6.3 Blood Vessels Flashcards
From the heart, oxygenated blood is pumped in pulses through arteries and then through smaller vessels called…
Arterioles
Arterioles travel to…
All organs of the body
Inside organs blood flows through…
Capillaries
Blood in the capillaries supplies the organ with…
The substances it needs (oxygen & glucose) and removes waste products (carbon dioxide)
Deoxygenated blood leaves the organs and carries it back to the heart in…
Venules - which join together to form veins
Arteries have a…
- thick muscular wall
- much elastic tissue
- small lumen relative to diameter
- capable of constriction
- not permeable
- no valves
- transports blood from the heart
- oxygenated blood except in pulmonary
- blood under high pressure
- blood moves in pulses
- blood flows rapidly
The elastic wall springs backs after it has stretched to keep the blood under pressure and smoothing out the pulses…
Elastic recoil
Outermost of tough collagen fibres…
Stop the artery bursting under pressure
The lumen is relatively small which…
Keeps the blood under high pressure
Vessel is lined with a smooth layer called…
Endothelium - reduces friction as blood flows rapidly through
Veins have…
- thin muscular wall
- little elastic tissue
- large lumen relative to diameter
- not capable of constriction
- not permeable
- valves throughout all veins
- transports blood to the heart
- deoxygenated blood except in pulmonary vein
- blood under low pressure
- no pulses
- blood flows slowly
Has a thinner layer of elastic fissure in its wall because blood in the veins is under…
Much lower pressure than in the arteries
The muscle layer is also…
Thin because it carries blood away from organs (can’t carry blood to organs)
Just as many collagen fibres as arteries…
Veins flow closer to the skin surface than arteries, and the collagen fibres protect the veins from injury
Wider lumen than in the artery because…
Blood is under lower pressure so it flows more slowly
Thin, smooth endothelium helps…
The blood to flow along without excessive friction
Veins contain valves which are…
Next to the body muscles (e.g. Legs) when muscles contract they press agains the blood inside the vein and make it move - prevent backflow and keep the blood moving back towards the heart.
Capillaries have…
- no muscle
- no elastic tissue
- large lumen relative to diameter
- not capable of constriction
- permeable
- no valves
- links arteries to veins
- blood changes from oxygenated to deoxygenated
- blood pressure reducing
- no pulses
- blood flow slowing
Capillaries’ Lumen very small…
Just the right size for blood cells to move through one at a time
Capillaries have no collagen, muscle or elastic fibres in its wall, consists only of endothelium…
A layer of thin, flattened cells that make the vessel permeable, allow the capillary to exchange materials (including oxygen and carbon dioxide) with body tissues
Spaces between the endothelium cells in capillaries…
Allow white blood cells to escape from the capillaries into the tissues
