gas exchange

• What is the primary function of the lungs in mammals?

  Gas exchange
• The lungs are located in the thorax
• The trachea splits into left and right bronchi.
• Arrange the structures in the respiratory system in the correct order from the trachea to the alveoli:

  1️⃣ Trachea

  2️⃣ Bronchi

  3️⃣ Bronchioles

  4️⃣ Alveoli
• What are the air sacs in the lungs called?

  Alveoli
• The lungs have millions of alveoli in each lung.
• The ribs protect the lungs
• What is the term for breathing in?

  Inhalation
• Breathing works by changing the air pressure
• Air moves into the lungs when air pressure inside the chest cavity decreases.
• How does the diaphragm change during inhalation?

  Contracts and flattens
• During inhalation, the ribcage moves up
• Arrange the steps of inhalation in the correct order:

  1️⃣ Intercostal muscles contract

  2️⃣ Ribcage moves up and out

  3️⃣ Diaphragm contracts and flattens

  4️⃣ Chest volume increases

  5️⃣ Air pressure decreases

  6️⃣ Air is drawn in
• What happens to air pressure during exhalation?

  Increases
• During exhalation, the diaphragm relaxes and moves upward.
• During exhalation, the chest volume becomes smaller
• Arrange the steps of exhalation in the correct order:

  1️⃣ Intercostal muscles relax

  2️⃣ Ribcage moves down and in

  3️⃣ Diaphragm relaxes and moves up

  4️⃣ Chest volume decreases

  5️⃣ Air pressure increases

  6️⃣ Air is forced out
• How many alveoli are in human lungs?

  Approximately 700 million
• Gas exchange occurs in the bronchioles of the lungs.

  False
• Gas exchange in the alveoli depends on concentration gradients.
• Which gas moves from the alveoli into the blood during gas exchange?

  Oxygen
• Carbon dioxide moves from the blood into the alveoli.
• Oxygen binds with hemoglobin in red blood cells.
• What are three adaptations of alveoli for efficient gas exchange?

  Large surface area ||| Moist surface ||| Thin walls
• What are three variables to control in the breathing rate experiment?

  Age ||| Sex ||| Exercise type
• Repeating an experiment makes the data more reliable.
• Steps to investigate the effect of exercise on breathing rate

  1️⃣ Determine resting breathing rate

  2️⃣ Calculate breathing rate during exercise

  3️⃣ Repeat the experiment

  4️⃣ Control variables to ensure validity
• The moisture in alveoli increases the rate of diffusion.
• Exercise increases the breathing rate to provide more oxygen to muscles.
• Which gas turns lime water milky?

  Carbon dioxide
• Steps to prove carbon dioxide is released in respiration using a huff and puff apparatus

  1️⃣ Inhale through the mouthpiece

  2️⃣ Exhale through the second flask

  3️⃣ Observe the cloudiness of lime water
• In the huff and puff experiment, the second flask becomes more cloudy due to higher CO2 levels.
• Lime water becomes more cloudy with higher levels of carbon dioxide.