Human Body Systems
Lesson 11 Terms and Definitions
Characteristics of the lungs
• Elastic – they can expand and contract
• Inside is like a sponge
– Contains bronchi and alveoli
– Alveoli surrounded by capillaries
• Diffusion of gases occur between the
alveoli and the capillaries.
Oxygen and
Carbon
Dioxide
Exchange
Q: How much air can
you exhale?
Tidal Volume
• Tidal Volume – The volume of air that is
moved in and out of your lungs with each
breath.
– Avg. adult breath – 500mL of air in and out
Average Adult Male Lungs
• Lungs of avg. adult male
– Hold 3000 mL air
– Can forcibly inhale an additional 3000 mL
• Total lung capacity – 6000 mL air
Vital Capacity
• Vital Capacity – the amount of air that a
person can forcibly exhale after breathing
in as much air as possible.
– Avg. adult male – 4800 mL
Residual Volume
• Residual Volume – the amount of air still
in the lungs after you force out as much as
possible.
– Avg adult male – 1200 mL
Total Lung Capacity
• Total Lung Capacity – the sum of vital
capacity and residual volume.
– The total volume of air the lungs can hold.
• Avg. healthy adult male 6000 mL.
4800 mL – Vital Capacity
+1200 mL – Residual Volume
6000 mL – Total Lung Capacity
What affects Vital Capacity?
• Body size, age, strength of respiratory
muscles…
• Older you get – lungs are less elastic
– 70 yr old persons 2/3 the vital capacity of a
healthy young adult
Respiratory Rate
• The amount of time it takes to breath in
and out.
– Often determined by respirations per minute
• Active person – higher respiratory rate
• Inactive person – lower respiratory rate
Macrophages
• Macrophages – Cells that clean the
respiratory tract.
– Destroy dust and other harmful things we
inhale.