bio b8.1 - gas exchange and respiration

how air travels through body

Sinus -\> Trachea-\> Larynx -\> Bronchi -\> Bronchioles -\>
Lungs -\> Air Sacs-\> Diaphragm

where gas exchange takes place

* alveoli (bulges on air sacs, covered w/blood capillaries)
* CO2 & O2 exchanged between blood & air in lungs

movement of air across surface of alveoli

ventilation

requirements for gas exchange in lungs

- large SA
- thin, moist, good blood supply
- good air ventilation

oxygen in inspired air

21%

oxygen in expired air

16%

carbon dioxide in inspired air

0.04%

carbon dioxide in expired air

4.5%

water in inspired air

variable

water in expired air

high

test for CO2

- place limewater in both tubes
- breathe in and out through plastic tube
- one tube has inhaled bubbles through it, the other has exhaled
- cloudy limewater indicates presence of CO2

inhalation

* diaphragm contracts and moves down
* the EIC muscles contract,
* ribs move up (outwards),
* volume of thorax increased,
* pressure in thorax increases
* pressure in lungs decreases

exhalation

* the diaphragm relaxes
* the IIC muscles contract,
* ribs move down (inwards),
* volume of thorax decreases,
* pressure in thorax increases.
* pressure in lungs increased,
* air pressure from inside forces air out of lungs

effects of physical activity + breathing

* max amount of air breathed in and out in one breath is the vital capacity breathing rate
* depth increases to absorb more oxygen for muscles when exercising.

mucus

traps pathogens, dust

cilia

sweep in coordinated motion to move mucus lungs --\> mouth

tobacco effects

* smoke particles irritate air passage, causing mucus build up
* resulting in coughing and alveoli walls breaking
* COPD, CHD

tar

* carcinogen,
* increases risk of lung cancer,
* paralyzes and damages cilia

carbon monoxide

* binds irreversibly to the hemoglobin in red blood cells preventing them from carrying oxygen

lymphocyte

a type of white blood cell that make antibodies to fight off infections

phagocyte

a cell that ingests and destroys (digests) foreign matter or microorganisms

goblet cells

* secrete mucus in lining of trachea, bronchi, bronchioles

difference in composition between inspired and expired air

- inspired gas is the gas we take in during breathing which mostly contains oxygen in adequate amount
- expired gas is the gas we breathe out which is mostly carbon dioxide.