Respiratory System Anatomy Quiz

Respiratory System

• Consists of two parts: Conducting Part (responsible for passage of air and conditioning of inspired air) and Respiratory Part (involved in exchange of oxygen and carbon dioxide between blood and inspired air)

General Anatomy of the Respiratory System

• Consists of a tube that divides into small branching tubes in the lungs
• External nares → nasal cavity → nasopharynx → laryngopharynx → larynx → trachea → primary bronchi → lungs (secondary bronchi → tertiary bronchi → bronchioles → alveolar sacs → alveoli)
• Histology along the respiratory tract changes from the trachea to the tertiary bronchi
• Tracheal tract is lined with ciliated pseudo-stratified columnar epithelium, smooth muscle, and cartilage rings
• Bronchioles are lined with cuboidal epithelium
• Alveolar ducts to alveoli are lined with simple squamous epithelium

Anatomy of Respiratory Organs

Nose and Nasal Cavity

• External nares contain hairs to prevent dust particles from entering
• Nasal cavity is lined with ciliated pseudostratified columnar epithelium to provide a defense mechanism against foreign substances

Larynx (Voice Box)

• Rigid, short passage for air between the pharynx and trachea
• Wall is reinforced by hyaline cartilage and smaller elastic cartilages, connected by ligaments
• Elastic tissues allow for generation of different sounds when air flow passes through the larynx
• Epiglottis, a cartilage at the top, remains upright when gases are entering or exiting the trachea through the glottis

Trachea

• Long, straight tube beginning from the larynx to the lungs
• Cilia on its inner wall lining expel foreign substances trapped in mucus back to the naso-pharynx and oropharynx
• Trachea is open due to support by 20 C-shaped cartilage rings, allowing gases to pass freely

Histology of Trachea

Mucosa

• Epithelium: pseudo-stratified ciliated columnar
• Types of cells: ciliated columnar cells, goblet cells, brush cells, basal cells, granule (Kulchitsky) cells, and secretory cells (Clara cells)
• Lamina propria: loose connective tissue and elastic fibers
• Lymphocytes, mast cells, and blood vessels are present

Submucosa

• Loose connective tissue
• Tracheal glands: mixed (serous and mucus) glands
• Blood vessels and ducts are present

Cartilage and Smooth Muscle Layer

• "C" shaped hyaline cartilage with perichondrium and chondrocytes
• Ends of cartilage are connected by smooth muscles

Adventitia

• Fibro-elastic tissue