Respiratory System

Tracheal System in Insects

• https://www.youtube.com/watch?v=quwhcgkVO3c

• Tracheal system• Branched air tubes• Air sacs• spiracle

Path of air

1. pharynx2. Larynx3. Trachea4. Bronchi5. Bronchioles6. Alveoli (air sacs)

Alveolus/alveoli• 300 million/lung• Surrounded by capillary bed coming from right atriapulmonary

arteries (low O2)-why?!• 1 cell thick walls….why?!

Ventilation V Gas Exchange V Cellular Respiration

• https://www.youtube.com/watch?v=nJuFmyXeHkA&oref=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DnJuFmyXeHkA&has_verified=1• https://www.youtube.com/watch?v=LaOBcF6N7e4

Gas Exchange• Uptake of O2 from environment and discharge of CO2

• Involves lungs and capillary beds

Alveoli Details• Large S.A• Flat, single cell• Moist lining• Nearby capillary bed

Gas Exchange cont.• Atmosphere =21% O2 by volume• O2 and CO2 move into and out of lungs via PASSIVE transport (we need

a concentration gradient)• Lung surface=thin, folded, moist, and branched to maximize gas

exchange

Gas Exchange cont.• Rate of diffusion is proportional to surface area and the inverse of

distance needed to travel…see size of lung and distance to capillary bed

Ventilation • Act of breathing• Increase flow of respiratory medium (source of O2) over respiratory

surface• Ex: human breathing• EX: fish and gills

• https://www.youtube.com/watch?v=cVFqME-NW9s

Why do we need ventilation?• Creates a concentration gradient for O2 and CO2

• O2 needed for aerobic respiration• O2 from lungs to blood• CO2 from blood to lungs • Cycles lung air with atmosphere

Ventilation • Muscles surrounding lungs include• Diaphragm, abs, intercostal muscles

• Lungs located in thoracic cavity• Lungs “open” to atmosphere via trachea

Pressure V Volume in lungs• Inverse relationship

Inspiration V Expiration

Inspiration• Inside lungs, volume increases so pressure….?• Creates a partial vacuum inside of the lung• Air that comes in via your mouth or nasal passageway counteracts the

partial vacuum• The air fills your alveoli

Inspiration Interactive

• http://highered.mheducation.com/sites/0072507470/student_view0/chapter23/animation__alveolar_pressure_changes_during_inspiration_and_expiration.html

Blood’s Role

• Hemoglobin Structure

4 O2 = saturated

Myoglobin• Heme protein found in muscle that stores 1 oxygen molecules• Releases the oxygen as needed

Oxygen Dissociation Curve• X-axis= partial pressure of oxygen• Y-axis= % Oxygen saturation in hemoglobin• Oxygen’s partial pressure increases as more Oxygen binds to

hemoglobin and myoglobin (changes shape so O2 binds easier)

Fetuses need more oxygen than adults

Bohr Shift

• When CO2 binds to hemoglobin, O2 is released• https://www.youtube.com/watch?v=Qrvrs6RXxwY

Exercise

• Medulla oblongata controls the diaphragm and intercostal muscles• Increase in CO2= decrease in pH in blood=more nerve

impulses=increased ventilation to get more O2

Asthma• Airways=inflamed, produce extra mucous

Smoking• Stiffens cilia=mucous accumulates• Emphysema= alveoli walls loose elasticity so air gets stuck

High Altitude

• Air pressure changes• Increase RBC• Increase capillaries in lungs and muscles• Increase lung size• Increase myoglobin