Defence Mechanisms💘 Flashcards
Conducting zine epithelia
Pseudo stratified with three cell types
Ciliated (mucociliary escalator)
Secretory goblet cells (non ciliated)
Basal cells (acts as stem cells and may contribute to structure)
Columnar in nasal trachea and bronchi
Cuboidal in bronchioles with club Clara cells replacing goblet cells
Mucociliary escalator
Where mucus overlies the epithelium protecting the mucosa
Covered with gel phase over a thin sol phase creating a semipermeable barrier allowing exchange of nutrients water and gases
Impermeable to most pathogens
Respiratory zone
Bronchiole is simple cuboidal with thin coat of smooth muscle and elastic fibres and has thin evaginatjons in its wall
Alveoli covered with type 1 pneumocytes mostly simple squamous and can’t replicate
Type 2 are cuboidal and can replicate and produce surfactant fluid reducing surface tension and prevents alveolar collapse
Types form occluding junctions with one another
Immunity stuff
Alveolar macrophages which migrate into airway
Lymphoid tissues and antibodies
Lymphocytes along tract and importance of igA
Under pathological conditions influx of large numbers leukocytes receptors cytokines and chemokines etc
BALT is bronchus associated lymphoid tissue which diffuse into laminate propria
Respiratory tract lining
Lined with respiratory mucosa nose also has olfactory receptors
Epithelia and laminate propria
Laminate propria consist of loose connective tissue blood vessels nerves secretory glands lymphocytes and other lymphoid cells and rigid components keeping airways open
Mucus prevents drying out and cell damage
Sneezing pathway
Irritation occurs
Afferent from trigeminal and olfactory nerves pass to sneezing centre in medulla
Efferent fibres pass from medulla via trigeminal,facial ,glassopharyngeal, vagus and inter coastal nerves
Activation of pharyngeal tracheal and respiratory muscles
