Structure and function of airways Flashcards
Describe the structure and function of type 1 alveolar cells.
Squamous and very thin and facilitate gas exchange.
Describe the structure and function of type 2 alveolar cells.
Granular and cuboidal. Replicate to replace type 1 alveolar cells. Secrete pulmonary surfactant. Secrete antiproteases. Have a role in xenobiotic metabolism.
What makes up most of alveolar surface by surface area?
Type 1 alveolar cells.
What makes up most of alveolar surface by cell count?
Type 2 alveolar cells.
What does pulmonary surfacant do?
Reduces surface tension prevents alveolar from collapsing.
What other cells can you find in the alveolar region?
Macrophages and fibroblasts.
What is the function of the airway?
O2 to alveoli and CO2 out of lungs.
What are the structural components that make up the airway and can you explain the function of these components?
Cartillage is for mechanical stability.Smooth muscle to control airways (constriction and dilation).
How is the nose adapted for breathing?
Conchae in the nose are highly vascular. This warms and humidifies nasally inhaled air. Nasal hairs filter out large particles.
What produces mucus in the airways?
Goblet cells and submucosal glands.
How are cilliated cells adapted?
Contain lots of mitochondria.
Two kinds of cells in the submucosal gland? What are their functions?
Mucous and serous cells. Mucuous cells secrete mucus. Serous cells secrete anti bacterial enzymes.
Apart from mucus what else is released from the submucosal gland?
Antibacterial enzymes, water and salts.
Describe ciliary structure?
Axoneme that has a 9 + 2 microtubule arrangement.
What is the movement of mucus by cilia called? What is the function?
Mucociliary clearance. Physical barrier to infectious agents.
Regulatory and inflammatory mediators you would find in the airways?
Nitric oxide, carbon monoxide and arachidonic acid metabolites.
What does inflammation of airway smooth muscle cell result in?
Hypertrophy and proliferation of smooth muscle. Contraction and relaxation of smooth muscle. Cytokine and chemokine secretion. Nitric oxide and prostaglandin release.
Describe and explain airway vascalature?
Requires high amounts blood flow. To warm inspired air, clear inflammatory mediators and clear inhaled drugs.
What nerves controls airway function?
Parasympathetic and sensory nerves.
What regulatory and inflammatory mediators can control airway function?
Histamines, Arachinodic acid metabolites, cytokines and chemokines.
What other molecules can control airway function?
Proteases (e.g neutrophil elastase) and reactive oxygen species.
Explain airway constriction by nerves
Solid enters airway and detected by sensory receptors. Excitation of sensory nerves up to brain stem, Excitation of parasympathetic nerves cause release of ACh from preganglionic terminal ends. This results in release of ACh from post ganglionic fibres. ACh cause contraction of smooth muscle in airways and mucus secretion.
What cause airway relaxation.
Release of adrenaline from adrenal gland and release of nitric oxide from nerves from spinal cord.