Respiratory System Anatomy Quiz

Respiratory System Anatomy

• The respiratory system is categorized by structure and function into upper and lower tracts.
• Upper respiratory tract: includes the external nose, nasal cavity, paranasal sinuses, and pharynx.
• Lower respiratory tract: includes larynx, trachea, bronchi, respiratory bronchioles, and lungs.

Functional Zones

• Conducting Zone: Composed of nose, nasal cavity, pharynx, larynx, trachea, bronchi, and terminal bronchioles. Its role is to filter, warm, and moisten air while conducting it into the lungs.
• Respiratory Zone: Contains respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli. This zone is the primary site of gas exchange between air and blood.

Conducting Portions

• Transports air
• Organs include:
  • Nasal cavity
  • Pharynx
  • Larynx
  • Trachea
  • Main bronchus
  • Lobar bronchus
  • Segmental bronchus
  • Terminal bronchioles

Respiratory Portions

• Gas exchange
• Organs include:
  • Respiratory bronchioles
  • Alveolar ducts
  • Alveoli

Trachea (Windpipe)

• Mobile, fibrocartilaginous tube, 5 inches long, 1 inch in diameter.
• Begins in the neck below the cricoid cartilage of the larynx.
• Ends in the thorax at the level of the sternal angle, bifurcating into the right and left primary bronchi.
• The ridge at the bifurcation is called the carina.
• 15-20 incomplete cartilaginous rings keep the trachea open during respiration.
• The posterior part is made of trachealis muscle, allowing esophageal expansion during swallowing.
• Important structures related in the neck include the sternocleidomastoid muscle, thyroid gland, arch of the aorta, and esophagus.

Primary Bronchi

• Project laterally towards the lungs.
• Enter the hilus of each lung, with pulmonary vessels, lymphatic vessels, and nerves.
• Divide into secondary (lobar) bronchi.
• Right primary bronchus is shorter, wider, more vertical than the left, thus increasing likelihood of foreign particles lodging in it.
• Left primary bronchus is longer, narrower, and more horizontal, passing below the aortic arch and in front of the esophagus.

Bronchial Divisions

• Conduction zone branches: Primary, secondary (lobar), tertiary (segmental) bronchi, smaller bronchi, bronchioles, terminal bronchioles.
• Respiratory zone branches: Respiratory bronchioles, alveolar ducts, alveolar sacs, alveoli.

Lungs

• Half conical spongy organs found in the thoracic cavity.
• Enclosed by pleural sacs.
• Divided into lobes by fissures.
• Regions include: Apex, hilum, anterior border, posterior border, costal surface, medial surface, vertebral surface, and base (diaphragmatic surface).
• The hilum is a depression where bronchi, vessels, and nerves enter and exit the lung.

Lung Lobes and Fissures

• Right lung has three lobes (superior, middle, inferior) and two fissures (oblique, horizontal).
• Left lung has two lobes (superior, inferior) and one fissure (oblique).

Broncho-pulmonary Segments

• Anatomical, functional and surgical unit of each lung.
• Pyramid shaped.
• Contains segmental bronchus, pulmonary artery branch, lymph vessels, autonomic nerves, and connective tissue with interspersed veins.

Parts of Parietal Pleura

• The pleura includes two layers (visceral and parietal) of tissue protecting and cushioning the lungs.
• The parietal pleura covers the outer surface and extends into the interlobar fissures; it is subdivided as mediasitinal, cervical, costal, and diaphragmatic based on the body part it contacts with.