Respiratory System II Flashcards
Air conducting ducts (1 mm in diameter or less) which supply (pulmonary lobules)
Bronchioles
Terminal bronchioles branch to form several respiratory bronchioles which open into …..
Alveolar ducts
These passages are lined by simple cuboidal epithelium with Ciliated and Clara cells and circumferential smooth muscle
Terminal Bronchiole
Cuboidal cells with domed or club shaped apical surface
– Well developed basal rER
– sER , golgi apparatus and secretory granules.
Clara cells/ Club cells
Clara cells/ Club cells secrete Surface active agent (lipoprotein which prevents adhesion) and Clara Cell Protein (CC16) that……
– Marker for the diagnosis of chronic lung diseases like COPD and Asthma
– CC16 leaks across blood gas barrier in lung injury and is found elevated in serum and decreased in broncho-alveolar lavage.
Bronchial Asthma is…..
Widespread constriction of smooth muscles in the bronchioles, causing decrease in the diameter
Bronchial Asthma Symptoms:
- Extreme difficulty in expiration of air
- Accumulation of mucus in the passage ways
- Infiltration of inflammatory cells.
Bronchial Asthma Treatment:
- Albuterol, which can relax the smooth muscles and dilate the passage-ways
- Corticosteroids, which is anti inflammatory
Transition airways involved in both conduction and respiration.
• These are the first sites where gaseous exchange takes place
Respiratory Bronchiole
………. have simple cuboidal epithelium with ciliated and Clara cells and discontinuous walls interrupted by alveoli
Respiratory Bronchiole
……… have Bundles of smooth muscle cells found between alveolar outpocketing (interalveolar septum)
Alveolar ducts
…………. are thin walled polyhedral terminal sacs where gaseous exchange takes place.
Alveoli
Alveoli are separated from each other by an …..
Interalveolar septum
Alveolar Cell types that line the alveoli walls
– Type I pneumocytes ( majority)
– Type II pneumocytes (septal cells)
……….. move freely between the interalveolar septum and surface and phagocytize inhaled particles on the alveolar surface
Alveolar Macrophages
…….. are squamous cells that line 95% of the alveolar wall.
Type I pneumocytes
The most effective blood-air barrier is at the points where……..
Type I pneumocytes fuse with the endothelial cells of the interalveolar septum.
Dome shaped secretory cells which secrete surfactant and congregate at the septal junctions
Type II Pneumocytes
Type II Pneumocytes contain stacks of parallel membrane lamellae which contain phospholipids , neutral lipids and proteins
called……
Lamellar Bodies
The content of the lamellar bodies is secreted by exocytosis to form …… on the alveolar lining
Surfactant
Contains the phospholipid Dipalmitoylphosphatidylcholine (DPPC) which is critical for reducing the surface tension in the alveolus and preventing collapse
Surfactant
Surfactant Proteins: Function of SP-A
SP-A: Regulates synthesis and secretion of surfactant and modulates immune response . SP-A and SP-D regulates the allergic response to airborne antigens.
Surfactant Proteins: Function of SP-B and C
– SP-B and SP-C :Surfactant organizing protein regulates spreading of surfactant on the alveolar surface.
Surfactant Proteins: Function of SP-D
– SP-D:Binds to microorganisms and lymphocytes therefore SP-D is involved in the local inflammatory response to acute lung injury.
Premature babies with underdeveloped lungs and………… have alveoli which tends to collapse with each successive exhalation
Inadequate surfactant secretion
Leads to RDS: Respiratory Distress Syndrome of the newborn
Disease: Infant respiratory distress syndrome causing high surface tension in lungs, difficulty in alveolar expansion and labored breathing
Hyaline membrane disease
…….. can help induce the synthesis of surfactant if given to the mother before an possible preterm delivery
Glucocorticoids
In patients with Hyaline Membrane Disease, the walls of the collapsed alveoli are ……, and the lymphatics are filled with ………..
Thick
Proteinaceous material
Thin layer of connective tissue found between adjacent alveoli that contain .
– collagen fibers
– elastic fibers
– capillary network(continuous capillaries
Intreralveolar Septum
The elastic fibers of the interalveolar septum contributes to the …………needed for expiration.
Pulmonary recoil
Site of the air-blood barrier
Blood-gas Barrier has two portions
Thin and Thick Portion
Most effective portion of the blood-air barrier that contains:
- Surfactant
- Type I pneumocyte(P1)
- Fused basal lamina of P1 and capillary endothelium.
- Endothelial cells
Thin Portion
This portion of the Blood-gas barrier contains:
- Surfactant
- Type I pneumocyte(P1)
- Basal lamina of P1
- Connective tissue elements (cells, elastic and collagen fibers)
- Basal lamina capillary endothelium.
- Endothelial cells
Thick Portion
Pores of Kohn interruptions in the interalveolar septa which allow ………….between alveoli.
Circulation of Air
This permits collateral flow in instances of obstruction of a lobular bronchiole but may also facilitate spread of infection from one lobule to another
The blood supply of lung parenchyma is supplied by
Pulmonary arteries and veins
Bronchial arteries from the aorta supplies bronchial tree
The lymphatics of lung parenchyma are drained following the
Bronchopulmonary tree to hilum
Chronic obstructive pulmonary disease (COPD) used to describe two related lung diseases:
Chronic Bronchitis
Emphysema
Emphysema:
The walls of alveoli are damaged by inflammation and lose natural elasticity. The alveoli may overstretch and rupture.
Bronchitis:
Chronic bronchitis is a chronic inflammation and thickening of the walls of your bronchial tubes, which narrows them. It often induces coughing spells
- Mucinous secretions or casts filling airways. -Increase in size of mucous glands
- Bronchial or bronchiolar mucous plugging, inflammation and fibrosis.
- Squamous metaplasia or dysplasia of bronchial epithelium
Symptoms of Bronchitis
Persistent smoking elevates the neutrophils as well as elastase levels beyond levels that can be counteracted by …….
Alpha 1 anti-trypsin (AAT) produced by the liver
Excess amounts of elastase causes destruction to the elastic fibers which leads to permanent ………..
Dilation of alveoli
