Respiratory System: Air Entry and Passages

Air Entry Points

• Air can enter the body through the two nostrils and the mouth
• The nasal openings are located on the upper part of the upper lip

Nasal Passage and Chambers

• The pathway from the nostrils to the chamber, is referred as the nasal passage
• Air travels from the nostrils through the nasal passage into the nasal chamber or nasal cavity

Pharynx as a Common Passage

• The nasal chamber opens into the pharynx
• The oral cavity also opens into the same pharynx
• The pharynx serves as a shared route for both food and air

Larynx and its Function

• Following the pharynx is the larynx, commonly known as the sound box
• This sound box is composed of multiple cartilages

The Trachea (Windpipe)

• After the larynx comes the trachea, which is the windpipe

Division of the Trachea

• The trachea divides into left and right primary bronchi at the level of the fifth thoracic vertebra (T5)

Bronchial Branching

• Primary bronchi divide into secondary bronchi
• Secondary bronchi branch into tertiary bronchi
• Further divisions include quaternary bronchi and then into bronchioles
• The progression continues to initial bronchioles and finally to terminal bronchioles

Alveoli and Alveolar Ducts

• Terminal bronchioles lead to alveoli and alveolar ducts

Characteristics of Alveoli

• Alveoli are irregular, bag-like, vascularized structures
• Alveoli are responsible for the exchange of oxygen and carbon dioxide with the blood

Epiglottis Function

• Epiglottis is a cartilaginous flap that covers the glottis
• Prevents food from entering the windpipe (trachea)

The Esophagus vs. the Trachea

• The esophagus is the food pipe
• The trachea is the windpipe

Vertebral Regions

• The initial vertebrae of the spine are called cervical vertebrae
• There are seven cervical vertebrae (C1-C7)
• Following the cervical vertebrae are the thoracic vertebrae
• The trachea divides into the primary bronchi at the level of the fifth thoracic vertebra (T5)

3D Anatomy of the Respiratory System

• The respiratory system starts with the external nostrils
• The nasal passage leads to the nasal cavity
• The oral cavity and nasal cavity connect to the pharynx (common chamber)
• The pharynx connects to the larynx (sound box)
• After the Larynx is the trachea

C-Shaped Cartilaginous Rings of the Trachea

• The trachea has C-shaped incomplete cartilaginous rings for support
• These extend into the primary and secondary Bronchi

Lungs Parts

• The lungs consist of the primary, secondary, tertiary, and quaternary bronchi
• They consist of initial and terminal bronchioles, and alveoli, and alveolar ducts
• The trachea is not part of the lungs

Additional Functions of the Epiglottis

• The epiglottis ensures that food enters the food pipe (esophagus) rather than the windpipe (trachea)

C-Shaped Rings Details

• C-shaped incomplete cartilaginous rings are found from the trachea to the initial bronchioles
• These rings provide support and prevent collapse of the airways

Alveoli Count

• Lungs contain a high number of alveoli, around 100 million per lung

Diaphragm Details

• Diaphragm is a muscular structure
• It is located beneath the lungs like a dome