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35 Cards in this Set
- Front
- Back
Cell types in the nasal respiratory epithelium
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Goblet cells Basal cells Brush cells |
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What kind of epithelium in in the nose? |
Pseudostratified columnar epithelium (the nucleus isn't situated in the baseline so appears stratified, but really only one cell thick)
Each cell has 200-300 motile cilia to help remove the particles |
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Goblet cells
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•wine glass mucus secreting cells
•No cilia |
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Basal cells
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•Attached at base of epithelium
•Can differentiate into other epithelial cell types |
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Brush cells
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•Thick microvilli (NOT cilia)
•Sensory receptors associated with trigeminal nerve |
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Where are the nasal glands located? |
In the lamina propria |
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What is the purpose of the serous glands in the nose? |
make a watery fluid secretion to humidify the air and keep the nose moist |
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What is the purpose of the mucus glands in the nose? |
Make a viscous fluid in the nose to bind and absorb foreign particles |
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How do the olfactory cells work? |
Sensory cell. They have microvilli that go into the lumen of the nose. They bind odors and once sensed it changes the polarity of the membrane and you get an action potential which generates another action potential, and then the olfactory nerve which will send an afferent signal to the brain. |
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What are the sustentacular cells? |
Support cells. They sit next to the olfactory cells and provide physical and metabolic support to the olfactory cells |
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How does the nose clear away smells? |
The lamina propria has "Bowman's glands" that help clear away the smells |
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What are the cellular and tissue changes as the airways get smaller? |
• Columnar to cuboidal epithelium
• Goblet cells become less • Lamina propria decreases in thickness • Smooth muscle prominent in bronchi, less in respiratory airways, absent in alveoli • C shaped cartilage rings in trachea become plates in small in smaller bronchi, absent in bronchioles • Clara (Club) cells evident in bronchioles • Mucous glands become less common, absent in bronchioles |
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How is the Trachea able to get nutrients and oxygen? |
The lamina propria has blood vessels |
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What kind of cells are located in the trachea? |
Pseudostratified columnar epithelium |
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What is the purpose of the mucus? |
Mucus can trap foreign particles, can be cleared via coughing |
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What are the structures in the bronchi? |
Cartilage plates. |
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What makes up the bronchi? |
The lamina propria has lots of smooth muscle that spirals, and sensory nerves. There are also blood vessels that come off the aorta for nourishment. |
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Describe the histology of the bronchioles? |
1/2mm-1mm diameter. The lamina propria is very small. There are no glands (could interfere with gas exchange; very small airway, any mucus produced will block airway). No cartilage. Smooth muscle control of airway calire (if contracts, can almost close completely. |
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What is the purpose of the elastic fibres in the bronchiole? |
they help to keep the bronchiole open. When the lung expands on inspiration, the fibres pull the airways open. When it collapses on expiration, prevents complete collapse; keeping the airways open. |
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What are alveoli attachments? |
Where the alveoli connect with the airway. In the attachments are elastic fibres all the way around. |
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What is the histology in the respiratory bronchioles? |
This is the site where some gas exchange occurs. The epithelium is flattened cuboidal, no lamina propria, they receive blood from the capillaries. VERY small amount of smooth muscle, empties into the alveoli where gas exchange occurs. |
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What is the distribution of cells types/tissue in the trachea? |
Epithelium: Pseudostratified columnar |
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What is the distribution of cells types/tissue in the bronchus?
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Epithelium:Pseudostratified columnar (starting to become shorter)
Goblet cells: ++ Clara cells: Absent Mucous glands: ++ Cartilage: ++ |
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What is the distribution of cells types/tissue in the Segmental Bronchi?
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Epithelium:Pseudostratified columnar (becoming shorter)
Goblet cells: + Clara cells: Absent Mucous glands: + Cartilage: + |
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What is the distribution of cells types/tissue in the bronchiole?
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Epithelium: Columnar/cuboidal
Goblet cells: + Clara cells: + Mucous glands: Absent Cartilage: Absent (elastic fibres and smooth muscle provides support) |
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What is the distribution of cells types/tissue in the respiratory bronchiole?
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Epithelium: Cuboidal
Goblet cells: Absent Clara cells: + Mucous glands: Absent Cartilage: Absent (elastic fibres and smooth muscle provides support) |
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What are the defense mechanisms of the respiratory system? |
• Nasal hairs
• *Cough & sneeze reflexes • Lymphoid organs - tonsils & adenoids • *Epithelium (lumenal) • *Mucociliary clearance • *Specialised small airway defence cells (Club cells) • Alveolar macrophages |
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How does the columnar epithelium assist in airway defense mechanisms? |
• boundary to outside world (if this is degraded, allergens and other stuff will interact with the internal environment stimulating immunity) |
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What is mucociliary clearance? |
Faster in the larger airways due to faster beating of cilia. |
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What is the problem with mucociliary clearance in cystic fibrosis? |
There's a faulty iron channel so we no longer have the serous layer, so the mucous just sits on the cilia and bogs them down so they can't beat and the mucous is stuck. |
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What happens to mucociliary clearance in asthma? |
Mucociliary clearance (MCC) impaired in some diseases eg in asthmait is impaired up to three weeks following allergen challenge(neutrophils: neutrophil elastase involved)
• Can be experimentally measured in sheep by following a radioopaqueTeflon disc up the trachea with a fluoroscope • Tracheal mucus velocity (a measure of MCC) is 5mm/min in sheep • Number of drugs devised to increase MCC in diseased states • Beta-2 agonists increase MCC |
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What are clara cells? |
Cub cells protect bronchiolar epithelium
• dome shaped cells • nonciliated, secretory bronchiolar epithelial cells • function as stem cells for repair in the bronchioles ciliated or nonciliated bronchiolar cells. • secrete Club cell secretory protein (CCSP, to keep the alveoli open) and a solution similar to the component of the lung surfactant. • secrtete glycosaminoglycans, proteins such as lysozymes, and conjugation of the secretory portion of IgA antibodies • Club cells engulf airborne toxins and break them down via their cytochrome P-450 enzymes |
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What is the sneezing reflex? |
The sneeze reflex is similar to the cough reflex, but it differs in several ways. The source of irritation thatinitiates the sneeze reflex is in the nasal passages instead of in the trachea and bronchi, and theaction potentials are conducted along the trigeminal nerves (CNV) to the medulla, where the reflexstimulus is processed and acted upon through efferent motor pathways. During the sneeze reflex, theuvula and the soft palate are depressed so the air is directed primarily through the nasal passages,although a considerable amount passes through the oral cavity. The rapidly flowing air dislodgesparticulate matter from the nasal passages and propels it a considerable distance from the nose.
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What are the steps in the sneeze reflex? |
• Irritant receptors in the nasal airways initiate protective reflex sneezing
• Deep inspiration • Brief closure of the glottis • Contraction of respiratory muscles • Abrupt forced blast of air directed mainly through the nasal passages (Sneeze) |
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What are the steps in the cough reflex? |
•Irritant receptors in the larynx and trachea (also pharynx (send their signal through the vagus nerve, goes to the cough center of the brain) & bronchi) initiate a protective cough reflex
•Deep inspiration •Brief closure of the glottis •Contraction of respiratory muscles (builds up pressure) •Abrupt forced blast of air directed through the mouth (cough) |