Respiratory System: Key Structures and Functions

Lung

Organ located in the pleural cavity

Epiglottis

Prevents food and liquids from entering the airways

Pharynx

Shared passageway for the respiratory and digestive systems

Respiratory bronchioles

Small muscular airways that branch to alveolar ducts

Thyroid cartilage

Adam's apple; largest piece of Larynx cartilage

Trachea

Wind pipe; extends from the pharynx to the bronchi

Larynx

Contains the vocal cords

Alveolus

Air sac; site of gas exchange in the lungs

Primary bronchus

Airway that branches from the trachea and enters the lungs

Nasal cavity

Contains membrane that warms, moistens, and filters incoming air

Auditory tube

equalizes pressure in the middle ear, drains fluid to the nasopharynx, protects the middle ear from pathogens and secretions from nose and throat

Laryngopharynx

Facilitates air passage to larynx and food to the esophagus

Nasopharynx

connects nasal cavity to the rest of the pharynx, allows air to flow to the lungs

Cribriform plate

transmits olfactory nerves from nasal cavity to the brain, allows for sense of smell

Oropharynx

acts as a conduit for air from nasal cavity/mouth to the lungs,

Maxillary sinus

humidifies and warms inhaled air, filters out pollutants, produce mucus to protect nasal cavity

Soft palate

regulates airflow, prevents food/liquid from entering nasal cavity during swallowing

Meatuses

spaces that drain paranasal sinuses and lacrimal ducts, serve as air passages that contribute to filtering, humidifying, and warming air, protecting olfactory system

Sphenoid & Frontal sinuses

producing mucus to trap pathogens, moisturize nasal passages, humidify inhaled air

Nares

external openings for air to enter and exit nasal cavity

Hard palate

rigid separation between nasal and oral cavities

Nasal concha

warms, humidifies, and filters inhaled air

Uvula

assists in preventing food/liquid entering nasal cavity

Hyoid bone

acts as an anchor for muscles that maintain upper airway

Nasal septum

divides nasal cavity into two distinct passages to facilitate proper flow of air

Vestibule

filtration of inhaled air by course hairs (vibrissae)

Diaphragm

Primary respiratory muscles of inspiration that flattens to increase volume of thoracic cavity

External Intercostals

Primary respiratory muscles of inspiration that elevates ribs, enlarging thoracic cavity

Sternocleidomastoid

Accessory respiration muscle of forced inspiration that elevates sternum

synergist for inspiration reserve volume

Scalenes

Accessory respiratory muscle of forced inspiration that elevates the first 2 ribs

Pectoralis muscles (major and minor)

Accessory respiration muscles that pull sternum anteriorly

Internal intercostals

Accessory respiration muscles of forced inspiration that elevates ribs

Internal intercostals

Accessory respiration muscles of forced expiration that draws ribs together, decreasing thoracic cavity volume

Diaphragm

Respiratory muscle of forced expiration whose slow recoil decreases the volume of the thoracic cavity

Rectus abdominus and external obliques

Respiratory muscles of forced expiration that compresses the abdomen, pushes up diaphragm, pulls lower ribs down, and decreases thoracic cavity

Elastic

Which type of cartilage allows structures to bend and recoil back to original position?

Hyaline

Which type of cartilage provides flexible support and keep respiratory passage open between breaths?

True vocal folds

wider, muscular structures produce sound as they vibrate

Pulmonary artery

carries low oxygen blood to pulmonary capillaries for gas exchange

Alveolar duct

connects respiratory duct to alveolar atrium and sacs

Pleural cavity

negative pressure here holds lung vacuumed to wall of chest

Cardiac notch

a concave space on the left lung in which the heart lies

Segmental bronchi

branch goes to areas of the lung so they have independent air, blood, and nerve supplies

Cricoid cartilage

Ring-like cartilage connecting larynx to trachea.

Corniculate cartilage

attach to vocal cord to adjust pitch of speech, loudness is affected by volume of air passing over

Hyloid bone

muscle raise this swallowing, so epiglottis covers airway, directing food and water posteriorly to esophagus

Carina

middle of tracheal cartilage, most sensitive for touch and triggering couching

Pulmonary vein

vessel that carries high oxygen blood to the left atrium of heart