Histology SDL Flashcards
(121 cards)
1
Q
3 components of nasal cavity?
A
- Olfactory area
- Conchae
- Vestibule
2
Q
A
3
Q
Organ of phonation?
A
Larynx
4
Q
2 portions of pharynx?
A
- Nasopharynx
- Oral pharynx
5
Q
Diameter of bronchioles?
A
1 mm or less
6
Q
Manner in which bronchi branch?
A
In a dichotomous fashion
7
Q
What does this show?
A
Nasal vestibule of nasal cavities
SEM showing the transition from outside fully keratinized stratified squamous epithelium at green arrow to non-keratinized stratified squamous epithelium at the yellow arrow
8
Q
What is this?
A
SEM of respiratory epithelium in more protected regions of the nasal cavities: a pseudostratified columnar epithelium characterized among other things by numerous “goblet cells” (seen at the green arrow) dispersed among numerous “ciliated cells” (seen at the red arrow)
9
Q
What is this?
A
This is a very well preserved H&E stained section of the respiratory epithelium:
- Black arrows: mucin within goblet cells
- Red arrow: the nucleus of a goblet
- Larger green arrow: the nucleus of a ciliated cell situated higher in the epithelium than goblet cell nuclei
- Smaller green arrow: nucleoli of the ciliated cells
- Blue arrow: numerous cilia can be seen on the free surfaces of the ciliated cells
- Small yellow arrow: numerous basal bodies subjacent to cilia
- Purple arrow: basal cell
- Large yellow arrow: thick basement membrane on which the respiratory epithelium rests
- Two headed pink arrow: prominent layer of connective tissue termed the lamina propria
10
Q
Respiratory epithelium: which are the most basally located cells? Describe them. Describe the layers of the respiratory epithelium.
A
The most basally located cells are the basal cells that are progenitor cells that can give rise to ciliated or goblet cells when the need arises. Therefore, you have three layers of cell nuclei at different levels in the epithelium that nevertheless all rest upon the same basement membrane.
11
Q
What is this?
A
Typical H&E stained section of the respiratory epithelium.
- Large black arrows: regions within goblet cells that once contained mucin that has been leached out as a result of histological processing with organic solvents
- Smaller black arrows: goblet cell nuclei
- Yellow arrow: one many basal cell nuclei.
- Small blue arrow: nucleus of a ciliated cell that is located higher in the epithelium than goblet cell and basal cell nuclei
- Larger blue arrow: cilia emerging from the surfaces of ciliated cells
- Large green arrow: thick basement membrane upon which the respiratory epithelium rests
- Under this basement membrane is connective tissue of the lamina propria
12
Q
What is this?
A
SEM showing a region of the respiratory epithelium that has been denuded of all but a few ciliated cells
- Red arrow: ciliated cells
- Yellow arrows: apical portions of goblet cells that are swollen due to accumulated mucin => as the accumulated mucin expands the apical plasmalemma, apical microprojections become incorporated into this membrane => apical microprojections accumulate along the cell borders, demarcating these borders and revealing the hexagonal or pentagonal surface outlines of these cells
- Green arrows: small “brush cells” dispersed between adjacent goblet cells ( identified by their brush-like microvilli on their apical surfaces)
13
Q
What is this?
A
TEM thin section showing the apical portion of the respiratory epithelium
- Labeled “G”: goblet cell seen filled with numerous mucin granules
- Red arrow: swollen apical portion of a goblet cell
- Blue arrow: one of many cilia that can be seen projecting from the apical surfaces of the ciliated cells
- Yellow arrow: basal bodies supporting the cilia
- Black arrow: mitochondrion of a ciliated cell
14
Q
Which cells of the respiratory epithelium contain many mitochondria?
A
Both ciliated and goblet cells
15
Q
A
TEM showing two brush cells, both labeled “B” with microvillous projections emerging from the apical portions
- Arrows: apical intercellular junctions between adjacent cells
16
Q
What would you see if you looked into the nasal cavities?
A
- Pinkish-red surface due to blood in the underling vessels
17
Q
What are the nasal conchae? Why are they called like this? List them.
Purpose?
Which ones are covered with respiratory epithelium?
A
3 shelf-like structures projecting from the lateral walls of each nasal cavity that have been termed “conchae” because they curl downward, not unlike shells
- The upper or superior conchae
- The middle conchae***
- The lower or inferior conchae***
Purpose: help create turbulence of the air entering the nasal cavities, thereby facilitating contact of the incoming air with the respiratory epithelium
18
Q
What is found within conchae? Where exactly? Role?
A
Large venous plexus termed “swell bodies” in the lamina propria of the conchae, which can become engorged with blood and result in a “stuffy nose”
Regulate the flow of air
19
Q
If you were to look at the roof of the nasal cavity, how would it appear? What is this?
A
Yellowish-brown in contrast to the reddish tint of the surrounding respiratory epithelium => this is the “olfactory region” of the nasal cavity specialized for the sense of smell
20
Q
Where is the olfactory epithelium in the nasal cavities?
A
Extends from the middle roof of the nasal cavity over the upper surface of the superior conchae and upper lateral side of the nasal septum
21
Q
What is this?
A
H&E stained section taken through a portion of the superior conchae
- a: olfactory epithelium
- b: numerous serous glands = the “glands of Bowman” in connective tissue under the olfactory epithelium
- c: respiratory epithelium
- d: bone
- Arrows from the small letter “e”: bundles of nerve fibers arising from the olfactory cells that have been termed “fila olfactoria”
22
Q
Purpose of glands of Bowman?
A
The watery secretions from these serous glands help bath the surface of the olfactory epithelium thereby facilitating the sensing of new odiferous compounds (cleansing of olfactory region)
23
Q
What is this? Describe each.
A
Olfactory epithelium with 3 basic cell types =
- Supporting or “sustentacular cells” that contain a brownish pigment similar to lipofucsin and gives the olfactory region its yellowish-brown color
- Bipolar neurons making up the sensory “olfactory cells”, and the “basal cells”
- Duct from passing through the olfactory epithelium and arising from an underlying serous gland of Bowman
24
Q
What kind of epithelium is the olfactory one?
A
Since all three of these cell types rest on the same basement membrane, this epithelium, like the respiratory epithelium, is a pseudostratified columnar epithelium
25
H&E section through a region of the olfactory epithelium
* Bracket: olfactory epithelium
* Small black arrows: serous glands of Bowman
* Larger back arrows: bundles of nerve fibers making up the fila olfactoria
26
What is this?
TEM thin section through the apical aspect of the olfactory epithelium
* Small back arrows: “sensory cilia” emerging from the “olfactory vesicle”
27
How many sensory cilia arise from each olfactory cell? How far do they extend? Arrangement of cilia?
* 10 to 15 of these nonmotile sensory cilia arise from each olfactory cell
* Extend for long distances (i.e., 100 to 200 microns) parallel to the surface of the mucosa
* Begin with the 9+2 microtubule arrangement, they become thinner and may have only one or two microtubules in their tapered ends
28
What is this?
TEM higher magnification image of a cross-section through the ends of sensory cilia (arrows) mixed with microvillous projections from sustentacular cells. You can make out cross-sectional images of one and two microtubules in the tapered ends of the sensory cilia
29
What is this?
Longitudinal H&E stained section through the true and false vocal cords
* “a”: non-keratinized stratified squamous epithelium
* "b": false vocal cord
* "c": ?
* "d": large vocalis muscle = the “true vocal cord”
* "e": ventricle
* "f": thyroid cartilage
30
What is a true vocal cord of the larynx covered with? Why?
Covered by a non-keratinized stratified squamous epithelium due to the trauma associated with phonation
31
What is the false vocal cord of larynx covered by? What does it contain?
Covered by respiratory epithelium and contains numerous sero-mucous glands
32
Role of thyroid cartilage of larynx?
Provides support
33
What is the ventricle of the larynx? What is it covered by?
Protected region between the true and false volcal cords lined by respiratory epithelium
34
Thickness of olfactory epithelium compared to respiratory?
Much thicker
35
How long is the trachea? Diameter?
Start? End?
* 11 cm long
* 2-2.5 cm in diameter
* Starts at the larynx
* Ends by dividing into two primary bronchi that enter the “roots” or “hilar region” of the lungs
36
What is this?
Low magnification H&E stained cross-section through the trachea.
* Small blue arrows: lining respiratory epithelium
* Small black arrows: extensive serous mucous glands in the submucosa
* Large black arrow: piece of the “trachealis muscle”
* C: cartilage
37
Role of trachea cartilage?
Provides flexible mechanical support
38
What is this?
Higher magnification toluene blue stained section of through the apical aspect of the tracheal lumen showing the:
* respiratory epithelium
* underlying connective tissue
* smooth muscle
* hyaline cartilage
* serous glands
39
Do the primary bronchi have the same histological characteristics as the trachea?
YUP
40
Evolution of cartilage after the bronchi enter the lungs?
The cartilage rings that support the bronchi, break up into cartilage plates
41
What is this?
H&E stained section through a portion of an intrapulmonary bronchus
* Green arrow: respiratory epithelium
* Yellow arrow: smooth muscle
* Blue arrow: piece of the hyaline cartilage plate that supports the bronchus
42
Bronchi smooth muscle: where is it originally derived from? How does it wind down the bronchi?
Derived originally from the trachealis muscle
Winds down the bronchi in a spiral fashion
43
Do bronchioles have glands in the lamina propria?
NOPE
44
Respiratory epithelium of bronchioles?
Significantly reduced respiratory epithelium with few, if any, goblet cells.
45
What is this?
H&E cross-section through a bronchiole
* Black arrow: reduced respiratory epithelium
* Blue arrow: prominent layer of smooth muscle, characteristic of bronchioles
46
What are terminal bronchioles lined by?
* Dome-shaped secretory cells termed “Clara cells”
* Shorted ciliated cells
47
Lining epithelium of respiratory bronchioles? What is it characterized by?
Simple columnar or cuboidal characterized by short cilia
48
What is this?
Low magnification SEM view of the lungs showing:
* terminal bronchioles (at “T”)
* respiratory bronchioles (at “R”)
* Alveolar duct at “D”
* blood vessel at “V”
49
What is this? What to note?
Higher magnification view of the luminal surface of the terminal bronchiole
Note the dome shaped groups of Clara cells surrounded by shortened cilia from surrounding ciliated cells
50
What is this?
H&E stained section showing dome-shaped Clara cells and surrounding ciliated cells (at the arrows) in a terminal bronchiole
51
What are alveolar sacs?
Groupings of alveoli
52
Label.
53
What is this?
Low magnification light microscopic section showing a respiratory bronchiole giving rise to an alveolar duct
54
Label.
55
What are alveolar macrophages derived from? Role?
Monocytes
Role: barrier to bacterial infection
56
Type 1 pneumocytes kind of cells?
Flattened squamous cells
57
Role of reticular fibers and elastic fibers in alveolar wall?
Supporting the alveolar wall
58
Role of alveolar pores?
Can facilitate flow of air between alveoli if the supply route becomes obstructed
59
What is this?
Light microscopic section of the interalveolar septum showing blood capillaries and type I and type II pneumocytes
60
What is this?
SEM of the luminal surface of an alveolus.
* Small black arrows: outline of RBC in underlying capillary deminstrating the thinness of Type I pneumocytes
* The number 2: type II pneumocyte.
* Larger arrows: 2 alveolar pores
61
Label.
62
Describe the process of surfactant synthesis and secretion in type II pneumocytes.
1. Surfactant is synthesized in the RER and packaged in the Golgi into what have been termed “multi-lamellar bodies”
2. Multi-lamellar bodies fuse with the apical plasmalemma and secrete the surfactant onto the luminal surface of the alveolus
63
What is this?
This SEM shows an alveolar macrophage attached to the alveolar luminal surface
A type II pneumocyte is also visible at the number 2
Arrow: RBC
64
What is this?
H&E section showing several alveolar macrophages that have become separated from the alveolar wall = “dust cells” because they accumulate a significant amount of particulate material
65
What does the blood-air barrier consist of? 4 components
* Layer of surfactant
* Thin type I pneumocyte
* Fused basal lamina produced of type I pneumocyte and alveolar endothelium
* Alveolar endothelium
66
Label.
67
What is this?
TEM of the interalveolar septum:
* Ep: type I pneumocytes (labeled Ep)
* Ed: alveolar endothelium
* BM: fused basal lamina
* Ca: capillary lumen
* Al: alveolar lumen
* Er: RBC
68
List the 6 structures of the conducting portion of the respiratory system.
1. Nasal cavity
2. Nasopharynx
3. Larynx
4. Trachea
5. Bronchi
6. Bronchioles
69
Other than air conduction, what 2 other functions does the conducting zone have?
1. Olfaction
2. Vocalization
70
Epithelium of conducting zone?
* From nasal cavity to bronchioles: pseudostratified columnar ciliated
* Terminal bronchioles: simple columnar ciliated
71
Epithelium of respiratory zone?
Simple cuboidal ciliated
72
Describe changes in presence of goblet cells throughout the respiratory system.
1. Nasal cavity to trachea: abundant
2. Large bronchi: present
3. Small bronchi: few
4. Bronchioles: scattered
5. Terminal and respiratory bronchioles: none
73
Describe changes in presence of glands throughout the respiratory system.
1. Nasal cavity to larynx: abundant
2. Trachea to large bronchi: present
3. Small bronchi: few
4. All bronchioles: none
74
Describe changes in presence of cartilage throughout the respiratory system.
1. Larynx: complex (hyaline and elastic)
2. Trachea: C rings
3. Large bronchi: complete rings
4. Small bronchi: plates and islands
5. Bronchioles: none
75
Describe changes in presence of elastic fibers throughout the respiratory system.
1. Nasal cavity: none
2. Nasopharynx to trachea: present
3. Large bronchi to respiratory bronchioles: abundant
76
Describe changes in presence of smooth muscle throughout the respiratory system.
1. Nasal cavity to larynx: none
2. Trachea: spanning open ends of C rings
3. Large bronchi to respiratory bronchioles: crisscrossing spiral bundles
77
Label.
78
Function of respiratory epithelium?
Condition the inspired air
79
What is Kartagener's syndrome?
Dynein-deficiency in cilia resulting in immobility = chronic respiratory tract infection
80
Role of goblet cells?
Produce and contain mucin (polysaccharide rich mucous) droplets
81
Role of lamina propria?
Diffuse lymphatic tissue and elastic fibers
82
6 components of respiratory epithelium?
1. Ciliated cells
2. Goblet cells
3. Brush cells
4. Basal cells
5. Basement membrane
6. Lamina propria
83
Role of ciliated cells?
Movement of mucin produced by goblet cells
84
What is the mucosa of the respiratory system?
Respiratory epithelium
85
What glands are in the submucosa of the respiratory system?
Sero-mucous glands
86
Connective tissue in adventitia or serosa of respiratory system?
* Cartilage
* Elastic fibers
* Reticular fibers
87
Types of cartilage in respiratory system?
1. Primarily hyaline
2. Elastic cartilage in larynx
88
What is elastic fiber concentration in the respiratory system proportional to?
Diameter of the conducting tubule (i.e. the smallest bronchioles have the highest proportion of elastic fibers)
89
Name of thick short hair in nasal cavity? Purpose?
Vibrissae
Filter incoming air
90
What is the upper surface of the superior conchae covered by?
Olfactory epithelium
91
What are paranasal sinuses? List them. What are they lined by?
Spaces in bones that are continuous with the nasal cavity
* Frontal
* Ethmoidal
* Sphenoidal
* Maxillary
Lined by respiratory epithelium
92
What are olfactory receptor cells?
Bipolar neurons with modified cilia that have chemoreceptors to detect smells
93
What are the sustentacular
94
Label.
95
Structural composition of larynx?
* Larger hyaline and smaller elastic cartilage
* Ligaments articulated by skeletal muscles
96
Epithelium on upper portion of epiglottis?
Stratified squamous
97
Composition of epiglottis? Role?
Elastic cartilage and fibers
Guards against entry of anything but air
98
Epithelium lining true vocal cord?
Stratified squamous epithelium
99
Epithelium lining false vocal cord?
Respiratory
100
Structural composition of true vocal cord of the larynx?
* Framework of cartilages and dense connective tissue
* Skeletal muscles
* Elastic vocal ligaments
101
What does the false vocal cord contain?
Many sero-mucous glands
102
Muscle of trachea? Purpse?
Bundles of smooth muscle (trachealis muscle) bind to the perichondrium (connective tissue that envelops cartilage) and bridge the open ends of the C-shaped cartilages (close to the esophagus wall)
Arrangement prevents over distention of the lumen, while contraction of the muscle allows the narrowing of the tracheal lumen; used in cough response
103
What does each bronchiole enter?
Pulmonary lobule
104
Label.
105
What is this? Label.
Detailed structure of the mucous membrane and the submucosa of the trachea
106
What is this? Label.
Coronal section of larynx
107
Label.
108
What does the lamina propria of bronchi consist of?
* Crisscrossig bundles of spirally arranged smooth muscle
* Elastic fibers
* Mucous glands
109
How to the sphincter like smooth muscle bundles of alveolar ducts appear?
As knobs between adjacent alveoli
110
Mucosa of bronchioles?
Simple to cuboidal epithelium with cilia decreased in size and appearance of dome-shaped secretory Clara cells in ther terminal ones
111
Explain asthma. Treatment?
Inflammatory cells surround the airways and narrow them + constriction of bronchioles' smooth muscle = increased airway resistance
Treatment: epinephrine and other sympathomimetic drugs to relax the smooth muscle under control of vagus nerve during an attack
112
Do interalveolar walls contain capillaries?
YUP
113
Other name for type II pneumocytes?
Great pneumocytes
114
What do both type I pneumocytes and endothelial cells of the pulmonary capillaries contain?
Abundant pinocytotic vesicles
115
What does the surfactant layer in the alveoli consist of?
Aqueous protein covered by a monomolecular phospholipid film composed primarily of dipalmitoyl lecithin
116
3 roles of surfactant?
1. Reduces surface tension thereby making it easier for alveolar walls to separate from one another and become inflated with air
2. Facilitates the transport of gases between air and liquid phases
3. Bactericidal effect
117
Label.
118
Label.
119
What are brush cells?
Columnar cells in respiratory epithelium with short microvilli (considered receptor cells)
120
At what level do the bronchial circulation and pulmonary circulation anastomose?
At the level of the respiratory bronchioles
121
Which of the following components increase(s) as a proportion of the respiratory tract wall from trachea to alveoli?
A: Cilia
B: Elastic fibers
C: Smooth muscle
D: Cartilage
E: Goblet cells
C: Smooth muscle
