Circulatory System

• Circulatory system


  Concerns the distribution of substances after being absorbed or secreted in the body
• Substances distributed by the circulatory system

  • Gaseous materials
  • Hormones
  • Digested products
  • Vitamins
  • Minerals
  • Metabolic wastes
  • Other substances which every cell needs for its metabolism
• Vertebrate circulatory system

  • Heart
  • Closed system of vessels (arteries, veins, lymphatic vessels, capillaries)
  • Blood and lymph
  • Carrier media
• Pulmonary circulation


  1. Right ventricle pumps deoxygenated blood to lungs

  2. Oxygenation and CO2 excretion in lung capillaries

  3. Oxygenated blood flows from lungs to left atrium
• Systemic circulation


  1. Oxygenated blood from left ventricle pumped into aorta

  2. Gaseous exchange between tissues and capillaries

  3. Venous system returns CO2-laden blood to right side of heart
• Heart


  • Located in thoracic cavity
  • Surrounded by pericardium
  • Consists of left and right ventricles, left and right atria
• Coronary artery

  • On surface of heart and its branches
• Superior vena cava


  • Returns blood from head and shoulder to right heart
• Inferior vena cava


  • Returns blood from organs below diaphragm to right heart
• Pulmonary artery


  • Carries blood from right ventricle to lungs
• Aorta


  • Arches to left just anterior to heart
• Pulmonary veins


  • Empty into left atrium
• Pulmonary semilunar valve


  • Valve at exit of pulmonary artery from right ventricle
• Tricuspid valve


  • Separates right ventricle from right atrium
• Chordae tendineae


  • Connective tissue strands that hold valves to papillary muscle of ventricle, preventing blood from being forced into atrium when ventricle contracts
• Atrial myocardium


  • Thinner than ventricular myocardium
• Septa


  • Walls between right and left heart
  • Interatrial septum separates left and right atria
  • Interventricular septum separates left and right ventricles
• Pulmonary artery


  • Leaves right ventricle to lungs
• Aorta


  • Vessel that leaves left ventricle
• Ascending aorta


  • First part of aorta, gives rise to coronary arteries
• Brachiocephalic artery


  • Large straight artery running anteriorly on right side of aortic arch
• Right subclavian artery


  • Branch of brachiocephalic artery running to right arm
• Right and left common carotid arteries

  • Branches of brachiocephalic passing anteriorly alongside trachea
• Internal mammary artery


  • Springs from ventral surface of subclavian artery
• Vertebral artery


  • Arises from dorsal surface of subclavian artery
• Costocervical axis


  • Branch of subclavian artery
• Thyrocervical axis


  • Branch of subclavian artery
• Axillary artery


  • Subclavian artery passing in front of first rib into axilla
• Ventral thoracic artery


  • Passes medially to medial ends of pectoral muscles
• Long thoracic artery


  • Passes posteriorly along middle region of pectoral muscle and then to latissimus dorsi
• Subscapular artery


  • Large artery near the arm
• Left subclavian artery


  • Arises directly from arch of aorta, has same branches as right side
• Thoracic aorta


  • Aorta coursing along thorax, gives off paired intercostal arteries
• Abdominal aorta


  • Gives off unpaired median visceral branches to digestive tract, paired lateral visceral branches to kidneys and reproductive organs, and paired somatic branches to body wall
• Coeliac artery


  • Anterior branch of abdominal aorta, divides into hepatic, left gastric, and splenic arteries
• Superior mesenteric artery


  • Supplies greater part of intestine, gives rise to middle colic, posterior pancreaticoduodenal, and ileocolic arteries
• Adrenolumbar arteries


  • Small paired branches supplying adrenal gland and muscles of back and diaphragm
• Renal arteries


  • Large paired arteries supplying kidneys
• Genital arteries


  • Posterior to renal arteries, supply reproductive organs (spermatic/testicular artery in males, ovarian artery in females)
• Inferior mesenteric artery


  • Unpaired, caudal to genital arteries, supplies large intestine