Respiratory system anatomy

Nasal Cavity

sits above the hard palate and helps with humidifying, warming, and filtering the air

External portion of Nasal Cavity

Consists of Nasal Septum (made up of bone + hyaline cartilage)

Nares (nostrils & opening)

Internal portion of Nasal Cavity

The superior, middle, and inferior nasal concha

Increases surface area & air turbulence for warming, filtering, and humidifying

Internal portion of Nasal Cavity pt.2

Paranasal Sinuses lighten the skull and also create a resonating chamber for speech

Organs and tissues of the Pharynx (throat)

• Uvula

• Nasopharynx

• Oropharynx

• Laryngopharynx

Uvula

The uvula closes the entrance of the nasopharynx when eating to prevent food from getting into the nasal cavity

Nasopharynx

• An air passage from the nose to the lower respiratory tract

• Eustachian tubes maintain pressure balance in the middle ear for eardrum vibration

• Pharyngeal tonsil traps airborne pathogens and support immune defense

Oropharynx

• Responsible for swallowing, breathing, and vocalization

• Palatine tonsils recognize pathogen antigens and protect against pathogens

• Lingual tonsils are located at the base of the tongue and work against pathogens

Laryngopharynx

a shared passageway for both air and food. directs air to the larynx and trachea

Components of the Larynx

Hyoid bone

Thyroid cartilage

Epiglottis

Vocal Folds

Hyoid Bone

Supports the larynx and anchor muscles involved in swallowing, speech, and tongue movement

Thyroid Cartilage

Made of Hyaline cartilage to protect the vocal folds posteriorly

• The laryngeal prominence is a ridge that was formed from the cartilage coming together

Epiglottis

Prevents food from entering the larynx

• during swallowing the pharynx and larynx will rise

• elevation of the pharynx widens to receive food

• elevation of the larynx causes the free edge of the epiglottis to move down and form a lid over the glottis, closing it to close.

Vocal folds

cause speech and sound

Components of the Trachea

Hyaline cartilage

Tracheal cartilage

Trachealis muscle

Tracheal Cartilage

C-shaped rings in the tracheal wall to prevent collapse during inhalation and exhalation. Contributes to the stability of the respiratory tract.

Trachealis Muscle

smooth muscle that forms the posterior wall of the trachea

• does airway constriction

• airflow regulation

• Swallowing accommodation

Components of the Bronchial Tree

Primary Bronchi

Secondary Bronchi

Tertiary Bronchi

Terminal Bronchiole

• all responsible for air conduction

Respiratory Bronchiole

• Responsible for gas exchange

Primary Bronchi

Right and left bronchi. Each bronchus enters its respective lung at the hilum

Secondary Bronchi

3 bronchi on right side

2 bronchi on left side

Tertiary Bronchi

Supply bronchopulmonary segments

Terminal Bronchiole

regulate airflow through bronchodilation and bronchoconstriction

Respiratory Bronchiole

initiates gas exchange

Gas Exchange in the Lungs

• Respiratory Bronchioles

• Alveoli

Cells in the alveoli: Type I

• Type I: simple squamous that allows oxygen to diffuse into the blood and carbon dioxide to diffuse out

Cells in the alveoli: Type II

• Type II: secretes surfactant onto the surface of the alveoli to reduce surface tension during exhalation (prevents collapse)

Cells in the alveoli: Macrophages

eat the debris that makes it into the air sacs

External anatomy of lungs

• Apex (top)

• Base (bottom)

• Right lung- 3 lobes

• Left lung- 2 lobes (cardiac notch)

• Parietal pleura

• Visceral pleura

• Pleural cavity

Parietal pleura

covers the thoracic wall (ribcage)

Visceral pleura

covers the lungs

Pleural cavity

space between the visceral and thoracic pleura, filling the space with serous fluid

Oxygen levels

oxygen levels decrease as it travels down, PO2 drops lowest in the alveoli

The flow of air

nasal cavity—> pharynx—>larynx—>trachea—>primary bronchi—>secondary bronchi—>tertiary bronchi—> bronchioles—>terminal bronchioles—>respiratory bronchioles—> alveolar ducts—> alveolar pores—> alveoli