What is the purpose of surfactant in the respiratory system?
|A)||To reduce surface tension in the alveoli|
|B)||To increase surface tension in the alveoli|
|C)||To reduce surface tension in the pleural cavity|
|D)||To increase surface tension in the pleural cavity|
Primary cancers of the lung usually arise in the
|C)||epithelium of the bronchioles|
The force responsible for normal expiration comes mainly from
|A)||contraction of intercostal muscles|
|B)||elastic recoil of tissues in the lung and thoracic wall|
|C)||changes in the surface tension within the alveoli|
|D)||contraction of abdominal muscles to push the diaphragm upward|
The air that enters and leaves the lungs during one quiet, resting respiratory cycle is called the
|C)||total lung capacity|
|D)||functional residual capacity|
The neurons most important in stimulating the diaphragm are located in the
|A)||dorsal respiratory group|
|B)||ventral respiratory group|
|C)||pontine respiratory group|
|D)||midbrain respiratory cells|
The respiratory areas respond mainly to concentrations of
The inflation reflex is activated by
|A)||stretch receptors in the bronchioles and alveoli|
|B)||an increase in hydrogen ions|
|C)||a decrease in oxygen saturation|
|D)||a sudden fall in blood pressure|
The walls of the alveoli are composed of
|A)||simple squamous epithelium|
|B)||simple cuboidal epithelium|
|C)||stratified squamous epithelium|
|D)||simple columnar epithelium|
The most abundant gas in room (atmospheric) air is
Oxyhemoglobin forms when
|A)||oxygen levels in the tissue are low|
|B)||oxygen dissolves in the blood plasma|
|C)||oxygen binds to hemoglobin|
|D)||carbon dioxide binds to hemoglobin|
Choose the true statement regarding transport of carbon dioxide in the blood.
|A)||Carbaminohemoglobin is found in the plasma.|
|B)||Conversion of carbon dioxide to bicarbonate ions occurs primarily in the plasma.|
|C)||Most of the carbon dioxide is dissolved in the plasma.|
|D)||Carbon dioxide can be carried by hemoglobin.|
Nasal conchae, found on the lateral wall of the nasal cavity, increase the surface area of the nasal mucous membrane.
Moisture is removed from air as it moves through the nasal cavity.
The larynx conducts air in and out of the trachea, keeps foreign objects out of the trachea, and houses the vocal cords.
The glottis is a flap-like structure that closes the larynx.
As the branches of the bronchioles become smaller, there are fewer smooth muscle fibers in their walls.
The right and left lungs each have three lobes: an upper, middle, and lower lobe.
As the diaphragm contracts, the size of the thoracic cavity increases, and pressure within the cavity decreases.
Attraction of the pleural membranes to each other helps expand the lungs in all directions and maintain reduced pressure in the thorax compared to the atmosphere.
Both inspiration and expiration are normally active processes.
Contraction of the internal intercostal and abdominal muscles can squeeze higher than normal volumes of air from the lungs.
An increase in hydrogen ion and carbon dioxide concentration will cause the respiratory rate and tidal volume to increase.
Hyperventilation is safely used by swimmers to hold their breath while swimming.
Gases in the alveoli must cross two layers of epithelium and a layer of fused basement membrane to reach the blood.
There are two folds of muscle and connective tissue in the larynx called the vocal cords or vocal folds; the inferior pair are the true vocal cords involved in speech.
Less oxygen is released from oxyhemoglobin in an acidic environment.
Carbon monoxide is toxic to the body because it forms a stable compound with hemoglobin.
Why is the cartilage of the trachea shaped like a C instead of an O?
|A)||the aorta is directly behind it|
|B)||so when swallowing, the esophagus can expand behind it.|
|C)||C rings are more stable than O rings|
|D)||the inferior vena cava is directly behind it|