Anatomy Anf Physiology Flashcards
Tunica intima
Inner layer of the vessel.
It has elastic lining of the endothelial cells that facilitates blood flow and prevents the blood cells from sticking to the walls
Tunica media
Middle layer which consists of smooth muscles and elastic tissues
Contains nerve fibre that respond to temp changes
These fibres cause spasm of the veins if there is a chemical or mechanical irritation to the vein
Tunica adventitia
Outer vessels layer consisting of tissue,collagen and nerve fibres. The nerve fibres are mainly from the sympathetic system which allows the vessels to constrict and dilate.
Vein assessment
A good vein for venepuncture or cannulation will be:
Bouncy
Soft
Devils easily when depressed
Visible
Large lumen
Well supported
Straight
Avoid veins that are:
Tortuous
Sclerosed
Thrombosed
Directly over joints
Small and visible but impalpable
Adjacent to localised infection site
Previous site of cannulations
Where there is inflammation
Choice of arm veins for venepuncture
Median cubital vein due to :
Proximity- closest to the surface
Immobility- most stationery
Comfort- less skin discomfort as skin is less sensitive above this vein
Of median cubital vein is absent the cephalic is next to be used
Which vein should you avoid using at all
The basilic as it could result in injury to the ante brachial cutaneous nerve and if the basilic artery is punctured it could result in bleeding to cause compartment syndrome
