L1.8 Conducting and Respiratory zone microanatomy Flashcards
List the parts of the conducting and respiratory zone and which of them are part of the anatomical “upper airway”
Conducting zone: Nasal cavity, pharynx, larynx, trachea, bronchi (1 primary, 2 lobar, 3 segmental) and (terminal) bronchioles
Respiratory zone: respiratory bronchioles, alveolar ducts, alveolar sacs, alveoli.
What are the three regions of the pharynx
naso (nasal cavity to soft palate), oro (soft palate to epiglottis) and laryngo, (epiglottis to start of trachea)
What is the purpose of the conducting system and liquid lining of the respiratory system- what provides this
To conduct air to respiratory zone as efficiently as possible and condition it for gas exchange through filtering, warming and humidifying air.
Liquid lining helps with humidifying and stopping dessication of cells. Provided by type 2 pneumocyte in resp zone and goblet, club (bronchiole) and seromucus glands in conducting zone.
What are the 4 cell/ tissue types still in the conducting system and their purpose
- Pseudostratified columnar ciliated epithelium (changes to columnar as you go along). Found in nasal cavity until larger airways. Motile cilia for mucocilliary clearance
- Goblet cells: mucus secretion, numbers and level of activity affected by environment and disease. Found from the nasal cavity to bronchi:
- Seromucus glands: watery mucus
- Club cells that have club secretions with antimicrobial properties (lysosomes) and lipoproteins to prevent luminal adhesion if airway collapse. Found in term and resp bronchioles:
What are the 3 cell/tissue types in the respiratory zone and their purpose
- Type 1 pneumocyte: flatness helps gas exchange decreasing distance for molecules to travel
- Type 2 pneumocyte/ surfactant cell reduce the work of breathing by producing surfactant.
- Macrophages (alveoli): phagocytose foreign body.
What are the 4 types of CT found in the respiratory tract, where exactly and function
- Cartilage: found in trachea and bronchi: help to keep airways patent- reduce work of breathing. Reduces impact of elastic fibres and SM
- Elastic fibres: Lung & throughout: help recoil and compliance of the lungs
- Collagen: throughout but less in the interalveolar septa to decrease distance for diffusion. Mainly support. (Too much = interstitial fibrosis
- Smooth muscle: Trachea–> alveolar duct. Controls tone of airway, biggest impact in the bronchioles.
What is the makeup of mucus in the mucocilliary escalator
Mucus layer is biphasic: serous sol layer in which cilia beat and above this the viscoelastic/gel layer which the tips of cillia catch when they beat.
What are the features in the nasal cavity that help to prepare air for gas exchange
Filtering: the Vibrassae (nose hairs) trap particles >4um. On the wall, P/S cilliated columnar epithelium help filter.
Warming by blood vessels in the lamina propria to 37.
Humidifying by goblet cells and seromucus gland.
Overall: Turbinate folds/Nasal conchae. It maximises SA for epithelium, slows air flow, increase turbulence to mix air.
What is Anatomy, histological appearance and function of Trachea
-C shaped rings of cartilage linked posteriorly with trachealis muscle
which allows changing the diameter for coughing and accomodating swallowing in the oesophagus.
Histological: has p/c columnar epi and goblet cells as well a seromucus glands.
Function: patent tube, air conditioning
What is Anatomy, histological appearance and function of Bronchus
Irregular cartilage plates which disappear with more branching. Histological: p/c columnar epi + goblet cells on top of mucus glands and smooth muscle.
Function: patent tube and air conditioning
What is Anatomy, histological appearance and function of Bronchioles -> (goes to the end of the conducting zone)
Anatomy: no cartilage, mucus gland, just discontinuous layer of smooth muscle in a spiral.
Histological: transition to columnar and then simple cuboidal epithelium with club cells in term + resp bronchioles
Function: mainly control airflow to different parts of lung. Conditioning is minor.
What is a lobule compared to an acinus
A division of a lung supplied by a terminal bronchiole-> respiratory bronchiole (3 orders)–> alveolar ducts-> sacs-> alveoli.
Whereas acinus is area supplied by a respiratory bronchiole onwards.
What is emphysema presentation and cause - part of COPD, often presents with chronic bronchitis
Due to increased inflammatory enzymes destroying elastin and collagen, the reduction of elastin in the lungs causes air spaces to enlarge therefore reduced area for gas exchange (one big alveoli) and decreased recoil force/ increased compliance so presents as shortness of breath as well as expanded chest due to trapped air.
What are heart failure cells and dust cells
alveolar macrophage. They are called heart failure cells when they eat blood
Over what distance does gas exchange occur in the alveoli and what condition affects this q
O2 and CO2 diffuse across distance between endothelium - fused basement membrane - pneumocyte type 1. This is 0.5 um but can be increased during Cystic fibrosis due to extra thickening.
