Respiratory System Flashcards
1
Q
what does the respiratory tract originate from embryologically
A
as outgrowth of GI tract
2
Q
what is the respiratory system derived from in the GI tract
A
laryngeotracheal groove
3
Q
where does the respiratory system develop from and when
A
along ventral midline of posterior pharynx at the 4th week of development -> develops into respiratory diverticulum, an outgrowth of the esophagus -> grows and interacts with surrounding mesoderm
4
Q
what is the primary function of the respiratory system
A
air conduction, filtration and gas exchange
5
Q
what are the secondary functions of respiratory system
A
oflaction in nasal cavity and phonation from larynx
6
Q
what is respiration divided into
A
mechanical respiration and cellular respiration
7
Q
what is mechanical respiration
A
associated with the lungs and functions in gas exchange
8
Q
what is cellular respiration
A
O2 is carried to the tissues for cellular respiration (oxidative metabolism -> ATP/energy
9
Q
what is the diaphragm
A
thin, dome shaped muscle, separates thoracic cavity from abdominal cavity in mammals
10
Q
what happens in inspiration
A
intercostal muscles contract, raise ribs; diaphragm contacts (lowers) which increases intrathoracic volume and causes negative pressure in thorax
11
Q
what happens in expiration
A
intercostal muscles relax, lower ribs
-diaphragm relaxes (raises) which decreases intrathoracic volume and increases intrathoracic pressure
12
Q
what are pleural cavities lined by
A
simple, squamous to cuboidal mesothelium that overlays thin layer of connective tissue containing elastic fibers
13
Q
what layers make up the pleura
A
mesothelium and CT layer
14
Q
what does the parietal pleura line
A
thoracic wall
15
Q
what does the visceral pleura line
A
outer surfaces of lung
16
Q
what separates the visceral and parietal pleura and what is its function
A
pleural space containing pleural fluid which acts as lubricant to decrease friction
17
Q
what does the pleural space contain that assists with inspiration
A
a partial vacuum that results in negative intrathoracic pressure
18
Q
what is a pneumothorax
A
breach of pleural space
19
Q
what does a pneumothorax cause
A
- positive intrathoracic pressure, difficulty breathing from collapsed lung
20
Q
how does the pneumothorax remain unilateral
A
due to mediastinum which is a loose CT layer separating L and R hemithoraces
21
Q
where does air enter the upper respiratory tract
A
at nostrils which open into the vestibule
22
Q
what does the vestibule contain
A
hairs to help filter and trap particulate matter
23
Q
what are vibrissae
A
“sinus hairs”
-the hair follicle is surrounded by a blood-filled sinus
- large sensory hairs (whiskers) in cats and dogs
24
Q
where does the air go after the nares and vestibule
A
nasal cavity
25
what does the nasal cavity contain
thin, scroll shaped bones called nasal turbinates/conchae
26
what are nasal turbinates/conchae lined with
moist, pseudostratified columbar epithelium covered by mucous
27
what receptors does the nasal cavity contain
olfactory receptors
28
what do olfactory receptors synapse with
olfactory nerve (CN I)
29
what do olfactory epithelium contain
small number of brush cells
30
what are brush cells and what is their function
- columnar cells with apical microvilli
-function: generalized sensory cells of olfactory and respiratory epithelia
31
where does air travel after the nasal cavity
paranasal sinuses and nasopharynx
32
what do paranasal sinuses do
filter, humidify, and warm inspired air
33
what does the nasopharynx connect to and how
middle ear via auditory (eustacian) tubes
34
what do auditory (eustacian) tubes do
allows equilibrium of air pressure
35
what is the entire upper respiratory tract lined by
pseudostratified ciliated columnar epithelium with numerous goblet cells
- aka "respiratory epithelium"
36
what is respiratory epithelium supported by
underlying lamina propria of loose CT
37
what glands does the upper respiratory tract contain
sero-mucus glands
38
what is the mucociliary ladder
cilia in respiratory epithelium of trachea and bronchi synchronously beat in metachronal rhythm
39
what is the purpose of the metachronal rhythm in the mucociliary ladder
moves surface mucus towards larynx at a rate of ~1 cm/min
40
what triggers the sneeze reflex
irritation to upper airways (nasal passages)
41
what triggers the cough reflex
irritation to lower airways (trachea and bronchi)
42
where does the lower respiratory tract begin
at larynx
43
where does the digestive system intersect with respiratory system
where upper and lower respiratory tracts meet at larynx
44
where is the opening of the esophagus
directly behind the trachea
45
what is the function of the epiglottis
protects trachea during swallowing by covering the opening of the larynx
46
what is a tracheostomy
sharp object in jugular/suprasternal notch
47
what are the 3 single cartilages in the larynx
thyroid, cricoid, and epiglottic
48
what are the 3 paired cartilages in the larynx
arytenoid, corniculate, and cuneiform
49
what cartilages make up the larynx
hyaline or elastic
50
where are the false and true vocal cords located
below glottis and covered by epiglottis
51
where are false vocal cords located
superior and lateral
52
where are true vocal cords locatedd
inferior and medial
53
what are the functions of vocal cords
- speech
- vocal folds protect lower respiratory tract from entry of foreign bodies
54
what are false vocal cords covered by
respiratory epithelium with seromucus glands
55
what are epiglottis and true vocal cords covered by
stratified squamous nonkeratinized epithelium
56
what does the true vocal cords contain
vocalis muscle and ligament
57
what do the larynx and epiglottis develop from
the 4th and 6th pharyngeal pouches
58
what is the larynx innervated by
branches of the vagus nerve
59
what innervates the portion of the larynx derived from the 4th arch
superior laryngeal nerve
60
what innervates the portion of the larynx derived from the 6th arch
recurrent laryngeal nerve
61
what is inferior to the larynx
the trachea
62
what lines the trachea
respiratory epithelium with numerous goblet cells and seromucus glands
63
what is the trachea supported by
C-shaped rings of hyaline cartilage that face caudally to facilitate swallowing
64
what do caudal openings contain
connective tissue membrane and smooth muscle, trachealis muscle
65
how do the bronchi divide after the trachea
primary bronchi -> secondary bronchi -> tertiary bronchi
66
what are the other names for primary, secondary, and tertiary bronchi?
primary - mainstem
secondary - lobar
tertiary - segmental
67
how do you identify bronchi
presence or absence of cartilage rings or plates and accompanying layer of smooth muscle with or without seromucus glands
68
what does cartilage provide support for
larynx, trachea, and bronchi to prevent collapse during inspiration
69
where does cartilage become absent in bronchi
beyond tertiary bronchi
70
what are all bronchi lined with
respiratory epithelium with goblet cells and submucosal seromucus glands
71
what is the anatomical dead space
air in upper respiratory tract, trachea and bronchi not used for gas exchange
72
what is the size of the anatomical dead space
about 150 mL
73
what is the order of bronchioles
tertiary bronchi -> bronchioles -> terminal bronchioles -> respiratory bronchioles -> alveolar ducts -> alveolar sacs/alveoli
74
where is the site for gas exchange
alveoli
75
describe what makes up bronchioles
lacks cartilage and seromucus glands; smooth muscles performs support function instead
76
what is the trend as bronchioles get smaller
thinning of epithelium with loss of goblet cells
77
what is the epithelium of terminal bronchioles
tall, pseudostratified ciliated columnar epithelium
78
what is the epithelium of respiratory bronchioles
simple, cuboidal to columnar ciliated and non-ciliated epithelium with occasional alveoli
79
where does gas exchange begin
at the level of respiratory bronchioles
80
what do alveolar ducts contain
numerous alveoli lined with simple squamous epithelium
81
where are clara cells located
in terminal and respiratory bronchioles, they replace goblet cells
82
describe clara cells
non-ciliated dome-shaped cuboidal to columnar cells
83
what do clara cells produce
lipoproteins, primary components of surfactant within airways
84
what surfactant do
prevents sticking together of bronchiole walls
85
what do clara cells do
function as reserve stem cells capable of differentiation into other respiratory cells following damage
86
where are K cells located
scattered throughout respiratory tract
87
what is the function of K cells
secrete various GI hormones
88
what are K cells
historical remnants of evolutionary origins from gut
89
what are brush cells
generalized sensory cells (columnar with apical microvilli)
90
what are MALT
throughout respiratory tract lymphoid aggregates - BALT or MALT
91
where is MALT found
in lamina propria
92
what is the lamina propria
layer of subepithelial connective tissue
93
what is the primary function of MALT
to secrete IgA onto mucosal surface to provide protection from micro-organisms
94
what is deep to mucosa
smooth smooth muscle layer called muscularis mucosae
95
where are muscularis mucosae prominent
smaller airway of respiratory bronchioles and alveolar ducts as alveolar rings
96
what is the function of alveolar rings
controls luminal diameter of airways and resistance to airflow, regulates alveolar air movement, takes over support function of cartilage
97
what are alveolar ducts and alveoli lined by
simple squamous epithelium
98
what are alveoli
thin- walled structures surrounded by rich capillary network supplied by pulmonary artery
99
what are alveolar septa
walls between alveoli
100
what do septa contain
alveolar pores
101
what are type 1 pneumocytes
flattened epithelial cells modified for gas exchange
102
what covers 95% if alveolar surface area
simple squamous epithelium consisting of type 1 pneumocytes
103
what is the air blood barrier
2 cell layers that separate air within alveolus from blood
104
what does the air blood barrier consist of
type 1 pneumocytes of alveoli
- endothelial cells lining capillaries and shared, fused BM
105
what are type 2 pneumocytes
larger, rounded dome-shaped cells
106
what can type 2 cells differentiate into
type 1 cells
107
what do type 2 pneumocytes posses
intracytoplasmic granules, called lamellar bodies containing phospholipid
108
what do type 2 pneumocytes secrete and what does it do
surfactant which decreases surface tension and keeps cells moist for gas exchange
109
what is the cause of respiratory distress syndrome in premature infants
lack of surfactant
110
what are dust cells and where are they located
throughout lungs they are alveolar macrophages
111
what do dust cells do
phagocytize particulate matter and microorganisms
112
how often are dust cells eliminated and how
eliminated from lung at rate of ~50 million/day via mucocilliary ladder
113
how is lymph drained from alveoli
no direct drainage, only indirect via interstitium of interalveolar septa
114
what drains the pleural space
second system of pleural lymphatic within visceral pleura
115
what can lymphatic obstruction lead to
pleural effusion or pulmonary edema
116
what is pleural effusion vs pulmonary edema?
pleural effusion- fluid within pleural space
pulmonary edema- fluid within alveoli of lungs
117
what is common with pneumonia
pleural effusion and pulmonary edema
118
what is a pneumonia
bacterial and or viral infection of lung with increased inflammatory cell infiltrate (especially neutrophils and macrophages)
119
what do infections associated with pneumonia cause
decreased production of pleural fluid -> damage to pleura (pleurisy)
120
what are connective tissue tags
adhesions between visceral and parietal pleura
121
what is anthracosis
originally seen in coal miners from inhaling anthracite coal dust, now common in urban environments
122
what is silicosis
from inhlaed silica particles primary source, coal dust and asbesots
123
how does silicosis occur
sharp crystals, difficult to phagocytose -> pulmonary fibrosis due to accumulation of silicic acid in lungs which stimulates fibroblast proliferation and collagen production
124
what causes mesothelioma
asbestos inhalation
125
what is tuberculosis
formation of multifocal nodules or tubercles
- bacterial foci surrounded by inflammatory cells, especially macrophages walled off by fibrotic capsule
126
what happens in the lungs in response to smoking
mucus production increased -> smokers hack
- cilia lose synchronicity then die
127
what is bronchitis
fibrosis, thickening of airways
128
what is metaplasia
replacement of one tissue type by another
129
what is the metaplasia that occurs with smoking
pseudostratified ciliated columbar epithelium of URT replaced by stratified squamous epithelium
130
what can metaplasia in the lungs be incited by
physical trauma (chronic coughing), chemical, or thermal insult (smoking)
131
what can metaplasia be the first step in
neoplasia (cancer)
132
what is emphysema characterized by
permanent enlargement of alveoli -> bulla formation
133
what is emphysema caused by
chronic obstruction of air flow -> destruction of alveolar septa and decreased surface area for gas exchange
134
what is emphysema initiated by
chronic inhalation of smoke and particulate matter (dust, smoke), mucus accumulation -> destruction of alveolar wall
135
what is the destruction of alveolar wall due to
release of lysosomal enzymes from neutrophils and macrohpages
136
what is COPD
bronchitis, asthma and emphysema
137
what is asthma characterized by
chronic airway obstruction, inflammation or irritation and increased responsiveness -> exaggerated bronchoconstriction
138
what is asthma initiated by
formation of antigen-antibody complexes on cell membranes, requires phagocytosis
139
what cells are present in large numbers in submucosa in asthmatics
mast cells and eosinophils
140
what does irritation in asthma cause
mast cells to release histamine and SRS that causes smooth muscel contraction of bronchioles and vasodilation ->acute asthma attack
141
how do eosinophils counteract effects of histamine
with histaminase and eosinophil derived inhibitor that inhibits mast cell degranulation
