Pulmonary System: Structure, Function, and Control

Flashcards covering the structure, function, mechanics, control, circulation, and assessment of the pulmonary system, based on lecture notes.

Pulmonary System

Composed of two lungs, upper and lower airways, blood vessels, chest wall, and diaphragm, with the purpose of gas exchange.

Upper Respiratory Tract

Includes structures like the nasal cavity, nasopharynx, oropharynx, laryngopharynx, pharynx, and larynx, responsible for filtering, humidifying, and warming inspired air.

Lower Respiratory Tract

Comprises the trachea, bronchioles, capillaries, alveolar sacs, alveolar ducts, and alveoli, where gas exchange primarily occurs.

Right Lobe (Lungs)

Consists of three lobes (upper, middle, lower) separated by horizontal and oblique fissures.

Left Lobe (Lungs)

Consists of two lobes (upper, lower) separated by an oblique fissure.

Mediastinum

The space separating the lungs, containing the heart, great vessels, trachea, esophagus, and thymus, protecting vital organs.

Great Vessels

Includes the aorta, superior and inferior vena cava, pulmonary artery, and pulmonary veins, located within the mediastinum.

Diaphragm

A dome-shaped muscle located inferior to the mediastinum, serving as the primary muscle for breathing.

Boyle's Law

Physiological principle applied to breathing, stating that as lung volume increases, pressure decreases (inhalation), and as volume decreases, pressure increases (exhalation).

Inhalation

The process where the diaphragm moves down, increasing lung volume, decreasing pressure inside the lungs, and allowing air to flow in.

Exhalation

The process where the diaphragm moves up, decreasing lung volume, increasing pressure inside the lungs, and pushing air out.

Pharynx

Commonly known as the throat, divided into the nasopharynx, oropharynx, and laryngopharynx.

Larynx

Also known as the voice box, it contains the epiglottis.

Epiglottis

A flap within the larynx that covers the trachea during swallowing to prevent food or liquid from entering the lungs.

Trachea

The windpipe, which bifurcates at the carina into the primary bronchi.

Carina

The point at which the trachea divides into the left and right primary bronchi.

Bronchi

Airways branching from the trachea, including primary, secondary (lobar), and tertiary (segmental) bronchi.

Bronchioles

Smaller air passages that branch off the bronchi, leading to the alveoli.

Alveoli

Tiny air sacs in the lungs that are the primary site of gas exchange.

Gas Exchange

The process of swapping oxygen and carbon dioxide between the lungs (specifically the alveoli) and the bloodstream.

Type I Alveolar Cells

Cells that form the walls of the alveoli, allowing gases like oxygen and carbon dioxide to pass in and out of the lungs.

Type II Alveolar Cells

Cells that produce surfactant, a substance that reduces surface tension and prevents the alveoli from collapsing.

Surfactant

A slippery substance produced by Type II alveolar cells that reduces surface tension in the alveoli, keeping them open.

Red Blood Cells (RBCs)

Cells that pick up oxygen from the alveoli and transport it to the rest of the body, containing hemoglobin.

Hemoglobin

The protein within red blood cells that binds to oxygen for transport throughout the body.

Pulmonary Circulation

A circulatory system that starts in the right ventricle, ends in the left atrium, and functions to oxygenate blood in the lungs.

Systemic Circulation

A circulatory system that starts in the left ventricle, ends in the right atrium, and functions to deliver oxygenated blood to the body.

Oxygenation

The process of gas exchange where oxygen binds to hemoglobin in red blood cells and is transported to tissues and organs.

Ventilation

The mechanical process of moving air in and out of the lungs (inhalation and exhalation).

Accessory Muscles of Respiration

Muscles like external intercostals, neck muscles (sternocleidomastoid, scalenes), and abdominal muscles that assist with forceful breathing.

Ventilation Control Centers

Located in the brainstem (medulla oblongata and pons), including the pontine respiratory group, chemosensitive center, apneustic center, dorsal respiratory group, and ventral respiratory group, controlling inspiration and expiration.

Central Chemoreceptors

Located in the brainstem, sensitive to changes in hydrogen ions (H+), oxygen (O2), and carbon dioxide (CO2) in the blood, primarily regulating pH.

Peripheral Chemoreceptors

Located in the carotid bodies and aortic bodies, sensitive to changes in O2, CO2, and pH levels in the blood.

Ventilation (V)

Refers to the amount of air reaching the alveoli.

Perfusion (Q)

Refers to the amount of blood reaching the alveoli via capillaries.

V/Q Ratio

The ratio of ventilation to perfusion, normally 0.8, indicating the balance between air and blood flow in the lungs.

Dead Space

A V/Q mismatch where there is ventilation but no perfusion (V/Q = ∞), meaning air reaches alveoli but no blood flow for gas exchange.

Shunt

A V/Q mismatch where there is perfusion but no ventilation (V/Q = 0), meaning blood flows through alveoli but no air for gas exchange.

Pleura

A double-layered membrane encasing the lungs, consisting of visceral and parietal layers.

Visceral Pleura

The inner layer of the pleura, adhered directly to the surface of the lung, protecting and supporting them.

Parietal Pleura

The outer layer of the pleura, lining the inner chest wall, which produces and absorbs pleural fluid.

Pleural Space

The space between the visceral and parietal pleura that contains lubricating pleural fluid, reducing friction and maintaining negative pressure essential for lung inflation.

Pleural Fluid

Lubricating fluid found in the pleural space that reduces friction between the pleural layers during breathing.

Auscultation

The act of listening to lung sounds, typically with a stethoscope, to assess the respiratory system.

Bronchial Breath Sounds

Loud, high-pitched breath sounds typically heard around the trachea.

Bronchovesicular Breath Sounds

Medium-pitched breath sounds heard in the 1st and 2nd intercostal spaces beside the sternum.

Vesicular Breath Sounds

Soft, low-pitched breath sounds heard throughout the entirety of the lung fields.