respiratory system

• What is the structure of the respiratory system?

  Nasal cavity, larynx, trachea, bronchus, bronchioles, alveoli- gas exchange

  Ribs- protect respiratory organs, intercostal muscles- aid with breathing, diaphragm- dome shaped
• What are lung volumes measured with?

  Spirometer
• What is tidal volume and how does it change during exercise?

  Volume of air breathed in and out per breath

  Increases/ more frequent peaks
• Why does tidal volume increase during exercise?

  More oxygen is needed at the working muscles
• What is inspiratory reserve volume and how does it change during exercise?


  Volume of air that can eb forcibly inspired after a normal breath/ vol of air that could be used when breathing in

  Decreases
• Why does inspiratory reserve volume decrease during exercise?

  Due to an increase in tidal volume
• What is expiratory reserve volume and how does it change during exercise?

  Volume of air that can be forcibly expired after a normal breath/ vol of air that could be used when breathing out

  Slight decrease
• Why does expiratory reserve volume have a slight decrease during exercise?

  Due to an increase in tidal volume
• What is residual volume and how does it change during exercise?


  Volume of air that remains in the lungs after a maximal expiration

  Stays the same
• Why does residual volume stay the same during exercise?


  Unable to measure and some air remains in the lungs to prevent them from collapsing
• What is minute ventilation and how does it change during exercise?

  Volume of air breathed in and out per minute

  Big increase
• Why does minute ventilation have a big increase during exercise?

  More oxygen is needed at working muscles
• What is the equation for minute ventilation?


  tidal volume x respiratory rate
• What are the units for minute ventilation?

  L/min
• Why does an increase in tidal volume and minute ventilation allow a performer to maintain performance during an endurance event?

  Allows more oxygen to be exchanged at the alveoli so more O2 can be delivered to the working muscles

  Allows the muscles to work aerobically for longer and less lactic acid is produced

  CO2 is removed faster at the alveoli and the effects of lactic acid can be buffered/delay OBLA
• Why does a trained athlete have a lower resting minute ventilation than an untrained athlete?

  Have more red blood cells and haemoglobin, high mitochondria density and increased surface area of alveoli

  Increase in efficient O2 diffusion, transportation and utilisation

  They will therefore take fewer breaths per minute at rest
• What is the breathing in ventilation phase called?

  Inspiration
• What is the breathing out ventilation phase called?


  Expiration
• What muscles are used at rest during inspiration?

  Diaphragm contract- increases volume and decreases pressure

  External intercostals contract
• What muscles are used during inspiration when exercising?

  Diaphragm, external intercostals

  Sternocleidomastoid contracts

  Scalenes contract

  Pectoralis minor contracts
• What is the role of the rib cage during inspiration when exercising?

  Lifts up to increase volume, creating low pressure in lungs so air rushes in
• What do the additional muscles used during inspiration when exercising cause?

  Deeper, faster breaths
• What muscles are during expiration at rest?

  Diaphragm rests- pushing up against chest cavity

  External intercostals rest- increases pressure in chest cavity
• What muscles are used during expiration when exercising?

  Diaphragm, external intercostals

  Internal intercostals contract

  Abdominals contract
• What is the role of the rib cage during expiration when exercising?

  Relaxes and increases pressure in chest cavity
• What do the additional muscles used during expiration when exercising cause?

  CO2 to be rid more effectively
• How have alveoli adapted for gas exchange?

  Capillary network provides large blood supply for more gas exchange

  Thin wall/ 1 cell thick- short diffusion pathway

  Huge surface area created- millions of alveoli in each lung and in a folded shape
• How thick are alveoli?

  1 cell thick
• What is diffusion?


  Movement of gases from a high concentration to low concentration down a concentration gradient
• What is needed for diffusion to take place?


  A difference in partial pressures

  The bigger the pressure differences, the faster the diffusion
• What is partial pressure?

  The pressure that an individual gas exerts within a mixture of gases eg in the alveoli there is a high partial pressure of oxygen
• What happens to oxygen during gas ex at the lungs?

  Partial pressure of oxygen is higher in the alveoli than pp in the capillaries

  O2 diffuses from alveoli into the capillary from to low partial pressure

  Oxygen then combines with haemoglobin in the blood to create oxyhemoglobin
• What is the partial pressure of oxygen in the alveoli before diffusion?

  pO2 104mmHg
• What is the partial pressure of oxygen in the capillary before diffusion?

  P02 40mmHg
• What happens to carbon dioxide during gas ex in the lungs?

  Partial pressure is higher in capillary than in alveoli

  CO2 diffuses from the capillary to the alveoli high-low

  Then breathed out
• What is the partial pressure of carbon dioxide in the lungs before diffusion?

  PC02 46 mmHg
• What is the partial pressure of carbon dioxide in the lungs before diffusion?

  PC02 40 mmHg
• What happens to oxygen during gas exchange in the muscle?

  Partial pressure is higher in the capillary than in the muscle

  Oxygen diffuses form the capillary to the muscle

  Myoglobin has a higher affinity for oxygen in the muscle than haemoglobin so pulls O2 in to be stored
• What happens to carbon dioxide during gas exchange in the muscle?

  Partial pressure is higher in the muscle compared to capillaries

  CO2 diffuses from the muscle into capillary

  CO2 taken to the lungs
• What are the short term effects of exercise on gas exchange at the alveoli?

  Duw to muscles using up oxygen, blood in the capillaries at the lungs will have a lower concentration of oxygen compared to high concentration of the alveoli in the lungs due to it being breathed in

  The concentration of CO2 will be higher in the capillary due to it being a by product of aerobic respiration and a low PC02 in the alveoli.