PULMONARY NURSING
GENERAL FUNCTION OF THE RESPIRATORY SYSTEM
Gas exchange through ventilation ? external respiration and internal respiration

Respiratory Anatomy & Physiology
The respiratory system consists of two main parts- the upper and the lower tracts

The UPPER respiratory system consists of:
1. nose 2. mouth 3. pharynx 4. larynx

The Nose
> First part of the upper respiratory system ; contains numerous hairs called vibrissae
> There are numerous superficial blood vessels in the nasal mucosa
> Fxns: - To filter the air
- To humidify the air
- To aid in phonation
- Olfaction
The pharynx
> musculo-membranous tube that is composed of three parts: Nasopharynx, Oropharynx, Laryngopharynx
> Fxn: - As passageway for both air and foods (in the oropharynx)
- To protect the lower airway
The Larynx
> Also called the voice box
> Made of cartilage and membranes and connects the pharynx to the trachea
> Fxn: 1. Vocalization
2. Keeps the patency of the upper airway
3. Protects the lower airway (epiglottis)
The Paranasal Sinuses
> 4 paired bony cavities that are lined with nasal mucosa and ciliated pseudostratified columnar epithelium
> Named after their location: frontal ethmoidal sphenoidal maxillary
> Fxn: Resonating chambers in speech

Respiratory Anatomy & Physiology
The LOWER respiratory system consists of:
1. Trachea 2. Bronchus 3. Bronchioles 4. Respiratory unit 5. Lungs- 3R/ 2L

The Trachea
> A cartilaginous tube measuring 10-12 cm
> Composed of about 20 C-shaped cartilages, incomplete posteriorly
> Fxn: conducts air towards the lungs
> The mucosa is lined up with mucus and cilia to trap particles and carry them towards the upper airway
> Goblet cells - produce mucus for trapping and transporting foreign substances

The Bronchus
> The right and left primary bronchi begin at the carina
> Fxn: for air passage
1. RIGHT BRONCHUS - wider, shorter & more vertical
2. LEFT BRONCHUS - narrower, longer & more horizontal

The Bronchioles
The primary bronchus further divides into secondary bronchus, tertiary bronchus, bronchioles, terminal bronchioles and respiratory acinus (respiratory bronchioles, alveolar duct, alveolar sac)
The Respiratory Acinus - chief respiratory unit that consists of:
> Respiratory bronchiole
> Alveolar duct
> Alveolar sac
The Respiratory Acinus
The respiratory membrane is composed of epithelial cells
> Type I pneumocyte - gas exchange
> Type II pneumocyte - surfactant
> Type III pneomocyte - macrophage
Accessory Structures of the Respiratory System:
> Pleura
> Thoracic Cavity
> Mediastinum
The PLEURA
> Epithelial serous membrane lining the lung parenchyma
> composed of: Visceral Pleurae, Parietal Pleurae and Pleural Space (contains pleural fluid)
The Thoracic Cavity
> The chest wall composed of the sternum and the rib cage
> The cavity is separated by the diaphragm ? the most important respiratory muscle
The Mediastinum
The space between the lungs, which includes the heart, pericardium, aorta and vena cavae

Physiology of the Lungs
Function:
> Supplies O2 for metabolic needs of the cells.
> Removes waste materials of cellular metabolism.
1. External Respiration - absorption of O2; removal of CO2 from the lungs.
2. Internal Respiration - exchange of gases between cells and blood

*Partial pressures of atmospheric gases
at sea level � 760 mm Hg
below sea level � higher than 760 mm Hg
above sea level � lower than 760 mm Hg

Medulla oblongata � controls rate and depth
Hering-breuer reflex � prevent overdistention of the lungs (alveoli); terminates inspiration and initiates expiration
Apneustic center � inspiratory center (pons)
Central chemoreceptors/medulla oblongata � blood chemical changes
? CO2 ? ? pH ? ?RR and depth to release CO2
?CO2 ? ? pH ? ? RR and depth to retain CO2
Peripheral chemoreceptors (aortic arch and carotid artery) - triggered by PaO2, PaCO2 and pH changes
Baroreceptors (aortic arch and carotid artery)
? BP -- vasodilation ? ? RR
? BP -- vasoconstriction ?? RR
Pneumotaxic center � controls the pattern (pons)
Proprioceptors ? respond to movement (exercise) ? ? RR
Phrenic nerve ? from C4 to C6 (diaphragm) ? quiet breathing
Intercostal nerves ? T1 to T11 ? spinal nerves ? innervation of IC muscles (respiratory muscles)

ASSESSMENT
I. Dyspnea - subjective feeling (inability to get enough air)
- Dyspnea on exertion - due to an increased myocardial demand