respiratory system Flashcards
respiratory zone
site of gas exchange in respiratory bronchioles, alveolar ducts, alveolar sacs, alveoli
conducting zone
conduits to gas exchange sites
includes all other respiratory structures
cleanses, warms, humidifies air
nose
provides an airway for respiration
moistens and warms entering air filters and cleans inspired air
serves as resonating chambers for speech
houses olfactory receptors
respiratory mucosa
pseudostratified ciliated columnar epithelium
mucous and serous secretions contain lysozymes and defensins
cilia move contaminated mucus through throat
inspired air warmed by plexuses of capillaries and veins
sensory nerve endings trigger sneezing
nasal conchae
enhance air turbulence
during inhalation, filter, heat, and , moisten air
during exhalation reclaim heat and moisture
paranasal sinuses
secrete mucus
warm and moisten air
larynx
provides patent airway
routes air and food into proper channels
voice production
houses vocal folds (true vocal folds)
cartilages of larynx
thyroid
cricoid
arytenoid (2)
corniculate (2)
cuneiform (2)
epiglottis
glottis
opening b/w vocal folds
voice production
folds vibrate to produce sound as air rushes up from lungs
trachea
mucosa ciliated pseudostratified epithelium w/ goblet cells
submucosa CT w/ seromucous glands
adventitia outermost layer of CT; encases C shaped rings of hyaline cartilage
secondary bronchi
3 on right
2 on left
each supplies one lobe of lung
terminal bronchi
smallest
less than 0.1 mm diameter
alveoli
site of gas exchange via simple diffusion
simple squamous epithelium (type I)
cuboidal epithelium (type 2)-> secrete surfactant and antimicrobial proteins
alveolar pores
equalize air pressure throughout lung
left lung
smaller than right
contains cardiac notch
separated into superior and inferior lobes via oblique fissure
right lung
superior, middle, inferior lobes separated by oblique and horizontal fissures
pleural fluid
provides lubrication and surface tension
assists in expansion and recoil
intrapulmonary pressure
aka intra-alveolar pressure
eventually always equalizes w/ Patm
diaphragm contracts, leading to decrease in pressure during inhalation; allows for more space so lungs can fill w/ air
intrapleural pressure
pressure in pleural cavity
always a negative pressure (4 mmHg lower than intrapulmonary pressure->creates suction)
transpulmonary pressure
keeps airways open
Ppul-Pip
lungs collapse if Pip=Ppul or Patm
prevents lungs from collapsing
boyle’s law
reduced size=increased pressure
P1V1=P2V2
inspiration
diaphragm and external intercostals contract pulling ribs downwards
active process
expiration
passive process
forced inspiration
can be due to vigorous exercise or COPD
scalenes, sternocleidomastoid, pectoralis minor contract
forced expiration
active process
abdominal (oblique and transverse) and internal intercostals contract
flow
is equal to delta P (2 mmHg or less) over R
surface tension
attracts liquid molecules to one another at gas-liquid interface
resists any force that tends to increase SA of a liquid
water-high surface tension of alveolar walls reduces them to smallest size
surfactant
lipid and protein complex produced by type 2 alveolar cells
reduces surface tension of alveolar fluid and discourages alveolar collapse
infant respiratory distress syndrome
insufficient quantity of surfactant in premature infants
alveoli collapse after each breath
pulmonary ventilation
aka breathing
moving air into and out of lungs
done by respiratory system
external respiration
O2 and CO2 exchange b/w lungs and blood
done by respiratory system
internal respiration
O2 and CO2 exchange b/w systemic blood vessels and tissues
done by circulatory system (also transports O2 and CO2 in blood)
pressure
decreases during inhalation and increases during exhalation
volume
increases during inhalation and decreases during exhalation
bronchi->bronchioles
smaller diameter
less cartilage, more SM
epithelium changes from columnar to cuboidal (loss of cillia)
increase in blood CO2 levels
H+ levels increase
increases breathing rate to expel CO2
decrease pH
air flow
external nares->nasal cavity->internal nares->nasopharynx->oropharynx->laryngopharynx->larynx->trachea->primary bronchus->secondary bronchus->tertiary bronchus->bronchiole->terminal bronchiole->respiratory bronchiole->alveolar duct->alveolar sac->alveolus
total lung capacity
TV+IRV+ERV+RV
max amount of air contained in the lungs after a max inspiratory effort
IRV
IC-TV
amount of air that can be forcefully inhaled after a normal TV inspiration
RV
FRC-ERV
amount of air remaining in the lungs after a forced expiration
IC
TV+IRV
max amount of air that can be inspired after normal TV inspiration
FRC
volume of air in the lungs after normal exhalation
RV+ERV
ERV
max amount of air that can be exhaled after normal exhalation
VC
IRV+TV+ERV
max amount of air that can be exhaled after max inhalation
TV
IC-IRV
amount of air inhaled or exhaled w/ each breath under resting conditions
ADS
aka anatomical dead space
no contribution to gas exchange
air remaining in passageways (~150 mL)
alveolar dead space
non-functional alveoli due to collapse or obstruction
total dead space
sum of anatomical and alveolar dead space
dalton’s law
total pressure exerted by mixture of gases=sum of pressures exerted by each gas
partial pressure
pressure exerted by each gas in mixture
directly proportional to its percentage in mixture
aka henry’s law
venous blood PO2
40 mmHg
alveolar PO2
104 mmHg
venous blood PCO2
45 mmHg
alveolar PCO2
40 mmHg
perfusion
BF reaching alveoli
ventilation
amount of gas reaching alveoli
oxyhemoglobin
hemoglobin + O2
fully saturated if all 4 heme groups carry O2
partially saturated when 1-3 heme carry O2
increased affinity
deoxyhemoglobin
hemoglobin - O2 (binds to H+)
decreased affinity
histotoxic hypoxia
cells unable to use O2, as in metabolic poisons
hypoxemic hypoxia
abnormal ventilation; pulmonary disease
carbonic acid formation
CO2+H2O via carbonic anhydrase in RBCs
chloride shift
outrush of HCO3- from RBCs balanced as Cl- moves into RBCs from plasma
pulmonary capillaries
HCO3-+H+=H2CO3 (split via carbonic anhydrase into CO2 and water)-> CO2 diffuses into alveoli
haldane effect
amount of CO2 transported affected via PO2
encouraged CO2 exchange in tissues and lungs
dissociated Hb from O2 binds w/ CO2 to form carbaminohemoglobin.
bohr effect
as more CO2 enters blood more O2 dissociates from Hb
VRG
aka ventral respiratory group
rhythm generating and integrative center
sets eupnea (normal rate and rhythm)-> 12-15 breaths/min
inspiratory neurons include phrenic and intercostal nerves
in medulla
DRG
aka dorsal respiratory group
integrates input from peripheral stretch and chemoreceptors; sends info to VRG
in medulla
pontine respiratory centers
influence and modify activity of VRG->transmit impulses to VRG
smooth out transition b/w inspiration and expiration
hypercapnia
increased CO2 levels
CO2
most potent and soluble
majority transported as bicarbonate ions
hyperventilation
increased depth and rate of breathing which removes CO2
hypocapnia
decreased CO2 levels
may lead to apnea (breathing cessation)
peripheral chemoreceptors
activated when PO2 falls below 60 mmHg
hyperpnea
increased ventilation in response to metabolic needs
COPD
irreversible decrease in ability to force air out of lungs
hypercapnic
“blue bloater”
chronic bronchitis
inhaled irritants
chronic excessive mucus
obstructive airways
impaired lung ventilation and gas exchange
frequent pulmonary infections
inflamed and fibrosed lower respiratory passageways
asthma
reversible COPD
active inflammation of airways due to immune response caused by the release of interleukins, IgE, and recruitment of inflammatory cells->magnify effect of broncospasm
TB
infectious disease caused by bacteria
treated via 12 month course of antibiotics
emphysema
loss of elastic fibers in alveoli making them collapse
reduces SA
“pink puffers”
spirometry
can distinguish COPD, pulmonary fibrosis, respiratory failure, scoliosis
restrictive disorders
pulmonary fibrosis, respiratory failure, scoliosis
decrease VC, TLC, FRC, RV, FVC
obstructive disorders
COPD, bronchitis, asthma
increase TLC, FRC, RV
decrease FEV
adenocarcinoma
originates in peripheral lung areas (bronchial glands and alveolar cells)
~40% of cases
squamous cell carcinoma
in bronchial epithelium
20-40% of cases
small cell carcinoma
contains lymphocyte like cells that originate in primary bronchi and metastasize
~20% of cases
positive cooperativity
increased pressure increases binding of O2 to heme molecule
henry’s law
solubility of a gas in a liquid increases as the partial pressure of the gas above the liquid increases
solubility of gases decreases with increasing temperature
decreased alevolar PO2
pulmonary arteriole vasoconstriction
decreased alveolar PCO2
bronchial constriction
increased alveolar PO2
pulmonary arteriole vasodilation
increased alveolar PCO2
bronchial dilation
increased temperature
decreased affinity for O2
Hb curve shifts to right
decreased temperature
increased affinity for O2
Hb curve shifts to left
H+
directly stimulates central chemoreceptors, increasing respiration
phrenic nerve
causes diaphragm to contract
pulmonary stretch receptors
inhibit inspiration during hyperinflation of the lungs
arytenoid cartilage
anchors vocal cords
inspiration
intrapulmonary pressure is less than atmospheric pressure
recoil of lungs and surface tension of the alveolar fluid
forces that pull the lungs away from the thoracic wall and collapse the lungs
bronchial arteries
provide systemic blood to lungs (oxygenated)
CO2
7% dissolved directly into plasma
23% carried in the form of carbinaminohemoglobin
70% transportsed as bicarbonate ion in plasma
bicarbonate
returned to RBC in pulmonary capillary
bronchial veins
carry deoxygenated blood away from lungs to the heart
exhalation
intrapulmonary pressure is greater than atmospheric pressure
