Arteries

ARTERIES

  • The tubes which convey blood from the heart to various organs are called arteries. These are pulmonary and systemic arteries.
    • Pulmonary artery leaves the heart by a single trunk, subdivides and reaches the lungs. This is called as pulmonary circulation.
    • The systemic arteries originate from the aorta, which arise from the left ventricle and conveys pure blood to all parts of the body.
    • The branches which result from the division of an artery at the termination of its course are named as terminal branches.
    • The branches arising from an artery at varying intervals along its course are called collateral branches.
    • The arteries are surrounded by a layer of connective tissue and may become related to the structures like veins, nerves, muscles, bones and skin.
    • In bone marrow, heart, liver and small blood vessels differ from the capillaries as they are wider with irregular lumen and have no connective tissue covering.
    •  Their endothelial cells are in direct contact with cells of the organs and their walls are often incomplete. These vessels are called as sinusoids.

Anastomoses

  • Branches of adjacent arteries communicate with each other and form anastomoses.
  • When two vessels converge and unite with each other at their termination it is termed as anastomoses by convergence.
  • When two branches are directed towards each other and unite to form a single curved tube it is called as anastomoses by arches.
  • When the transverse branches connect the two adjacent parallel arteries it is termed as anastomoses by transverse communication.

Histology

  • The structure of the artery composed of three coats as tunica intima, tunica media and tunica adventitia.
  • The tunica intima is an endothelial lining with delicate layer of connective tissue and internal elastic lamina.
  • The tunica media consist of smooth muscle cells with varying amount of collagenous and elastic tissue.
  • The tunica adventitia consists of external elastic lamina and connective tissue.
Last modified: Wednesday, 2 May 2012, 7:07 AM