3rd topic

• Gas Exchange


  The process of exchanging oxygen and carbon dioxide between an organism and its environment
• Transport System


  The system that moves materials, such as food, water, and oxygen, within an organism
• Immune Response


  The biological response of an organism's immune system to a foreign substance, cell, or tissue that is perceived as an invader
• Gas Exchange in Plants

  • Plants do not have specialized gas exchange mechanisms, but they have stomata in leaves and lenticels in stems that are involved in gaseous exchange
  • Plants exchange gases with the environment in a simple manner despite being complex organisms
  • In aquatic plants, gas exchange occurs through leaves using aerenchyma and stomata
  • In terrestrial plants, oxygen and carbon dioxide diffuse through stomata and intercellular spaces of leaves, and lenticels of bark
• Gas Exchange in Plants

  • Water lily
  • Sunflower
• Gas Exchange in Animals

  • Oxygen and carbon dioxide move by diffusion across moist membranes
  • Skin, spiracles, gills, lungs, and air sacs are used for gas exchange in different animals
• Human Respiratory System


  • Consists of a complex set of organs and tissues that capture oxygen from the environment and transport it into the lungs
  • Includes the nose, pharynx, trachea, and lungs
• Transport System in Plants

  • Uses the xylem and phloem to transport food, water, and minerals
  • Xylem vessels are composed of dead lignified cells connected end to end
  • Phloem is composed of sieve tubes closely associated with companion cells
• Transpiration


  The evaporation of water from plants
• Types of Transpiration


  • Stomatal transpiration - evaporation of water from stomata
  • Cuticle transpiration - evaporation of water from the cuticle
  • Lenticular transpiration - evaporation of water from lenticels

  
• Transport System in Animals

  • Generally called a circulatory system as the blood flows through a circuit
  • Most animals have one or more organs called hearts for pumping blood
  • Blood flows through arteries, veins, and capillaries
• Human Circulatory System


  • Functions to transport blood and oxygen from the lungs to the various tissues of the body
  • Consists of the heart, blood, and blood vessels
• Blood


  The medium of transport in the body
• Blood Vessels


  • Arteries have thick walls and take blood away from the heart
  • Arterioles take blood to capillaries with only epithelial cell walls
  • Venules take blood from capillaries and merge to form veins with thinner walls than arteries
• Immune Response in Plants

  • Plants lack mobile defender cells and a somatic adaptive immune system
  • They rely on the innate immunity of each cell and on systemic signals from infection sites
  • Plant immunity requires multiple signaling processes that vary according to the lifestyle of the invading pathogen
• Immune Response in Animals