unit 3

Cards (114)

  • Things organisms need to exchange with their surroundings
    • Oxygen, carbon dioxide, water, ions
  • As the organism gets bigger
    The SA:vol ratio decreases
  • Thermoregulation
    Control of body temperature
  • Organisms that maintain a constant internal body temperature
    • Mammals and birds
  • Metabolic rate
    The amount of energy expended by an organism in a given time period
  • Elephants have a small surface area to volume ratio
  • Adaptations large animals have to lose heat
    • Large, flat ears / Sweating or panting / Vasodilation
  • Being flat or hollow helps multicellular organisms exchange respiratory gases by increasing the surface area to volume ratio, allowing for faster rates of diffusion
  • How insects reduce water loss
    Close their spiracles, waterproof exoskeleton
  • Difference between tracheae and tracheoles
    Tracheae are larger and have rings of cartillage
  • Insects close the spiracles to reduce water loss
  • How some insects increase ventilation
    Abdominal pumping
  • Water is more dense than air
  • Water contains less oxygen than air
  • Warm water contains less oxygen than cold water
  • Diffusion of gases is slower in water than in air
  • Water flow across the gills of fish
    Counter-current system
  • Key components of the gill
    • Filament and lamellae
  • Operculum
    Gill flap
  • Gills
    • Large surface area as filaments at right angles with lamallae
  • The countercurrent flow in fish gills maintains a concentration gradient along the whole length of the lamellae
  • The countercurrent flow is important as it allows water to flow in the opposite direction to blood, maintaining the concentration gradient
  • Leaf adaptations for gas exchange
    • Large surface area / Spongy mesophyl with air spaces to maintain concentration gradient
  • The gas needed for leaves to photosynthesise is carbon dioxide
  • The gas that will diffuse into the palisade mesophyll cells at night is oxygen
  • Stomata
    Openings on the underside of leaves that allow gas exchange
  • Stomata are sometimes closed to reduce water loss
  • Xerophyte
    A plant adapted for dry environments
  • Adaptations of xerophytic plants
    • Sunken stomata / Reduced surface area of leaves / Hairs at stomata / Thick waxy cuticle / Rolled leaves
  • Path of oxygen from air to blood in mammals
    Into mouth/nasal passage, down trachea, into bronchi, into bronchioles, into alveoli, across epithelium and capillary endothelium into blood
  • Ventilation
    Breathing - movement of ribs and muscles/diaphragm to increase air flow to lungs
  • The rings of cartilage in the trachea prevent collapse
  • Intercostal muscles
    They work in pairs with opposite motions of contraction and relaxation
  • When the diaphragm contracts, the volume of the thorax increases
  • The external intercostal muscles contract to pull the ribs up and out
  • When the volume of the thorax increases, the pressure inside the thorax decreases
  • Tidal volume
    Volume of air in/out of the lungs at rest with each breath
  • How breathing rate is measured
    Spirometer - number of breaths per minute
  • Pulmonary ventilation rate
    Calculated as tidal volume x breathing rate
  • Fibrosis
    Thickening or scarring of tissue