RESPIRATORY SYSTEM

Respiratory System

The organs and structures responsible for the exchange of gases between the blood and external environment.

Nose

The externally visible part of the respiratory system, consisting of the external nares and nasal cavity.

Pharynx

The muscular passage from the nasal cavity to the larynx, divided into nasopharynx, oropharynx, and laryngopharynx.

Larynx

The voice box that routes air and food into proper channels and plays a role in speech.

Trachea

The windpipe that connects the larynx with the bronchi, lined with ciliated mucosa to expel mucus and debris away from the lungs.

Bronchi

The two main branches of the trachea that enter the lungs and further divide into smaller bronchioles.

Lungs

The primary organs of the respiratory system, responsible for gas exchange in the alveoli.

Alveoli

Tiny air sacs within the lungs where the exchange of gases takes place between the blood and external environment.

Paranasal Sinuses

Cavities within the bones surrounding the nasal cavity that lighten the skull, act as resonance chambers for speech, and produce mucus.

Pleura

A double-layered serous membrane that covers the lungs and lines the thoracic cavity, reducing friction during breathing.

Pulmonary Arteries

Arteries that carry deoxygenated blood from the heart to the lungs for oxygenation.

Bronchial Arteries

Arteries that supply oxygenated blood to the tissues of the bronchi and bronchioles.

Lobes of the Lungs

Divisions of the lungs separated by fissures, with the left lung having two lobes and the right lung having three lobes.

Pleural Effusion

Excess fluid accumulation in the pleural space, causing difficulty in breathing.

Respiratory Mucosa

The lining of the nasal cavity that moistens air, traps foreign particles, and warms and humidifies incoming air.

Venule

A small blood vessel that carries deoxygenated blood from the capillaries to the veins.

Respiratory bronchioles

Microscopic branches from the terminal bronchioles that are involved in gas exchange.

Alveolar ducts

Subdivisions of respiratory bronchioles that lead to the alveolar sacs.

Bronchopulmonary segments

Anatomic, functional, and surgical units of the lungs surrounded by connective tissue.

Right lung lobes

Superior, middle, and inferior lobes with specific sub-segments.

Left lung lobes

Superior, lingular, and inferior lobes with specific sub-segments.

Principal bronchi

The main branches of the trachea that enter the lungs and further divide into lobar bronchi.

Lobar bronchi

The branches of the principal bronchi that supply each lobe of the lungs.

Bronchioles

Smaller branches that further divide from the lobar bronchi.

Alveoli

Tiny air sacs where gas exchange takes place.

Respiratory membrane

The thin squamous epithelial layer lining the alveolar walls where gas exchange occurs.

Gas exchange

The process of oxygen entering the blood and carbon dioxide exiting the alveoli through diffusion.

Macrophages

Cells that provide protection in the respiratory system.

Surfactant

A substance that coats the alveolar surfaces and helps with gas exchange.

Pulmonary ventilation

The movement of air in and out of the lungs.

External respiration

Gas exchange between the pulmonary blood and alveoli.

Respiratory gas transport

The transport of oxygen and carbon dioxide via the bloodstream.

Internal respiration

Gas exchange between blood and tissue cells in systemic capillaries.

Inspiration

The flow of air into the lungs, facilitated by the contraction of the diaphragm and intercostal muscles.

Expiration

The flow of air out of the lungs, largely a passive process relying on lung elasticity.

Intrapleural pressure

The negative pressure within the pleural space that prevents lung collapse.

Nonrespiratory air movements

Reflexive or voluntary actions that cause air movement, such as coughing, sneezing, laughing, crying, yawning, and hiccups.

Tidal volume (TV)

The amount of air moved in and out of the lungs during normal breathing.

Residual volume

The amount of air that remains in the lungs after maximal expiration.

Inspiratory reserve volume (IRV)

The additional volume of air that can be forcibly inhaled after a normal inhalation.

Expiratory reserve volume (ERV)

The additional volume of air that can be forcibly exhaled after a normal exhalation.

Vital capacity

The total amount of exchangeable air, calculated as the sum of tidal volume, inspiratory reserve volume, and expiratory reserve volume.

Dead space volume

The volume of air that remains in the conducting zone and does not reach the alveoli.

Functional volume

The volume of air that actually reaches the respiratory zone.

Spirometer

A device used to measure respiratory capacities.