Histology Flashcards
Give 5 functions of the respiratory system
1) Supplies oxygen to the blood for delivery to the cells in the body
2) Removes carbon dioxide that has been accumulated in the blood from tissue in the body
3) Phonation- speaking, singing
4) Olfaction- smelling
5) Blood pressure control via the RAAS system
The nasal cavity provides an area for warming, moistening and filtering inspired air. What assits this process?
Turbinates which produce turbulence to further warm and moisten air
What filters the air inspired through the nose?
Nasal hairs within the vestibule
What cells within the nasal cavity allow us to smell?
Olfactory epithilium on the roof of the cavity
What is respiratory epithilium?
Pseudostratified cilliated columnar epithilium with goblet cells
What cells is the vestibule made up from?
Keritenised stratified squamous epithilium
Where in the nasal cavity does respiratory epithilium begin?
Anterior margins of the turbinate bones
What is mucosa?
Mucus membrane
Where is olfactory mucosa found?
On the roof of the nasal cavity, inferior to the olfactory bulb
What lies beneath respiratory epithilium in the nasal cavity?
The lamina propria which is a band of connective tissue with seromucus glands and a rich venous plexus that can engorge with blood to block the nose (especially in allergic reactions)
What cells line the oropharynx and why?
Non- keratinised stratified squamous epithilium. It carries air and food so must resist abrasion
What lines the epiglotis on its anterior and posterior surface
Anterior-stratified squamous epithilium
Posterior- respiratory epithilium
What comprises the conducting airway?
Trachea to terminal bronchioles
What comprises the respiratory airway?
Respiratory bronchioles to alviolar sacs
What is the larynx and where is it found?
The most supirior part of the trachea containing the vocal folds.
What are the walls of the larynx made from and what cells line the surface?
Respiratory epithilium lines the surface and the walls are made from muscle and cartilage
What cells line the vocal folds?
Stratified squamous epithilium
Where does the trachea terminate?
Carina where it bifurcates to form the right and left main bronchi
What type of cartilage is found in the trachea and what shape is it?
Hyaline cartilage. Its C shaped.
What spans the open side of the C shaped cartilage in the trachea?
Fibroelastic tissue and smooth muscle called the trachealis muscle
List the layers of the trachea from the inside out.
Respiratory epithilium, Basal lamina, Lamina propria, Submucosa (with seromucus glands), Hyaline cartilage, Adventicia
Do the bronchi have cartilage in their walls?
Yes, They are not C shaped but spiral shaped cartilage plates
List the layers of the bronchi from the inside out.
Respiratory epithilium, basal lamina, lamina propria, muscularis, sub mucosa, cartilage
What happens to the cartilage as you go further down the bronchial tree?
It becomes more discontinuous
When is the hyalinie cartilage lost from the airway walls?
When the diameter of the airway is <1mm. We now refer to the airway a bronchioles
What happens to the depth of the columnar epithilium as you go down the bronchial tree?
It decreases. Transforms from columnar to cuboidal epithilium
Do goblet cells and cillia exist at the level of the bronchioles and below?
Goblet cells = No Cillia = Yes
How can you distinguish between terminal and respiratory bronchioles?
Terminal bronchioles do NOT have any gas exchange function, whereas respiratory bronchioles do.
What type of cells line the terminal bronchioles
Cuboidal cilliated epithilium and non-cilliated club cells.
What are the functions of club cells?
Stem cells to replace epithilium, detoxification, immune modulation and they produce a small amount of surfactant
Do alvioli interupt the continuity of respiratory bronchioles?
Yes
What lines the respiratory bronchioles?
Discontinuous squamous type 1 pneumocytes
Which cells make up the alviolar epithilium?
Type 1 and 2 pneumocytes
What is the function of type 1 pneumocytes?
They line up to 90% of the alveolar surface and they are simple squamous epithilium that is thin and permeable to gasses for exchange.
What is the function of type 2 pneumocytes?
Polygonal shape and the surface has microvilli. The cytoplasm contains laminar bodies that contain surfactant. This is released by exocytosis and reduces alveolar surface tension at the air/fluid interface. This reduces tendency for alveolar collapse at the end of expiration
What is the function of alveolar macrophages?
Phagocytose inhailed particles that have escaped entrapment by mucus. They can then migrate up the mucocillary escalator or remain in the septal connective tissue
Where are alveolar macrophages found?
Free cells either in the septa or migrating over the luminal surfaces of alveolar.
Where are the capilaries found in the lungs?
The septa between the alvioli
What is the function of alviolar pores?
To equilibriate the pressure between the alvioli
What makes up the visceral pleura?
Mesothilium backed by layers of fibrous, elastic and connective tissue
