Histology of the Respiratory System Flashcards
What two process does respiration involve?
Physical and chemical
What does the physical process of respiration entail?
Ventilation involves inspiratory and expiratory movements of the chest.
What does the chemical process of respiration involve?
The exchange of gases between air and blood takes place at the cellular level
What does parasympathetic innervation do in the lungs?
Bronchioconstriction, mucous secretion and vasodilatation
What does the sympathetic innervation do in the lungs?
Bronchodilatation
What is the total distance for gas to be exchanged?
0.2 micro meters
What happens during breathlessness?
There is fluid in the gap between the alveol and the capillary and so the distance is increased and so the gas can’t diffuse properly.
What are the four main layers of the respiratory system?
Mucosa
Submucosa
Cartilage and supporting muscle
Adventitia
What consists of the mucosa?
There is a epithelium and a connective tissue layer which consists of connective tissue which is known as the lamina propria.
What does the sub mucosal layer have?
Seromucous glands
What do the seromucous glands have?
They have a duct that opens up into the lumin of the mucosa and it release mucous and serous fluids.
What is the adventitia?
It s the fibrous connective tissue which covers the tracheal bronchial treee.
What kind of cartilage makes up the rings of the trachea?
Hyaline
What are the gaps between the cartilage ring filled up with?
They are filled with trachealis muscle and fibroelastic tissue
What is the function of the respiratory mucosa and submucosal layer?
It warms and moistens the air and traps any foreign particle in the mucous
What cells are present in the mucosal layer?
Goblet cells
What cells can differentiate and act as stem cells?
Basal cells
What kind of cells are found in the trachea?
Pseudostratified ciliated columnar cells
What does the lamina propria contain?
It contains areolar connective tissue which has elastine and also blood vessels. (there might also be some macrophages and immune cells.)
Where do the pseudostratified ciliated cells start and where do they end?
It starts at the nose and finishes at the level of the terminal bronchiole
What type of cells starts from the terminal bronchiole?
Non-ciliated columnar single layer cells.
What kind of tissue makes up the lamina propria?
Loose connective tissue
What is in between the submucosal layers?
Elastic fibres
What is found in the perichondrium?
Cartilage
What is the function of the adventitia?
It connects and supports the trachea to the surrounding tissue. It also contains nerves, vessels and adipose tissue.
What two groups can we divide the bronchi into?
Intrapulmonary bronchi and extrapulmonary bronchi
What is the histology of the extrapulmonary bronchi?
They represent the histology of the trachea.
What is the histology of the intrapulmonary bronchi?
They have less cartilage and it does not completely encircle the lumen and there are layers of smooth muscle between the mucosa and sub-mucosa.
What is the diameter of a bronchiole?
less than 1mm
What are bronchioles covered in?-
Ciliated columnar epithelium (however in the smaller bronchioles it is non-ciliated)
What is different about the histology of bronchioles?
Smooth muscle increases, Clara cells are present which secrete surfactant, no goblet cells, no ciliated cells, no submucosal glands, no cartilage,
What type of cells make up the respiratory bronchioles?
Ciliated cuboidal epithelium
What are alveolar ducts surrounded by?
Collagen, elastin and smooth muscle
What surrounds the alveoli and the alveolar sacs?
by blood vessels and pulmonary capillaries
What surrounds the alveoli and the alveolar sacs?
by blood vessels and pulmonary capillaries
What type of epithelium makes up the bronchioles?
Simple epithelium wth few cilia
How many glands are in the lamina propria in the bronchioles?
None
How does the smooth layer in the broncholes compare to that of the bronchi?
It is thicker.
Describe the alveolar-capillary interface.
Gaseous exchange takes place through the endothelial cell of the capillary, basement membrane and type I pneumocyte
The walls of the capillary endothelial cell is fused to that of the alveolar cell, there is only a very thin basement membrane between these two cells.
What is correct about the club cells (Clara cells)?
Protect airways, regenerate bronchiolar epithelium, produce surfactant.
