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Termini in questo insieme (24)

  • Respiratory system

    Designed for gas exchange between an organism and its environment

  • Circulatory/Cardiovascular system

    Transports gases in the blood

  • Respiratory surfaces

    Cell surfaces where O2 diffuses in, and CO2 diffuses out

  • Respiratory surfaces are: (3)

    Moist, as gases must dissolve in water to diffuse

    Thin, to facilitate diffusion

    High surface area, for efficient gas exchange

  • Why some organisms can use their entire skin’s surface as a respiratory surface

    Their capillaries are in direct contact with the skin

  • Specialized body parts used for gas exchange

    Gills (fish)

    Tracheal systems (insects)

    Lungs (humans, mammals)

  • 3 phases of gas exchange in humans:

    Breathing (inhalation)

    Transport (O2 and CO2)

    Exchange (of gasses within body cells)

  • Air inhaled through the mouth

    Passes through the oral cavity

  • Air inhaled through nose

    Passes through nasal cavity

  • Nasal cavity

    Air is filtered by hair and mucus

    Air is warmed and humidified

    Air is sampled for odours

  • Direction of inhalation:

    Nasal cavity

    Pharynx

    Larynx

    Trachea

    Paired bronchi

    Bronchioles

    Alveoli

  • Alveoli

    Grape-like clusters of air sacs at the ends of small bronchioles

    Have a high SA of capillaries for efficient gas exchange

    Diffuse O2 into blood and CO2 out of blood

  • Emphysema

    A breakdown of alveolar walls caused by smoke inhalation, reducing the area of the respiratory surface and limiting necessary elasticity

  • Surfactants

    Specialized secretions that keep the walls of the alveoli from sticking closed

  • Inhalation

    Air enters the lungs through branching tubes as the chest cavity increases in volume

    Rib/diaphragm muscles contract -> volume of chest cavity increases -> air moves in to fill the space

  • Exhalation

    Muscles relax -> volume decreases -> air is pushed out

  • Control of breathing

    Brain sends nerve signals to contract muscles

    Breathing control centre responds to pH of blood and cerebrospinal fluid

    Nerve signals -> CO2 and O2 levels

  • Cardiovascular system

    Responsible for gas transport in humans

  • Right side of the heart

    Pumps oxygen to lungs

  • Left side of heart

    Pumps blood into the body

  • Diffusion

    How gasses move

  • Gasses in alveoli

    Have more O2 and less CO2 than gasses in blood

    Gives O2 to blood, takes CO2 from blood

  • Gasses in tissues

    Have more CO2 and less O2 than gases in the blood

    O2 from blood -> tissues

    CO2 from tissues -> blood

  • Hemoglobin

    A protein found in very high levels in RBC

    Consists of 4 polypeptide chains and iron containing heme groups that cause O2 to bind

    Used because oxygen is not soluble in water, and therefore not in blood either