Respiratory System Flashcards
Does intrapulmonary pressure increase or decrease during inspiration?
Decrease
What pressure is always negative and helps to keep lungs inflated?
Intrapleural
When is intrapleural pressure most negative?
During inspiration
If there is a breach between pleural membranes such that air and blood flow in what will happen to the lungs?
They will collapse
When bronchioles constrict what happens to airflow?
It decreases because resistance increases
Fibrosis decreases lung compliance. How does this affect inflation?
It makes it more difficult
A decrease in surfactant will increase or decrease compliance?
Decrease
When pO2 is low and pCO2 is high what happens to the pulmonary arteries and bronchioles?
Pulmonary Arteries: Constrict
Bronchioles: Dilate
What is the mixture of gases of the atmosphere?
O2: 21%
CO2: 1%
N2: 78%
What is the partial pressure of Oxygen at sea level
.21(760mmHg) = 160mmHg
As tissue builds up CO2 what happens to affinity for O2
It decreases
As temperature rises in tissues what happens to affinity for Hb for O2?
It decreases
At rest what is the saturation of Hb in the heart?
98%
What is the graph that shows Hb affinity at various pHs/temperatures?
Hemoglobin Saturation/Dissociation Curve
What do H+ bind to inside RBCs when H2CO3 dissociates?
Hemoglobin
What nerves are innervated by the inspiratory centers?
Vagus and Glossopharyngeal
What nerve carries stretch information from the lungs?
Phrenic
What muscles elevate the ribs during inspiration?
External intercostals and diaphragm
Inspiration does what to the volume of the thoracic cavity? What does this do to pressure?
Increases volume, decreases pressure
What nerve controls the diaphragm?
The phrenic nerve
True or False: the automatic act of breathing is controlled by efferent fibers from the ANS
True
What is eupnea?
Normal breathing. Normal pO2 and pCO2
What is Hypernea?
Increased breathing rate (decreases PCO2)
What is Hyperventilation?
Deep, slow breathing (decreases PCO2)
What is hypoventilation?
Shallow breathing (increases PCO2 levels)
What are the two pairs of respiratory centers in the medulla oblongata?
Dorsal and Ventral
What mediates the action of CO2 on the respiratory center?
Stimulation of afferent fibers from the carotid bodies and aortic bodies exclusively because CO2 cannot pass the blood brain barrier
True or false: Exhalation is normally a completely passive process
True
What part of the brain is responsible for setting the basic rhythm of breathing?
The medulla oblongata
What part of the brain is reaponsible for forceful expiration?
Ventral respiratory group
What part of the brain is responsible for smooth transitions between inspiration and expiration?
Pneumotaxic area of pons
What gas stimulates the central chemoreceptors in the medulla oblongata?
CO2
What gas stimulates peripheral chemoreceptors in the aorta and carotid bodies?
O2
Peripheral chemoreceptors are stimulates when arterial O2 drops below what pressure?
60 mmHg
What factors increase the rate of respiration?
O2 concentration
CO2 concentration
Blood pH
What is the important factor controlling the rate and depth of breathing?
CO2
What are the structures of the Conductive Zone?
Nose
Pharynx
Larynx
Trachea
Bronchii
Does gas exchange happen in the Conductive Zone?
No
What happens to air in the nose?
-It warms and humidifies as it goes via nasal capillaries
-It is cleaned and filtered by pseduostratified ciliated tissue
What chambers are used for sound production and resonance?
Nose - Resonating Chamber
Paranasal Sinuses - Resonating Chamber
Vocal folds of glottis - Sound production
What is the purpose of paranasal sinuses?
Lighten the skull and moisten air
Serve as resonating chambers
What isn true about tissue as one goes down the conductive zone to the respiratory?
Move from stratified squamous ET to pseudostratified in bronchioles to simple squamous in respiratory zone
What are the vocal cords? What is the difference between them and vestibular folds?
Ligaments in the larynx attached to cartilage
The opening between the folds is the glottis
Inferior to the vestibular folds, which produce no sound but help to close glottis
What is the respiratory zone?
Respiratory Bronchioles
Alveolar Ducts
Alveolar Sacs
Where is the site of gas exchange between the alveoli and the blood?
Respiratory membrane
What is the purpose of pleural fluid?
Fills the area between visceral and parietal pleura to allow gliding and resist separation of pleaura as lungs inflate and deflate
What is speech?
The intermittent release of expires air while opening and closing the glottis.
Pitch - determines by length and tension of cords
Loudness - Determines by force of expelled air
What structures shape sound?
Pharynx. tongue, soft palate, lips
What are the overall functions of the respiratory system?
Gas exchange between environment and pulmonary capillaries
Filtering, humidifying, and warming of air
Production of sound
Smell
Maintaining pH homeostasis
What is 0mmHg for respiration?
Pressure at sea level: 760 mmHg
What is intrapulmonary pressure?
The pressure in alveoli
What is intrapleural pressure?
Negative pressure within the pleura cavity that keeps airways open
What is transpulmonary pressure?
The difference between intrapulmonary (Ppul) and intrapleural (Pip)
What happens in a puncture wound to the lungs?
Equalizing with external air, causing collapse
What is pulmonary ventilation?
Air coming from atmosphere into the lungs
What is the difference between external and internal respiration?
External: Gas exchange between air and alveoli
Internal: Gas exchange within tissue/blood (O2 to tissue, CO2 to blood)
What muscles cause pulmonary ventilation?
Contraction of diaphragm (vertical) and external intercostals (lateral) increase volume of thoracic cavity, decreasing pressure
What’s Boyle’s Law?
P1V1 = P2V2
What are the events of inspiration?
Flow of air into the lungs
-Diaphragm descends, external intercostals expand laterally
-Pressure decreases as volume increases
This is an active process (requires energy)
What are the events of expiration?
Volume decreases and pressure increases, forcing air out of the lungs
Passive process under resting conditions
What three factors needs to be overcome for inspiration?
Airway Resistance
Alveolar Surface Tension
Ling Compliance
What is Lung Compliance?
The ease with which lungs can be expanded
-Reduced by factors that decrease distention of thoracic cavity (edema, spine shape, fibrosis)
What is Elasticity?
How readily lungs will recoil to original shape
Reduced by fibrosis, surfactant production, thorax flexibility
What is surface tension?
The attraction of liquid molecules in the alveolus (water from capillaries esp.)
What is surfactant?
A detergent-like compound that reduces surface tension between water molecules
What is the name for the strength between two substances, such as a an antigen and antibody or gas and protein?
Affinity
What is the largest source if airway resistance?
Friction
What is air flow?
Change in pressure over resistance
(F=deltaP/R)
What role does the ANS play on air flow
Efferent input affects diameter of bronchioles
-Sympathetic causes bronchiodilation, decreases resistance
-Parasympathetic causes bronchioconstriction, increases resistance
What are nonrespiratory air movements?
Cough
Sneeze
Cry
Laugh
Hiccup
Yawn
What’s Dalton’s Law?
Total pressure is equal to the sum of independent gas pressures. The partial pressure of each gas is directly proportional to it ls percentage in the mix
What is Henry’s Law?
Gas will dissolve into liquid proportional of it partial pressure, the bigger the pressure the more it will dissolve
What is the most soluble gas?
CO2, nearly 20x more soluble than O2
True or False- Nitrogen is virtually insoluble in plasma at sea level
True
What is external respiration?
Gas exchange between simple squamous tissue of pulmonary capillaries and alveoli’s reapiratory membrane
What factors affect external respiration?
Partial gas gradients and gas solubility
Matching of alveolar ventilation and blood perfusion
Structural charcteristics
How long does it take for hemoglobin to saturate with O2?
About 1/3 of the time it is in the alveolus
How does Hb act as a storage depot for O2?
Hb removes O2 from the plasma as soon as it is dissolved into blood, which decreases its partial pressure and allows more in, causing a large net transfer of O2
What is ventilation?
The amount of gas to reach an alveoli
What is perfusion?
Blood reaching the alveoli
What will happen if ventilation is bad?
CO2 higher than O2, bronchioles dilate and arterioles constrict
What happens is perfusion is poor?
Low CO2 and high O2, bronchioles will constrict and arterioles will dilate
How thick is the respiratory membrane?
.5-1 micrometer, allowing for efficient gas exchange.
Total surface area is about 60 m^2 (40x that of skin)
What will thickening the respiratory membrane cause? What about decreasing surface area?
Thickening: inadequate gas exchange, inflammation, edema, fibrosis
Decreasing SA: emphysema
What direction are the pressure gradients for CO2 and O2
Blood returning from tissue has higher CO2, easily moves into alveoli
Air diffuses from O2 to blood
What is equilibrium for O2? How long does it take an RBC to reach that?
104mmHg, about .25 seconds or 1/3 total time spent
Where is 98% of O2 in the body?
Attached to Hb in blood. A very small amount is in the plasma.
How many atoms bind to Hb?
4
What is the partial pressure of O2 in an exercising muscle?
About 20mmHg (30%)
What factors affect Hb saturation?
Temperature
pH
CO2 pressure
2-3 diphosphoglycerate or DPG (a glycolysis byproduct)
True or False: O2 and CO2 are competitors, fighting for a common binding site on Hb
False.
How is most CO2 carried through the body?
As HCO3 in plasma (about 70%)
Which binds to Hb more easily, O2 or CO2?
CO2
What is Chloride shift?
At the tissues HCO3 diffuses into plasma to counterbalance the out rush of these negatively charged ions Cl ions move into the plasma
What does bicarbonate do in the lungs?
Moves into RBCs to bind with H+ and form H2CO3 (Carbonic acid), which binds with O2 to make water, which is released into the air
What is the Haldane Effect?
The amount of CO2 transported is affecres by the pressure of Oxygen in the blood (pO2)
The lower the pO2 the more CO2 can be carried
What is the Bohr Effect?
In the tissues as more CO2 enters the blood more O2 dissociates from Hb and Hb bonds with the CO2
How does CO2 affect acidity?
The more CO2 the more H+ ions, so the more acidic (lower pH)
What is the alkaline reserve of the bicarbonate buffer system?
HCO3- in plasma
How does slow shallow breathing affect blood pH?
Increases blood CO2 levels, causing pH to drop
Where are the central chemoreceptors?
The medulla oblongata
What is the function it the Dorsal Respiratory Group?
Integrates input from peripheral stretch and carotid/arterial chemoreceptors
What is the function of the Ventral Respiratory Group?
Generates eupnea (regular respiratory rate)
Is involves in forces resperation
What is the normal respiratory rate?
12-15 BPM
What is the function of the pneumotaxic and pneustic areas in pons?
Smooths inspiration and expiration transitions
What is breathing depth determined by?
How actively the resp. center stimulates the muscles
What controls breathing rate?
How long the Inspiratory Center is active
What are cortical controls?
Direct signals from the cerebral motor cortex that bypass medullary controls (things like taking a deep breath, holding one’s breath)
What does the hypothalamus have to do with breathing?
Emotional controls act through the limbic system to modify rate and depth (ie hyperventilating when angry)
What is hypercapnia?
Increase in PCO2
What does hyperventilation cause?
Low CO2 levels: cerebral vasoconstriction and ischemia
What are the 3 Chemical Factors affecting ventilation/respiration?
CO2 Levels (most important)
O2 levels
Blood pH
What causes apnea (a breathing cessation)?
Abnormally low O2
What nerve transmits carotid chemoreceptor information? What kind of information is this?
Vagus nerve; O2 levels
What factors increase ventilation?
Low blood pH, O2 below 60mmHg
What is the Pulmonary Irritant Reflex?
The reflexive constriction of airways
What is the Hering-Breuer reflex?
A stretch reflex that limits further increase of lungs when they hit max capacity
What happens to respiration during exercise?
pH lowers due to lactic acid build-up, proprioceptors stimulate respiration,
Hyperna occurs (10-20x increase in ventilation)
What happens to blood O2 at higher elevations?
Pressure decreases so pO2 decreases
High Altitude Pulmonary Edema - constriction of arteries in response tonlow blood O2, can cause coughing up “pink foam” due to bleeding alveoli
High Altitude Cerebral Edema - Increases cerebral blood flow. Decline in blood O2 stimulates erythrogenesis in bone marrow, eventuallt conpensates
What is the pressure conversion factor below sea level?
33ft = 1atm
What are COPDs, what are their leading causes?
Chronic Obstructive Pulmonary Disorders
Ex. Bronchitis, emphysema
Decrease ability to force air out of lungs
Huge ties to smoking
What is asthma?
A reversible COPD characterized by coughing, wheezing, inflammation, and broncgjhiospasms
Caused by an abnormal response from IgE
What causes tuberculosis?
Myobacterium
Why do premature babies have trouble breathing if the lungs function at 28 week?
Low surfactants, secretion does not start until 35-37 weeks
What is spirometry?
The measurement of inspiratory and expiratory respiratory volumes
What is Tidal Volume?
Avg 500mL, the volume of air inspired/expired at resting conditions
What is Inspiratory Resting Volume?
The largest volume of air one can inspire in addition to TV. IRV + TV= IC (bottom of curve to highest peak)
What is Expiratory Reserve Volume?
Largest volume one can expire after TV. TV + ERV = EC (top of curve to bottom of lowest)
What is residual volume?
Air trapped in the bon-collapsible airways (about 1200mL in male, 1100 in females) that exists to prevent lung collapse
What are the rates of tachypnea/bradypnea?
Above 20/below 12
What is Vital Capacity?
The maximum amount of air that can be exhales after a maximum inhalation (TV + IRC + ERC)
What is Alveolar Ventilation Rate?
RRx (TV-Dead Space) Dead Space is a constant roughly equal to weight in lbs in mL that does not contribute to gas exchange
What is minute ventilation rate?
Total amount of gas flow in or out of respiratory tract in one minute (RR x TV)
What is the difference between an obstructive pulmonary disorder and a restrictive pulmonary disorder?
Obstructive - Limits airflow due to increased resistance, deduce by measuring flow rates
Restrictive - Ability to inflate and deflate lungs reduced
