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Flashcards in Respiratory System Deck (35):

Functions of Respiratory System

*main: breathing - involves inhalation & exhalation

-Gas exchange
-Gas conduction (warmed, humidified, cleansed)
-Sound production
-Olfaction (olfactory epithelium)
-Defense (i.e. hairs w/in) nostrils - brisae)


Division of Respiratory System;


Anatomically; Can be divided into tracts:
i) Upper respiratory tract (nose to pharynx)
ii) Lower respiratory tract (larynx down to and including the lungs)

Functionally; the system can be divided into functional zones
i) Conducting zones (passageways that transport air; nose to terminal bronchioles)
ii) Respiratory zone: small airways dedicating to gas exchange (respiratory bronchioles to alveoli)


Upper Respiratory Tract

Comprised of;
-nose and nasal cavities
-paranasal sinuses

*are all part of the conducting portion of respiratory system


Lower Respiratory Tract

Comprised of:



-Is main conducting airway for inhaled air
-supported superiorly by paired nasal bones (form bridge of nose)
-Supported anteroinferiorly from the bridge by fleshy, cartilagenous dorsum nasi


Nasal Cavity & associated structures;-

-conchae, nasal meatus, vestibule

-begins as internal component of nose, ends as openings to nasopharynx (CHOANAE)
-nasal septum divides nasal cavity into right & left portions
-shell like bony scrolls form lateral walls (superior, middle & inferior nasal conchae)
-conchae = condition air in the spaces between (nasal meatus)
-anterior region of nasal cavity = vestibule
-lined w/ psuedostratified ciliated columnar epithelium
-most superior part = olfactory epithelium


Paranasal sinuses - function & name (4)

-Four bones of the skull contain paired air sacs = paranasal sinuses
-make bones lighter in weight



Pharynx - features

-3 regions

*Shared by two organ systems - digestive & respiratory*
aka throat
-funnel shaped
-lined by mucosa
Divided into 3 regions;-



-most superior region
-conducts air
-lined w/ psuedostratified ciliated columnar epithelium
-Continous w/ nasal cavity & superior to soft palate
-opening of auditory tubes found in lateral walls
-posterior nasopharynx wall houses single pharyneal tonsil



-begins at end of soft palate & ends at lvl of hyoid bone
-opening of oral cavity into oropharynx = fauces (throat)
-has 2 pairs of muscular arches on lateral walls
-conducts air & serves as passageway for food/air
-non-keratinized stratified squamous epithelium (strong enough to w/stand abrasion)
-lymphatic organs: First line of defense when foreign materials digested



-Starts inferior to hyoid bone - continuous w/ larynx and esophagus
-Same function & structure as oropharynx


Lower Respiratory Tract (conducting portion)

Comprised of;-
-bronchioles - terminal



-(aka voicebox)
-continuous w/ larynopharynx
-supported by framework of cartilages, ligaments & muscles
FUNCTIONS: passageway for air, prevents ingested matter from entering, sound for speech, assist. in increasing pressure in ab. cavity, participates in sneeze & cough reflex
3 major cartilages:
1. Thyroid Cartilage
2. Cricoid cartilage
3. Epiglottis


Major Cartilages of the larynx; Thyroid Cartilage

-largest cartilage
-has anterior & lateral wall only (shield shaped)
-V shaped anterior projection = laryngeal prominence (Adam's Apple)
-usu. larger in males due to testoterone's influence on cartilage growth
-composed of hyaline cartilage


Major Cartilages of the larynx: Cricoid Cartilage

-inferior to thyroid cartilage
-complete ring-shaped cartilage
-maintains openness of windpipe
-composed of hyaline cartilage


Major cartilages of the larynx: Epiglottis

-Spoon shaped cartilage that projects superiorly into pharynx
-swallowing causes epiglottis to close opening - prevents materials entering lower respiratory tract
-made of more elastic elastic cartilage


Sound Production

-vocal folds found in larynx comprised of vocal ligaments covered by mucous membrane
-opening b/w vocal folds = rima glottidis
-vocal folds + rima glottidis = glottis
-when air forced through rima glottidis, causes vibration of vocal folds = sound



aka windpipe
-inferior to larynx, superior to primary bronchi, anterior to oseophagus
-12-14cm in length
-supported by C-shaped tracheal cartilages (to help maintain & keep trachea open)
-mucosa lined w/ psuedo-stratified columnar epithelium & mucin-secreting goblet cells (helps humidify air & trap debris)
-bifurates into 2 smaller tubes = bronchi
-ridge where they separate = carina


Bronchial Tree

-highly branched system
-begin w/ primary bronchi & end w/ terminal bronchi
-belong to conducting portion
-reside w/in substance of lungs
-branches into left & right primary bronchi @ carina
-right wider & more vertical - divides into 3 secondary bronchi
-left divides into 2 secondary bronchi
-secondary bronchi divide into 8-10 tertiary bronchi (or segmental/lobar)


Patterns observed in structure as Bronchial tree divides

-incomplete rings of cartilage becomes smaller and less numerous
-all bronchi lined w/ pesudostratified columnar epithelium to trap debris
-bronchi branch into bronchioles - these lack rings and lined with simple columnar or simple squamous epithelium



-less than 1 mm in diameter
-walls composed of relatively thick layer of smooth muscle
-contraction of muscles = narrowing of brionchioles = bronchoconstriction (aka asthma)
-relaxation of muscles = bronchodilation
-branch into terminal bronchioles - are last part of of conducting portion


Respiratory Portion of respiratory system

-respiratory bronchioles
-aveolar ducts & sacs
-pulmonary alveoli


Structures between terminal bronchioles -> alveolus

-Terminal bronchioles branch into respiratory bronchioles
-respiratory bronchioles branch into alveolar ducts
-alveolar ducts end w/ small saccular outpocketings called alveoli
-thin walls of alveolus is where respiratory gases diffuse


Alveolus - 2 types of cells

-alveolar macrophages

Walls formed by 2 types of cells;-
-Alveolar type 1 cells: simple squamous (majority - is where gas exchange occurs)
-Alveolar type 2 cells: almost cuboidal (produce pulmonary surfactant - decreases surface tension w/in alveolus and prevents collpase of alveoli

-alveolar macrophages: engulf any microorganism or particulate matter that makes it way into alveolus


Respiratory Membrane - function

-3 components

-Is the diffusion barrier across which respiratory gases exchanged between blood and air in alveoli
Consists of:
-plasma membrane of type 1 alveolar cells
-plasma membrane of capillary cell
-fused basement membrane of both cells


Pleura - what it is

-cell type

-visceral vs parietal

-pleural cavity

-Pleura = serious membrane that lines outer lung surface & adjacent thoracic wall
-formed from simple squamous epithelium (called mesothelium)
VISCERAL PLEURA: outer surface of lung
PARIETAL PLEURA: interior thoracic wall, lateral mediostinum and superior surface of diaphragm

-secrete serious fluid - for lubrication & tension b/w pleural membranes
Pleural cavity: space b/w visceral and parietal cavities




-conical in shape - base inferiorly rests on diaphragm, apex = superior most portion
-apex projects slightly superior and posterior to clavicle
-costal surface comes in contact w/ ribs
mediastinal surface housed concaver region = hilum (is where bronchi, pulmonary vessels, lymphatic vessels & nerves pass into and out of lungs
-hilum and its structures = root of lung


Left lung vs right lung

Left Lung:
-slightly smaller (due to heart projecting)
-heart makes indentation on medial surface = cardiac impression/cardiac notch
-oblique fissure - divides lungs into 2 LOBES (superior & inferior)
Right Lung:
-2 fissures (oblique & horizontal)
-divided into 3 LOBES (superior, middle & inferior)


Blood supply to & from lungs

-Pulmonary and bronchial circulation

-pulmonary circulation conducts blood to and from gas exchange surfaces of the lungs
-Bronchial circulation is a component of systemic circulation that delivers blood directly to and from bronchi and bronchioles
-is what actually oxygenates lungs


Pulmonary Ventilation - what is it

-what happens during inhalation & exhalation in terms of;

-volume, pressure and air flow

(AKA breathing)
-Is the movement of air into and out of respiratory system
-movement of gases follows Boyle's law (pressure)
-volume of thoracic cavity increases
-intrapulmonary pressure decreases
-air flows into lungs
Exhalation: opposite of inhalation


Thoracic wall dimension changes during respiration

-during inhalation & exhalation, thoracic cavity changes in 3 dimensions;

-Vertically: movement of diaphragm
-Lateral: rib cage is elevated and thoracic cavity widens (or rib cage depresses)
-Anterior/posterior: inferior position of sternum moves anteriorly and then posteriorly


Muscles of Respiration

-External intercostals: elevates ribs during inhalation
-Internal intercostals: depresses ribs during forced exhalation
-Diaphragm: major muscle of respiration



-Internal dome-shaped muscle that physically separates thoracic and abdominopelvic cavities
-possesses central tendon - all of its fibres converge (has holes that allows diff. structures to pass through)
-Contraction of diaphragm causes a depression of muscle, thus increasing the vertical dimensions of thoracic cavity


4 continuous and simultaneous process of gas exchange

1. Pulmonary ventilation: movement of respiratory gases b/w atmosphere and alveoli of lungs
2. Alveolar gas exchange: exchange of resp. gases b/w alveoli and blood
3. Gas transport: transport of resp. gases w/in blood b/w lungs and systemic cells of body
4. Systemic gas exchange: exchange of gases b/w blood and systemic cells of body


Mechanisms of breathing

Several integrated aspects;
-specific actions of skeletal muscles
-volume changes w/in thoracic cavity
-pressure changes from volume changes
-pressure gradients
-volumes and pressures involved in breathing