Name
Anatomy Review
1. What is the main
function of the respiratory system?
To bring oxygen into
the body and eliminate carbon dioxide from the body.
2. Trace the pathway of
air from the outside of the body into the body.
Air
enters the nose through the external nares. Then the air passes through the nasal cavity, pharynx, larynx,
trachea, primary bronchus, and
into the lungs.
3-4. Describe the location
of the visceral and parietal pleura.
Visceral
pleura covers the surface of the lungs. Parietal lines the mediastinum, the
diaphragm, and the thoracic wall.
5. What is the function
of pleural fluid?
Assists
in breathing movements by acting as a lubricant.
6. Trace the pathway of
air from the trachea to the respiratory zone.
Trachea, to primary bronchi, to secondary bronchi, to tertiary bronchi, to smaller bronchi, to bronchioles, to terminal bronchioles, to respiratory zone.
7. Describe the
difference between bronchi and bronchioles in terms of smooth muscle and
cartilage.
Bronchi have rings of cartilage that keep them open. Bronchioles have no cartilage, but they do have smooth muscle in their walls.
8. What is the function
of the smooth muscle of the bronchioles?
To allow airflow
regulation by altering the diameter of the bronchioles.
9. Where is the
conducting zone and what is its function?
The conducting zone is the airway from the nasal cavity through the terminal bronchioles. Its function is to moisten, warm, and filter the air.
10. Where are three
places alveoli are found?
(1) In respiratory bronchioles where they are scattered in the walls. (2) In alveolar ducts, which are completely lined by alveoli. (3) In alveolar sacs, where they are found in clusters.
11. What are the names
of the blood vessels that carry blood to the lungs?
The
pulmonary arteries and branches of the pulmonary arteries.
12. What are the names
of the blood vessels that carry blood away from the lungs?
The
pulmonary veins and branches of the pulmonary veins.
13. Which contain blood
that is higher in oxygen, the pulmonary arteries or the pulmonary veins?
The
pulmonary veins.
14. Where are the
pulmonary capillaries found within the lung?
They
surround each alveolus.
15. What three cell
types are found within alveoli?
(1)
simple squamous epithelium, (2) alveolar macrophages, (3) surfactant-secreting
cells
16. What is the function
of the alveolar macrophages, or dust cells, within alveoli?
They creep along the
inner surface of the alveoli, removing debris and microbes.
17. What is the function
of the surfactant-secreting, or Type II cells, within alveoli?
They
secrete surfactant.
18. What is
present on the inside surface of alveoli?
Alveolar
fluid, which is composed of water and surfactant.
19. What
would happen if there were no surfactant in alveolar fluid?
The
alveoli would collapse due to the surface tension of the water.
20. Why is there no interstitial fluid in
between the two layers of simple squamous epithelium in the respiratory
membrane?
Because pulmonary blood pressure is so low that little fluid filters out of the capillaries into the interstitial space.
21. What two important gases diffuse across the
respiratory membrane? In which
direction does each gas flow?
Oxygen gas diffuses from the alveoli to the pulmonary capillaries. Carbon dioxide diffuses from the pulmonary capillaries to the alveoli.
Control
of Respiration
22. What controls the basic rhythm of
breathing?
Respiratory
centers located in the brainstem.
23. What monitors changes in arterial PCO2,
PO2
and pH?
Sensory
receptors called chemoreceptors.
24. Explain how the inspiratory center
initiates inspiration.
The inspiratory center sends nerve impulses
along the phrenic nerve to the diaphragm and along the intercostal nerves to
the external intercostal muscles which continue for a period of about 2
seconds. This stimulates the inspiratory muscles to contract, initiating
inspiration.
25. Explain how the inspiratory center
initiates expiration
The inspiratory center causes the
phrenic nerve to stop firing for about 3 seconds, which allows the muscles of
respiration to relax. The elastic recoil of the lungs and chest wall leads to
expiration.
26-35. In each of these blanks, put "increase(s)"
or "decrease(s)":
If the arterial PCO2
increases, there is a(an) a. __increase__ in the PCO2 in the
fourth ventricle. This causes
a(an) b. __ increase___ in hydrogen ions in the cerebrospinal fluid, which c. _decreases_ the pH of the
cerebrospinal fluid. The hydrogen
ions stimulate the central chemoreceptors to d. _ increase__ their rate of firing,
which e. _ increases_ the nerve impulses to the respiratory centers. This f. _ increases_ the rate of nerve
impulses to the respiratory muscles, resulting in a(an) g. _ increase _ in breathing rate and
depth. As a result, there is a(an)
h. __ increase
__ in carbon dioxide exhalation which i. _ decreases_ the blood PCO2
to normal levels.
36.
Do peripheral chemoreceptors directly respond to changes in the arterial
blood, venous blood, or cerebrospinal fluid?
Arterial
blood
37-41. In each of these blanks, put "increase(s)"
or "decrease(s)":
An increase in carbon dioxide levels in the
arterial blood
result in a(an) a. __ decrease __ in blood pH. There is a(an) b. _ increase __ in the rate of
firing of the peripheral chemoreceptors, which c, __ increases__ the rate of
respiration. As a result there is a(an) d. __ increase__ in carbon dioxide exhalation, which drives
the chemical reaction to the left and e.
_ decreases__
PCO2
and pH returns to normal
levels.
42-50. In each of these blanks, put "increase(s)" or
"decrease(s)": The
peripheral chemoreceptors also respond to acids such as lactic acid, which a. _
increases
_ during strenuous exercise. The lactic acid enters the blood and b. _ increases _ the concentration of hydrogen ions which c. _ decreases _ the pH which d. _ increases _ the firing rate of the peripheral
chemoreceptors. There is a(an) e.
__ increase_
in nerve impulses to the respiratory centers, which f. _ increases _ the breathing rate
and depth. There is a(an) g. _ increases_ in carbon dioxide is exhalation which
h. __ decreases
__ the PCO2 in blood, driving the chemical reaction to the left, and
i. _ decreases
_ hydrogen ion levels.
51.
What is the Hering-Breuer reflex?
Stretch receptors in the visceral pleura and
large airways send inhibitory signals to the inspiratory center during very
deep inspirations, protecting against excessive stretching of the lungs.
52. Do changes in PCO2 and PO2
play a significant role in stimulating increased ventilation due to exercise?
No they do not play a significant
role.
53. What are the factors that stimulate
increased ventilation during exercise?
Learned responses, Neural input from the
motor cortex, Receptors in muscles and joints, Increased body temperature,
Circulating epinephrine and norepinephrine and pH changes due to lactic acid.
Pulmonary
Ventilation
54. How is the volume of the thoracic
cavity changed?
By
muscle contraction and relaxation.
55. What two muscles contract during quiet
inspiration? What is the effect of
their contraction?
The diaphragm and the external
intercostals. As a result the
thoracic cavity enlarges in all dimensions.
56. What happens to pressure when we
increase the volume within the thoracic cavity and the lungs?
Pressure
decreases.
57. Explain what happens in quiet
expiration.
The diaphragm and the external intercostal
muscles relax, and the elastic lungs and thoracic wall recoil inward.
58. What effect does quiet expiration have
on the volume of the thoracic cavity?
How does this effect the pressure within the cavity?
The
volume is decreased and therefore the pressure increases within the thoracic
cavity.
59-61. What three factors cause the
intrapleural pressure to be less
than intrapulmonary (alveolar) pressure?
(1) The surface tension of the alveolar fluid. (2) The elasticity of the lungs. (3) The elasticity of the thoracic wall.
62. Why does a lung collapse if you cut
into the pleural cavity?
Because the pressure of the intrapleural cavity becomes equal to atmospheric pressure. There is no longer less pressure in the intrapleural cavity compared to within the alveoli so the lung collapses.
63. If a pneumothorax occurs in one lung,
why doesn't it also occur in the other lung?
Each lung has its own pleural cavity and pleural membranes so that changes in the intrapleural pressure of one lung do not affect the other lung.
64. Does histamine constrict or dilate
bronchioles?
Constrict
65. Does epinephrine constrict or dilate
bronchioles?
Dilate
66. What two factors is lung compliance dependent
upon?
(1) The
stretchability of the elastic fibers within the lungs. (2) The surface tension within the
alveoli.