bio b8.1 - gas exchange and respiration

how air travels through body

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.