Respiratory system Flashcards

1
Q

What are the different ways to classify a glandular epithelia?

A
  1. According to cell number → Unicellular (Goblet cells) vs Mutlicellular (sweat glands)
  2. Fate of secretion → Exocrine (salivary glands) vs Endocrine (endocrine pancreas)
  3. Way the secretory product leaves the cell → Merocrine (sweat gland) vs Holocrine (sebaceous gland) vs Apcorine (mammary gland)
  4. Ducts → Simple (gastric gland) vs Compound (salivary gland)
  5. Secretory protion → Tubular (sweat gland) vs Acinar {Mucous (sublingual) vs Serous (parotid)}
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2
Q

What is the difference between an exocrine and and endocrine gland?

A

Endocrine:
- Releases secretory product through a duct on a surface
Exocrine:
- No duct
- Production of hormone released direclty to the blood stream → act far from site of secretion
- In maturation, the duct disappears → mass of cell detached from epithelium → capillaries

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3
Q

2 types of endocrine glands….

A
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4
Q

What are the 4 possibilities for glandular classifications based on the secretory portion?
*For simple ducts

A
  • Simple tubular (Gastric gland)
  • Simple coiled tubuler (sweat gland)
  • Simple branched tubular (Pyloric glands)
  • Simple branched acinar (trachea)

*acinus = 1, acini = more than 1

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5
Q

What are the different possibilities of glandular classifications based on secretory portion?
*For compound ducts

A
  • Compound Tubule-Acinar (Submandibular gland)
  • Compound Tubular
  • Compound Acinar (Parotid/Sublingual glands)
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6
Q

What are the 2 portions of the respiratory system?

A

Conducting portion:
Nasal cavity → Nasopharynx → Oropharynx → Larynx → Trachea → Bronchi → Bonchioles (regular and terminal bronchioles)

Respiratory portion:
Respiratory bronchioles → Alveolar ducts → Alveolar sacs → Lung alveoli

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7
Q

What are the fuctions of the conducting and respiratory portions of the respiratory system?

A

Conducting portion: warming, humidifying, cleaning, and delivery of air
*Structure to ensure uninterropted supply of air (cartilage, smooth muscles, CT → provide rigidity, flexibility and extensibility)
*Possess glands and ciliated cells to remove foreign particles

Respiratory portion: site for gas exchange (O2, CO2)

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8
Q

What are the general components of the conducting portion of the trachea? (layers)

A

Lumen → Outside:
Lumen → Epithelium (Mucosa) → Lamina propria (Mucosa) → Submucosa (contains glands) → smooth muscles + Hyalin cartilage → Adventitia (dense irregular CT)

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9
Q

How is the Epithelium of the mucosa classified?
How is the Lamina propria classified?

A

Pseudo stratified columnar ciliated epithelium with goblet cells
Lamina Propria = Loose C.T., contains elastic fibers, capillaries

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10
Q

What structures are considered to be in the submucosa?

A
  • Denser C.T.
  • Glands (serous and mucous acini)
  • A bit of Trachealis muscle (smooth muscles)
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11
Q

How is the CT of the adventitia classified?

A

Dense irregular C.T.

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12
Q

What are the features of the serous acinus and the mucous acinus in the submucosa?

A

Serous Acinus:
- Pyramidal cells
- Small lumen
- Acidophilic granules (which are?)
- Myoepithelial cells
- BM
- Aqueous secretions to humidify the air and facilitate breathing

Mucous Acinus:
- Columnar cells w/ ground/basal nucleus
- Secretes mucus to stick to foreign particles
- Pale cytoplasm (doesn’t stain well with eosin)
- No myoepithelial cells

**FINISH AND CONFIRM

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13
Q

What are the different cells found on the BM of the pseudo stratified columnar ciliated epithelium of the mucosa?

A
  1. Goblet cells → columnar, triangular nucleus, secrete mucous, Unicellular glands
  2. Ciliated cells → Columnar, most abundant, 100s of cilia (up to 5um long)
  3. Brushy cells (sensory cells?) → not seen in light microscope, CD8 precursors
  4. Small Granule cells → granules stained with Argentaffin, granules contain serotonin (permeabilty of capillaries), norepinephrine (smooth muscle constriction)
  5. Short cells → stem cells giving rise to the other types
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14
Q

How does the mucosa epithelium change in smoking individuals?

A

Smoking causes Squamous Metaplasia
Short cells stop producing a pseudo stratified epithelium → produce squamous, dry epithelium

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15
Q

What sections will cilia never be found in?

A

Longitudinal section

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16
Q

What is the general structure of a cilia?

A
  1. Basal body at the base
  2. Axoneme is the “continuation” of the basal body
  3. Axoneme is covered by a plasma membrane
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17
Q

What is the structure of a single microtubule?

A

Wall of 1 complete microtubule composed or 13 protofilaments (alternation of a and b tubulin)

+ end = where a/b-tubulin dimers are added for growth of the microtubule
- end = where a/b-tubulin dimers are removed for shortening of the microtubule

18
Q

What is the structure/composition of an Axoneme?

A
  • 9 peripheral doblets of microtubules (1 complete + 1 incomplete/10 protofilaments)
  • 1 central pair of complete microtubules
  • Radial Spokes → connects outer doublet to central pair
  • Nexin → connects outer doblet between eachother
  • Dynein Arm → Allow for movement of the cilia (2/doblet)
  • Inner sheath → surrounds the central pair
  • Tectins → small stabilizing protein inside outer complete microtubules
19
Q

How is the basal body different/similar to the axoneme in cilia?

A

Basal body as peripheral triplets of microtubules (1 complete + 2 incomplete) → 2/3 are continuous with the axoneme peripheral doblets

Protein Linker in basal body is the equivalent of Nexin in the axonemes (not the same)

20
Q

What are centrioles?

A

Centrioles are paired barrel-shaped organelles located in the cytoplasm of animal cells near the nuclear envelope. Centrioles play a role in organizing microtubules that serve as the cell’s skeletal system
- 1 centriole = 9 pairs of microtubules (similar to axoneme)
- Microtubules grow from centrioles in the cells

21
Q

What are the main roles of microtubules in the cell?

A
  1. Carry vesicles around the cell with the help of motor proteins walking on the microtubules
    - Motor protein = Kinesin
  2. Movement of Cilia
    - Motor protein = Dynein
  3. Involved in Cytokenisis (cell division) by pulling on chromosomes (makes kinetochore by attaching to centrosomes)
    - During cell division, centrioles are on the sides of the cell and allow for microtubules to pull and divide the cell in 2
22
Q

Which 2 mutations affect the axoneme?

A
  1. Primary Ciliary Dyskinesia (PCD)
    - No movement of the cilia bc lack of Dynein arms
    - Impairs mucus clearing (bronchiectasis)
    - Chronic sinusitis
    - Situs Inversus (Kartagener’s syndrome) 50% of patients → all organs are on other side of normal
    - Male infertility (spermatosoa’s tail ahs axoneme for motility)
  2. Radial Spoke Protein Mutations
    - Result in immotile cilia and sperm
    - Radial spokes are composed of at least 20 other proteins
23
Q

Which 3 bronchi types terminate the conducting portion?

A
  1. Pulmonary Bonchi
  2. Regular Bronchioles
  3. Terminal Bonchioles
24
Q

What are the characteristics of pulmonary bronchi tissues?

A

Mucosa:
Wavy Epithelium, less goblet cells,
Lamina propria → loose CT with LOTS of capillaries to warm air
Submucosa:
- Only serous glands (no more mucous)
- Complete layer of smooth muscle cells (4-5 layers)
- Hyalin cartilage
Aventitia:
- Mixed with the lungs

25
Q

What are the characteristics of regular bronchioles tissues?

A

Mucosa:
- Most Wavy Epithelia → Simple Columnar Ciliated Epithelium without Goblet cells (no more short cells)
Submucosa:
~2 layers of smooth muscle cells
- Thin Lamina propria
- No cartilage
Adventitia:
- Hard to see mixed with lungs

26
Q

What are the characteristics of the Terminal Bronchiole tissue?

A

Mucosa
- Less wavy than regular bronchiole
- Columnar Ciliated and non-ciliated “club cells”
- Very thni LP (last structure with LP)
Submucosa:
- Thin SM cell layer
- No cartilage or glands
No distinguishable Adventitia
*Last structure with complete wall + Last structure of the conducting portion

27
Q

What are club cells?
Where are they found?

A
  • Start as Columnar/Cuboidal cells and get shorter and shorter
  • Not ciliated (no basal body compared to ciliated cells)
  • Appear clear, almost transparent
  • Produce surfactant
28
Q

What are characteristics/tissues found in Respiratory bronchioles?

A

*Wall of respiratory bronchioles is interrupted and opens onto alveolar sacs

Mucosa:
- Only club cells, no Lamina Propria
Submucosa:
- Thin, protruded SM layer
No distinguishable Adventitia

29
Q

What are characteristics/tissues found in the Alveolar duct?

A

Mucosa:
- Only club cells (very short, almost squamous)
- Highly interrupted, only pieces of mucosa (fist protrusions)
Submucosa:
- Discontinuous SM

30
Q

Which cells and structures line Alveolar sacs and Alveoli?

A

Pneumocytes type I → Squamous, covers the whole surface
Pneumocytes type II → Bulky, Small granules, Stain pale, less in number, Usually in corners, Secrete surfactant

In the septi → Important capillary network for gas exchange (endothelial cells sharing a BM with pneumocytes)
Inside the lungs → Macrophages
In the septi → Reticular fibers (Collagen Type III)

31
Q

What happens to macrophages in the alveoli/alveolar sacs when they encounter foreign particles?

A
  1. They eat it → carried to lysosomal compartment
  2. Can’t digest it (ex: polluant)
  3. Macrophage migrates to the septum
  4. Macrophage (which can normally move around) is fixed into the septum and stays there (impairs elastic fibers synthesis)
    *Eventually they will dye and release their contents including lysosomal compartments → release proteolytic enzymes + elastase which degrades elastic fibers from the septum → Emphysema
32
Q

What organelles are found in Pneumocytes Type II?

A

Small lamellar bodies fuse to become bigger → fuse with the PM and release their contents everywhere in the alveoli

Lamellar bodies contain surfactant protein A, B, C, D + Phospholipids (Lecithin primarily) → helsp reducing surface tension of the pneumocytes type I

33
Q

What composes the Blood-Air barrir in the alveoli?

A

Alvolar lumen - Penumocyte type I - Joint BM - Endothelial cells - Capillary lumen (with erythrocytes)

34
Q

What reaction is catalysed by Carbonic Anydrase?

A

H2CO3 ←→ CO2 + H2O
*For transport of CO2 under the H2CO3 form in RBC

35
Q

What are the 3 main ways by which CO2 is transported in the bloodstream?

A
  1. Dissolved gas
  2. Bicarbonate (H2CO3 by carbonic anhydrase)
  3. Carbaminohemoglobin bound to hemoglobin
36
Q

What causes the Respiratory distress syndrome of the newborn?

A

When premature new-born → can’t produce surfactant → collapse of airways during expiration

37
Q

What is the last structure which has Gands in its submucosa?

A

Intrapulmonary bronchi → only serous

38
Q

What is the last structure which has Hyalin Cartilage in its submucosa?

A

Intrapulmonary bronchi

39
Q

What is the last structure which has a Lamina Propria in its mucosa?

A

Terminal bronchioles (end of the conducting zone)

40
Q

What is the last structure which has a distinguishable adventitia?

A

Regular bronchioles (but hard to see)