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| functions of respiratory system (6) |
1. gas exchange 2. regulation of blood pH 3. Voice production 4. olfaction 5. protection against microorganisms |
| gas exchange |
respiratory system allows oxygen to enter blood & carbon dioxide to leave the blood; working with cardio system |
| regulation of blood pH |
respiratory system can alter blood pH by chaing blood carbon dioxide levels |
| voice production |
air movement past the voacl folds makes sound and speech possible |
| olfaction |
sensation of smell occurs when airborne molecules are drawn into the nasal cavity |
| protection |
respiratory system provide protection against microorganisms by preventing them from entering body & removing them from respiraotry surfaces |
| respiratory system consists of (7 parts) |
external nose, nasal cavity, pharanynx, larynx, trachea, the bronchi & the lungs |
| upper respiratory tract |
nose, pharynx and associated structures |
| lower respiratory tract |
larynx, trachea, bronchi & lungs |
| what organs are responsible for respiratory movements? |
diaphragm, muscles of the thoracic and abdominal walls |
| nose or nasus |
consists of external nose & nasal cavity |
| external nose |
consists of visible structure; cartilage plates; bridge consists of nasal bones plus extensions of the fronatal & maxillary bones |
| nasal cavity extends |
from nares (or nostrils) to the choanae (opening into the pharynx) |
| vestibule |
anterior portion of each naris (or nostril); lined with stratified squamous epithelium |
| hard palate |
a bony plate covered by mucous membrane that forms the floor of the nasal cavity; it separates the nasal cavity from the oral cavity |
| nasal septum |
partition dividing the nasal cavity into right & left parts - anterior portion is cartilage; posterior part consists of the vomer bone & the perpendicular plate of the ethmoid bone |
| deviated nasal septum occurs |
when septum bulges to one side or other |
| conchae |
resembling a conch shell - on side walls of nasal cavity - |
| meatus |
beneath each conchae is a tunnel or meatus |
| paranasal sinuses |
several bones associated with nasal cavity have large cavities within them called paranasal sinuses, which open into the sinus cavity; their purpose is to decrease weight of skull & act as resonating chambers during voice production |
| nasal cavity has 5 functions: |
1. passageway for air 2. cleans the air 3. humidifies & warms the air 4. olfactory epithelium is located in nasal cavity 5. nasal cavity & paranasal sinuses are resonating chambers for speech |
| passageway for air |
even when mouth is full of food |
| cleans air |
vestibule is lined with hairs that trap particles; nasal septum & nasal conchae have mucous membrane which traps debris |
| how do nasal cavity & nasal conchae work? |
mark ariflow more turbulent; thereby forcing air toward mucous membran lining nasal cavity |
| what is nasal cavity/mucous membrane? |
pseudostratified ciliated columnar epithelium with goblet cells; which secreate a layer of mucus; cilia sweep mucus poteriorly to the pharynx; where it is swallowed & elminated by digestion |
| nasal cavity humidifies & warms air |
moisture from mucus & from excess tears that drain into nasal cavity are added to air; also, warm blood flowing through mucous membrane warms the air |
| olfactory epithelium |
sensory organ for smell, is in superior part of nasal cavity |
| pharynx |
common opening of both the digestive and respiratory systems; receive air from nasal cavity and air, food & drink from oral cavity |
| oropharynx |
extends from soft palate to the epiglottis |
| fauces |
oral cavity opens into the oropharynx through the fauces; space between the cavity of the mouth & the pharynx |
| larynx cartilages |
6 are paired; 3 are single |
| largest cartilage in larynx? |
thyroid "shield" or Adam's apple |
| most inferior cartilage in larynx? |
cricoid "ring-shaped" forms the base of the larynx on which the other cartilages rest |
| 3rd unpaired cartilage? |
epiglottis |
| how is epiglottis different from other cartilages in larynx? |
is consists of ELASTIC cartilage [others consist of hyaline cartilage] |
| what does epiglottis do? |
attached to thyroud cartilage & projects as a free flap toward the tongue;during swallowing, it covers the opening of they larynx and prevents materials from entering it |
| superior ligament |
covered by vestibular folds also called "false vocal" folds - 2 purposes; keep food & liquids out and prevent air from leaving lungs when person holds breath |
| inferior ligament |
covered by true vocal cords also called vocal folds |
| what is glottis? |
opening between vocal folds |
| functions of larynx (3) |
1. thyroid and cricoid cartilages maintain open passageway for air movement 2. epiglottis & vestibular folds prevent swallowed material from moving into the larynx and vocal cords provide soundproduction |
| voice production |
air vibrates folds & produces sound waves |
| what produces louder sound? |
greater air pressure |
| what causes male voices to be lower? |
vocal cords are longer - it is vocal cord length & diameter which determine variation in voice |
| what determines pitch? |
frequency of vibrations; higher frequency vibrations producing higher pitched sounds |
| where are higher-pitched tones produced? |
anterior of vocal folds; progressively lower tones result when longer sections of the folds vibrate |
| movement of arytenoid & other cartilages is controlled by |
SKELETAL muscles which change the position and length of vocal folds |
| trachea |
tube shaped |
| trachea consists of (3) main components |
1. a membranous tube that consists of DENSE Regular connective tissue and 2. smooth muscle 3. 15-20 C-shaped pieces of cartilage |
| the posterior of the trachea |
a.) is devoid of cartilage b.) contains the trachelis muscle |
| what is trachealis muscle? |
elastic ligamentous membrane and bundles of smooth muscle - contraction narrows the trachea; during coughing, this action expels mucus and foreign objects. |
| mucous membrane has (3 main) |
1.pseudostratified ciliated columnar epithelium cells 2. goblet cells 3. cilia |
| smokers cause constant irritation to trachae |
1. lose regular cells 2. become moist stratified squamous epithelium instead 3. Lacking in cilia 4. lose goblet cells |
| How long is trachea? |
length of 10-12 cm, descending from the larynx to the level of the FIFTH thoracic vertebra |
| what happens at FIFTH thoracic vertebra? |
trachea divides to form main or primary bronchi - each of which extends to a lung |
| what structure actually forms the separation of the trachea? |
the CARINA is the most inferior tracheal cartilage which separates the openings into the main bronchi |
| carina contains |
mucous membrane which is very sensitive to mechanical stimulation, materials reaching the carina stimulate a powerful cough reflex |
| larynx - ligaments extend |
from arytenoids to thyroid cartilage |
| superioir ligament |
is covered by vestibular folds or false vocal folds |
| what is purpose of vestibular folds (also called false vocal folds?) |
prevents air from leaving when holding breath |
| inferior ligament |
is covered by true vocal cords or vocal folds |
| where is the opening between the tru vocal cords |
called the glottis |
| where is arytenoid? what does it mean? |
means ladle-shaped; skeletal muscles enable it to move vocal folds into position for breathing, speaking or singing |
| larynx: 3 functions |
1.) thyroid and cricoid cartilages maintain open passageway for air movement 2; epiglottis and vestibular folds prevent swallowed material from going into larynx and 3. vocal folds are primary source of sound production |
| voice production: (5) |
1. air vibrates vocal folds and produces sound waves 2. greater air pressure produces louder sound 3. variation in voice depends on vocal cord length and diameter 4. males have longer vocal cords 5. modifications are made by tongue, lips & teeth |
| trachea |
"tube shaped" |
| predmoninant cell type |
pseudostratified ciliated columnar epithelium with numerous goblet cells |
| what else lines the trachea |
cilia (in the pseudostrtified ciliated columnar epithelium) |
| smokers |
have moist stratified squamous cells - lose cilia and goblet cells |
| trachea descends |
from larynx to level of 5th thoracic vertebrae (the trachea loves the 5th dimension) |
| main (primary) bronchi |
the trachea branches to right & left to form two smaller tubes |
| carina |
cartilage - the most inferior cartilage of trachea - |
| trachea blockage 3 ways to stop |
1. Heimlich maneuver 2. intubation & 3. tracheostomy |
| heimlich maneuver |
force object out of the air passage by application of pressure to abdomen |
| intubation |
insert tube through mouth or nose through trachea - sometimes, an opening must be made to pass the tube |
| tracheostomy |
make an opening in trachea-intended to be permanent, and tube is insert |
| tracheotomy |
"tome" means incision - this is the actual cutting - should not be done in emergency because arteries, nerves, etc. lie over the anterior surface of the trachea |
| what is another name for all branches of the respiratory system? |
tracheobronchial TREE |
| what are the two divisions of the tracheobronchial tree? |
the conducting zone & the respiratory zone |
| conducting zone |
extends from trachea to samll tubes called terminal bronchioles |
| what are functions? |
conducting zone functions as a passageway for air movement and contains epithelial tissue that helps to remove debris from the air & move it out of the tracheobronchial tree |
| respiratory zone |
extends from terminal bronchioles to alveoli |
| main bronchi divide into |
lobar or secondary bronchi within each lung |
| how many lobar bronchi in right lung? |
three |
| how many lobar bronchi in left lung? |
two |
| which main bronchus is shorter, has a wider diameter and is more vertical? |
the right bronchus is shorter than the left |
| main bronchi are supported by (2) |
C-shaped cartilage and smooth muscle |
| in lobar bronchi, C-shaped cartilages are replace with |
cartilage plates; and smooth muscle forms a layer between cartilage & mucous membrane |
| as bronchi become smaller |
cartilage becomes more spares and mooth muscle becomes more abundant |
| terminal bronchiles have _______ and smooth muscle becomes _______________ |
terminal bronchioles have NO cartilage & the smooth muscle layer is prominent |
| Why is there less & less cartilage in bronchioles? |
Relaxation & contraction of smooth muscle within bronchi & bronchioles changes diameter of air passageways & volume of air |
| During exercise, what happens in airpassageways? |
diameter of bronchioles can increase, which reduces resistance to airflow |
| asthma attack |
contraction of smooth muscle in terminal bronchioles (with no cartilage in walls) results in decreased diameter, increased resistance to airflow & greatly reduced airflow; even causing death |
| bronchi are lined with (4 characteristics) |
pseudo stratified ciliated columnar |
| larger bronchioles are lined with |
ciliated simple columnar epithelium |
| terninal bronchioles |
ciliated simple cuboidal epithelium |
| what is the function of the epithelium in the conducting part of the air passageway? |
functions as a mucus-cilia escalator - which traps debris in the air & removes it from respiratory system |
| terminal bronchioles divide to form |
respiratory bronchioles |
| respiratory bronchioles divide to form even smaller respiratory bronchioles & then |
alveolar ducts |
| what are alveolar ducts like? |
long branching hallways with many open doorways |
| the "open doorways" open into |
alveoli |
| alveolar duct "walls" are composed of a succession of |
alveoli |
| alveolar ducts end as |
alveolar saces - whcih are chambers connect tot to more alveoli |
| tissue surrounding the alveoli contains |
elastic fibers |
| how man alveoli in two lungs? |
300 million !! |
| What two types of cells form the alveolar wall? |
Type I pneumocytes & Type II pneumocytes |
| Type I pneumocytes |
thin, squamous epithelial cells |
| Type II pneumocytes |
round or cube-shaped secretory cells that produce surfactant |
| alveoli (definition) |
Means "hollow cavity" small air-filled chambers which are the sites of gas exchange between the air and blood |
| alveoli are covered with |
Elastic fibers - lungs are very elastic & can expand & recoil during inspiration & expiration |
| respiratory membrane |
where gas exchange between air & blood takes place-formed by alveolar walls & surrounding pulmonary capillaries--also by respiratory bronchioles & alveolar ducts |
| what are components of respiratory membrane? |
alvolar epithelium plus the basement membrane of alveolar epithelium then there is a space, then basement membrane of capillary endothelium , then the capillary endothelium itself - enables CO2 & Oxygen to diffuse across surface |
| Lungs - principal organs of respiration and by volume |
they are among the largest organs of the body |
| lung is _____ in shape |
CONICAL (not comical)like a cone |
| the base of the lung rests on the |
diaphragm |
| the top of the lung is the |
apex - extending superiorly to the clavicle |
| which lung is larger? |
Right lung |
| how many lobes does each lung have? |
right lung-three lobes left lung - 2 lobes |
| root of the lung is called |
the hilum |
| Hilum of lung (there are other "hilums" in body) |
region on medial surface of lung where structures, such as main bronchus, blood vessels, nerves & lymphatic vessels, enter or exit the lung |
| Are lobes connected to each other? |
No-each lobe is seperated by promnent fissures & supplied by a lobar bronchus |
| Why are lobes independent? |
if one becomes diseased, it can be cut out, because major blood vessels don't cross the connective tissue partitions |
| lobes are then subdivided into |
broncho pulmonary segements - connective tissue makes each one stand alone |
| broncho pulmonary segments-in each lung? |
Right lung has 10 - left lung has nine |
| bronchopulmonary segements are subdivided into lobules |
lobules have "incomplete" connective tissue walls - supplies by bronchioles |
| thoracic cavity |
space enclosed by thoraci wall & diaphragm |
| thoracic wall |
thoracic vertebrae, ribs, costal cartilages, the sternum & associated muscles |
| muscles of inspiration |
diaphragm, external intercostals, pectoralis minor(on chest) & scalenes (neck muscles) also sternocleidomastoid) |
| muscles of expiration |
internal intercostals & abdominal muscles |
| pleural membrane |
each lung has separate pleural cavity |
| what separates the lungs? |
the mediastinum (which contains heart; pluse trache esophagus & associated structures) |
| parietal layer |
cover inner thoracic wall, superior surface of the diaphram & and the mediastinum |
| where is parietal layer continuous with the visceral layer? |
they connect at the hilum |
| visceral pleura |
covers surface of lung & fissures between lobes |
| pleural fluid two things: |
1.lubricates as lungs & thorax changes shape during respiration 2. hold the parietal & visceral pleural membranes together - like glass pieces with water - they will slide past each other but you can't separate them |
| blood supply |
1. pulmonary circuit 2. systemic circulation and 3. anatomic shunt |
| pulmonary circulation |
deoxygenated blood flows from the right ventricle to the pulmonary arteries to plumonary capillaries, become oxygenated, and returns to the heart through plumonary veins. |
| systemic circulation - for the lungs |
bring oxygenated blood to the tissues of the bronchi down to the respiratory bronchioles; oxygenated blood flows from the thoracic aorta through bronchial arteries to capillaries, where oxygen is released; then deoxygenated blood returns to the heart thro |
| anatomic shunt |
results when deoxygenated blood from bronchi mixes with blood in the pumonary veins (normal) |
| "Shunted" blood |
blood that is not completely oxygenated |
| physiologic shunt |
shunted blood that pas through pumonary capillaries but does not become fully oxygenated - occurs during heart attack or asthma attack |
| lymphatic supply (two sources) |
1) superficial 2.) deep |
| superficial lymphatic supply |
"superficial" but still meaningfull-drains visceral pleura & superficial lung tissue-exits lung at hilum |
| deep lymphatic vessels |
follow bronchi & bronchioles-also exits lung at hilum |
| do alveoli have lymph? |
NO |
| how does dirt & carbon get out of lungs? |
phagocytic cells within lungs eat them, move them to lymphatic vessels - older people can have grey lungs if they live in polluted city |
| ventilation |
process of moving air into & out of the lungs |
| general gas law |
Pressure of gas is inversely proportional to volume (the greater the volume, the less pressure) Boyle's Law |
| Dalton's Law |
partial pressure of a gas in a mixture of gases is the percentage of the gas in the mixture times the total pressure of the misture of gases |
| why is dalton's law important? |
gases move from areas of higher to areas of lower pressure - maintaining partial pressure differences (such as the difference between oxygen & carbon dioxide) ensure gas will move |
| Henry Law - re: gas dissolved in liquid |
gas does not dissolve easily in liquid; however carbon dioxid is 24 times more soluble than oxygen--CO2 passes out through respiratory membrane easier than oxygen |
| external respiration |
gas exhcnage between air in lungs & blood |
| internal respiration |
gas exchange between blood & tissues |
| Pulmonary ventilation is explained by |
Pressure differences between atmosphere & pressure inside lungs |
| what is atmospheric pressure (to respiratory physiologists) |
P(with B subscript) always expressed as "zero" even if on a mountain or at sea level |
| what is alveolar pressure: |
P (subscript alv) pressure inside an alveolus |
| quiet breathing - what is barometric pressure & alveolar pressure at END of expiration? |
they are equal |
| during inspriation |
inspriatory muscles INCREASE VOLUME of lungs & alveolar |
| what happens to alveolar pressure during inspiration?? |
as VOLUME INCREASES - pressure DECREASES - falling to -1cm H2O |
| what happens at end of inspriation? |
alveolar pressure becomes equal to barometric air pressure (because enough air has come into lungs) |
| during expiration |
volume of thorax DECREASES, therefore alveolar volume decreases--this increases the pressure inside the alveolar to 1 cam H20 - air flows out of lungs because pressure is greater inside the lungs (and gases always flow from greater to lesser pressure) |
| why don't the lungs collapse when all the air rushes out??? |
because of lung recoil |
| lung recoil occurs because of two factors: |
1.) elastic recoil & 2. surfactant |
| elastic recoil |
keeps alveoli from collapsing - have elastic fibers woven throughout alveoli (Like a balloon!!) |
| surfactant |
like a bubble, the lung produces lipoprotein molecules (Type II pneumocytes) which reduce water surface tension |
| water surface tension |
water molecules produce force from polarity (such as when spiders walk on water) - surfactant reduces this "pull" which would collapse alveoli when air is leaving |
| respiratory distress syndrome |
also called hyaline membrane disease |
| hyaline membrane disease occurs |
in infants with less than 7 months gestation aga |
| surfactant is produced after 7 months of age |
therefore, the lungs collapse in premature infants - Mom is given steroid injection -or they try to stop labor |
| pleural pressure |
P subtext pl - pressure in the pleural cavity |
| when pleural pressure is LESS than alveolar pressure |
alveoli tend to expand |
| in normal breathing, pleural pressure is slightly less than avleolar pressure |
pleural pressure is -5 cm H2O & alveolar pressure is ) cm H20 |
| why is pleural pressure lower? |
"suction effect" of fluid removal by lymphatic system & lung recoil |
| why don't deflated lungs pull away from thoracic wall? |
because pleural fluids holds visceral & parietal pleurae together (like glass pieces with water in between) |
| lungs collapse because of |
knife or gunshot wound-air is introduced into pleural space |
| what is medical term for introduction of air into pleural cavity? |
pneumo thorax |
| pneumo- |
presence of air or gas |
| what happens in pneumothorax? |
bond between 2 pleural layers is broken - there is nothing to counteract lung recoil |
| tension pneumothorax |
pressure within thoracic cavity is higher than barometric air pressure; causing dangerous increase in pressure that can comppress blood vessesl & affect flow of blood to the heart |
Ch.18 LTI-MA 509
