lecture 15 Flashcards
respiration steps (3)
pulmonary ventilation
external respiration
internal respiration
pulmonary ventilation
gas exchange between atmosphere and lung tissues
external respiration
gas exchange between lung tissues and blood
internal respiration
gas exchange between blood and body tissues
functions of respiratory system (3)
exchange gases
regulate blood pH
permits phonation (vocal sounds)
sense of smell, filters air
oto(rhino)laryngology
the study of the respiratory system
why do cells need o2?
aerobic cellular respiration (acts as terminal receptor) = ATP
upper respiratory system parts
nose, nasal cavity, pharynx, associated structures
lower respiratory system parts
larynx, trachea, bronchi, lungs
two zones of respiratory system
conducting zone
respiratory zone
conducting zone
directs air toward the respiratory zone
filters, warms, humidifies air as it enters the body
respiratory zone
site of gas exchange
includes respiratory bronchioles, alveolar sacs and ducts
the nose
made of bone , cartilage, and CTs
contains nasal cavity and external nares
air enters the nose through;
teh external nares
nasal cavity
contains paranasal sinuses, nasal conchae, and olfactory epithelium
nasal septum function
divide nasal cavity in 2
olfactory epithelium (where, goblet cells? cilia?)
located in the nasal cavity
ciliated with no goblet cells
pharynx
- tube of skeletal muscle lined with a mucous membrane
- starts at internal nares and ends at cricoid cartilage
3 subdivisions
3 subdivisions of the pharynx
nasopharynx
oropharynx
laryngopharynx
nasopharynx (tissue and function)
ciliated pseudostratified columnar epi
sweeps mucus into pharynx
oropharynx
non keratinized stratified squamous epi
- contains fauces
- passageway for air and food
- contains tonsils
function of the tonsils
facilitate immune response
tonsils (3)
pharyngeal tonsil
palatine
lingual
laryngopharynx
basically the same as oropharynx but lower
thyroid cartilage
hyaline cartilage that forms anterior surface of the larynx
(adams apple)
epiglottis
flap of elastic cartilage that covers the trachea during swallowing
cricoid cartilage
ring of hyaline cartilage that makes up the inferior wall of larynx
- landmark for tracheotomies
true vocal cords
aka vocal folds
non keratinized stratified squamous epi
- form elastic ligaments
false vocal cords
aka vestibular folds
come together when breath is held
trachea
has 16-20 rings of hyaline cartilage to keep it patent (from collapsing)
- lined with ciliated pseudostratified epi
bronchi
split off of trachea (left and right bronchus)
- branch into the lungs as narrowing pathways
carina
ridge at the branchpoint of the trachea
how do the mucous membranes change throughout the bronchiole tree?
list tissues
the tissues get thinner and thinner
ciliated pseudostrat
ciliated simple cuboidal
nonciliated simple cuboidal -
simple squamous - alveolar sacs
pleural membrane
two serous membranes (parietal/visceral?)
- pleural cavity - space between
secretes pleural fluid
function of the pleural fluid
reduce friction and provides surface tension
inferior portion of the lungs
base
superior portion of the lungs
apex
mediastinal surfaces (2)
hilum
cardiac notch
hilum
mediastinal surface
- permits passage of the bronchi, blood vessels, nerves, and lymph vessels
cardiac notch
mediastinal surface
- provides space for the heart
- decreases left lung relative to right by 10%
fissures
divide lungs into lobes
oblique fissure
separates inferior and superior lobes
horizontal fissure
borders middle lobe and superior lobe on right lung only
lobar bronchi names
based on what lobe they branch into
superior lobar bronchus
middle (right only)
inferior
lobar bronchi branch into:
segmental bronchi
bronchopulmonary segment
13 in right, 8 in left
- damaged segments can be removed without disturbing others
lobules
smaller components of bronchopulmonary segments consisting of:
- branch of terminal bronchi
- arteriole/venule
- lymphatic vessel
all of these are wrapped in elastic CT
respiratory bronchioles
microscopic bronchial branches
- simple cuboidal epi
- branch into alveolar ducts
alveoli
air sacs where pulmonary and external respiration occur
type 1 alveolar cells
simple squamous epi
thinness facilitates gas exchange
type 2 alveolar cells
nonciliated cuboidal epi at the septa between alveoli
- secrete surfactant that prevents alveolar walls from sticking together
respiratory membrane
very thin - 0.5 micrometres
liens alveoli and associated capillaries
4 layers
layers or respiratory membrane (superficial to deep)
alveolar wall - type 1/2 cells + macrophages
epithelial basement membrane
capillary basement membrane
capillary endothelium - contacts blood
pulmonary arteries
bring deoxy blood from heart to be oxy
- constrict in response to hypoxia
- responsible to ventilation-perfusion coupling
ventilation perfusion coupling
if ventilation is high in a segment, perfusion will be high as well
this ensures that only healthy lung tissues are maximally used
bronchial arteries
branch from aorta
deliver oxy blood to muscular tissue of the lungs
patency
the ability of a passageway to remain unobstructed
just before inhalation, pressure inside the lungs is _______ to atmospheric pressure
equal
gases move from ______ to _____ partial pressure
high to low
for inhalation to occur, pressure must be ______
below atmospheric pressure
partial pressure
the pressure a gas exerts on its surroundings
boyles law
states that the pressure inside a container is inversely proportionate to the volume of that container
to decrease the pressure in the lungs (to inhale air) we can:
increase the volume of the lungs
how much does the diaphragm depress?
normal inhalation - 1cm
strenuous - up to 10
what is responsible for the % of air inhaled? (2)
75% - depression of diaphragm
25% - external intercostal muscles
intrapleural pressure
ensures lung tissue expands during inhalation
- negative pressure within thoracic cavity
- keeps pleural membrane suctioned to thoracic cavity wall, so when the cavity expands, the lungs do too
is inhalation active or passive process
active
is exhalation active or passive process
passive
active exhalation
during vigorous exercise or playing a wind instrument
pleural effusion
accumulation of pleural fluid in the pleural cavity
- leads to decreased lung volume
compliance
distensibility of elastic tissues
air resistance is determined by:
airway diameter
obstruction of airways (like in COPD)
COPD
chronic obstructive pulmonary disorder
lung volumes
a specific measure of air inhaled, exhaled, or stored
lung capacity
sums of specific lung volumes
spirometer
used to measure lung volumes
carbon is _____X more soluble in water than O2
24x
therefore there is more CO2 in blood plasma than O2
why is the partial pressure of O2 in alveoli even lower than at rest during exercise?
because we are using lots of it, and so we can take in more of it
what maximizes oxygenation of blood
slow movement of blood through capillaries
why do tissue cells constantly produce CO2, and what does it result in
as a waste product of aerobic respiration
results in constantly higher partial pressure of CO2 outside capillaries, because CO2 moves from tissues to the blood, down its C gradient
factors affecting respiration (4)
- partial pressure gradient of gas
- surface area over which gas is exchanged
- diffusion distance
- solubility of gas / molecular weight
how does partial pressure gradients of gas affect respiration?
pressure gradient is needed to allow gas to move in and out of the lungs
(eg. at high altitudes, pressure is lower, making the pressure inside and outside the lungs closer. leads to slower respiration - altitude sickness)
how does surface area over which gases are exchanged affect respiration?
more contact with gases to be exchanges = higher rate of diffusion
(eg. alveolar surface area is massive to allows efficient gas exchange)
how does diffusion distance affect respiration
shorter distance = more efficient diffusion
(eg. thin alveolar walls = shorter distance for gas to move)
how does solubility of gas/molecular weight affect respiration
O2 weighs less, but CO2 is more water soluble.
this means you will run out of O2 faster than you will accumulate excess CO2
how is O2 transported (percentages)
98.5% - hemoglobin
1.5% - dissolved in blood plasma
how is the binding and dissociation of O2 to/from hemoglobin summarized (reaction)
Hb + O2 –> Hb - O2
what affects the saturation of hemoglobin? (6)
partial pressure of O2
blood acidity
Partial pressure of CO2
temperature
products of glycolysis
types of hemoglobin
how does partial pressure of O2 affect the saturation of hemoglobin?
higher the pressure (mmHg), the closer Hemoglobin is to being saturated
between 60-100 mmHg, hemoglobin is almost 100% saturated, which is why external respiration is so effective (average atmospheric pressure - 760mmHg)
graph drawing for final - what are the x and y axis names?
x - partial pressure of O2 (Po2 (mmHg))
y - percent saturation of hemoglobin
blood pH graph lines
superior line -
middle line -
inferior line -
which is which?
superior line - higher blood pH
mid - normal blood pH
inferior line - low blood pH
why might increased percent saturation of hemoglobin be a bad thing?
if Hb bind too well to O2 (like in higher pH, low PCo2, or low temp) O2 will be less reversible, and Hb wont let go of it
affinity
the tendency for a substance to bind another
how does affinity for O2 affect saturation of Hb?
the affinity of Hb is affected by acidity and PCo2
most CO2 is transported as _____ in blood plasma
H2CO3
blood PCo2 graph lines
superior -
mid -
inferior -
which is which?
remember, low PCo2 = higher pH
superior - low PCo2
mid - normal
inferior - High PCo2
blood temperature graph lines
superior -
mid -
inferior -
which is which
superior - low temp
mid - normal
low - higher temp
how does temperature affect affinity for Hb to bind O2?
skeletal muscle generates heat, which favours release of o2 to tissues
how does temperature affect affinity of Hb for O2
skeletal muscle produces heat which heats the blood and favours the release of O2 to tissues
how do the products of glycolysis affect the affinity of Hb for O2?
one product (BPG) binds Hb and changes it structure, decreasing its affinity
how does the type of Hb affect its affinity for O2?
fetal Hb (Hb-F) can bind up to 30% more O2 than adult Hb (Hb-A)
how is CO2 transported in the body? (%)
7% - dissolved in blood plasma as CO2
23% - bound to protein to form carbamino compounds (Hb+CO2 = carbaminohemoglobin)
70% - transported as bicarbonate
bicarbonate reaction (carbonic acid dissociation)
CO2 + H2O <-> H2CO3 <-> H+ HCO3
chloride shift ensures:
that erythrocytes maintain electrical balance
chloride shift
when HCO3 diffuses out of the cell from high to low concentration in plasma, and Cl- ions diffuse into the cell to restore ion homeostasis in RBCs
reverse chloride shift ensures:
that CO2 can be eliminated at the pulmonary capillaries
reverse chloride shift reaction
HCO3 + H -> H2CO3 -> H2O + CO2
reverse chloride shift
turns bicarbonate back into CO2 to be exhaled. as HCO3 decreases, Cl moves out of cells
where does the chloride shift happen
at systemic capillaries
where does teh reverse chloride shift happen
at pulmonary capillaries
brief overveiw of chloride shift and reverse
chloride shift
- at systemic capillaries
- CO2 enters cell from tissues
- CO2 converted to HCO3 in RBCs
- Cl then moves into RBCs to restore homeostasis
reverse chloride shift
- at pulmonary capillaries
- HCO3 converted to CO2 in RBCS
- CO2 leaves cell to alveoli
- Cl leaves the cell to restore homeostasis
two main centres of breathing
medulla oblongata
pons
medullary respiratory group
divided into dorsal and ventral respiratory groups
dorsal - quiet normal exhalation/inhalation
ventral - forceful inhalation/exhalation
dorsal respiratory group
controls normal quiet breathing
part of the medullary respiratory group
ventral respiratory group
part of the medullary group
controlled by dorsal group
- work with Dorsal for inhalation
- control exhalation
- only forceful breathing
pontine respiratory group
affect normal breathing by influencing the DRG in the medullary group
what permits us to control breath?
teh cerebral cortex
why cant we hold our breath for too long?
increased Pco2 and H+ in blood stimulate DRG neurons which force normal breathing to resume
how do chemoreceptors influence breathing
sense changes in blood chemicals
(Pco2 and H+)
central - near medulla oblongata
peripheral - in aortic/carotid walls
hyperventilation is a response to:
low blood pH
- when pH is low, Pco2 is likely high
- chemoreceptors signal DRG to breath more
hypocapnia
when Pco2 is low, chemoreceptors do not send signals to the DRG
- can cause fainting due to hypoxia
- can result from hyperventilation
inflation reflex
prevents overstretching of lung tissue
- baroreceptors sense stretching and signal the vagus nerve to relax the respiratory muscles
other things that affect breathing (5)
emotions - both
temperature - lower/stop
pain - both
irritation of airways - increase
increased BP - lower
pulmonary perfusion
the extent of blood flow to the lungs
COPD - name and what it does
chronic obstructive pulmonary disease
- increased # of goblet cells and mucus secretion
- excess mucus impairs cillary function
emphasyma
immune destruction of alveolar walls
- leads to decreased surface area and decreased O2 acquisition
