Question

True or False. Indicate whether the statement is true or false. If false, explain in the space provided the statement why it is false, or simply correct the statement.

Smooth muscle contraction is regulated by the autonomic nervous system. During exercise, the sympathetic nerves that innervate the smooth muscles of bronchioles and arterioles regulate the contraction of these smooth muscles to increase ventilation and cardiac output.

2. Multiple choice: Choose one best statement.

An infant born prematurely has neonatal respiratory distress syndrome caused by a lack of adequate surfactant in the immature lung.

Which of the following would be expected in this infant?

1. Increased breathing rate.
2. Decreased surface tension of the alveoli.
3. Increased lung compliance.
4. Increased secretion by type I alveolar cells.
5. Increased secretion by type II alveolar cells

Answer 1

1. Autonomic nervous system is a part of peripheral nervous system. It consists of two branches that innervate the target organ: sympathetic and parasympathetic.
These two branches innervate the smooth muscles of visceral organs, glands and blood vessels and help regulate their function. Stimulation of sympathetic branch evokes fight or flight response that increases heart rate, blood pressure, pupillary dilatation, slows digestion, cause vasoconstriction and bronchodilation. The vasoconstriction of blood vessels through sympathetic stimulation increases stroke volume and cardiac output. The bronchodilation results in increased ventilation.
So the statement is true.
2. Pulmonary surfact is a lipoprotein that is present in lungs and secreted by type ll alveoli.
The surfactant helps increase lung compliance and reduce surface tension in the alveoli and prevents collapse of lung (atelectasis) during expiration. This results in reduced work of breathing and decreased respiratory rate.
In premature infants lungs are not developed to produce surfactant ehich results in respiratory distress. This is characterised by increased breathing.
So the correct option is "increased breathing rate".