Respiratory System Flashcards
1
Q
Many forms of epithelial tissue
A
- squamous
- cuboidal
- columnar
- pseudostratified
2
Q
Main function of respiratory system
A
- allows passage from nose/mouth to alveoli
3
Q
Upper conducting portion
A
- nasal cavity
- pharynx
- larynx
4
Q
Lower conducting portion
A
- trachea
- bronchi
- bronchioles
- terminal bronchioles
5
Q
Respiratory portion
A
- respiratory bronchioles
- alveolar ducts
- alveolar sacs and alveoli
6
Q
Types of bronchus
A
- primary bronchus
- secondary (lobar) bronchus
- tertiary (segmental) bronchus
7
Q
Types of lobes
A
- superior lobe (right and left)
- middle lobe
- inferior lobe
8
Q
Olfaction
A
- olfactory mucosa in nasal cavity
9
Q
Phonation
A
- vocal folds
10
Q
Conduction and conditioning of air
A
- transport of air to respiratory portion
- warmth
- air clearance
11
Q
Gaseous exchange
A
- respiratory portion - blood-gas barrier
12
Q
Endocrine
A
- hormones
- neuroendocrine cells
13
Q
Immune functions
A
- bronchial associated lymphoid tissue (BALT)
- alveolar macrophages
14
Q
Vestibule (nasal cavity)
A
- cartilage framework
- stratified squamous (skin)
- short firm hairs (vibrissae)
- sweat and sebaceous glands
- Glands and vibrissae trap large particles
15
Q
Respiratory portion (nasal cavity)
A
- Respiratory epithelium
- Lamina propria
- Vessels (capillaries) lined up perpendicular to
the airflow warms the air. - Clinical correlate: nasal congestion
- Turbinates increase the surface area covered by
respiratory mucosa
16
Q
Olfactory region (nasal cavity)
A
- Found at the roof of nasal cavity and the superior
nasal conchae. - Lined by pseudostratified columnar epithelium with
four cell types.
17
Q
Infections in nasal cavity
A
- Allergic reactions or viral infections (e.g., common
cold) - Rhinitis/coryza (Inflammation of the nasal mucous membrane)
18
Q
What happens in these infections of nasal cavity?
A
- Capillaries that reside near the surface of the lamina propria become engorged
- Lamina propria becomes distended with fluid
- Marked swelling of the mucous membrane
- Restriction of the air passage
- Breathing difficult.
19
Q
Serous Olfactory (Bowman’s) glands
A
- produce serous fluid that bathes the olfactory cilia + serves as a solvent to dissolve odour molecules for detection by the olfactory cells.
- Their secretory units lies in the the lamina propria
- Acinar cells have lipofuscin granules
- Serous secretion; lysozyme and IgA
20
Q
Cell types in olfactory epithelium
A
- olfactory receptor cells
- supportive
- brush cells
- basal cells
21
Q
Cell types of respiratory epithelium
A
- Ciliated columnar cells
- Mucus cells
- Brush cells
- Small granule
- Basal cells
22
Q
Respiratory epithelium (pseudostratified)
A
- Lines most of the conducting part of the respiratory system
- Ciliated columnar cells
- Mucus cells
- Brush cells with microvilli
- Small granule
- Basal cells
23
Q
Ciliated columnar cells
A
- Histology; Columnar and extend to surface 250 cilia
- Function; Sweeping motion helps expel particles trapped
in mucus - Clinical note; Primary ciliary dyskinesia in Kartegener’s syndrome
24
Q
Mucus cells
A
- histology; short blunt microvilli
- function; Secretes mucin granules which forms a protective barrier
- clinical note; Increased in smokers and chronic inflammation
25
Brush cells
- histology; columnar and extend to the apical surface - short microvilli
- function; synapse with afferent nerves - sensory function
- clinical note; sensory receptors – transduction of
sensation
26
Small granule or Kulchitsky cells
- histology; Most numerous at bifurcation of primary bronchi - basal granules
- function; Enteroendocrine cells; Secrete catecholamines, ADH, ACTH, serotonin and bombesin
- clinical note; Primary cells affected in small cell carcinoma of the lung
27
Basal cells
- histology; near basement membrane
| - function; stem cells that regenerate all other cell types
28
Kartagener syndrome - immotile cilia syndrome
- genetic disorder - (autosomal recessive) involving mutation in genes
that code for ciliary proteins (dynein).
- results in situs inversus (organ reversal as a result of faulty migration during embryogenesis) , recurrent sinus and pulmonary infections ( inability to
move mucus), and sterility.
29
Larynx
- tubular region between the pharynx and trachea
- skeletal framework consists of plates of hyaline cartilage
- functions include air conduction and phonation
30
Mucosa in trachea
- RE - Respiratory epithelium
- LP - lamina propria --> loose
connective tissue
- Longitudinal elastic fibers in deep LP
31
Submucosa in trachea
- loose connective tissue
| - seromucous glands
32
Cartilaginous layer in trachea
- C-shaped hyaline - open posteriorly “Gap” between free cartilage ends is completed by a fibroelastic
membrane and Trachealis muscle (smooth)
33
Adventitia in trachea
- connective tissue - binds trachea to adjacent structures
34
Bronchi
- Primary or main bronchi are
structurally like trachea
- Primary bronchi --> 2-3 secondary bronchi --> total 8
-10 tertiary or segmental bronchi per lung
- Segmental bronchi supply a bronchopulmonary segment
- can also be classified as; extrapulmonary or intrapulmonary: surrounded by lung tissue
35
Mucosa of bronchi
- respiratory epithelium
36
Muscular layer of bronchi
- Spirally oriented smooth muscles in --> regulates the airway diameter
37
Submucosa of bronchi
- Loose CT with sero-mucus glands (Gl) in larger bronchi
38
Cartilage layer of bronchi
- extrapulmonary bronchi - cartilage rings
| - intrapulmonary bronchi - cartilage plates (CP)
39
Adventitia of bronchi
- connective tissue in the extrapulmonary part then surrounded by lung tissue in intrapulmonary bronchi
40
Squamous metaplasia of respiratory epithelium
- Columnar to squamous metaplasia of the respiratory epithelium
• Basal cells generate squamous cell
• Smoking: loss of ciliated cell
activity --> cough --> metaplasia
• Bronchitis, bronchiectasis --> Chronic cough --> metaplasia
• Metaplasia --> dysplasia --> squamous cell carcinoma
41
Bronchioles
- Diameter is 1 mm or less
| - Larger (regular) bronchioles --> terminal bronchioles (B) --> respiratory bronchioles (RB)
42
Larger bronchioles
- Ciliated, pseudostratified columnar that transition into simple ciliated columnar (Goblet cells present)
43
Smaller bronchioles (terminal and respiratory)
- simple cuboidal with secretory club (Clara) cells interspersed among ciliated cells (no Goblet cells)
• No subepithelial glands
• Smooth muscle replaces cartilage plates (branching points may contain small elements of cartilage)
44
Bronchial asthma
- inflammatory airway disease
- symptoms; short breath, wheezing and coughing
- airway obstruction; increased mucus, increased smooth muscle, bronchiolar wall inflammation
- treated with; Albuterol (β2 agonist), anticholinergic medications which relax the
smooth muscles, Corticosteroids - anti-inflammatory
45
Epithelium change in respiratory tract
- ciliated pseudostratified
- ciliated simple columnar
- ciliated simple cuboidal
- simple squamous
46
Typical changes at the respiratory tract descends
- loss of cartilage and mucous glands
- loss of goblet cells
- loss of cilia
- cells also become progressively flattened (squamous)
47
Type I pneumocytes
- Squamous cells which line 95% of alveolar surface
- Terminal cells not capable of mitosis.
- Surface is covered by surfactant
48
Type II pneumocytes
- Cuboidal cells which secrete surfactant
- Found at the septal junctions --> AKA septal cells
- Most numerous but cover only 5% of alveolar surface
- Apical lamellar bodies --> foamy appearance
49
Alveolar surfactant
- adequate amount of surfactant is produced after 35th week of gestation.
- Regulated by cortisol, insulin, thyroxin and prolactin
50
Neonatal respiratory distress
- Premature infants especially < 28 weeks old
- Management: Exogenous surfactant at birth
- Glucocorticoids to the mother with possible preterm delivery a few days prior to.
51
Interalveolar septum
- Contains: Collagen fibres, Elastic fibres (pulmonary recoil), Continuous capillaries, permanent and transient cells.
- site of the air-blood barrier
- Adjacent alveoli communicate through alveolar pores (of Kohn) which allows collateral airflow --> spread of Pneumonia
52
Pulmonary effects of cigarette smoking
- Loss of cilia
- Mucus gland hyperplasia
- Increased number of goblet cells
- Histological changes (pseudostratified
ciliated epithelium to squamous metaplasia)
53
Chronic Obstructive Pulmonary Disease (COPD)
- Large alveolar air spaces giving reduced functional efficiency
- Neutrophils release proteases including elastase, which break down elastic fibers in the small airways
- Serum Alpha 1 antitrypsin
(AAT) counteracts the elastase activity.
- Persistent smoking elevates the neutrophils and elastase levels --> increased destruction of elastic fibers --> leads to permanent dilation of airways
54
Cystic fibrosis
- autosomal recessive, mutation of both copies of the cystic fibrosis transmembrane conductance regulator (CFTR) protein and chloride channel
- diagnosed by sweat test for concentration of chloride excreted in sweat + by genetic testing
- channel protein is involved in alteration of mucus + digestive secretions, sweat and tears
- almost all exocrine glands secrete abnormally viscid mucus that obstructs the glands and their excretory ducts
