GENBIO2L - M8

• The circulatory system primarily functions for transport of respiratory gases, food materials, waste products, hormones, and minerals within the body
• The circulatory system also functions for defense against foreign organisms
• The circulatory system maintains body temperature in warm-blooded or homeothermic animals
• Closed type of circulatory system in vertebrates

  • Heart
  • Arteries
  • Arterioles
  • Veins
  • Venules
  • Capillaries
• The heart pumps deoxygenated blood to the lungs and distributes oxygenated blood to all the organs
• Arteries and arterioles


  Convey oxygenated blood from the heart to capillaries
• The pulmonary artery delivers deoxygenated blood to the lungs for oxygenation
• Deoxygenated blood is collected from the capillaries to venules and to the veins before it returns to the heart
• The pulmonary vein collects oxygenated blood from the lungs and delivers it back to the heart
• Procedure for dissection


  1. Obtain etherized toad

  2. Place ventral side up

  3. Lift skin with forceps

  4. Make a slit from abdomen to jaw

  5. Separate skin from muscle
• Procedure for observing the heart

  1. Lift cut muscle

  2. Observe anterior abdominal vein

  3. Cut sternum longitudinally

  4. Pull apart pectoral girdle

  5. Study parts of the heart
• Heart


  Cone-shaped muscular organ lying in the thorax
• Associated structures and parts of the heart

  • Pericardium
  • Pericardial cavity
  • Atria
  • Ventricle
  • Conus arteriosus
  • Sinus venosus
• Pericardium


  A thin transparent membrane covering the heart
• Pericardial cavity


  Coelom/cavity where the heart is situated
• Atria


  Two globular structures atop the ventricle
• Ventricle


  Most posterior conical structure of the heart
• Conus arteriosus


  A cone-shaped tube arising from the ventricle on its ventral side
• Sinus venosus


  A thin-walled triangular sac on the dorsal side of the heart continuous with the right atrium
• Internal structures in the heart

  • Inter-atrial septum
  • Atrioventricular valves
  • Semilunar valves
• Inter-atrial septum


  Wall separating the right from the left atrium
• Atrioventricular valves


  Thin flaps between the atria and ventricle
• Semilunar valves


  Flaps that open into the conus arteriosus
• Venous system areas


  • Systemic veins
  • Portal veins
  • Pulmonary veins
• Systemic veins


  Receive deoxygenated blood from different parts of the body
• Portal veins


  Include hepatic portal and renal portal
• Hepatic portal vein


  Can be seen by deflecting the left lobe of the liver
• Renal portal veins


  Located on the lateral margin of each kidney
• Pulmonary veins


  Enter the left atrium or auricle
• Arterial system


  Supplies oxygenated blood to different parts of the body
• Conus arteriosus


  A cone-shaped or bulb-shaped structure located between the auricles
• Branches of truncus arteriosus

  • Common carotid artery
  • Systemic arch
  • Pulmocutaneous artery
• The term urogenital is a combination of the Greek word ouro meaning urine and genitales referring to reproduction
• The urinary or excretory system and reproductive system are functionally separate but develop from a common germ layer origin
• The main organs of the excretory system are the kidneys
• The kidneys are retroperitoneal in position
• Nephrons remove waste products of metabolism from the body and regulate the amount of ions inside the body
• Urine from the kidneys is collected by mesonephric ducts which convey the urine to the urinary bladder
• The urinary bladder lies ventral to the cloaca
• Principal organs of the reproductive system

  • Testes
  • Ovaries