Respiratory System ppt. I

? T e structures which are responsible for the inhalation of air, exchange of gases between the air and
blood and exhalation of carbon dioxide constitute the respiratory system.
? Apart from respiration, this system is also responsible for olfaction and sound production.
? T e respiratory system consists of two parts—a conducting part (which carries air) and a respiratory
part (where gas exchange takes place).
? T e conducting part consists of nasal cavity, paranasal sinuses, nasopharynx, larynx, trachea, bronchi,
bronchioles and terminal bronchioles .
? T e respiratory part consists of respiratory bronchioles, alveolar ducts, alveolar sacs and alveoli.
The olfactory epithelium is composed of the following cell types:
 
• Olfactory receptor cells are bipolar neurons that span the thickness of the epithelium and enter the central nervous system.
 
• Supporting or sustentacular cells are columnar cells that are similar to neuroglia cells and provide mechanical and metabolic support to the olfactory receptor cells.
• Basal cells are stem cells from which new olfactory receptor cells and supporting cells differentiate.
• Brush cells are the same cell type that occurs in the respiratory epithelium.
Brush cells are columnar cells specialized for transduction of general sensation.