Respiratory System

Respiratory system

Function: breathing, gas exchange, gas conditioning, sound production, olfaction, and defense

Upper respiratory tract

Includes: nose, nasal cavity, pharynx, larynx

Lower respiratory tract

Includes: trachea, bronchi, bronchiole, alveolar ducts, alveolar sacs, alveoli

Nasal cavity

Location: continuous posteriorly with the nasopharynx via paired openings choanae

Structure: lined with pseudostratified ciliated columnar epithelial tissue with goblet cells,

Function: filtration, conditioning, olfaction, provides resonance of sound for sound production

External nares

Location: inferior aspect of the external nose

Structure: 2 piriform pear shaped openings, cartilage, skin, lined with hair, small muscles

Function: entry point for air, initial filtration, olfaction, directing air flow, facial expression

Nasal conchae

Location: lateral walls of nasal cavity

Structure: 3 paired bony projections,

Function: increase air turbulence

Paranasal sinuses

Location:

Structure: 4 bones of the skull, frontal ethmoid sphenoid and maxillary sinuses, lined with pseudostratified ciliated columnar epithelial tissue

Function: decrease skull bone weight, warm and humidify inhaled air, provide resonance to speech

Nasopharynx

Location: posterior to nasal cavity

Structure: pseudostratified columnar epithelial tissue

Function: equalize air pressure in the middle ear

Pharyngeal tonsil

Location: lateral walls of the nasopharynx

Structure: mass of lymphoid follicles, contain B and T cells, pseudostratified ciliated columnar epithelial tissue, surface folds

Function: immune defense

Larynx

Location: anteroinferiorly to the laryngopharynx and superior to trachea

Structure: 9 pieces of cartilage

Function: serves as a passage way for air, prevents ingested material from entering trachea, produces sound for speech, assists in increasing pressure in the abdominal cavity, participates in sneezing and coughing

Thyroid cartilage

Location: lateral and anterior walls of the larynx, Adam’s Apple, anterior part of the neck, superior to thyroid gland and trachea, inferior to hyoid

Structure: largest laryngeal cartilage, shaped like a shield, hyaline cartilage

Function: protects vocal cords, voice production, airway support

Cricoid cartilage

Location: anterior part of the neck, inferior to thyroid cartilage, superior to trachea ring

Structure: hyalin cartilage, the only complete ring of laryngeal cartilage

Function: maintenance of airway latency, foundation for the larynx, voice production, protection

Epiglottis

Location: in the pharynx at the top of the larynx

Structure: elastic cartilage, leaf shape

Function: protect the airway from entry of food and liquid during swallowing

Arytenoid cartilage

Location: posterior part of larynx, superior surface of the cricoid cartilage

Structure: small 3 sided pyramidal structure, hyaline cartilage

Function: voice production and airway protection

Cuneiform cartilage

Location: embedded within the aryepiglottic folds, superior and anterior to the corniculate cartilage

Structure: small elongated club shaped, elastic cartilage

Function: structural support, airway protection

Corniculate cartilage

Location: at the apex of each arytenoid cartilage, posterior part of the aryepiglottic folds, medial and inferior to cuneiform cartilage

Structure: small conical horn shape, elastic cartilage

Function: support, airway protection

Ventricular folds/ false vocal cords

Location: inside the larynx, superior to the true vocal cords

Structure: paired thick muscular folds

Function: protection and support

Glottis

Location: middle region of the larynx

Structure: composed of the true vocal cords and rima glottidis

Function: voice production and regulation of airflow for breathing

Vocal folds/true vocal cords

Location: within the larynx, posteriorly attach to the vocal process of the arytenoid cartilage, inferior to ventricular folds

Structure: paired, stratified squamous epithelial tissue

Function: voice production

Rima glottis

Location: between true and false vocal cords within the larynx

Structure: an opening

Function: regulation of airflow and voice production and airway protection

Hyoid

Location: anterior part of the neck, superior to thyroid cartilage

Structure: bone, small U shaped

Function: support for the tongue, swallowing, speech, attachment

Trachea

Location: neck and upper chest, begins at larynx, ends at bronchi, anterior to the esophagus

Structure: tube, pseudostratified ciliated columnar with goblet cells epithelial tissue, contains tracheal glands, tracheal ring of hyaline cartilage, retroperitoneal, no muscularis mucosa

Function: conducting air, participates in cough reflex

Tracheal rings

Location: trachea

Structure: hyaline cartilage, C shape

Function: maintains trachea airway and support

Trachealis muscle

Location: posterior side of the trachea

Structure: smooth muscle

Function: regulate diameter of the trachea and allow for expansion of the esophagus

Primary bronchi

Location: branch off trachea

Structure: hyaline cartilage and smooth muscle, pseudostratified ciliated columnar with goblet cells epithelial tissue

Function: supply the lungs

Secondary bronchi

Location: branch off primary bronchi

Structure: hyaline cartilage and smooth muscle, pseudostratified ciliated columnar with goblet cells epithelial tissue

Function: supply lobes

Tertiary bronchi

Location: lungs

Structure: hyaline cartilage and smooth muscle, pseudostratified ciliated columnar with goblet cells epithelial tissue

Function: supply secondary bronchi

Bronchioles

Location: lungs branching off tertiary bronchi

Structure: no cartilage, smooth muscle, smaller conducting airways of bronchial tree, simple ciliated columnar → simple cuboidal epithelial tissue

Function: conduct air

Alveolar ducts

Location: lungs

Structure: tiny airways that branch off bronchioles, no cartilage, no smooth muscle, simple squamous epithelial tissue

Function: gas exchange

Alveolar sacs

Location: lungs

Structure: simple squamous epithelial tissue

Function: gas exchange

Alveoli

Location: lungs

Structure: tiny microscopic air sacs, no cartilage, no smooth muscle, simple squamous epithelial tissue

Function: gas exchange

Type I alveolar cells

Location: alveoli of the lungs

Structure: simple squamous epithelial tissue

Function: gas exchange

Alveolar macrophages

Location: alveoli of the lungs

Structure: macrophages of the lungs

Function: phagocytosis

Type II alveolar cells/septal cells

Location: alveoli of the lungs

Structure: cuboidal epithelial cells

Function: produce surfactant which reduces surface tension

Pulmonary artery

Location: originates from the right ventricle of the heart

Structure: divides into right and left, 3 tunics

Function: transport deoxygenated blood from the heart to the lungs

Pulmonary veins

Location: originates in the left and right lobes of the lungs emerging from the hilum ending in the left atrium

Structure: 3 tunics, 4 superior and inferior left and right,

Function: transport oxygenated blood from the lungs to the heart

Lungs

Location: thoracic cavity

Structure: 5 lobes, 3 on the right 2 on the left

Function: oxygen uptake, carbon dioxide removal

Visceral pleura

Location: surface of the lungs

Structure: mesothelium = simple squamous epithelial tissue and areolar connective tissue

Function: frictionless movement during respiration and protection

Lung lobes

Location: thoracic cavity

Structure: right lung = 3 parts = superior middle and inferior, left lung = 2 lobes = superior and inferior

Function: oxygen uptake, carbon dioxide removal

Cardiac notche

Location: anterior border of the superior lobe of the left lung

Structure: indentation

Function: anatomical accommodation for the heart

Hilus/hilum

Location: medial surface of each lung

Structure: wedge shape depression

Function: central point for lungs functions for a collection of structures

Root

Location: medial surface of each lung

Structure: collection of structures that pass into the lungs: bronchi, pulmonary artery, pulmonary vein, nerves, lymphatic vessels

Function: lifeline for the lung