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.