Veterinary Histology and Embryology

CIRCULATORY SYSTEM

• The circulatory apparatus consists of a cardio vascular system and lymphatic system.
• Cardiovascular system consists of
  • A central propelling organ- the heart
  • A series of efferent tubes - the arteries, which by branching constantly increase in number and decrease in caliber and which serve to carry the blood form heart to the tissues,
  • Minute anastamosing tubules - the capillaries into which the arteries empty and through the walls of which the interchange of elements between blood and the other tissue takes place,
  • A system of converging tubes (the efferent tubes) - the veins which receive blood form the capillaries, unite to form large vessels as they approach the heart; and serve for draining the blood from that organ.
• The lymphatic system consists of lymphatic glands or nodes and lymphatic capillaries and various sized lymphatic vessels, which ultimately drain into two main trunks, the thoracic duct and right lymphatic duct.