respiratory system ch 22 Flashcards
What is the major function of the respiratory system?
Respiration
What is the purpose of respiration?
-To supply the body with oxygen
-Dispose of carbon dioxide waste products
Besides respiration what are two other functions of the respiratory system?
-Olfaction (smell)
-Speech
What are the four processes of respiration?
-Pulmonary ventilation (breathing)
-External respiration
-Transport
-Internal respiration
What happens during pulmonary ventilation?
Movement of air into and out of lungs
What happens during external respiration?
Oxygen and carbon dioxide exchange between lungs and blood
What happens during transport?
Oxygen and carbon dioxide in blood is transported
What happens during internal respiration?
Oxygen and carbon dioxide exchange between the blood and tissues
What is the respiratory zone used for?
gas exchange
What are the microscopic structures in the respiratory zone?
Bronchioles, alveolar ducts, and alveoli
What is the conducting zone used for?
channel that cleanses, warms, and humidifies air at gas exchange sites
What does the diaphragm do?
promotes ventilation or breathing
How many orders of branching do air passages undergo?
23
What are the 23 branches called?
bronchial tree (respiratory)
Where does each bronchus enter the lung?
Hilum
What does the bronchus branch into?
Lobar (secondary) bronchi
Starting with the primary bronchus and ending with the alveoli, what are the different segments of the lung?
Bronchus, lobar bronchus, bronchioles, terminal bronchioles, respiratory bronchioles, alveolar ducts, alveolar sacs, alveoli
Where is the site of gas exchange in the lung?
alveoli
What is the respiratory membrane made up of?
-Alveolar
-Capillary walls
What type of diffusion happens during gas exchange in the membrane?
simple
What type of cells are in the alveolar walls?
-Type I
-Type II
What makes up Type I alveolar cells?
single layer of squamous epithelium
What is secreted by Type II alveolar cells?
-Surfactant
-Antimicrobial proteins
What connects adjacent alveoli?
Alveolar pores
What do alveolar pores do for the lung?
equalize air pressure through out the lung
What do alveolar macrophages do?
keep alveolar surfaces sterile
What are the three parts of the lung?
-Apex
-Base
-Hilum
What part of the lung is the apex?
superior tip
What part of the lung is the base?
inferior surface; rest on diaphragm
What is the site for entry/exit of the lungs?
Hilum
True/False: the right side of the lung is larger than the left side
True
what is the smallest subdivision of the lungs, visible to the naked eye?
lobules
What are the lobules served by?
bronchioles and their branches
what do the pulmonary arteries do?
deliver systemic venous blood (CO2 blood from tissues) to lungs for oxygenation
what do the pulmonary veins do?
carry oxygenated blood from the respiratory zones (lungs) to the heart
What does lung capillary endothelium contain?
enzymes that act on substances in the blood
what does ACE do
activate blood pressure hormone
what do bronchiole arteries do?
provide oxygenated blood to lung tissue
what are bronchiole veins?
anastomose with pulmonary veins
what is the pleurae made up of?
thin double layered serosa
what does the pleura do?
divides the thoracic cavity into two pleural compartments and mediastinum
Where is the parietal pleura located?
-thoracic wall
-superior face of diaphragm
-around the heart
-between lungs
Where is the visceral pleura located
on the external lung surface
what does the pleural fluid do?
fills slitlike pleural cavity by lubrication and surface tension
what are the two phases of pulmonary ventilation?
-Inspiration
-Expiration
What is inspiration?
gases flow into the lungs
What is expiration?
gasses flow out of lungs
What kind of pressure is exerted by air?
atmospheric pressure
what is the pressure in the alveolar called?
Intrapulmonary pressure
what is the intrapulmonary pressure always eventually equalize with?
atmospheric pressure
what is the pressure in the pleural cavity called?
Intrapleural pressure
True/False: the intrapleural pressure is always positive compared to the atmospheric pressure
False
what does a transpulmonary pressure do
keeps airways open
increase transpulmonary pressure –> larger lungs
What is atelectasis?
lung collapse
what causes atelectasis?
-plugged bronchioles
-pneumothorax
what is pneumothorax?
air in the pleural cavity
What does pulmonary ventilation depend on?
volume changes in the thoracic cavity
what does pressure change cause in the lung?
causes gases to flow to equalize pressure
what is boyle’s law
relationship between pressure and volume of a gas
-P1V1=P2V2
True/False: inspiration is a passive process
False
What are the inspiratory muscles that contract?
diaphragm and external intercostals
what does force inspiration do?
increase volume in the lungs
True/False: expiration is a passive process
True
How does volume decrease in the lungs during respiration?
elastic lungs recoil
when is expiration active?
when it is forced
what are the three physical factors influencing pulmonary ventilation?
-airway resistance
-alveolar surface tension
-lung compliance
What is the major non elastic source of resistance to gas flow?
friction
is flow inversely related or directly related to resistance?
inversely
True/False: resistance is usually insignificant
True
Where does resistance disappear in the lungs?
terminal bronchioles
True/False: epinephrine constricts bronchioles
False
What attracts liquid molecules to one another at gas-liquid interface
surface tension
what molecule has high surface tension
water
What is surfactant?
detergent like lipid in protein complex that reduces surface tension of alveolar fluid and discourages alveolar collapse
what makes surfactant?
Type II alveolar cells
What causes infant respiratory distress syndrome?
insufficient quantity in premature infants
(alveoli collapse after each breath)
What is lung compliance?
measure of change in lung volume
What causes high lung compliance?
distensibility of lung tissue and surfactant
what causes diminished lung compliance?
fibrosis, reduced production of surfactant, and decreased flexibility
what is total respiratory compliance decreased by?
-deformities of thorax
-ossification of costal cartilage
-paralysis of intercostal muscles
what are the 4 volumes used to express respiratory status?
-tidal volume
-inspiratory reserve volume
-expiratory reserve volume
-residual volume
What is tidal volume?
amount of air inhaled or exhaled with each breath under resting conditions
what is inspiratory reserve volume?
amount of air that can be forcefully inhaled after tidal volume
what is expiratory reserve volume?
amount of air that can be forcefully exhaled after a normal tidal volume
what is residual volume?
amount of air remaining in the lungs after a forced expiration
what is anatomical dead space?
air remaining in the passage ways
(no contribute to gas exchange)
what is alveolar dead space?
non-functional alveoli
what is total dead space?
anatomical and alveolar dead space
True/False: dead space is usually changing
False
What is minute ventilation?
total amunt of fas flow into or out of respiratory tract in one minute
what is alveolar ventilation rate?
flow of gases into or out of alveoli during a particular time
What are the some examples of nonrespiratory air movements?
-Cough
-Sneeze
-Crying
-Laughing
-Hiccups
-Yawns
What is dalton’s law of partial pressure?
total pressure exerted by mixture of gases = sum of pressures exerted by each gas
What is Henry’s law?
Gas mixtures in contact with liquid
True/False: alveoli contain more CO2 and water vapor than atmospheric air
True
Why does alveoli contain more CO2 and water vaport than atmospheric air?
Because CO2 goes into alveoli, alveoli humidifies air, alveolar gas is mixed with each breath
TF: Respiratory membrane has a large total surface area
True
for gas exchange
What can cause an reduction in surface area of the respiratory membrane?
Emphysema, tumors, inflammation and mucus
There is a steep partial pressure gradient for _____ in lungs
A. CO2
B.Surfactant
C. Bicarb
D. O2
D. O2
Why is there a smaller partial pressure gradient for CO2 in the lungs than Oxygen when they both diffuse in equal amounts?
CO2 is twenty times more soluble in the plasma than oxygen
_____ - blood flow reaching alveoli
A. Perfusion
B. Ventilation
A. Perfusion
_____-amount of gas reaching alveoli
A. Perfusion
B. Ventilation
B. Ventilation
What are the two reasons ventilation and perfusion are never balanced for all alveoli?
-Regional variations (gravity on blood and air flow)
-Some alveolar ducts plugged with mucus
Where alveolar O2 is high, arterioles ____
A. Dilate
B. Constrict
A. Dialate
Where alveolar CO2 is high, bronchioles _____
Dilate
How is most molecular O2 carried in the blood?
By loosely binding to each Fe of hemoglobin
What helps loading and unloading of O2 of hemoglobin?
Change in shape of hemoglobin
(more that is bound to Hb the higher the affinity it has for O2)
How many oxygens are carried by one heme? during full saturation
4
What 5 factors affect the rate of loading and unloading of O2?
Po2
Temp
Blood pH
Pco2
Concentration of BPG
What produces BPG?
Red blood cells during glycolysis
When does the concentration of BPG increase?
When O2 levels are very low
What happens to blood Hb saturation when you are at a higher altitude (lower PO2)
Hb saturation decreases
What does the oxygen-hemoglobin dissociation curve show?
Hemoglobin saturated agains PO2 (not linear)
What is the venous reserve?
Oxygen remaining in venous blood
What causes increase release of O2 by hemoglobin?
Increase of blood Pco2 and H+
Declining bood pH
Bohr effect
Heat production increases (increased oxygen unloading to active tissues)
What is the Bohr effect?
Oxygen only unloaded where it is needed most
(Hb-O2 bond weakens)
What are the 3 ways CO2 is transported in the blood?
Dissolved in plasma
Bound to globin of hemoglobin
Transported as bicarbonate ions in plasma
In what form of CO2 is most of it transported in the blood?
Bicarbonate ions in the plasma
What enzyme reversibly and rapidly catalyzes the break down of H2CO3 into water and CO2?
Carbonic anhydrase in the red blood cells
In systemic capillaries _____ quickly diffuses from RBCs into plasma
HCO3-
What is chloride shift in systemic capillaries?
Outrush of bicarbonate from RBCs balanced as CL- moves into the RBCs from plasma
AKA when chloride goes out of RBCs, bicarb comes in to replace the missing negative charge
What moves into the red blood cells in pulmonary capillaries?
Bicarbonate
What does bicarb bind to to form H2CO3?
H+ ion
What is H2CO3 split into and by what?
Carbonic anhydrase splits H2CO3 into water and co2
What happens to the CO2 that split from H2CO3?
It diffuses into the alveoli
What is the amount of CO2 transported affected by?
Po2
What happens if there is less oxygen saturation?
Carbaminohemoglobin is formed and is able buffer H+ more easily and more CO2 is transported in the blood
What does the Haladane effect encourage?
CO2 exchange in tissues and lungs
What does the arbonic acid-bicarbonate buffer system do?
Resists changes in blood pH
What is an alkaline reserve of the carbonic acid-bicarbonate buffer system?
HCO3-
What kind of breathing causes increased CO2 in the blood and increased acidity of the blood?
Slow and shallow breathing
What kind of breathing decreases co2 in the blood and increases pH?
Rapid, deep breathing
What is involved in the control of respiration?
Higher brain centers
Chemoreceptors
Other reflexes
Where are neurons located that control respiration?
Medulla
Pons
What are the two medullary respiratory centers?
Ventral respiratory group (VRG)
Dorsal respiratory group (DRG)
What does the VRG do?
Creates rhythm of breathing
Integrative center
What is eupnea?
Breaths per minute
usually 12-15
The VRG has what kind of neurons to excite inspiratory muscles? What nerves allows this excitment?
Inspiratory neurons excite
Phrenic and intercostal nerves allow
What does the DRG do?
Integrates input from peripheral stretch and chemoreceptors
Sends information to the VRG
What do the pontine respiratory centers do?
Influence and modify activity of VRG
Smooth out transition between inspiration and expiration
Transmits impulses to VRG to modify and fine tun breathing rhythms
What is one hypothesis that explains the generation of respiratory rhythm?
Pacemaker neurons with intrinsic rhythmicity
What is breathing depth determined by?
How actively respiratory center stimulates respiratory muscles
What is breathing rate determined by?
How long inspiratory center is active
What senses change in breathing depth and rate?
Central and peripheral chemoreceptors
What chemical factor is most important for gas exchange and maintenance of pH of blood?
Carbon dioxide
What happens to the brain if blood CO2 levels rise?
CO2 accumulates in the brain
CO2 in brain is hydrated to make carbonic acid
Carbonic acid is dissociated releasing H+ (decrease pH)
What happens to breathing when CO2 levels rise?
Breathing depth is increased and so is the rate of breathing to increase pH
What happens to blood CO2 levels during hyperventiation?
Decrease in blood CO2
Cerebral vasoconstriction and maybe stroke
May pass out
What is apnea?
Breathing cessation
Where does PO2 influence respiration?
Peripheral chemoreceptors in the aortic and carotid bodies
What is the most powerful respiratory stimulant?
Rising CO2 levels
What happens during Hering-Breuer Reflex?
Stretch receptors in pleurae and airways stimulated by lung inflation
Sends inhibitory signals to medulla to end inhalation
