Respiratory Anatomy 2 - Lower Respiratory Tract Flashcards
This component of respiratory system preps the air for gas exchange, helps with olfaction and resonance of sound
Upper respiratory system
What are the 3 main types of epithelium found in the upper respiratory system?
Stratified squamous epithelium, olfactory epithelium, respiratory epithelium
What are the 5 key components of the lower respiratory system?
Larynx, trachea, bronchi, bronchioles, alveoli
What are the 3 main functions of the LRT?
1) gas exchange (conducts air to/from sites of gas exchange)
2) completes cleaning, warming, and humidifying of air
3) provides blood-air barrier and large SA for gas exchange
This allows the passage of air only. It lies anterior to the esophagus. (Main airway)
Larynx
What is the role of cartilage in the larynx?
It protects and maintains an open airway
This closes over the airway when swallowing.
Epiglottis
This is known as the ‘true’ vocal cord. The passing air causes vibrations which results in sound waves; it is used for normal phoation.
Vocal folds
These are known as the ‘false’ vocal cords. It is superior to the vocal folds and prevent foreign object entry into the glottis
Vestibular folds
This affects cartilage and muscle in the vocal folds which results in longer and thicker folds, and thus a deeper voice.
Testosterone
This can produce very deep sounds.
Vestibular folds
This maintains the patent airway (keeps it open and obstruction free). It is anterior to the esophagus and sits between the larynx and the primary bronchi
Trachea
What is the trachea made of? (2 components)
C-shaped cartilage rings, elastin fibres in lamina propria + submucosa
What type of epithelium lines the trachea?
Respiratory epithelium
This has structures known as cilia that move the debris to the pharynx to be swallowed and digested. Mucus and mucosal glands line the surface of the epithelium.
Mucociliary escalator
The ends of C-shaped cartilage rings are connected by a band of smooth muscle known as?
Trachealis
Why is the cartilage of the trachea C-shaped?
To allow the esophagus to expand and stretch.
Helps to keep airways open and allows trachealis muscle to contract (to generate a cough)
What is the function of the trachealis muscle?
Contracts and dilates (contracts to cough as well) but it helps the trachea to expand during swallowing, and constrict when not being used (to save space)
This structure prevents food from entering the larynx (main airway)
Epiglottis
What are the 2 folds of the larynx? What is their difference?
Vocal folds: passing air causes vibration (sound waves) ‘true’ vocal cords; used for normal phonation
Vestibular folds: prevent foreign object entry to the glottis; ‘false’ vocal cords; can produce deep sounds
This is a part of the lungs where the bronchi and blood vessels enter.
Hilum
How many lobes does the lungs have?
Right lung has 3 lobes
Left lung only has 2 lobes (because of the position of the heart)
This is a dome-shaped structure that sits on top of the diaphragm.
Lungs
The bronchial tree consists of what structures:
Trachea, primary, secondary and tertiary bronchi and terminal bronchioles
How does the epithelium change throughout the bronchial tree?
Trachea - Respiratory epithelium
Primary bronchi - respiratory epithelium
Secondary and third bronchi - respiratory epithelium decrease in height - goblet cell numbers reduce
Bronchioles - cuboidal epithelium
Terminal bronchioles - no epithelium
Pattern: respiratory epithelium gets smaller, and the number of goblet cells decreases so less mucus is present as you go down the bronchial tree
How does the structure of the cartilage change throughout the bronchial tree?
Trachea - C-shaped cartilage (to allow for constriction of dilation of trachea to accomodate food and also close when there’s no food present)
Primary bronchi - cartilage and smooth muscle rings are complete
Secondary and tertiary bronchi - cartilage plates
Bronchioles - no cartilage (only thick smooth muscle for bonchoconstriction and dilation)
Terminal bronchioles - no cartilage
Pattern: amount of cartilage decreases as you go down the bronchial tree. But amount of smooth muscle increases.
Why is there no cartilage in the bronchioles?
Because there’s only smooth muscle to control bronchoconstriction/dilation
These structures provide pulmonary lobules. This directs the air to the alveoli
Terminal bronchioles
This zone is made of pulmonary lobules made of many alveoli (air sacs) arranged like bunches of grapes.
Respiratory zone
Why are alveolar walls very thin? What kind of epithelium lines these walls?
Alveolar walls are lined with simple squamous epithelium on a thin basement membrane.
- it is thin to provide a greater surface area for gas exchange
Approximately how much alveoli are in each lung?
150 million alveoli
The external surface of alveoli is covered in a network of?
Pulmonary capillaries
These are pocket-like structures covered by a dense capillary network meant for gas-exchange.
Alveoli
This is the main type of epithelial cell found in the lungs/alveoli.
alveoli are found in the lungs
Pneumocytes
This is a type of pneumocyte that forms the respiratory membrane/blood air barrier with capillary wall and shared basement membrane. Important for gas exchange .
Type 1 squamous pneumocytes
This is a type of pneumocyte scattered amongst Type 1 squamous pneumocytes. They secrete surfactants.
Type 2 cuboidal pneumocytes
This is a complex lipoprotein (phospholipid) that reduces the surface tension of the alveolar fluid.
Surfactant
This removes the debris that makes it into the alveoli.
Macrophages
This connects the alveoli to the bronchial tree/bronchii.
Alviolar duct
What structures form the respiratory membrane?
Alveolar cell layer, fused basement membranes of alveolar and capillary epithelium, capillary endothelium + type 1 epithelial cells
