respiratory system

Define ventilation

breathing: consists of inspiration and expiration

define external respiration

process of gas exchange that occurs in the lungs

define internal respiration

gas exchange b/w blood and tissues

define cellular respiration

metabolic processes in which ATP is produced

Distinguish between the conducting zone and the respiratory zone of the respiratory system. Anatomically, what is the first structure in the respiratory zone?

conducting zone: all of the respiratory passageways from the nose to the respiratory bronchioles

• conduits for air to reach gas exch sites

• cleanse, humidify, and warm incoming air

respiratory zone: actual site of gas exchange

• composed of the respiratory bronchioles (first structure in the respiratory zone), alveolar ducts, and alveoli

What are the functions of the larynx? What structural features support these functions?

function:

• provide a patent/open airway

• acts as a switching mechanism to route air and food into the proper channels

• voice production (houses vocal cords)

structural features:

• arytenoid cartilages anchor the vocal folds

• the epiglottis tips to cover the laryngeal inlet during swallowing to switch from air route to food route

• vocal ligaments attach the arytenoid cartilages to the thyroid cartilage and form the true vocal cords

• the glottis includes the medial opening between the vocal folds, which allows air to pass through

• vestibular folds help to close the glottis when we swallow

• epithelium of the larynx is lined w/ stratified squamous epithelium that contacts food

• below the vocal folds is a pseudostratified ciliated columnar type that filters dust, moving mucus away from the lungs

Describe the general location and function of thyroid cartilage

location:

• anterior midline of the neck

• formed by the fusion of two cartilage plates at the midline

function: protect and support the vocal cords

Describe the general location and function of cricoid cartilage

location:

• inferior to the thyroid cartilage; perched atop and anchored to the trachea inferiorly

• ring shaped

function:

• maintains airway patency

Describe the general location and function of epiglottis

location:

• composed of elastic cartilage and is almost entirely covered by a taste bud-containing mucosa

• extends from the posterior aspect of the tongue to its anchoring point on the anterior rim of the thyroid cartilage

function:

• "guards" the airways

• during swallowing, the epiglottis tips to cover the laryngeal inlet

Describe the general location and function of glottis

location:

• vocal cords the medial opening b/w them through which air passes

function:

• opens into the windpipe and is responsible for the production of sound

Describe the general location and function of arytenoid cartilage

location:

• posterior side of the larynx and inferior to the corniculate cartilage

function:

• anchors the vocal folds.

Describe the general location and function of vestibular folds (false vocal cords)

location:

• superior to the vocal folds

• pair of mucosal folds

function:

• no direct part in sound production but help close the glottis when swallowing

Describe the general location and function of vocal folds (true vocal cords)

location:

• vocal ligaments (composed of elastic fibers) lie under the laryngeal mucosa on each side

• form the core of the mucosal folds

• appear pearly white b/c lacking blood vessels

function:

• vibrate to produce sound as air rushed up from the lungs

Of what type of cartilage are the thyroid cartilages composed?

hyaline cartilage

Identify the structures comprising the upper respiratory system.

external nose, nasal cavity, paranasal sinuses, and pharynx

What are the general functions of the nostrils and nasal cavity? What structural features support these functions?

functions:

• produces mucus

• filters, warms, and moistens incoming air; also reclaims heat and moisture during exhalation

• movement of mucosa for swallowing and digestion

• resonance chamber for speech

• receptors for sense of smell

structure:

• the nasal septum divides the nasal cavity; formed anteriorly by the septal cartilage and posteriorly by the vomer bone and perpendicular plate of the ethmoid bone

• the olfactory mucosa lines the slitlike superior region of the nasal cavity and contains smell receptors in the olfactory epithelium

• seromucous nasal glands contain mucus-secreting mucous cells and serous cells that secrete a watery fluid containing enzymes w/ lysozyme and defensins

• nasal conchae increase mucosal surface area exposed to air and enhance air turbulence in the cavity - deflecting heavier, nongaseous particles onto the mucus-coated surfaces, where they're trapped

Name and describe the location of the three levels of the pharynx. How does the epithelial lining change from one level of the pharynx to another? How does the change in epithelium support the function of each level of the pharynx?

1. nasopharynx

• most superior

• posterior to the nasal cavity, inferior to the sphenoid, superior to the level of soft palate

• serves only as an air passageway

• pseudostratified ciliated epithelium propels mucus where the nasal mucosa leaves off

2. oropharynx

• posterior to the oral cavity; continuous w/ it via isthmus of fauces

• both swallowed food and inhaled air pass through it

• stratified squamous epithelium that accommodates increased friction and chemical trauma

3. laryngopharynx

• directly posterior to the larynx, where respiratory and digestive pathways diverge, extending to inferior edge of the cricoid cartilage

• continuous w/ the esophagus posteriorly

• passageway for food and air

• stratified squamous epithelium

Identify and describe the three layers of the tracheal wall.

1. mucosa

• goblet cell-containing pseudostratified epithelium that propels debris-laden mucus to the pharynx

• epithelium rests on lamina propria w/ rich elastic fiber supply

2. submucosa

• CT layer deep to the mucosa