lecture 6: respiratory system Flashcards
what is function of respiratory system
exchange O2/CO2
uptake O2 and expel CO2
what does cellular respiration produce
CO2
what does too much CO2 in blood cause
causes blood to become acidic
how many processes does respiration involve
4
name the 4 respiration processes
pulmonary ventilation
external respiration
transport of O2 and CO2 in the blood
internal respiration
describe pulmonary ventilation
movement of air into lungs
describe external respiration
exchange of O2/CO2 between lungs and blood
gas exchange
describe transport of O2 and CO2 in the blood
hemoglobin and bicarbonate
describe internal respiration
exchange of O2/CO2 between blood and tissues
describe respiratory epithelium
pseudo stratified ciliated columnar
cilia and mucus trap dust, particles and pollen
beating cilia move mucus towards pharynx to be swallowed
pseudo stratified columnar lines the
nasal cavity
trachea and bronchi (cilia beats upwards, away from lungs)
what happens to nose when it’s cold out
runs
cilia get cold and beat less
describe air entering nasal cavity
enter through nostrils
air is filtered by hairs, warmed, humidified and sampled for odors
pharynx connects nasal cavity to larynx
name parts of larynx
epiglottis
vocal fold
thyroid cartilage
describe epiglottis (larynx)
covers glottis (opening to larynx) while swallowing
describe vocal folds (larynx)
vocal cords
membranes that produce sound when air passes through
describe thyroid cartilage (larynx)
hyaline cartilage shaped like shield
reinforces larynx walls
includes adams apple
what is trachea
10-12 cm long windpipe reinforced with C shaped rings of hyaline cartilage
describe cartilage of trachea
keeps trachea open for air to pass
C shaped to allow esophagus to expand
ciliated cells in trachea move mucus up away from lungs
what does trachea branch into
trachea —> 2 primary bronchi —> secondary bronchi —> tertiary bronchi —> bronchioles
name parts of lungs (3 parts)
bronchi and bronchioles (respiratory tree)
alveoli
elastic connective tissue
describe lung alveoli
sac like structures at end of bronchioles
lined with simple squamous epithelium
forms bulk of lungs (~300 million)
describe elastic connective tissue of lungs
makes lungs spongy and soft and allows them to expand
what is surface area of lungs
100m^2
many branches allow surface area for exchange to increase
what is pleura
serous membrane
name parts of pleura
visceral pleura
parietal pleura
pleural cavity
describe visceral pleura
inner
covers lungs
describe parietal pleura
outer
attached to chest wall
describe pleural cavity
space between the visceral and parietal pleura
filled with serous fluid that allows lungs to expand without friction
describe how lungs expand
expand with thoracic cavity
serous fluid in pleural cavity creates tight bond between parietal and visceral pleura
pleural layers can slide past each other easy but can’t be pulled apart
describe alveoli (gas exchange)
walls of alveoli much thinner than sheet of tissue
simple squamous
must be moist for diffusion to occur
what are alveoli surrounded by
dense network of pulmonary capillaries to form respiratory surface (respiratory membrane)
describe respiratory membrane
alveolar wall + fused basal lamina + capillary wall form respiratory membrane (air blood barrier)
how does gas exchange occur
simple diffusion across respiratory membrane (2 cell layers)
what produces surfactant
scattered cuboidal cells of respiratory membrane
describe gas exchange
O2 and CO2 move by passive diffusion
from high to low concentration
partial pressure is proportional to concentration
describe gas exchange of external respiration
alveoli/pulmonary capillaries
CO2 diffuses into alveoli (45–>40 mmHg)
O2 diffuses into pulmonary capillaries (104–>40 mmHg)
describe gas exchange of internal respiration
systemic capillaries/tissues
CO2 diffuses into systemic capillaries (45–>40 mmHg)
O2 diffuses into tissues (100–>40 mmHg)
describe ventilation
humans ventilate lungs by negative pressure breathing
diaphragm and rib cage muscles contract to increase volume of thoracic cavity
why does air enter the lungs when thoracic cavity expands
P1V1=P2V2
v decreases and pressure increases
how does pleura allow us to breathe
parietal pleura (wall of thoracic) and visceral (lungs) cannot be pulled apart - easily slide past each other
if thoracic cavity expands the lungs expand with it
describe inspiration
muscles contract
describe external intercostal muscles during inspiration
contract and pull ribs upwards and sternum outwards
describe diaphragm during inspiration
contracts and moves downward
volume of thoracic cavity increases and lungs expand
air pressure in alveoli becomes lower than atmospheric pressure and air moves in
describe expiration
muscles relax
describe external intercostal muscles during expiration
relax
ribs move back downwards and sternum inwards
describe diaphragm during expiration
relaxes and moves back upwards
volume of thoracic cavity decreases and lungs passively recoil
air pressure in alveoli becomes higher than atmospheric pressure and air moves out
name 2 other types of breathing (not at rest)
during vigorous exercise
forced expiration
describe breathing during vigorous exercise
muscles in neck, back and chest contract to raise rib cage even more
increase ventilation volume
describe forced expiration
internal intercostal muscles contract pulling ribcage inwards
abdominal muscles contract topush up on diaphragm
ex: coughing, sneezing, blowing out candle
describe surfactant
detergent like molecule substance
makes it easier for alveoli to stay open and expand during inspiration
what does surfactant do
reduces surface tension of fluid within alveoli
when to fetuses begin to produce surfactant
24-28 weeks
premature - problem (lungs will not expand)
what is a collapsed lung
when bond between parietal and visceral pleura is disrupted
lungs will no longer expand during inspiration (will recoil)
caused by air or fluid entering pleura cavity (like in a chest wound)
how much O2 does person consume during exercise
~2L of O2 per minute
how much O2 does person consume normally
4.5 mL of O2 can dissolve per litre of blood
what would happen if only dissolved O2 was available
the heart would need to pump 500L of blood every 2 mins
how is most of O2 in blood carried
by respiratory pigment hemoglobin
increases amount of O2 in blood to ~200mL per L
what is the part of hemoglobin that binds oxygen
heme group
what does erythrocyte stand for
bags of hemoglobin
when is hemoglobin synthesized
when cells are developing in bone marrow
how does hemoglobin bind O2
reversible and cooperatively
makes gas exchange more efficient
what does O2 binding to one subunit cause
other subunits to change shape and increase affinity for O2
what does O2 unbinding cause
hemoglobin decreases affinity for O2
as PO2 increases
rate of O2 binding to hemoglobin increases
steep slope portion of dissociation curve shows
cooperativity (brining of O2 to hemoglobin)
a slight change in PO2 in tissues causes
hemoglobin to unload/load a substantial amount of O2
more O2 unloaded to tissues that are very metabolically active (low PO2)
less O2 will be unloaded to tushes that have higher PO2
name and describe 2 factors that affect hemoglobin
temperature - affinity of hemoglobin for O2 decreases with increasing body temp
pH - affinity of hemoglobin for O2 decreases as pH decreases (Bohr effect)
describe transport of gasses in blood of CO2
CO2 primarily transported as bicarbonate ions dissolved in blood plasma
what happens inside rbcs (transport of CO2)
inside rbcs CO2 reacts with water to from carbonic acid (catalyzed by carbonic anhydrase, also catalyzes reverse reaction)
as CO2 levels increase
equilibrium shifts to right increasing concentration of H+ and lowering pH
describe transport of gasses in blood of CO2 - distribution (percentages)
bicarbonate ions - 70%
dissolved CO2 - 7%
bound to the amino groups in hemoglobin - 23%
name all 4 respiratory volumes
tidal volume
inspiratory reserve volume
expiratory reserve volume
residual volume
describe tidal volume
TV
volume of air inhaled and exhaled with each breath
~500mL at rest
describe inspiratory reserve volume
IRV
volume of air that can be inspired forcibly beyond the tidal volume
1900-3100mL
describe expiratory reserve volume
ERV
volume of air that can be expired forcibly beyond the tidal volume
700-1200mL
describe residual volume
RV
volume of air that always remains in lungs
needed to keep alveoli open
newly inhaled air is always mixed with O2 depleted residual air
PO2 in alveoli will always be lower than atmospheric PO2
what is a respiratory capacity
combo of two or more respiratory volumes
name all 3 respiratory capacities
inspiratory capacity
vital capacity
total lung capacity
describe inspiratory capacity
IC = TV + IRV
describe vital capacity
VC = TV + IRV + ERV
describe total lung capacity
TLC = VC + RV = (TV + IRV + ERV) + RV
what is dead space
volume of air that remains in passageways (~150mL of TV)
does not contribute to gas exchange
name the 3 pulmonary function tests
forced vital capacity
forced expiratory volume
minute ventilation
describe forced vital capacity
FVC
volume of gas forcibly expelled after taking a a deep breath
describe forced expiratory volume
FEV
volume of gas expelled during a specific time interval of FVC
healthy individuals can expel 80% of FVC in 1 sec (FEV1)
describe minute ventilaton
rough estimate of respiratory efficiency
volume of gas that flows into or out of the respiratory tract in 1 min
normal at rest ~6L/min
normal with exercise ~200L/min
how do we control our breathing (names)
voluntary (conscious control)
involuntary (autonomic control)
describe voluntary control of breathing (generally)
conscious control
limited
respiratory centers in brain will ignore messages from brain cortex if O2 levels are too low or pH levels are too low or high
describe involuntary control of breathing (generally)
autonomic control
coordinated with cardiovascular system
and body’s metabolic demands for gas exchange
control centers in brain (medulla/pons) regulate the rate and depth of breathing
describe involuntary control of respiration (specifics)
medulla oblongata sets basic breathing rhythm by sending signals to the diagram and internal intercostal muscles to contract
pons helps smooth out the rhythm set by medulla
what is the stimuli (involuntary control of respiration)
change in blood pH
low O2 levels
stretching of alveoli
what are the receptors (involuntary control of respiration)
sends info to medulla
pH sensors in medulla (measures CSF)
O2 sensor in aorta and carotid arteries in the neck
stretch receptors in lungs
what are the effectors (involuntary control of respiration)
diaphragm
internal intercostal muscles
which stimulus is most important for breathing
change in blood pH
decrease in pH levels is caused by…
increasing CO2 levels
CO2 is converted into carbonic acid
what is a pulmonary function test
tests that measure the rate of gas movement
