respiratory system
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Respiratory system. Enduring understanding: The structure of organs affect their function. Essential Question: How do we breathe?. Functions of respiratory system: Gas exchange- oxygen to the blood carbon dioxide out of the blood. organs involved in respiratory system. Nose: - PowerPoint PPT PresentationTRANSCRIPT
Respiratory system
Enduring understanding:
The structure of organs affect their function.
Essential Question:
How do we breathe?
Functions of respiratory system:
Gas exchange-oxygen to the bloodcarbon dioxide out of the
blood
organs involved in respiratory system
Nose:-external nares = nostrils-nasal cavity-nasal septum - divides right and left half-conchae - three lobes - increase surface area
-increase air turbulence-mucous covered-trap particles so don't go to
lungspalate - partition between nasal
and oral cavity- hard palate - bone-soft palate - tissue
conchae
problem with nose:-rhinitis - inflammation of nasal mucosa
-cause - cold viruses, allergens- sinusitis - sinus inflammation
-passageways to sinuses are blocked or infected
Pharynx (throat):-passageway for food
and air-auditory tubes drain
into nasopharynx-tonsils located here (immune sys)
-pharyngeal tonsil (adenoid)-palatine tonsil-lingual tonsil
problem: tonsillitis - inflammation of tonsils(remove pharyngeal and palatine
tonsils)
nasopharynx
oropharynx
laryghgopharynx
pharyngeal tonsil
palatine tonsil
lingual tonsil
Larynx (voice box):-air and food go through-inferior to pharynx-thyroid cartilage = Adam's apple-epiglottis at top
-covers trachea when swallowing
food-cough reflex
-doesn't work when unconscious
http://www.yorku.ca/earmstro/journey/images/larynx.gif
looking down from top
http://www.aic.cuhk.edu.hk/web8/Hi%20res/Larynx%201.jpg
vocal folds
glottis
Trachea (windpipe):
http://www.fotosearch.com/LIF116/trachea/
-lined with ciliated mucosa-propels mucus-catches dust particled-inhibited by smoking
-C rings of hyaline cartilage-support-allow food to be swallowed in
esophagus
-Heimlich maneuver
Tracheostomy - provides alternate route for air if trachea blocked
http://www.fotosearch.com/LIF139/nu120015/
Primary Bronchi:-branches at end of trachea-run obliquely-right = wider, shorter and straighter, food usually gets lodged here-air entering this area is warm, cleansed and moist-goes to smaller subdivisions
http://www.medidoktor.hu/images/bronchi-bronchioles-alveoli.jpg
Lungs:
http://www.lungusa.org/atf/cf/%7B7A8D42C2-FCCA-4604-8ADE-7F5D5E762256%7D/clean_lung_hr.jpg
-paired-in thoracic cavity-visceral pleura - covering on lungs-parietal pleura - walls of thoracic cavity
-pleural fluid in between-Pleurisy = inflammation of pleura
-due to decreased fluid -painful
- or increased fluid -creates pressure on lungs-less painful
Bronchioles:
-smallest branches, farthest from bronchi-have cartilage in walls
Alveoli:-air sacs-site of gas exchange-millions of these in lungs-rest of tissue = stroma
-elastic connective -give "sponginess"
http://academic.kellogg.cc.mi.us/herbrandsonc/bio201_McKinley/f25-9a_bronchioles_and__c.jpg
SEM of Human lung tissue
-surface area of lung tissue of healthy man = 50-70 square meters
-in alveoli - have macrophages that pick up bacteria, carbon particles and debris
-have surfactant = lipid material produced by alveolar cells -lower surface tension of water lining the cells so that
the alveoli do not collapse between breaths
-premie babies (before 28-30 weeks) do not make this yet
-called infant respiratory distress syndrome
Alveolar membrane
Mechanics of breathing:-"Volume changes lead to pressure changes which lead to flow of gases to equalize pressure"
Inspiration:-diaphragm and external intercostals contract
-diaphragm moves inferiorly and flattens-thoracic cavity increases in size-lungs attached to thoracic cavity stretch-gases in lungs spread to fill space, decreases gas pressure -creates a vacuum to suck air in-when internal pressure = external pressure inspiration stops
Expiration:-depends on elasticity lungs rather than muscles-inspiratory muscles relax-ribcage retracts-lungs recoil-volume decreases and gas pressure increases above atmospheric pressure-gases flow out
nonrespiratory movements:-due to reflexes
1. cough- clears lower passageways
2. sneeze-clears upper respiratory passageways
3. crying-emotion mechanism
4. laughing-emotion mechanism
5. hiccups-spasms of diaphragm, irritation of diaphragm or phrenic nerve
6. yawn-ventilates all alveoli
Respiratory volumes:Normal breathing ~ 500 ml. = tidal volume (TV)
inspiratory reserve volume (IRV) = amount of air taken in forcilby over the tidal volume ~ 2100-3200 ml.
expiratory reserve volume (ERV) = amount of air forcibly exhales after tidal volume ~ 1200 ml
residual volume = air left in lungs after ERV blown out-keeps alveoli inflated-allows continued gas exchange
vital capacity = total amount of exchangable air = TV + IRV + ERV
Dead space volume - air that never reaches alveoli, is in conducting pathways
measure respiratory volumes with respirometer
Problems with respiratory system:
1. hypoxia - lack of oxygen to tissues-bluish tinge to skin-due to anemia, pulmonary disease or impaired
blood circulation
2. carbon monoxide poisoning-if present hemoglobin prefers this over oxygen to
carry-due to fires, faulty furnaces-kills victims quietly, no signs
3. emphysema:-walls of alveoli break becoming larger and larger
chambers-decreased gas exchange-fibrosis of tissue-barrel shaped chest due to overinflation of lungs
4. Bronchitis:- inflammation of bronchi (mucosa inflamed)-produce large quantities of mucus-can lead to pneumonia
5. cystic fibrosis:-lethal genetic disease (1 in 2400 children)-faulty CFTR protein - impairs regulation of Cl
channels-oversecretion of thick mucus - clogs passageways-can lead to infections
7. Asthma:-chronic inflammation of bronchial passageways-can be triggered by allegies, stress, exercise-leads to constriction of airways and increase mucus
production-can cause death if not treated-symptoms: coughing, wheezing
8. Lung cancer:-1/3 of all deaths in U.S.-aggressive, metastasizes quickly-low survival rate because diagnosed so late-cause - smoking, exposure to asbestos-treatment - removal of diseased lung
radiation/chemotherapy
nonsmokersmoker