Genbio2 lesson 3.2

• Circulatory system


  • Helps an organism transport nutrients, gases, and waste materials - all of which are necessary for life
• There are animals that have no circulatory system
• Diffusion


  Process by which an animal such as hydra with a body thickness of only one to three cells can use to digest food and transport nutrients to all its cells from the environment
• Types of circulatory systems

  • Open circulatory system
  • Closed circulatory system

  
• Open circulatory system


  • Used by invertebrates, mollusks, and arthropods
  • The circulatory fluid is not restricted to the vessels, it flows out of the vessels into the tissues
  • There is no separate circulatory and interstitial fluid
  • In insects, a heart pumps to distribute the body fluid (hemolymph) throughout the body, using body movements, during which the exchange of materials occurs

  
• Closed circulatory system


  • Used by earthworms, octopuses, and vertebrates
  • Has a circulatory fluid called blood
  • Blood is restricted inside the vessels and is different from the interstitial fluid
  • Three types of vessels are used: arteries, veins, and capillaries

  
• Atria


  Receive blood in the human heart
• Ventricles


  Pump blood to the lungs and the body in the human heart
• Atrioventricular valves


  Prevent the backflow of blood when it is pumped in the human heart
• Semilunar valve


  Prevent the backflow of blood when it is pumped from the left ventricle to the aorta in the human heart
• Blood circulation in the human body

  1. Oxygen-poor blood from the body goes back to the heart, then pumped to the lungs, where gas exchange occurs

  2. Oxygen-rich blood flows back to the heart to be pumped to the rest of the body
• Blood


  A connective tissue composed of 55% plasma liquid and 45% blood cells and other cells dissolved in the fluid
• Components of blood


  • Red blood cells (Erythrocytes)
  • White blood cells (Leukocytes)
  • Platelets (Thrombocytes)
• Red blood cells


  Transportation of gases and nutrients
• White blood cells


  Protection against illness and disease
• Platelets


  Function in blood clotting
• Photosynthesis


  Process by which plants produce their own food, using carbon dioxide from the air and water and minerals from the soil
• Cellular respiration


  Process by which plants break down sugar for energy production, using oxygen from the atmosphere or the soil
• Internal environment


  The fluid environment that bathes the cells composed of the interstitial fluid and blood
• Osmosis


  The movement of water within the body from the region of higher osmolarity to a region of lower osmolarity across a selectively permeable membrane
• Osmoregulation


  The physiological processes that maintain a fixed concentration of cell membrane-impermeable molecules and ions in the fluid that surrounds cells
• Water potential


  The driving force for the movement of water in plants, which is regulated by transpiration and the absorption of water by the roots
• Transpiration


  The process by which water loss occurs from the leaves and other plant surfaces, creating a negative pressure that pulls water up through the xylem