Biology 3.1.2 Blood vessels

What is this part of the artery called?

What is this part of the vein called?

Blood go away from the heart through the [blank_start]arteries[blank_end], blood goes back to the heart through the [blank_start]veins[blank_end]

The largest arteries divide into smaller ones called [blank_start]arterioles[blank_end], then divide into [blank_start]capillaries[blank_end], which then join up to form [blank_start]venules[blank_end] which finally merge to form [blank_start]veins[blank_end]

The inner layer of blood vessels ([blank_start]tunica[blank_end] [blank_start]intima[blank_end]) is a thin layer of [blank_start]elastic[blank_end] tissue allowing it to [blank_start]stretch[blank_end]

The middle layer of blood vessels ([blank_start]tunica[blank_end] [blank_start]media[blank_end]) contain [blank_start]smooth[blank_end] muscle and [blank_start]elastic[blank_end] fibres

The outer layer of blood vessels ([blank_start]tunica[blank_end] [blank_start]externa[blank_end]) contain [blank_start]collagen[blank_end] and [blank_start]elastic[blank_end] tissue

Arteries are lined with [blank_start]squamous[blank_end] cells so it is a very [blank_start]smooth[blank_end] surface

Arterioles contain more [blank_start]smooth[blank_end] [blank_start]muscle[blank_end] which allows them to [blank_start]vasoconstrict[blank_end] and [blank_start]vasodiolate[blank_end]

The lumen of capillaries are very [blank_start]narrow[blank_end] so there is a small [blank_start]diffusion[blank_end] [blank_start]pathway[blank_end]

The walls of capillaries are [blank_start]porous[blank_end] so [blank_start]plasma[blank_end] and disolved substances can leave the blood

Blood flows towards the heart [blank_start]opening[blank_end] the valve and if blood flows away from the heart, the valve [blank_start]closes[blank_end], preventing [blank_start]backflow[blank_end]