GAS EXCHANGE AND TRANSPORT/CIRCULATION

• Gas exchange


  The movement of gases across a cell membrane, which means taking in oxygen needed by cells and removing carbon dioxide as waste product
• Transport


  The movement of substances within an organism. Substances like oxygen must be transported across the cell membrane and within the organism
• Circulation


  The movement of blood through the vessels of the body induced by the pumping action of the heart
• All living organisms obtain energy by metabolizing compounds such as carbohydrates. The process by which organisms require oxygen for metabolism is called respiration. Carbon dioxide gas is produced and must be removed from the body of animals. In plants, carbon dioxide, a waste product of respiration, is needed for photosynthesis.
• Diffusion


  A process by which molecules move from an area of higher concentration to an area of lower concentration in the direction following a concentration gradient
• Ways animals obtain oxygen

  • From the air or water through the moist surface directly into the body
  • From the air or water through a thin, moist body wall of blood vessels
  • From the air through spiracles (opening on the thorax) or a tracheal system to a system of ducts to the tissues
  • From water through moist gill surfaces to blood vessels
  • From the air through moist lungs surface to blood vessels
• Respiratory system's function


  • To exchange oxygen and carbon dioxide between the air and the cells
• Types of gas exchange systems used by animals

  • Skin system
  • Gills system
  • Tracheal system
  • Lung system
• Breathing


  1. Inhale - Diaphragm contracts, ribs move up, chest cavity expands, air pushed in

  2. Exhale - Diaphragm relaxes, ribs and chest cavity return, air pushed out
• Plants exchange their gases with the environment in a straightforward way. In order to carry on photosynthesis, green plants need a supply of carbon dioxide and a means of disposing oxygen.
• Stomata


  Allow gas exchange between the surrounding air and the photosynthetic cells inside the leaf
• Mesophyll


  Region between the upper and lower epidermal layers of a leaf, consisting mainly of parenchyma cells specialized for photosynthesis
• Root hair


  Extension of the root epidermal cells, in direct contact with the soil, allowing oxygen diffusion into the roots
• Lenticels


  Small areas in the bark of woody stems that allow gaseous exchange of respiratory gases between air and living cells
• Plants take water and mineral nutrients from the soil through the roots and transport it to the leaves
• Using water and carbon dioxide, the leaves prepare food for the plant through the process of photosynthesis
• Xylem


  Tissues that form a continuous network of channels connecting roots to the leaves through the stem and transporting water and nutrients to the entire plant
• Phloem


  Tissues that transport sugars from the leaves down to the rest of the plant
• Transpiration


  1. Plants absorb mineral nutrients and water from the soil, but not all the water absorbed is utilized by the plant

  2. The water evaporates through the stomata present on the surface of the leaves

  3. The evaporation of water from leaves generates a suction pull, pulling the water to great heights in tall trees

  4. Transpiration cools the plant
• Plants have pipe-like vessels made of special cells, forming the vascular tissue, to transport water and nutrients from the soil
• Plants have pipes that transport water to the entire plant just like what we have at home for the supply water
• Root hairs play an important role in the absorption of water and minerals
• Stomata


  Facilitate transpiration
• Root hairs


  Absorb water and minerals
• Xylem


  Transport water and nutrients
• Phloem


  Transport sugars
• Transpiration generates a suction pull that pulls water to great heights in tall trees
• Transpiration cools the plant