Lung Cell Biology Flashcards
Where are epithelial cells found in the airway?
Conducting airways (ciliated, exocrine and endocrine function) - transport
Alveolar epithelium (lined with AT1 and secretory AT2, and brush cells) - gas exchange
Mosaic of cells, each with specialised function, lines the airways forming a barrier. There are however, regional differences.
List 5 cell junction types found between epithelial cells
- Tight junction (ZO1) - Tight barrier found near apical side
- Adherens - found below tight junction, not as tight
- Desmosome - very strong and resists mechanical stress
- Hemidesmosome - links cells to basal lamina (collagen IV and laminin)
- Gap junction: Allows ions and small molecule communicatino between cells
The conducting airway epithelium cells are arranged in a ____________ manner. The more distal in the airway, the more _________ and _________ the epithelium becomes. List 6 types of cells found in the pulmonary conducting airway epithelium.
The conducting airway epithelium cells are arranged in a pseudo-stratified manner. The more distal in the airway, the more columnar** and **cuboidal the epithelium becomes. List 6 types of cells found in the pulmonary conducting airway epithelium:
Ciliated epithelial cells (polarised)
Goblet cells (mucus)
Clara cells (glycoproteins)
Basal cells (NOT polarised)
Neurendocrine cells
Dendritic cells
List 5 features of type 1 alveolar cells
Simple cell, flat
Small nucleus
Glycoprotein coat on apical surface
Can not regenerate
Differentiated from AT2 cells
↓ metabolic activity (basic organelles)
List 4 features of type 2 alveolar cells
Cuboidal and thick
Lots of organelles
Produce surfactant
- 15% total lung volume, AT2>>AT1 but only 3% lung area*
- A549 cell line for adenocarcinoma*
Capillary endothelial cells are 1/4 the size of AT1 cells and make up 40% of the lung parenchyma. They have a ___________ ability allowing for __________ and __________. They are simple cells with central nucleus, thin cytoplasm and modest organelles.
Capillary endothelial cells are 1/4 the size of AT1 cells and make up 40% of the lung parenchyma. They have a proliferative ability allowing for growth and repair. They are simple cells with central nucleus, thin cytoplasm and modest organelles.
Endothelial cells also have tight junctions. Though the seal is not as tight as in epithelial cells. The adherens junction allows for the movement of ___________ and __________. ___________ or _____________ damage can cause leaky endothelium, leading to plasma and solutes passing into the _____________.
Endothelial cells also have tight junctions. Though the seal is not as tight as in epithelial cells. The adherens junction allows for the movement of fluid and soultes. Toxic or mechanicaldamage can cause leaky endothelium, leading to plasma and solutes passing into the interstitium.
Cytokines such as TNF-a and IL-1B break up VE-cadherin and disrupts barrier function. Slit upregulates VE-cadherin to repair damage and stem leakage.
Capillary endothelial cells are polairsed. Explain how we know this.
The apical side (facing blood/lumen) has a glycocalyx-polysaccharide coat attached to membrane proteins and lipids.
The basal side is in contact with smooth muscle-like pericytes
Compare the function of serous and mucous cells.
Serous cells: epithelial cells that secrete watery fluid containing proteins and glycoproteins
Mucous cells: epithelial cells that secret mucins
Describe the function of glycocalyx
Enables monitoring of blood flow
Captures enzymes
Harbours co-receptors
Regulates anti-oxidants
Decrease permeability (degradation in disease causes increased premeability
Name two cells found in the interstitium of the lungs.
Fibroblasts: contractile, forms fibres like elastin
Pericytes: contractile, involved in angiogenesis, blood flow regulation and repair and regeneration
