Ch 37 Gas Exchange

AP lecture

Background information

• Diffusion • Barometric pressure • Oxygen in the air

Mammal

• Oral cavity and nasal passage • Pharynx – Larynx

• Trachea• Bronchi – Bronchioles – Alveoli

Inhalation and exhalation

• Thoracic cavity houses lungs and diaphragm

Inhalation Exhalation

Diaphragm contracts Diaphragm relaxes

Thoracic cavity expands Thoracic cavity contracts

Lungs expand Lungs contract

Air in Air expelled

• http://teachhealthk-12.uthscsa.edu/studentresources/anatomyofbreathing3.swf

Negative feedback

• Breathing is an involuntary function of the CNS ; specifically medulla oblongata

• Rate is regulated by carbon dioxide • Major site medulla oblongata • Carbon dioxide indirectly controls breathing

via changes in pH levels

• Concentration gradient & pressure drives movement of gases into & out of blood at both lungs & body tissue

Diffusion of gases

blood lungs

CO2

O2

CO2

O2

blood body

CO2

O2

CO2

O2

capillaries in lungs capillaries in muscle

Transporting gases

• Oxygen carried by hemoglobin, protein in red blood cells

• Each hemoglobin can bind four oxygen molecules

• http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter25/animation__gas_exchange_during_respiration.html