Unit 16 - The Respiratory System Flashcards
1
Q
The _______ provides the means for gas exchange required by living cells.
A
“respiratory system”
2
Q
The respiratory and _______ systems are inseparable partners.
A
cardiovascular
3
Q
While the ___ exchanges gases between the atmosphere and the blood, the _______ transports those gases between the lungs and the body
cells.
A
respiratory system, cardiovascular system
4
Q
Anatomically, the respiratory system consists of an upper respiratory tract and a lower respiratory tract.
A
True
5
Q
Functionally, the respiratory system can be divided into a ________, which transports air, and a _______, where gas exchange with the blood occurs.
A
“conducting portion”, “respiratory portion”
6
Q
The conducting portion includes:
A
1) Nose
2) Nasal cavity
3) Pharynx
4) Larynx
5) Trachea
6) Progressively smaller airways (from the primary bronchi to the terminal bronchioles)
7
Q
The respiratory portion is composed of:
A
1) Small airways called respiratory bronchioles
2) Alveolar ducts
3) Air sacs called alveoli
8
Q
The primary function most of us associate with the respiratory system is breathing, also called ______.
A
pulmonary ventilation
9
Q
Breathing consists of two cyclic phases, what are they?
A
Inhalation and Exhalation
10
Q
Also called Inspiration
A
Inhalation
11
Q
Also called Expiration
A
Exhalation
12
Q
Inhalation draws gases into the lungs, T or F?
A
True
13
Q
Exhalation forces gases out of the lungs, T or F?
A
True
14
Q
There are two types of gas exchange, what are they?
A
External Respiration and Internal Respiration
15
Q
_______ involves the exchange of gases between the atmosphere and the blood.
A
“External respiration”
Oxygen diffuses from the lungs into the blood while carbon dioxide diffuses out of the blood into the air spaces in the lungs in order to be exhaled.
16
Q
_______ involves the exchange of gases between the blood and the cells throughout the body.
A
“Internal respiration”
17
Q
As inhaled gases pass through conducting airways the gases are _____ prior to reaching the gas exchange surfaces of the lungs.
A
“conditioned”
(a) The gases are warmed to body temperature.
(b) The gases are humidified (moistened).
(c) The gases are cleansed of particulate matter through contact with the respiratory epithelium and its sticky mucus covering
This conditioning is facilitated by the twisted pathways through the nasal cavity and paranasal sinuses, which cause the inhaled air to become very turbulent during inhalation.
18
Q
As air is forced out of the lungs and moves through the larynx, sound may be produced, such as speech or singing, T or F?
A
True
19
Q
What other anatomic structures aid sound production?
A
- Nasal cavity
- Paranasal sinuses
- Teeth
- Lips
- Tongue
20
Q
The superior region of the nasal cavity is covered with olfactory epithelium, which contains ______ for the sense of smell.
A
chemoreceptors
These chemoreceptors detect inhaled molecules that dissolve in the mucus overlying the olfactory epithelium
21
Q
The structure of the respiratory system, and some of the cells in the respiratory _____, protects the body against airborne infection.
A
epithelium
22
Q
Entrance to nose is lined with coarse hairs called what?
A
Vibrissae
Twisted passageways trap insects and microbes
23
Q
An enzyme that destroys microbial cell walls.
A
Lysozyme
24
Q
The ____ traps inhaled dust, microbes, insects, and pollen
A
mucus
25
Defensive ______ can increase when large quantities of irritating materials enter
Mucus production
26
Involves defective plasma membrane proteins that affect chloride ion (Cl−) channels in the membrane. These channels are transport proteins that use facilitated diffusion to move chloride ions across the plasma membrane
cystic fibrosis
The primary defect in these chloride channels results in an abnormal flow of chloride ions across the membrane, causing salt to be trapped within the cytoplasm of affected cells.
Ultimately, the normal osmotic flow of water across the plasma membrane breaks down.
The concentration of salt within the cytoplasm of these cells causes an increase in the osmotic flow of water into the cell, thereby resulting in thickening of the mucus in the respiratory passageways and the pancreatic ducts.
27
the most common serious genetic disease in Caucasians, occurring with a frequency of approximately 1 in 3500 births in the United States.
The condition is rare among people of Asian and African descent.
cystic fibrosis
28
The name cystic fibrosis refers to the characteristic scarring and cyst formation within the _____
pancreas
29
Chloride and sodium are not reabsorbed from the sweat, and so they become concentrated on the skin in individuals with _______
cystic fibrosis
30
Mothers of babies with cystic fibrosis often find that the baby tastes “salty” when kissed.
True
31
The “upper respiratory tract” is composed of:
a. Nose and nasal cavity
b. Paranasal sinuses
c. Pharynx (throat)
d. Structures associated with the above
These structures are all part of the conducting portion of the respiratory tract.
32
The _____ is the main conducting airway for inhaled a
“nose”
33
The nose is supported superiorly by paired ______ that form the bridge of the nose.
“nasal bones”
34
_______ open on the inferior surface of the nose.
Paired “nostrils” (“external nares”)
35
Anterioinferiorly from the bridge is the fleshy, _______.
cartilaginous portion of the nose
36
The nasal cavity is continuous posteriorly with the nasopharynx via paired openings called ______
“internal nares”
37
The roof of the nasal cavity is formed by:
(a) Frontal bone
(b) Nasal bones
(c) Cribriform plate of the ethmoid
(d) Sphenoid bone
38
The floor of the nasal cavity is formed by:
(a) Horizontal plate of the maxillae
| (b) Horizontal portions of the palatine bones
39
The anterior region of the nasal cavity, near the nostrils, is called the _____
“vestibule”
40
Near the vestibule are coarse hairs, called _____ to
| help trap large particles.
“vibrissae”
41
The nasal cavity is lined with _____ and covered with mucus that moves dust and debris ______ towards the _____.
ciliated epithelium, posteriorly, nasopharynx
42
The most superior portion of the nasal cavity contains ______, which has numerous chemoreceptors.
“olfactory epithelium”
43
The _____ divides the nasal cavity into left and right portions.
“nasal septum”
44
The nasal septum is formed anteriorly by _____
“septal cartilage”
45
The _______ contributes to the superior portion of the nasal septum
perpendicular plate of the ethmoid
46
The _____ contributes to the posterior portion of the nasal septum
vomer bone
47
The lateral walls of the nasal cavity are formed primarily by _______, that are also referred to as ______ because they create turbulence in inhaled air
“conchae”, “turbinates”
This turbulence ensures that air remains in the nasal cavity for a longer time so that the air becomes warmed and humidified.
48
The “superior nasal conchae”, which are part of the _____
ethmoid
49
The “middle nasal conchae”, which are also part of the _____
ethmoid
50
The “inferior nasal conchae”, which are independent ______
facial bones
51
Note the nasolacrimal ducts empty just inferior to the inferior nasal conchae, this is why snot come out of your mouth when you cry
True
52
Besides functioning in filtration, conditioning, and olfaction, the nasal cavity is a ______ that contributes to sound production.
resonating chamber
53
a. Four bones of the skull contain paired air spaces called the _____ which together decrease skull bone weight.
“paranasal sinuses”
54
All sinuses communicate with the nasal cavity by ducts and are lined by _______
ciliated epithelium with overlying mucus
55
What paranasal sinuses are there
1) Frontal sinuses
2) Ethmoidal sinuses
3) Sphenoidal sinuses
4) Maxillary sinuses
56
The nasal cavity and the paranasal sinuses are the primary structures that warm and humidify the air we inhale.
True
57
The common space used by both the respiratory and digestive systems is the ______, commonly called the throat.
pharynx
For most of its length, the pharynx is the common pathway for both inhaled and exhaled air (the respiratory system) and for ingested food (the digestive system).
58
The pharynx is funnel-shaped, meaning that it is slightly wider superiorly and narrower inferiorly.
True
59
The pharynx originates posterior to the nasal and oral cavities and extends inferiorly to the level of the bifurcation of the larynx and esophagus.
True
60
The pharynx is partitioned into three adjoining regions, what are they?
Nasopharynx, Oropharynx, Laryngopharynx
61
The _______ is the superior most region of the pharynx and is located directly posterior to the nasal cavity and superior to the soft palate, which
separates it from the posterior part of the oral cavity.
“nasopharynx”
62
The nasopharynx is lined with _____
ciliated epithelium.
63
Normally, only air passes through the nasopharynx.
- Food and drink are blocked from entering the nasopharynx by elevation of the
soft palate and “______”.
uvula
64
Severe vomiting may overcome the seal by the soft palate and uvula, T or F?
True
65
In the lateral walls of the nasopharynx, paired ______ connect the nasopharynx to the middle ear so air pressure can be equalized behind the ear drum.
“auditory (Eustachian) tubes”
66
The posterior nasopharynx wall also houses a single ______
“pharyngeal tonsil (commonly called the adenoids).
67
The middle pharyngeal region, the ______, is immediately posterior to the oral cavity.
“oropharynx”
68
The oropharynx is bounded superiorly by the soft palate and inferiorly by the _______.
hyoid bone
69
The epithelium (orophayrnx) has no cilia and is strong to withstand the abrasion of swallowed food.
True
70
______ in the oropharynx provide the first line of defense against ingested or inhaled foreign materials.
Lymphatic organs
71
“Palatine tonsils” on the _____
“Lingual tonsils” at the _______
lateral wall. the base of the tongue
72
The inferior, narrowed region of the pharynx is the _______ and it extends inferiorly from the hyoid bone and is continuous with the larynx and
esophagus
“laryngopharynx”
73
The laryngopharynx terminates at the superior border of the ______
esophagus.
74
The laryngopharynx is lined with strong epithelium with no cilia since it permits the passage of both food and air.
True
75
When large pieces of food get stuck, and block breathing, they typically lodge in the _____
laryngopharynx
76
The “larynx, also called the _______, is a short, somewhat cylindrical airway that
is bounded superiorly by the laryngopharynx and posteriorly by the esophagus and
inferiorly by the trachea.
“voice box”
77
The superior aspect of the larynx is lined with a ______
stratified squamous epithelium
78
Inferior to the vocal cords, the larynx lining becomes a _____.
ciliated epithelium
79
The larynx has several functions, what are they
1) Prevents swallowed materials from entering the lower respiratory tract.
2) Conducts air into the lower respiratory tract.
3) Produces sounds
80
The larynx is supported by a framework of nine pieces of cartilage that are held in
place by ligaments and muscles.
1) The largest cartilage is the _____”, which forms only the anterior and
lateral walls of the larynx
“thyroid cartilage
It has no posterior component and is formed from hyaline cartilage.
81
The V-shaped anterior projection of the thyroid cartilage is called the _______
“laryngeal prominence” (commonly referred to as the Adam’s apple).
82
The overall growth of the thyroid cartilage is stimulated by testosterone; thus, the
Adam’s apple is usually prominent and larger in males following puberty.
True
83
The ring-shaped ______ forms the inferior base of the larynx and connects to the trachea inferiorly.
“cricoid cartilage”
84
The cricoid cartilage is composed of _____.
hyaline cartilage
85
A dense connective tissue band, called the ______, attaches the cricoid cartilage to the inferior edge of the thyroid cartilage
“cricothyroid ligament”
The cricothyroid ligament is 4 fingers width above the sternal notch.
86
An emergency airway, called a ______, is sometimes opened in the larynx by making an incision through the cricothyroid ligament.
“cricothyrotomy”
A vertical incision is made just through the skin followed by a horizontal incision made through the cricothyroid ligament to allow air to enter the lower respiratory tract
87
The large, spoon- or leaf-shaped “epiglottis” is formed primarily of ________
elastic cartilage.
88
The epiglottis projects _____ into the pharynx from its attachment to the thyroid
cartilage.
superiorly
89
When a person swallows, the epiglottis closes over the _______, preventing
materials from entering the larynx.
laryngeal opening
90
Two pairs of strong connective tissue bands are stretched across the upper opening of the larynx and can be seen with a ______
“laryngoscope”
91
The superior ligaments (“vestibular ligaments”), along with the mucous membrane covering them, are called the “vestibular folds”, also known as the ____ because they have no function in sound production
“false vocal
| cords”
92
The inferior ligaments (“vocal ligaments”), along with the mucous membrane covering them, are called the “vocal folds”, also known as the ____
because they produce sound when air passes between them.
“true vocal cords”
93
The opening between the vocal folds is called the ______
“rima glottidis”.
This opening widens if the vocal folds are abducted and becomes narrower if the vocal folds are adducted
94
The term “glottis” refers to the ______
rima glottidis plus the vocal folds.
95
Increasing the tension on the vocal folds causes the vocal folds to vibrate more when air passes by them and produces a ______
The less taut the vocal folds, the less they vibrate and the ___ the pitch of sound.
higher sound, lower
96
Loudness depends on the ____ passing across the vocal folds.
force of the air
97
Keep in mind that recognizable speech also requires the participation of numerous structures.
(a) Pharynx
(b) Nasal and oral cavities
- Hold your nose and then speak. Notice that your voice sounds quite different when air doesn’t pass through the nasal cavity.
(c) Paranasal sinuses
- Young children tend to have high, nasal-like voices because their sinuses are not yet well-developed, so they lack large chambers where sounds can resonate.
(d) Lips
(e) Tongue
True
98
an inflammation of the larynx that may extend to its surrounding structures.
Laryngitis
99
Viral or bacterial infection is the number one cause of laryngitis. Less frequently, laryngitis follows overuse of the voice, such as yelling for several hours at a football game.
True
100
Children’s airways are proportionately smaller, and a swollen and inflamed epiglottis (called epiglottitis) may lead to sudden airway obstruction and become a medical emergency.
True
101
The ____ is a flexible, slightly rigid tubular organ often referred to as the “windpipe”.
“trachea”
102
The trachea extends through the mediastinum and lies immediately _____ to the esophagus, inferior to the larynx, and superior to the primary bronchi of the lungs.
anterior
103
The anterior and lateral walls of the trachea are supported by 15-20 _____.
C-shaped “tracheal cartilages
104
The open ends of each C-shaped piece are bound together by the _____ and by an elastic, ligamentous membrane.
“trachealis muscle”
During swallowing this muscle distends and bulges into the lumen of the trachea
to allow for expansion of the esophagus to accommodate larger materials being
swallowed.
105
Contraction of this muscle influences airflow by narrowing the diameter of the
trachea.
(a) For example, to expel a foreign object or mucus, narrowing the trachealis muscle causes air to move more rapidly and forcefully through the trachea.
True
106
The mucosa lining the trachea is a ______ with numerous mucin-secreting goblet cells and underlying mucin-secreting glands.
ciliated epithelium
The cilia propel mucus laden with particles toward the larynx and the pharynx, where it is swallowed or coughed out.
107
At the level of the sternal angle, the trachea bifurcates into two smaller tubes, called the right and left _____
“primary bronchi”
108
(a) It is interesting to note that the left primary bronchus, which needs to travel over the heart, leaves at a more acute angle than the right primary bronchus, which is shorter, wider, and has a more vertical position.
(b) This means that inhaled foreign objects or vomit are more likely to travel down into the ____ of the lungs than the left lobes.
right lobes
109
The most inferior tracheal cartilage separates the primary bronchi at their origin and forms an internal ridge called the _____
“carina”
110
The _____ is a highly branched system of air-conducting passages that originate from the left and right primary bronchi and progressively branch into narrower tubes as they diverge throughout the lungs before ending in the terminal bronchioles.
“bronchial tree”
111
Incomplete rings of _____ support the walls of the primary bronchi to ensure they remain open.
hyaline cartilage
112
The primary bronchi enter into the medial surface of the lungs together with the pulmonary vessels, lymphatic vessels, and nerves.
1) The medial surface of the lung is called the _____
“hilum”
113
Each primary bronchus then branches into _____
1) The left lung has ___ secondary bronchi since it has two lobes.
2) The right lung has ____ secondary bronchi since it has three lobes.
“secondary bronchi”, two, three
114
The secondary bronchi divide into even smaller _____, which in turn divide into even smaller bronchi.
“tertiary bronchi”
115
All bronchi are lined with ______
ciliated epithelium
116
A complete ring of _____ develops between the mucosa of the airways
and the cartilaginous support in the wall.
smooth muscle
117
The bronchi branch into smaller and smaller tubules that eventually reach a diameter of less than _____
These smaller tubules, called _____” are no longer lined with cilia.
1 millimeter, “bronchioles
118
Unlike the bronchi, which have irregular plates of cartilage in their walls, the walls of bronchioles contain no cartilage, since there smaller diameter alone prevents their collapse.
Instead, they have a thicker layer of smooth muscle than do large bronchi, a characteristic that helps them regulate airway constriction and dilation and the amount of air traveling through the bronchial tree.
True
119
(a) Smooth muscle contraction _____ bronchioles (“bronchoconstriction”).
(b) Smooth muscle relaxation ____ bronchioles (“bronchodilation”).
narrows, dilates
120
The _____ are the final segment of the conducting pathway.
They conduct air into the respiratory portion of the respiratory system.
“terminal bronchioles”
121
is inflammation of the bronchi caused by viruses or bacteria, or by inhaling vaporized chemicals, particulate matter, or cigarette smoke from the air.
Bronchitis
122
Clinically, bronchitis is divided into two categories, ____
acute and chronic.
123
develops rapidly either during or after an infection, such as a cold. Symptoms include cough, wheezing, pain upon inhalation, and fever
Acute Bronchitis
124
results from long-term exposure to irritants such as chemical vapors, polluted air, or cigarette smoke
Chronic Bronchitis
125
defined medically as the production of large amounts of mucus, associated with a cough lasting 3 continuous months.
Chronic Bronchitis
126
The respiratory portion of the respiratory system consists of the ____
Within this respiratory portion, the epithelium is much thinner than in the conducting portion, thus facilitating gas diffusion between pulmonary capillaries
and the respiratory structures.
respiratory bronchioles, alveolar ducts, and pulmonary alveoli.
127
Terminal bronchioles branch to form _____ which continue to divide and become smaller until they form thin airways called _____, which in turn terminate in a dilated ______
“respiratory bronchioles”, “alveolar ducts”, “alveolus (alveoli)
128
(a) _____ diffuses from the alveoli into the pulmonary capillaries so it can be carried by erythrocytes to the body’s metabolically active tissues
(b) ______ diffuses out of the pulmonary capillaries into the alveoli so it can be exhaled.
Oxygen, Carbon dioxide
129
The lungs contain approximately _____ alveoli.
300-400 million
130
The spongy nature of the lungs is due to the packing of millions of _____ together.
alveoli
131
_______ are migratory cells that continually crawl within the alveoli, engulfing microorganisms or particulate material that has reached the alveoli.
“Alveolar macrophages” (“dust cells”)
132
The ____ house the bronchial tree and the respiratory portion of the respiratory system.
lungs
133
The lungs are located on the lateral sides of the thoracic cavity and separated from each other by the _____
mediastinum
134
Lung outer surfaces and adjacent internal thoracic wall are lined by serous membrane called ____
“pleura”.
135
The outer surface of each lung is tightly covered by the _____, while the internal thoracic walls, the lateral surfaces of the mediastinum, and the superior surface of the diaphragm are lined by the _______
“visceral pleura”, “parietal pleura”.
136
The visceral and parietal pleural layers are continuous at the _____ of each lung.
hilum
137
The potential space between these serous membrane layers is a ______
“pleural cavity”.
138
When the lungs are fully inflated, the pleural cavity is a ______ because the visceral and parietal pleurae are almost in contact with each other.
potential space
139
The pressure in the pleural cavity is ____ than the pressure in the lungs.
- This partial vacuum causes the visceral and parietal pleurae to pull towards each other.
lower
140
The pleural membranes produce a non-viscous, _____ that acts as a lubricant, ensuring that opposing pleural membrane surfaces slide by each other with minimal friction during breathing
serous fluid
141
is a condition that occurs when free air gets into the pleural cavity, the space between the parietal and visceral pleura
Pneumothorax
142
The presence of free air in the pleural space sometimes causes the affected lung or a portion of it to deflate, a condition termed _____
atelectasis
143
A particularly dangerous condition is _____, in which a hole in the chest or lung allows air to enter and acts as a one-way valve.
tension pneumothorax
144
blood may collect in pleural cavity ______ due to a lacerated artery, a blood vessel that leaks as a result of surgery, heart failure, or certain tumors.
(hemothorax)
145
An accumulation of serous fluid within the pleural cavity is called ____, and an accumulation of pus, as occurs with pneumonia, is called ______
hydrothorax, empyema
146
b. Each lung has a conical shape.
1) Its wide, concave _____ rests inferiorly upon the muscular diaphragm, and its relatively blunt superior region, called the ______, projects superiorly to a point that is slightly superior and posterior to the clavicle.
“base”, apex
147
The right lung is subdivided into the:
1) “Superiorlobe”
2) “Middle lobe”
3) “Inferiorlobe”
148
Toward the midline, the lungs are separated by the ____
mediastinum.
149
The left lung is subdivided into the:
| ___
1) “Superiorlobe”
| 2) “Inferiorlobe”
150
The left and right lungs may be partitioned into _____ each with their own tertiary bronchus, surrounded by connective tissue, and each with its own arterial and venous blood supply.
“bronchopulmonary segments”
151
is an infection of the alveoli of the lung. Common causative agents include viruses and bacteria, and sometimes fungi. The infection may involve an entire lung or just one lobe.
Pneumonia
152
results in tissue swelling and accumulation of fluid and leukocytes in the alveoli, thus greatly diminishing the capacity for gas exchange
Pneumonia
153
is a contagious disease that is usually spread by respiratory droplets. Symptoms include cough, fever, and rapid breathing
Pneumonia
154
Blood supply to and from the lungs is supplied by both the ______
pulmonary and systemic
| circulations
155
The _____ conducts blood to and from the gas exchange surfaces of the lungs to replenish its depleted oxygen levels and get rid of excess carbon dioxide.
“pulmonary circulation”
156
The _______ is a component of the systemic circulation and consists of tiny bronchial arteries and veins that supply the bronchi and bronchioles of the lung.
“bronchial circulation”
This part of the circulation system is much smaller than the pulmonary system,
because most tiny respiratory structures (alveoli and alveolar ducts) exchange
respiratory gases directly with the inhaled air.
157
Approximately three or four tiny ______ branch from the anterior wall of the descending thoracic aorta and divide to form capillary beds to supply structures in the bronchial tree.
“bronchial arteries”
158
Increasingly larger ______ collect venous blood from these same structures and drain into the azygous system of veins.
“bronchial veins”
159
_____ and vessels are located within the connective tissue of the lungs as well as around the bronchi and pleura.
Lymph nodes
160
The _____ collect carbon, dust particles, and pollutants that were not filtered out by the ciliated epithelium
lymph nodes
161
The lymphatic drainage of the right lung drains into the right lymphatic duct, while the lymphatic drainage of the left lung drains into the ______
thoracic duct
162
Breathing, also known as _____ is the movement of air into and out of
the respiratory system.
“pulmonary ventilation”,
163
At rest, a normal adult breathes about ___ times per minute.
16
164
Approximately ____ of air are exchanged with the
| atmosphere per breath.
500 milliliters (one-half liter)
165
a chronic condition characterized by episodes of bronchoconstriction and wheezing, coughing, shortness of breath, and excess pulmonary mucus.
Asthma
166
The _____, which extend from a superior rib inferomedially to the adjacent inferior rib.
(a) The ribs elevate upon contraction of the external intercostals, thereby increasing the
transverse dimensions of the thoracic cavity during inhalation.
“external intercostal muscles”
167
The ______ lie at right angles to the external intercostals and deep to them.
(a) Contraction of the internal intercostals depresses the ribs, but this only occurs during
forced exhalation.
(b) Normal exhalation requires no active muscular effort and occurs by the elastic recoil
of lung tissue.
“internal intercostal muscles”
168
The trachea, bronchial tree, and lungs are innervated by the _____
autonomic nervous system
169
The main function of the sympathetic innervation is to open up and dilate the bronchioles (______).
2) The main function of the parasympathetic innervation is to decrease the airway diameter of the bronchioles (_____).
bronchodilation, bronchoconstriction
170
Regulatory respiratory centers are located in both the ______ (which establishes the rate and depth of breathing) and the ______ (which can also influence the breathing rate).
medulla oblongata, pons
171
Two distinct diseases, emphysema and chronic bronchitis, together encompass ______, which is often related to tobacco use.
“chronic obstructive pulmonary disease” (COPD)
The resulting airflow obstruction makes it hard for the patient to exhale.
172
an irreversible loss of pulmonary gas exchange areas due to inflammation of the terminal bronchioles and alveoli, in conjunction with the widespread destruction of pulmonary elastic connective tissue.
Emphysema
173
is a highly aggressive and frequently fatal malignancy that originates in the epithelium of the respiratory system. Smoking causes about 85% of all lung cancers. Metastasis, the spread of cancerous cells to other tissues, occurs early in the course of the disease, making a surgical cure unlikely for most patients
Lung Cancer
174
may develop when the pseudostratified ciliated columnar epithelium lining the lungs changes to a sturdier stratified squamous epithelium to withstand the chronic inflammation and injury caused by tobacco smoke. If the chronic injury continues, these transformed epithelial cells may accumulate enough genetic damage to become overtly malignant.
Squamous cell carcinoma
175
of the lung arises from the mucin-producing glands in the respiratory epithelium. It begins when DNA injury causes one of these cells to become malignant and begin to divide uncontrollably.
Adenocarcinoma
176
a less common type of lung cancer; it originates in the main bronchi and eventually invades the mediastinum
Small-cell carcinoma
177
also known as crib death, is the sudden and unexplained death of an infant younger than 1 year of age
Sudden infant death syndrome (SIDS)
178
To be counted as a SIDS death, the child must die for no apparent reason other than cessation of breathing.
True
179
It is now known that babies sleeping on their _____ are at greater risk for SIDS than those sleeping on their backs
stomachs
