1. Chapter 42
Respiration

2. Basics Respiratory medium – air or water
Get oxygen into the body; diffusion across a moist membrane
Need oxygen for cellular respiration (end of ETC)
Respiratory surfaces- gills, lungs
Have to be moist
Have to be large (surface area)
Way to get oxygen to cells
Need protection

3. Gills
Water goes in one direction, blood goes in the opposite direction.
Partial pressure gradient (moves from high to low)
Maximizes diffusion
Without this, you would reach equilibrium and you wouldn’t get a lot of oxygen.
Concurrent (NOT efficient)
Countercurrent (Efficient)

4. Tracheal systems Similar to the AC system in your house
Oxygen goes directly to your cells
Blood does not carry oxygen
Limits size of the animal
Bigger insects fly because flight muscles have lots of mitochondria and help bring in air

5. Lungs
Land snails, primitive fish, most amphibians, all reptiles, all birds, all mammals
Types of Respiration:
1. Breathing – inhaling and exhaling
2. External respiration – getting oxygen from the air and getting it into your blood
3. Internal respiration – getting oxygen from your blood to your tissues and organs
4. Cellular respiration – making ATP using oxygen

6. structures External nares (nostrils) Pharynx Larynx (voicebox) Glottis
Sensory receptors
Hair/cilia help filter the air
Blood vessels help warm the air
Mucus helps moisten the air
Pharynx
Larynx (voicebox)
Vocal cord – vibrate when air moves over it; the length, thickness, and elasticity influence the sound of your voice
Glottis
Trachea
Cartilaginous rings – keep trachea from collapsing
Cilia beat up to remove any debris from going down
Splits off into two bronchi
Bronchus
Splits into bonchioles

7. Alveoli Simple diffusion
Surfactant (phospholipids and proteins that reduce surface tension)
keep alveoli open
made during the very end of embryonic development, so if babies are born prematurely, they may have lung problems. You can blow surfactant into the lungs to fix this.

8. Pleural Membrane
Two membranes- one bound to lungs, one bound to ribcage
Contains fluid
Can cause lungs to collapse if air gets in

9. Just Breathe  As H+ and CO2 increases, pH decreases (not good!)
The hindbrain (pons, medulla oblongata) contains breathing control centers
Backup system- chemoreceptors (which check for low oxygen levels) in the aorta (should be highly oxygenated) and carotid arteries (go to brain so should have a lot of oxygen)

10. Negative Pressure Breathing
Inhalation
Diaphragm contracts (moves down), expands, pressure decreases so air comes into the lungs (since there is higher pressure outside the lungs), ribcage and alveoli expand
Exhalation
Diaphragm relaxes (moves up)

11. Terms Tidal air – normal volume of air
Vital capacity – max volume you can force yourself to inhale
Residual volume – air left after you try to exhale as much as you can

12. Birds are the true MVP More efficient breathing
Have air sacs (keep the oxygen when they exhale and sends the oxygen to the lungs) and parabronchi (NOT alveoli)