Respiratory System Introduction and Mechanics

Comprehensive vocabulary flashcards covering lung anatomy, cellular components, respiratory mechanics, and neurological control mechanisms.

Major Fissure

The structure that separates the left upper lobe from the left lower lobe.

Alveoli

Individual air sacs, approximately $300,000,000$ in total, that increase surface area for gas exchange and are enveloped by blood capillaries.

Surfactant

A sticky substance that acts as a film to keep the alveoli open during exhalation so the lungs do not completely deflate.

Type 1 Pneumocytes

Simple squamous epithelium cells responsible for diffusion and gas exchange, creating the perimeter of the alveoli.

Type 2 Pneumocytes

Simple cuboidal epithelium cells found at the corners of alveoli that secrete surfactant and help maintain airway openings.

Macrophages

Cells within the alveolar space that phagocytize particulates or pathogens that have penetrated physical and chemical barriers.

Pseudo-stratified Columnar Epithelium

The tissue type found in the nasal cavity, nasopharynx, trachea (with cilia), and bronchi (with cilia).

Stratified Squamous Epithelium

The tissue type primarily making up the mouth, oropharynx, and laryngopharynx.

Trachea

The airway characterized by pseudostratified columnar epithelium with cilia, C-shaped rings of cartilage, and smooth muscle.

Bronchioles

Airways containing simple columnar epithelium and smooth muscle, but no cartilage.

Pulmonary Arteries

Blood vessels carrying deoxygenated blood from the right ventricle of the heart to the lungs.

Pulmonary Veins

Blood vessels carrying oxygen-rich blood from the lungs back to the left atrium of the heart.

Bronchial Arteries

The main blood supply to the tissues of the lung which enter through the hilum.

Inspiration

The active process of inhalation where the diaphragm and intercostal muscles contract, increasing thoracic volume and lowering air pressure to bring air in.

Expiration

Usually a passive process of exhalation where the diaphragm and intercostal muscles relax, decreasing thoracic volume and forcing air out.

Tidal Volume

The small amount of air that moves in and out of the lungs with each normal breath.

Inspiratory Reserve Volume

The increased volume of air that can be moved into the lungs with effort after a normal inhalation.

Expiratory Reserve Volume

The increased volume of air that can be forced out of the lungs with effort after a normal exhalation.

Vital Capacity

The maximum amount of air that can be moved in plus the maximum amount that can be moved out during one breath (Tidal Volume + IRV + ERV).

Residual Volume

The volume of air that remains in the lungs even after exhalation, maintained by surfactant.

Spirometer

A device used to measure air displacement and provide assessments of forced vital capacity, often used to test for COPD, bronchitis, or asthma.

Medulla Oblongata

The primary respiratory control center of the nervous system that sends nerve impulses along the phrenic nerve to the diaphragm.

Phrenic Nerve

The nerve that innervates the diaphragm to cause muscle contraction during inspiration.

Sudden Infant Death Syndrome (SIDS)

A condition thought to occur when the respiratory control center in the medulla oblongata stops sending out nerve signals.

Chemoreceptors

Sensory receptors in the brain and circulatory system sensitive to carbon dioxide levels and drops in blood $pH$.