Question

question 50
what causes exhalation?
o the pressure in the blood causes gases to be forced out into the atmosphere
the pressure in the atmosphere decreases around the bodys exterior
the diaphragm contracts
pressure in the lungs becomes higher than atmospheric pressure

question 51
salivary amylase
o is an enzyme that is secreted into the esophagus
is an enzyme that is secreted into the mouth
o is part of gastric juice
o is part of intestinal juice

question 52
in which of the following structures does gas exchange with the atmosphere take place?
the alveoli
the trachea
the lungs
the pharynx

Explanation:

• Question 50: During exhalation, when the pressure in the lungs becomes higher than atmospheric pressure, air (gases) is forced out. Blood pressure is not directly related to gas expulsion in this context. The diaphragm relaxes during exhalation (not contracts). A decrease in atmospheric pressure around the body's exterior is not the mechanism for exhalation.
• Question 51: Salivary amylase is an enzyme. It is secreted by salivary glands into the mouth (not esophagus). Gastric juice contains pepsin, hydrochloric acid etc. Intestinal juice contains enzymes like sucrase, maltase etc.
• Question 52: The alveoli are the site of gas exchange (oxygen and carbon dioxide) with the atmosphere. The trachea is a passageway for air. The lungs are the organ that contains the alveoli (the specific gas - exchange structure is alveoli). The pharynx is part of the upper respiratory tract but not the site of gas exchange.

Answer:

• Question 50: pressure in the lungs becomes higher than atmospheric pressure
• Question 51: is an enzyme that is secreted into the mouth
• Question 52: the alveoli