BIOM1060 Lecture Notes - Lecture 19: Tunica Intima, Tunica Externa, Brachiocephalic Artery
BIOM1060 21/03/18
CARDIOVASCULAR SYSTEM ANATOMY (Part 2)
BLOOD VESSELS AND LYMPHATIC SYSTEM
Arteries vs veins vs capillaries
Function
Construction
Arteries
Carry oxygenated blood away
from heart
- Thick tunica media
- Small lumen
- Muscular wall
- Elastic lamellae (expand and recoil)
Veins
Return deoxygenated blood to
heart
- Thick tunica externa
- Large lumen
- Scant smooth muscle
Capillaries
Exchange of gases, nutrients and
waste products
- Only have thin tunica intima (allow
permeability for gas exchange)
Arteries
- Elastic artery: elastic laminae allow recoiling (resist large pressures)
o Eg. aorta, pulmonary trunk, brachiocephalic trunk, subclavian and iliac arteries
- Muscular artery: smooth muscle dominates wall (distributing)
o Eg. external carotid arteries, arteries of the limbs (ie.
brachial and femoral)
Veins
- Low pressure system - prevention against backflow needed
- Valves created by infolds of tunica intima
- Muscle spindlings contract and push on veins to propel blood
Distribution of blood
- Affected by pressure/resistance in cardiovascular system
- Blood vessel walls contain smooth muscle (alter diameter)
o Vasoconstriction or vasodilation
o Brain demands constant, uninterrupted blood supply
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Document Summary
Only have thin tunica intima (allow permeability for gas exchange) Elastic artery: elastic laminae allow recoiling (resist large pressures: eg. aorta, pulmonary trunk, brachiocephalic trunk, subclavian and iliac arteries. Muscular artery: smooth muscle dominates wall (distributing: eg. external carotid arteries, arteries of the limbs (ie. brachial and femoral) Low pressure system - prevention against backflow needed. Valves created by infolds of tunica intima. Muscle spindlings contract and push on veins to propel blood. Blood vessel walls contain smooth muscle (alter diameter: vasoconstriction or vasodilation, brain demands constant, uninterrupted blood supply. Right ventricle (deoxygenated) pulmonary trunk l or r pulmonary artery lung (oxygenated) l or r pulmonary vein (2 of each) left atrium. Ascending aorta: location of two coronary arteries (backflow during ventricular diastole closes aortic valve and blood flows into coronary arteries: supply cardiovascular muscles. Thoracic aorta: provides small branches to thoracic viscera and posterolateral wall: supplies pericardium, lungs and bronchi and oesophagus.
