Respritory System Bio 12 FINAL
respritorys system main function?
gas exchange (o2 and co2)
nose does what?
moistens air, mucus catches debrigh and warms air
Pharynx:
Shared passageway for air and food.
Glottis:
Opening to the larynx.
Larynx:
Voice box; contains vocal cords.
Trachea:
Windpipe supported by cartilaginous rings.
Bronchi:
Two main branches into each lung.
Bronchioles:
Smaller branches; no cartilage, smooth muscle instead.
Alveoli:
Tiny sacs where gas exchange occurs via diffusion.
Right lung: . Left lung:
3 lobes 2 lobes (to accommodate heart).
Pleural membrane:
Double membrane with fluid that reduces friction.
mechanics of breathing, inhalation
Diaphragm contracts (moves down).
External intercostal muscles contract, lifting ribs up and out.
mechanics of breathing exhalation
Diaphragm relaxes, moves up.
Intercostals relax, ribs fall.
External Respiration (lungs ↔ blood):
Occurs in alveoli.
O₂ diffuses from alveoli into capillaries.
CO₂ diffuses from blood into alveoli.
Based on partial pressures.
Internal Respiration (blood ↔ tissues):
O₂ diffuses from blood into cells.
CO₂ diffuses from tissues into blood.
Transport Proteins:
Hemoglobin (Hb): Carries 98.5% of O₂.
Oxyhemoglobin (HbO₂) in lungs.
In tissues: Hb releases O₂ due to low pH and high temp (Bohr effect).
O₂:( gas transport in blood)
~98.5% as oxyhemoglobin.
~1.5% dissolved in plasma.
CO₂:(transport in blood)
~70% as bicarbonate ion (HCO₃⁻) (via carbonic anhydrase).
~20% bound to hemoglobin (carbaminohemoglobin).
~10% dissolved in plasma.
Control of Breathing
Controlled by medulla oblongata and pons in the brainstem.
Chemoreceptors in:
Medulla: Sensitive to pH (indirect CO₂).
Carotid and aortic bodies: Sense O₂ and pH.
Main stimulus for breathing:
↑ CO₂, not ↓ O₂.
When CO₂ rises, pH drops → triggers increased breathing rate.
External Respiration:
Exchange of gases between air and blood.
Internal Respiration:
Exchange of gases between blood and tissues.
Cellular Respiration:
Mitochondria use O₂ to make ATP.
Explain the role of carbonic anhydrase in CO₂ transport.
Step 1: CO₂ combines with water to form carbonic acid (H₂CO₃).
Step 2: Carbonic acid dissociates into hydrogen ions (H⁺) and bicarbonate ions (HCO₃⁻).