Chapter 6: The Respiratory System

Question 1

How does air enter the respiratory tract?

Answer 1

Through the external nares of the nose, and then passes through the nasal cavity

Question 2

How is air filtered in the nasal cavity?

Answer 2

Through mucous membranes and nasal hairs (vibrissae)

Question 3

Which structure is a common pathway for air destined for the lungs and food destined for the esophagus?

Answer 3

Pharynx

Question 4

Where does the air go following the nasal cavity?

Answer 4

The pharynx, then the larynx

Question 5

How is food kept out of the respiratory tract?

Answer 5

The opening of the larynx (glottis) is covered by the epiglottis during swallowing

Question 6

Which structure contains vocal cords? How many?

Answer 6

The larynx contains two

Question 7

From the larynx, where does air pass?

Answer 7

Into the tracea and then into one of the two mainstem bronchi

Question 8

How is air filtered in the bronchi and trachea?

Answer 8

They contain ciliated epithelial cells to catch remaining material

Question 9

In the lungs, the bronchi continue to divide into smaller structures known as ____________, which divide further into _________

Answer 9

bronchioles alveoli

Question 10

Gas exchange occurs where?

Answer 10

At the alveoli

Question 11

What is each alveolus coated with? Why?

Answer 11

• A surfactant (detergent) - Lowers surface tension and prevents the alveolus from collapsing on itself

Question 12

Membranes known as _______ surround each lung

Answer 12

pleurae

Question 13

The surface adjacent to the lung is the _______ pleura, and the outer part is the _______ pleura

Answer 13

visceral parietal

Question 14

What does the diaphragm divide?

Answer 14

Divides the thoracic (chest) cavity from the abdominal cavity

Question 15

The diaphragm is under (somatic/automatic) control, and breathing is under (somatic/automatic)

Answer 15

somatic automatic

Question 16

What does the intrapleural space contain? Why?

Answer 16

Thin layer of pleural fluid, which helps lubricate the two pleural surfaces

Question 17

What ultimately drives breathing?

Answer 17

The pressure differentials that can be created across the pleura drives air into the lungs

Question 18

What structures do we use to expand the thoracic cavity?

Answer 18

Diaphragm and external intercostal muscles

Question 19

What happens when the diaphragm flattens and the chest wall expands? Why?

Answer 19

The intrathoracic volume increases, and the intrapleural space approaches the chest wall, which increases its volume

Question 20

What is Boyle’s law? How does it relate to breathing?

Answer 20

• States that the pressure and volume of gases are inversely related - As the chest wall expands, the pressure in the lungs drop, and air is drawn into the lungs

Question 21

When breathing in, what happens to the intrapleural pressure?

Answer 21

The intrapleural volume increases, so the pressure decreases

Question 22

When breathing in, how does the pressure of the lungs compare to the pressure of the intrapleural space? What does that cause?

Answer 22

• The pressure of the lungs is higher than the pressure of the intrapleural space - The lungs will therefore expand into the intrapleural space, and the pressure in the lungs will drop - Air will be sucked in from the high-pressure environment (outside world)

Question 23

What is negative-pressure breathing?

Answer 23

The driving force is the lower (relatively negative) pressure in the intrapleural space compared with the lungs

Question 24

How does exhalation occur? Is it an active process?

Answer 24

• Does not have to be an active process - Relaxation of the external intercostal muscles and diaphragm

Question 25

When breathing out, what happens to the pressure in the intrapleural space?

Answer 25

- Chest cavity decreases in volume - Intrapleural space pressure is higher than in the lungs, which results in air being pushed out

Question 26

How can we speed exhalation?

Answer 26

By using the internal intercostal muscles and abdominal muscles

Question 27

What is the instrument used in lung capacity and volume measurements?

Answer 27

Spirometer

Question 28

What is total lung capacity (TLC)? What is it usually around?

Answer 28

- The maximum volume of air in the lungs when one inhales completely - Usually around 6 to 7 liters

Question 29

What is residual volume (RV)?

Answer 29

The minimum volume of air in the lungs when one exhales completely

Question 30

What is vital capacity (VC)?

Answer 30

The difference between the minimum and maximum volume of air in the lungs (TLC - RV)

Question 31

What is tidal volume (TV)?

Answer 31

The volume of air inhaled and exhaled in a normal breath

Question 32

What is expiratory reserve volume (ERV)?

Answer 32

The volume of additional air that can be forcibly exhaled after a normal exhalation

Question 33

What is inspiratory reserve volume (IRV)?

Answer 33

The volume of additional air that can be forcibly inhaled after a normal inhalation

Question 34

What is ventilation primarily regulated by?

Answer 34

Collection of neurons in the medulla oblongata called the ventilation center

Question 35

What kind of receptors are neurons in the ventilation center?

Answer 35

They contain chemoreceptors that are primarily sensitive to carbon dioxide concentration

Question 36

What is hypercarbia (or hypercapnia)?

Answer 36

When there is a high concentration of carbon dioxide in the blood

Question 37

What happens when there is a high concentration of carbon dioxide in the blood?

Answer 37

The respiratory rate will increase so that more CO2 is exhaled

Question 38

What is hypoxia?

Answer 38

Low oxygen concentration in the blood

Question 39

How does the ventilation center respond to hypoxia?

Answer 39

Increases the ventilation rate

Question 40

How can ventilation be controlled consciously? What structure will override it?

Answer 40

- Controlled consciously through the cerebrum - The medulla oblongata will override during extended periods of hypo- or hyperventilation

Question 41

List the structures in the respiratory pathway, from where air enters the nares to the alveoli.

Answer 41

Nares, nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles, alveoli

Question 42

What is the mathematical relationship between vital capacity (VC), inspiratory reserve volume (IRV), expiratory reserve volume (ERV), and tidal volume (TV)?

Answer 42

VC = IRV + ERV + TV

Question 43

The capillaries bring deoxygenated blood from the \_\_\_\_\_\_\_\_\_\_\_\_\_, which originate from the _______ \_\_\_\_\_\_\_\_\_ of the heart.

Answer 43

pulmonary arteries right ventricle

Question 44

The oxygenated blood returns to the _____ \_\_\_\_\_\_ f the heart via the \_\_\_\_\_\_\_\_\_\_\_\_\_.

Answer 44

left atrium pulmonary veins

Question 45

When it initially arrives at the alveoli, blood has a relatively (low/high) partial pressure of oxygen, and a relatively (low/high) partial pressure of carbon dioxide

Answer 45

low high

Question 46

What happens if we moved to higher altitudes where less oxygen is available?

Answer 46

1) Breathe more rapidly to try to avoid hypoxia 2) Binding of hemoglobin to oxygen is altered to facilitate the unloading of oxygen at the tissues 3) Make more red cells to carry oxygen 4) Long run: develop more blood vessels (vascularization), which would facilitate the distribution of oxygen to tissues

Question 47

What is the natural response of hemoglobin to decreased carbon dioxide concentration in the environment?

Answer 47

Decrease the unloading of oxygen to tissues

Question 48

How is heat regulated through body surfaces?

Answer 48

- Vasodilatation and vasoconstriction - Sweat glands - Rapid muscle contraction (shivering)

Question 49

What happens in terms of thermal energy during vasodilatation?

Answer 49

When capillaries expand, more blood can pass through these vessels, and a larger amount of thermal energy can be dissipated

Question 50

What happens in terms of thermal energy during vasoconstriction?

Answer 50

When capillaries contract, less blood can pass through them, conserving thermal energy

Question 51

What is the first line of immune defense in the respiratory system?

Answer 51

Occurs within the nasal cavity, the small hairs (vibrissae) help to trap particulate matter and potentially infectious particles

Question 52

What enzyme does the nasal cavity contain? What is its function?

Answer 52

- Lysozyme - Able to attack the peptidoglycan walls of gram-positive bacteria

Question 53

What is the mucociliary escalator mechanism?

Answer 53

- The internal airways are lined with mucus, which traps particulate matter and larger invaders - Underlying cilia then propel the mucus up the respiratory tract to the oral cavity, where it can be expelled or swallowed

Question 54

What kind of immune cells do the lungs contain?

Answer 54

- Macrophages - Mast cells

Question 55

What is the function of macrophages?

Answer 55

Engulf and digest pathogens, and signal to the immune system of an invader

Question 56

What helps protect against pathogens that contact the mucous membranes?

Answer 56

Mucosal surfaces contain IgA antibodies

Question 57

What is the function of mast cells?

Answer 57

- Preformed antibodies on their surface - When the right substance attaches to the antibody, it releases inflammatory chemicals into the surrounding area to promote an immune response

Question 58

Which immune cells provide the inflammatory chemicals that mediate allergic reactions?

Answer 58

Mast cells

Question 59

What is the regular pH of the body?

Answer 59

7.35 to 7.45

Question 60

What happens during acidemia?

Answer 60

- Acid-sensing chemoreceptors signals the brain to increase respiratory rate - Increased H+ causes a shift in the bicarbonate buffer system, which generates more CO2 - Increased CO2 increases respiratory rate - CO2 is blown off, and the system shifts to the left, which lowers the amount of H+

Question 61

What happens during alkalemia?

Answer 61

- Respiratory rate is slowed, which retains more CO2 - System is shifted to the left, producing more H+ and bicarbonate ions

Question 62

What is the role of the kidneys in the maintenance of proper pH?

Answer 62

By modulating secretion and reabsorption of acid and base within the nephron

Question 63

Respiratory failure refers to inadequate ventilation to provide oxygen to the tissues. How would the pH change in respiratory failure?

Answer 63

- Less CO2 is blown off - Buffer equation shifts to the right, and more hydrogen ions are generated - Lower pH of the blood

Question 64

What is the bicarbonate buffer system equation?

Answer 64

CO₂*(g)* + H₂O*(l)* ⇔ H₂CO₃*(aq)* ⇔ H⁺*(aq)* + HCO₃^-*(aq)*