Breathing and Feeling

Respiratory System

• Why do we need this respiration thing?
• Need 02 in body for aerobic respiration, to make ATP
• Need to get the CO2 out!
• Some vocab, might be important
• Ventilation
• Exchange of air between lungs and atmosphere
• Gas Exchange
• The exchange of CO2 and O2 in the alveoli and blood stream via passive diffusion
• Cell Respiration
• Release of ATP from organic molecules
• Gas Exchange
• O2 and CO2 exchange between environ and cells
• Need a moist membrane
• Moisture maintains cell membrane structure
• Gasses only diffuse when dissolved in WATER
• High Surface Area
• Maximizes exchange rate
• CO2 and O2 move across cell membrane via diffusion
• Path through the system:
• In through schnozz, through pharynx, past epiglottis, larynx, trachea, bronchi, bronchioles, alveoli.  The Diaphragm goes up and down, the ribs squeeze and release
• Alveoli
• Singular- alveolus
• Total surface area ~100m
• TRIM
• Thin walls
• Rich capillary network
• Increase in SA/Volume ratio
• Moissst
• Pressure is important!
• Air flows from high to low pressure- regulated by ribs and diaphragm
• Partial pressure is the pressure exerted by a single gas type in a mix of gasses
• This partial pressure depends on:
• Concentration of the gas in a mixture of gasses
• The total pressure of the mixture
• Air pressure decreases at high altitudes!
• Automated breathing control
• Medulla sets rhythm
• Monitors the CO2 level of the blood
• As such, monitors the pH of the blood!
• CO2 becomes H2CO3 (carbonic acid)
• If pH decreases, then the depth and rate of breathing increases- CO2 must be eliminated
• Pons moderates the rhythm.
• CO2 transport !  OOH BOY
• CO2 diffuses into plasma, then into RBC
• Binds to H2O to make carbonic acid
• One hydrogen breaks off and attaches to hemoglobin
• Leaves Hydrogen Carbonate
• Hydrogen Carbonate exits and is replaced by a chloride molecule.
• Go to Alveolus, where this is repeated in reverse
• This is called CO2 Buffering!