doesn’t need to be as strong
how does blood flow through veins?
-Skeletal muscles contract
-Blood beyond site of contraction is forced towards the heart
-opening valves
-valves behind contraction site prevent blood being forced away from heart
role of lumen in capillary
-very narrow (diameter of one red blood cell)
-slows down blood flow so substances can diffuse in and out
-has a high SA to V ratio
role of the endothelium in a capillary
-very thin (one cell thick) to allow efficient diffusion
role of the basement membrane in a capillary
-is not a layer of cells
-rather, anchors capillaries in position within the tissues
parts of a capillary
-lumen
-endothelium
-basement membrane
relative size of lumen of all three vessels
Arteries>veinbs>capillaries
relative thickness of walls of all three vessels
Arteries>veins>capillaries
what are the tissues of the walls of capillaries
-only one layer of endothelial cells
what are the tissues in the walls of arteries and veins
-endothelium
-elastic tissue
-smooth muscle and connective tissue
difference between the tissues in the walls of arteries and veins
-veins have less smooth muscle and elastic tissue than arteries
-because they deal with low-pressure blood return and rely on passive mechanisms (like muscle pumps and valves) for blood movement
direction of flow of blood (relative to the heart) in all three vessels
Arteries- Away
Capillaries-Between arteries and veins where exchange/diffusion occurs
Veins- Towards the heart
type of blood (o2 content) in arteries
-oxygenated blood from heart to rest of body
-except pulmonary artery from heart to lungs for re-oxygenation
type of blood (o2 content) in capillaries
-oxygenated blood from arties into capillaries in tissues
-deoxygenated blood from capillaries into veins to return to heart
type of blood (o2 content) in veins
-deoxygenated blood back to heart after delivery of O2 and pickup of CO2
-except pulmonary veins which transport oxygenated blood from lungs to left atrium of heart
presence of valves in all 3 vessels
1)arteries- none
2)capillaries- none
3)veins- has valves
blood pressure in all 3 vessels
1)Arteries= high
2)Capillaries= low to facilitate exchange
3)Veins= very low as blood retuning to heart relies on muscle contractions and valves
role and structure of the arteriole
-contain smooth muscle to constrict diameter of arteriole to divert flow of blood to regions of body that need O2
-distributes blood from artery to capillaries
role and structure of the venule
-collect blood from capillary bed into the veins
-thin layers of elastic + muscle tissue and endothelium on outside
-thin outer layer of collagen
