PHYSIOLEC

• Unicellular organisms and some small metazoans lack circulatory systems
• Unicellular organisms and small metazoans rely on diffusion to transport molecules
• Large animals move fluid through their bodies by bulk flow or convective transport
• Bulk flow can transport over great distance
• Blood Function:
• Blood Function: remove toxic substance and supply nutrient and oxygen
• Moves fluid throughout the body by changing (increasing) pressure in the different parts of the body.
• Fluid flows through “Pressure gradient”
• 3 components:

  • Pump (e.g. Heart)
  • System of tubes, channels or vessels (e.g. arteries and veins)
  • Fluid (e.g. Blood and hemolymph)
• Arteries


  Vessels that carries blood away from heart
• Veins


  vessels that carries blood toward heart
• Blood


  Any fluid inside the vessel
• Components of Blood

  • Plasma
  • Buffy Coat (WBC, pH)
  • RBC
• Types of Pumps

  • Chambered hearts
  • Skeletal muscle
  • Pulsating blood vessels
  • One-way valves
• Chambered hearts are contractile chambers
• Skeletal muscle squeeze on vessels to generate pressure
• Peristalsis is the rhythmic contractions of vessel wall to generate pressure and pumps blood
• One-way valves help to ensure unidirectional flow
• Peristalsis are arteries that are responsible for the movement of blood through the body.
• Closed circulatory system

  Circulatory fluid remains within vessels and does not come in direct contact with the tissues
• In closed circulatory system circulating fluid is distinct from interstitial fluid
• Example of species belonging to closed circulatory system

  Annelid (oligochaete), Vertebrata
• Open circulatory system

  Circulatory fluid comes in direct contact with the tissues in spaces called sinuses
• In open circulatory system, circulating fluid mixes with interstitial fluid
• Species with Open circulatory system

  • Clams (bivalve mollusc)
  • arthropoda
  • cephalochordata
  • Urochordata
• Metazoans with no circulatory system

  • Echinodermata (water vascular system used to move O2 and nutrients)
  • Nematoda (muscle contraction moves interstitial fluids)
  • Platyhelminthes (ciliated cells move interstitial fluid by bulk flow)
  • Porifera (water pumped through body cavity by beating of flagellated cells)
  • Cnidaria (water pumped through gastrovascular cavity by muscle contractions)
• Interstitial fluid

  Extracellular fluid that directly bathes the tissues
• Blood


  Fluid that circulates within the vessels of a closed circulatory system
• Lymph

  Fluid that circulates in the secondary circulatory system of vertebrates; the lymphatic system

  Carries fluid (lymph) that has filtered out of the vessels
• Chyle


  milky bodily fluid consist of lymph and emulsified fats
• Lymphatic system

  secondary circulatory system that absorbs fat
• Lymph vascular

  absorb filtered blood
• hemolymph


  Fluid that circulates in an open circulatory system
• Lymph is similar in composition to blood except that it lacks blood cells and large proteins.
• Lymph is formed from blood by a process called ultrafiltration in the small blood vessels.
• most fish have a secondary circulatory system that may be the evolutionary progenitor of the lymphatic systems of terrestrial vertebrate
• Most fish, with the exception of lungfish, lack a true lymphatic system,
• Hemolymph flows through blood vessels, but when it enters the sinuses it directly contacts the tissues, and thus is continuous with the interstitial fluid
• Blood vessels are complex wall surrounding a central lumen.
• Blood vessels are made of three layers: tunica intima, tunica media, and tunica externa