Module 16: The Respiratory System

Question 1

Pulmonary ventilation

Answer 1

“Breathing”

Inhalation (inspiration) and exhalation (expiration)

Question 2

External respiration

Answer 2

Exchange of gases between the blood and the lungs

Question 3

Transport of respiratory gases

Answer 3

In RBCs and plasma

Question 4

Internal respiration

Answer 4

Exchange of gases between the blood and tissue cells

Question 5

Conducting zone (macroscopic)

Answer 5

Nose
Pharynx (throat)
Larynx (voice box)
Trachea (windpipe)
Bronchi
Terminal bronchioles

Question 6

Epiglottis

Answer 6

Covers the opening of the larynx

Closes off the larynx during swallowing

Question 7

Respiratory zone (microscopic)

Answer 7

Respiratory bronchioles

Alveolar ducts

Question 8

Respiratory bronchioles

Answer 8

Formed from branchings of the terminal bronchioles

Question 9

Alveolar ducts

Answer 9

Respiratory bronchioles lead into alveolar ducts

Alveolar ducts lead into clusters of alveoli

Question 10

Alveoli (air sacs)

Answer 10

300 million in each lung provide a lot of surface area
Found in clusters called alveolar sacs
Where gas exchange occurs

Question 11

Type I alveolar cells

Answer 11

Simple squamous epithelium

Provide the site for gas exchange between the capillaries and the alveoli

Question 12

Type II alveolar cells

Answer 12

Septal cells
Produce surfactant (reduces surface tension between fluid molecules inside the alveoli so they do not adhere to each other and collapse)

Question 13

Macrophages

Answer 13

Dust cells

Wander around “cleaning up” foreign material

Question 14

Hilus

Answer 14

Area in each lung where blood vessels, lymphatic vessels,

nerves, and the bronchus enter and leave the lung

Question 15

Boyle’s Law

Answer 15

With a constant temperature, when volume ↓ then pressure ↑

Question 16

Gas exchange in the lung

Answer 16

Air is inhaled
Oxygen diffuses from the alveoli into the capillaries
Carbon dioxide diffuses from the capillaries into the alveoli
Carbon dioxide is exhaled

Question 17

Gas exchange in the body cells

Answer 17

Oxygen leaves the capillary blood and diffuses into the cells where it can be used during cellular metabolism
Carbon dioxide diffuses into the capillary blood as metabolism occurs in the cell

Question 18

Transport of oxygen

Answer 18

Oxygen diffuses across the alveoli into the capillaries
Oxygen then dissolves in the plasma
About 3% of the oxygen is transported as a dissolved gas in the plasma
97% of the oxygen is carried by hemoglobin molecules in the erythrocytes

Question 19

Transport of carbon dioxide

Answer 19

Diffuses from the tissue cells into the capillaries
Blood returns the carbon dioxide to the lungs in three ways:
• dissolved in the plasma (7%)
• combined with hemoglobin in the erythrocytes (23%)
• as bicarbonate ions in plasma (70%)

Question 20

Medullary rhythmicity center

Answer 20

Sets the basic pattern of respiration
In a resting adult, inspiration lasts for about 2 seconds and expiration for about 3 seconds
Normal respiratory rate ranges between 12 and 20 breaths per minute in an adult and from 20 to 40 breaths per minute in a child

Question 21

Central chemoreceptors

Answer 21

Sensitive to increases in carbon dioxide and hydrogen ion levels

Question 22

Peripheral chemoreceptors

Answer 22

Detect decreases in oxygen levels

Question 23

Respiratory distress syndrome (RDS)

Answer 23

Also called hyaline membrane disease (HMD)
Most common cause of death of newborns – almost exclusively in those born before the 37th week of gestation
Caused by a deficient amount of surfactant
Characterized by difficult breathing, which exhausts the infant

Question 24

Aging and the respiratory system

Answer 24

Airways and tissues become less elastic – oxygen delivery to tissue cells is impaired
More susceptible to diseases due to the decrease in activity of the macrophages and ciliary action of the epithelial lining of the respiratory tract

Question 25

Vital capacity

Answer 25

Maximum volume of air that can be expelled from the lungs

Question 26

Tidal volume

Answer 26

The amount of air exchanged with a normal quiet breath

Question 27

Partial pressure

Answer 27

The pressure exerted by each gas in a mixture

Question 28

Inspiratory reserve volume

Answer 28

The volume of air over the tidal volume that can be forced into the lungs