Download Chapter 1 Homework - due Tuesday, Sept

Answers to Review Questions - Chapter 44
1. What is the sequence of inhaled airflow through the respiratory structures in a
mammal?
Inhaled air flows from the nostrils into the nasal cavities and then through the
pharynx, larynx, trachea, bronchi, bronchioles, and finally into the alveoli.
2. What is the function of hemoglobin? How does it work?
Hemoglobin combines with oxygen and greatly increase the capacity of blood to
transport it. Oxygen binds to hemoglobin forming oxyhemogloblin, and it is in
this form that oxygen is transported in the blood.
3. Why does alveolar air differ in composition from atmospheric air? Explain.
Not all of the air in the lungs is expelled with each breath, so inhaled
atmospheric air mixes with residual alveolar air which contains higher amounts
of carbon dioxide produced during cellular respiration, and thus alveolar air
contains a higher percentage of CO2 and a lower percentage of O2 than
atmospheric air
4. What mechanisms does the human respiratory system have for getting rid of
inhaled dirt?
The hair around the nostrils, the ciliated mucous lining in the nose and pharynx,
and the cilia-mucus elevator of the trachea and bronchi serve to trap foreign
particles in inspired air. This dirt can be moved to the throat and removed
through the digestive system. Any foreign particles that make it to the alveoli
will be engulfed by alveolar macrophages.
5. What happens when so much dirty air is inhaled that these mechanisms cannot
function effectively?
When the mechanisms fail due to too much inhaled dirty air, the body must resort
to coughing to clear the airways. Often, the bronchioles become constricted,
excess mucus is secreted, and chronic bronchitis, emphysema and/or lung cancer
may result.