Chapter 16: The Respiratory System: Pulmonary Ventilation

Question 1

What is the medical term for hiccups?

Answer 1

singultus

p. 453 of Principles of Human Physiology

Question 2

Hiccups are a _______ ___________ of the diaphragm, the muscle of inspiration. During a hiccup, air rapidly enters a person’s lungs and then rapidly stop as the glottis closes, producing the characteristic sound “hiccup”.

Answer 2

spastic contraction

p. 453 of Principles of Human Physiology

Question 3

Why may pregnant women have hiccups more frequently?

Answer 3

Due to the pressure the fetus puts on the diaphragm.

p. 453 of Principles of Human Physiology

Question 4

Some of the folk cures for hiccups are based on physiology of the respiratory system. Holding your breath, breathing into a paper bag, and standing on one’s head and drinking water, all have the potential to inhibit the ______ _______ for hiccups.

Answer 4

neural pathway

p. 453 of Principles of Human Physiology

Question 5

Our cells produce most of the ATP that they need through the process of _______ ____________, which requires oxygen.

Answer 5

oxidative phosphorylation

p. 454

Question 6

What is the difference between internal respiration and external respiration?

Answer 6

Internal respiration is also called cellular respiration, and refers to the use of oxygen within mitochondria, and the production of CO2 as a waste product. External respiration refers to the exchange of oxygen and carbon dioxide between the atmosphere and body tissues, which involves both the respiratory and circulatory systems.

(p. 454)

Question 7

External respiration encompasses 4 processes:

(1) pulmonary ventilation, the movement of air into the lungs (inspiration) and out of the lungs (expiration) by bulk flow
(2) exchange of oxygen and carbon dioxide between lung air spaces and blood __ __________
(3) transportation of oxygen and carbon dioxide between the lungs and body tissues by the blood
(4) exchange of oxygen and carbon dioxide between the blood and tissues __ _________

Answer 7

by diffusion
by diffusion

(p. 454)

Question 8

In addition to respiration, the respiratory system also performs a number of other functions, including:

(1) contributing to the regulation of acid-base balance in the blood
(2) enabling ____________
(3) participating in defense against pathogens and foreign particles in the airways
(4) providing a route for water and heat losses (via the expiration of air that was moistened and warmed during inspiration)
(5) enhancing ______ ______ (through the respiratory pump)
(6) activating certain ______ ________ as they pass through the pulmonary circulation

Answer 8

vocalization
venous return
plasma proteins

(p. 454)

Question 9

The term upper airways refers to air passages in the…

Answer 9

…head and neck.

p. 455

Question 10

What is the pharynx?

Answer 10

A muscular tube that serves as a common passageway for both air and food.

p. 455

Question 11

The respiratory tract can be functionally divided into what 2 zones?

Answer 11

conducting zone and respiratory zone

p. 455

Question 12

What does the conducting zone of the respiratory tract do?

Answer 12

conducts air from the larynx to the lungs

p. 455

Question 13

What does occurs in the respiratory zone of the respiratory tract?

Answer 13

gas exchange

p. 455

Question 14

The opening to the larynx is called the _______, and is covered by a flap of tissue called the __________.

Answer 14

glottis
epiglottis

p. 455

Question 15

The trachea is a tube about ___ cm in diameter and __ cm long that runs ________ _____ and ________ to the esophagus. Unlike the esophagus, which is collapsed except during swallowing, the trachea stays open because the front and sides of its wall contain __-__ C-shaped bands of cartilage that provide structural rigidity. The absence of this cartilage on the posterior wall of the trachea allows the esophagus behind it to ______ with the passage of food.

Answer 15

2.5 cm
10 cm 
parallel with
anterior
15-20 
expand

p. 456

Question 16

The inner diameter of the.... 
larynx is approximately \_\_ to \_\_ mm
trachea is \_\_ to \_\_ mm
primary bronchi is \_\_ to \_\_ mm
secondary bronchi is \_\_ to \_\_ mm
tertiary bronchi is \_\_ to \_\_ mm
smaller bronchi is \_\_ to \_\_ mm
bronchioles is \_\_ to \_\_ mm
terminal bronchioles is \_\_\_ mm
respiratory bronchioles is \_\_\_ mm
alveolar sacs is \_\_ mm

Answer 16

larynx, 35 - 45 mm 
trachea, 20 - 35 mm
primary bronchi, 12 - 16 mm 
secondary bronchi, 10 - 12 mm
tertiary bronchi, 8 - 10 mm
smaller bronchi, 1 - 8 mm
bronchioles, 0.5 - 1 mm
terminal bronchioles, <0.5 mm 
respiratory bronchioles, <0.5 mm 
alveolar sacs, 0.3 mm 

p. 457

Question 17

Clinical application:
Based on what you know about the size of the various airways of the lungs, what is the smallest type of airway which a bronchoscope can get into?

Answer 17

smaller bronchi
Most adult bronchoscopes are approx 5 - 6 mm in width. The smaller bronchi measure 1 - 8 mm in diameter, so theoretically, a bronchoscope could fit in the larger of these airways.

[“The role of bronchoscopy in the diagnosis of airway disease” (Paradis et al., 2016)]

Question 18

The conducting zone holds approximately ___ ml of air and is considered “____ _____” because the air does not participate in ___ ________ with blood.

Answer 18

150 ml
dead space
gas exchange

p. 457

Question 19

The alveolar sacs contain no _____, ______ _____, _________, or smooth muscle.

Answer 19

cilia, goblet cells, cartilage

p. 457

Question 20

Like the trachea, the bronchi contain cartilage; however, the cartilage forms rings around the entire circumference of the bronchus. Within each lung, the bronchi divide into secondary bronchi; ___ secondary bronchi conduct air to the lobes of the right lung, and ___ secondary bronchi conduct air to the lobes of the left lung. The cartilage in the secondary bronchi is less abundant than that in the primary bronchi and occurs as ______.

Answer 20

three
two
plates

p. 457

Question 21

The amount of cilia, goblet cells, and cartilage ________ as you move from the larynx to the trachea, to the bronchi to the bronchioles, and finally to the alveolar sacs (which have none of these). There is no smooth muscle in the larynx, and only a little bit in the trachea, however, the amount increases as you move toward the terminal bronchioles which contain a lot of smooth muscle. There is then a small amount in the respiratory bronchioles, and none in the alveolar sacs.

Answer 21

decreases

p. 457

Question 22

Goblet cells secrete a viscous fluid called mucus, which coats the airways and traps foreign particles. The cilia beat in a whiplike fashion to propel the mucus containing the trapped particles up toward the glottis and then into the pharynx. This function is known as the _____ ________ prevents mucus from accumulating in the airways and clears trapped foreign matter. Accumulation of mucus in the airways increases the likelihood of infections such as bronchitis and pneumonia because it promotes retention and growth of bacteria. Because cilia are easily paralyzed by tobacco smoke, smoking disables the mucus escalator, so that mucus and trapped debris accumulate in the airways and be cleared only by coughing; this is one reason for the familiar “smoker’s cough”. At levels below the bronchioles, __________ _____ called macrophages engulf foreign matter in the interstitial space and on the surface of the epithelium.

Answer 22

mucus escalator
phagocytic cells

p. 458

Question 23

In addition to changes in the epithelium, other tissue changes occur as the airways become smaller. As previously noted, _________ is plentiful in the walls of the trachea and bronchi, but it becomes less abundant as the diameter of the bronchi decreases, until in the bronchioles it is completely absent. Smooth muscle is sparse in the trachea and bronchi but increases in abundance as the airways become smaller. The lack of cartilage and the presence of ________ ______ ______ within the bronchioles enable these airways to change their diameter; such changes alter the resistance to air flow.

Answer 23

cartilage
circular smooth muscle

p. 458

Question 24

As we saw before, the rate at which substances diffuse across a membrane increases as membrane _______ ____ increases and as ________ ________ decreases. The arrangement of structures in the respiratory zone, maximizes surface area and minimizes thickness, such that the diffusion of oxygen and carbon dioxide between air and blood is facilitated.

Answer 24

surface area
membrane thickness

p. 459

Question 25

Past the site where the terminal bronchioles of the conducting zone branch, the respiratory zone begins. The first respiratory zone structures, respiratory bronchioles, terminate in alveolar ducts, which lead to alveoli, the primary structures where gas exchange occurs. Most alveoli occur in clusters called _______ ____, which resemble clusters of grapes; some alveoli open off of respiratory bronchioles. Adjacent alveoli are not completely independent structures. Because they are connected by alveolar _____, air flows between alveoli, allowing __________ of pressure within the lungs.

Answer 25

alveolar sacs
pores
equilibration

p. 459

Question 26

Alveolar structure facilitates diffusion of gases between blood and air. The wall of an alveolus consist primarily of a single layer of epithelial cells called ___ _ ________ _____ overlying a ________ ________. Recall that a capillary wall consists of a single layer of endothelial cells and an underlying basement membrane. In many places in the lungs, the alveolar epithelial cells and the endothelial cells of the nearby capillaries are so close together that their basement membranes are fused. Together the capillary and alveolar wall form a barrier, called the respiratory membrane, that separates air from blood. The thinness of the respiratory membrane – only about ___ ___ _____ – is essential for efficient gas exchange.

Answer 26

type I alveolar cells
basement membrane

0. 2 µm thick
   p. 459

Question 27

In addition to the thickness of the respiratory membrane, the abundance of alveoli and capillaries also facilitates the diffusion of gases. The approximately ___ _______ alveoli in the lungs have a total surface area of approximately 100 square meters, which is about the size of a ______ _____. The capillary supply to the alveoli so rich that many physiologists think of pulmonary vasculature not in terms of arterioles and capillaries but as a “sheet of blood” surrounding the alveoli.

Answer 27

300 million
tennis court

p. 459

Question 28

Also located in the alveoli are ____ __ _______ ________ and alveolar macrophages, which engulf foreign particles and pathogens inhaled into the lungs. These macrophages are cells that are free to roam around in the alveoli by ________ movements. Dead macrophages are moved from the alveoli into the conducting zone, where the mucus escalator carries the macrophages to the pharynx so that they can be swallowed with mucus.

Answer 28

type II alveolar cells
amoeboid

p. 459

Question 29

Muscles of the chest wall, which are responsible for breathing are the internal intercostals, and external intercostals, located between the ribs, and the dome shaped diaphragm, which seals off the lower end of the chest wall and separates the _______ and __________ ________. Muscles and connective tissue in the neck close off the chest wall at its upper end. Because the chest wall forms a ________ _______ around the lungs, the compartment enclosing the lungs is airtight.

Answer 29

thoracic and abdominal cavities
continuous barrier

p. 459

Question 30

Between the two pleurae is a very thin compartment called the intrapleural space, which is filled with a small volume (approximately __ ml) of intrapleural fluid.

Answer 30

15 ml

p. 459

Question 31

Transpulmonary pressure is the difference between __________ pressure and ____________ pressure.

Answer 31

intra-alveolar
intrapleural

p. 462

Question 32

What is the normal value of intrapleural pressure, intra-alveolar pressure, and transpulmonary pressure (absolute and relative)?

Answer 32

intrapleural pressure: 756 mm Hg (-4 mm Hg relative to atmosphere)
intra-alveolar pressure: 760 mm Hg (0 relative to atmosphere)
transpulmonary pressure: Palv - Pip = 4 mm Hg

(see diagram, p. 462)

Question 33

Ventilation occurs because of the presence of ________ _________ between the alveoli and the outside air (atmosphere).

Answer 33

pressure gradients

p. 462