Topic 6 & 11: Human

Physiology6.4 Gas exchange

Draw, label, and annotate the ventilation system + alveoli diagram

Teachpe.com

1 - VentilationRead & Consider 6.4.1, 6.4.4 - 6.4.6

• What do you know?• What questions do you have?

Ventilation System

In larger organisms not every cell has access to oxygen sources so a ventilation system is needed to maintain a concentration gradient in alveoli.

RESPIRATION

Muscles VentilationInspiration –

• The diaphragm contracts and flattens downwards

• External intercostal muscles contract, pulling ribs up and out this increases the volume of the thorax

• Increased volume decreases the pressure of alveoli and air flow in to equalize pressure

• Forced inspiration: accessory neck muscles contract to increase volume

Expiration -

Passive

• Diaphragm relaxes and curves upward.

• External intercostal muscles relax, allowing ribs to fall and decreasing the volume of the thorax

• This increases the pressure in the alveoli pushing air out of the lungs.

• During forced expiration (exercise) internal intercostal muscles and abdominal muscles contract for force exhalation.

PRESSURE ANIMATION -

2 - ExchangeRead & Consider 6.4.2 – 6.4.3

• What do you know?• What questions do you have?

Gas Exchange -Diffusion of gases; process of swapping one gas for

another. O2 & CO2

1. Alveoli – O2 diffuses into the blood from the alveoli and CO2 diffuses from the blood to the alveoli

2. Tissues – O2 diffuses from blood into the cells and CO2 diffuses from cells to the blood.

Pneumocytes

Type I

• Extremely attenuated (25nm)

• Cover 97% of alveolar surface

• Organelles gathered near the nucleus

• Vesicles to clear contaminates

Type II• Cuboidal in shape

• 60% of total cells, but <5% of surface area

• Production and secretion of surfactant

• Act as alveolar stem cells

Increasing Diffusion

Exchange occurs over the body surface or respiratory surface. Diffusion requirements:

• Large SA:V in-foldings (lungs or gills)

• Permeable

• Thin efficient up to 1mm thickness

• Moist O2 and CO2 diffuse in solution

• Transport system maintain a concentration gradient art..com

Alveoli

Disease

Emphysema Lung Cancer

Practical

How does vigorous exercise affect ventilation rate and tidal volume in humans?

Works Cited

• "Advanced Practice Providers." SIU School of Medicine. SIU School of Medicine, n.d. Web. 24 Oct. 2014.

• Bishop, Adrian. "Lung Cancer Tumours in Smokers Have 10-times More Genetic Mutations." Earth Times. N.p., n.d. Web. 24 Oct. 2014.

• "Laboratory Manual for Exercise Physiology: Pulmonary Function Testing a Valuable Diagnostic Tool." Human-kinetics. N.p., n.d. Web. 24 Oct. 2014.

• "Stock Photo - Human Alveoli, Computer Artwork." Human Alveoli, Computer Artwork. N.p., n.d. Web. 21 Oct. 2014.

• Zyga, Lisa. "Scientists Discover First Multicellular Life That Doesn't Need Oxygen." Phys.Org. N.p., 7 Apr. 2010. Web. 10 Oct. 2014.