Human Respiratory System

Comprehensive vocabulary flashcards covering anatomical divisions, structures, cartilages, tubes, and lungs of the human respiratory system.

Upper Respiratory Tract

One of the two anatomical divisions of the human respiratory system, located superior to the lower respiratory tract.

Lower Respiratory Tract

The anatomical division of the human respiratory system that begins at the larynx.

Conducting Zone

One of the two functional divisions of the human respiratory system dedicated to conducting air.

Respiratory Zone

One of the two functional divisions of the human respiratory system responsible for respiration.

Nose

The only externally visible part of the respiratory system; a triangular or pyramidal shaped structure on the face composed of both bony and cartilaginous framework.

External Nares

The exterior openings of the nose (external nostrils) that open inward into the nasal chamber or nasal cavity.

Nasal Cavity

The inner hollow space entered via the external nares, divided into right and left halves by the nasal septum.

Nasal Septum

The dividing wall that separates the nasal cavity into right and left halves.

Nasal Vestibule

The area of the nasal cavity that contains hairs, mucus membrane, and cilia to trap dust and filter inhaled air.

Internal Nares

The internal nostrils opening from the nasal cavity into the nasopharynx.

Air Conditioning (Nasal Function)

The process by which the nose adjusts the temperature of inhaled air to match the body temperature.

Humidification (Nasal Function)

The addition of moisture to inhaled air by nasal mucus to prevent dryness of the respiratory epithelium.

Pharynx

A muscular tube about $5\,\text{inches}$ long located behind the nasal and oral cavities that serves as a common passageway for both food and air.

Eustachian Tubes

Tubes that connect the pharynx to the middle ear cavity on either side.

Nasopharynx

The upper portion of the pharynx located posterior to the nasal cavity.

Oropharynx

The middle portion of the pharynx located posterior to the oral cavity.

Laryngopharynx

The inferior portion of the pharynx extending from the hyoid bone down to the larynx.

Larynx

Also known as the sound box, voice box, or voice chamber; a muscular and cartilaginous structure lined with cilia and mucus membrane where the lower respiratory tract begins and sound production occurs.

Thyroid Cartilage

The largest hyaline cartilage plate forming the anterior of the larynx, which features a central ridge called the Adam's apple or laryngeal prominence.

Adam's Apple

The prominent central ridge on the thyroid cartilage plate, also referred to as the laryngeal prominence.

Glottis

The opening of the larynx through which air enters the lower respiratory tract.

Epiglottis

A lid-like flap composed of elastic cartilage that is normally vertical/upright and shifts to a horizontal position during swallowing to cover the glottis.

Vocal Cords

Two horizontal folds arising inward from the mucus lining of the larynx that vibrate when air passes between them to produce sound.

Trachea

Also called the windpipe or airpipe; a ventral membranous tube about $10\text{--}12\,\text{cm}$ long extending from the larynx to the $5^{\text{th}}$ thoracic vertebra.

Tracheal Rings

A series of $15\text{--}20$ incomplete C-shaped hyaline cartilage rings arranged at regular intervals to support the trachea and prevent its collapse.

Right Bronchus

The primary branch of the trachea leading into the right lung; it is shorter, wider, and more vertical than the left bronchus.

Left Bronchus

The primary branch of the trachea leading into the left lung; it is longer, narrower, and more horizontal than the right bronchus.

Secondary Bronchi

Branches of the primary bronchi that lead into individual lung lobes, numbering $3$ in the right lung and $2$ in the left lung.

Tertiary Bronchi

Branches that arise from secondary bronchi and divide further into bronchioles.

Bronchioles

Fine branching airways arising from tertiary bronchi with a diameter of less than $1\,\text{mm}$.

Terminal Bronchioles

Airway branches derived from bronchioles that divide to form respiratory bronchioles.

Lungs

The principal paired, spongy, conical or triangular organs of respiration situated in the thoracic cavity, with their base at the diaphragm and apex towards the clavicle.

Hilum

A depression on the medial surface of each lung through which the primary bronchi enter.

Pleura

The double-layered serous membrane enclosing each lung, consisting of an outer parietal layer and an inner visceral layer.

Parietal Pleura

The outer layer of the double pleural membrane.

Visceral Pleura

The inner layer of the double pleural membrane that directly covers the lung tissue.

Pleural Cavity

The space located between the parietal and visceral layers of the pleura containing pleural fluid.

Pleural Fluid

The fluid inside the pleural cavity that acts as a lubricant to prevent friction, protects against mechanical shock, and holds the two pleural layers together.

Cardiac Notch

A depression located on the medial side of the left lung where the heart sits.

Right Lung

The larger and heavier lung, divided into three lobes: superior, middle, and inferior.

Left Lung

The smaller and lighter lung, divided into two lobes: superior and inferior.