Pulmonary/Respiratory Physiology

Question 1

Gas exchange occurs in the…

Answer 1

alveoli

Question 2

The lungs have many functions, list some.

Answer 2

• Gas exchange (alveolus)
• Regulation of H+ concentration (controls blood and body fluid pH)
• Partial or complete removal of neurotransmitters and paracrine agents from the bloodstream (endothelial cells of the pulmonary capillaries)
• Production and secretion of substances into the blood
• Acts as a sieve that traps and dissolves small blood clots

Question 3

Lungs are composed of elastic and inelastic properties. true or false?

Answer 3

true

Question 4

The surface tension of water in the fluid lining of the alveoli plays a major role in lung compliance with the strong attraction of water molecules to each other tending to…

Answer 4

pull the alveoli shut.

Question 5

Prevention of lung collapse as a result of water tension is due to the presence of a compound known as __________ (“soap” like compound found in the fluid of the lungs primarily composed of the phospholipid dipalmitoylphophatidylcholine (DPPC) plus proteins and produced by the type II alveolar cells).

Answer 5

surfactant

Question 6

Surfactant prevents the total collapse of the lungs by decreasing…

Answer 6

the surface tension of water.

Question 7

Pressures within the lungs are always compared to atmospheric pressure and calculated as a ______.

Answer 7

ΔP

Question 8

Intrapulomnary pressure at rest = _____________, so ΔP = __________

Answer 8

Intrapulmonary pressure = atmospheric pressure, so at rest ΔP = 0 mmHg

Question 9

Air moves from a region of _____ pressure to an area of ____ pressure.

Answer 9

high

low

Question 10

As lung volumes increase, alveolar opening/stretching pressures _________.

Answer 10

decrease

Question 11

As lung volumes decrease, alveolar wall recoil pressures _________.

Answer 11

increase

Question 12

Intrapulmonary pressure varies during respiration, such that intrapulmonary pressure is less than atmospheric pressure during __________ and greater than atmospheric pressure during ____________.

Answer 12

inspiration

expiration

Question 13

Intrapulmonary pressure refers to the pressure between _________.

Answer 13

alveoli

Question 14

Intrapleural pressure varies during respiration but is always _________ during normal breathing.

Answer 14

negative

Question 15

Transpulmonary pressure = measure of the…

Answer 15

distending force across the lungs. An increase in transpulmonary pressure = greater distending pressure across the lungs and the alveoli expand.

Question 16

Transpulmonary pressure = _________ - _________

Answer 16

Intrapulmonary pressure - Intrapleural pressure

Question 17

Increased volume occurs during ___________.

Answer 17

inspiration (to decrease pressure)

Question 18

Elevation of the ribs by the external intercostals = __________ anterior-posterior diameter of the chest.

Answer 18

increasing

Question 19

Downward movement of the diaphragm = lengthening of the __________

Answer 19

chest cavity

Question 20

As lung volumes increase, pressure within the lungs (intrapulmonary pressure) __________ and is now ______ than atmospheric pressure by -1 mmHg.

Answer 20

decreases

less

Question 21

Higher pressure outside the lungs than inside the lungs (pressure gradient) due to a decrease in intrapulmonary pressure creates a “_________” effect, therefore air moves from an area of _______ pressure (outside) to an area of ______ pressure (inside), filling the lungs with air until the pressure outside equals the pressure inside the lungs.

Answer 21

vacuum
high
low

Question 22

A(n) _______ in volume occurs during expiration.

Answer 22

decrease

Question 23

A(n) ________ in pressure occurs during expiration.

Answer 23

increase

Question 24

Relaxation of intercostals, upward movement of the diaphragm, and elastic recoil properties of the lungs decrease lung _________.

Answer 24

volumes (and decrease in thoracic cage volumes)

Question 25

Relaxation of the respiratory muscles stops the physical pull on the alveoli, causing the walls of the alveoli to recoil and "______" the alveoli.

Answer 25

close

Question 26

As lung volumes decrease, pressure within the lungs __________ and is now greater than _______________.

Answer 26

increase | atmospheric pressure

Question 27

During expiration the pressure gradient is from _______ to ________ and air flows...

Answer 27

inside outside out of the lungs until the pressure within the lungs is equal to atmospheric pressure.

Question 28

Dalton's Law:

Answer 28

each gas contributes to the total atmospheric pressure in direct proportion to it's relative concentration, therefore in mixture of gases, the pressure exerted by each gas is independent of the pressure exerted by the others.

Question 29

In the alveolus, changes occur such that partial pressure of O2 decreases, these changes are due to:

Answer 29

- Humidity - Temperature - CO2 mixing with incoming air

Question 30

There is a difference between the partial pressure of O2 in the alveolus and the arterial system, this is because not all O2 brought into the alveolus makes its way into the _________.

Answer 30

bloodstream

Question 31

A patient has an alveolar PO2 of 104 mmHg and an arterial PO2 of 80 mmHg. Could hypo-ventilation due to weakened respiratory muscles produce these values?

Answer 31

No. - The patient has normal alveolar PO2 of 104 mmHg, which means they must have normal respiratory activity with normal muscle contraction. - The patient has an abnormally low arterial PO2 of 80 mmHg, this is due to poor/altered gas exchange for example with infections, the alveoli can fill with cellular debris.

Question 32

Ventilation = __________ x __________

Answer 32

frequency (respiratory rate) x depth of breathing

Question 33

Total ventilation (at rest) = _________ /___________

Answer 33

amount inspired / (breath x respiratory rate) | = tidal volume / (respiratory rate)

Question 34

6000 cc/min =

Answer 34

normal healthy total ventilation for an adult

Question 35

Dead space ventilation =

Answer 35

amount of each tidal volume that remains in the non-gas exchanging portions of the airways

Question 36

Dead space is equal to body weight in lbs, a body weight of 150 lbs = _________ of dead space.

Answer 36

150 cc/breath

Question 37

Dead space ventilation/min = 1800 cc alveolar ventilation/min = 4200 cc and the ratio of dead space minute ventilation to total ventilation is: 1800/6000 = 0.30 A ratio increase or decrease can indicate...

Answer 37

ventilatory dysfunction

Question 38

Tidal volume = ___________________ and is usually ______cc

Answer 38

normal resting volume and is usually 500 cc

Question 39

Inspiratory reserve volume = __________________ and is usually ________cc

Answer 39

the maximum volume of air that can be increased above tidal volume and is usually around 2100 - 3200 cc

Question 40

Expiratory reserve volume = __________________ and is usually ________cc

Answer 40

the expiration of a volume of air after resting tidal volume has been expired and is usually around 1000 - 1200 cc

Question 41

Residual volume = ____________________ and is usually ________mL

Answer 41

volume of air remaining in the lungs after maximal expiration and is usually equivalent to 1200 mL

Question 42

_______________ is the amount of air retained after maximal expiration to help hold the alveoli open and prevent lung collapse.

Answer 42

Residual volume

Question 43

Forced vital capacity = ______________________ and is equal to ______ + _______ + ______ (is the measure of stretch and recoil)

Answer 43

maximum volume of air a person can expire after maximal expiration and is equal to inspiratory reserve volume + tidal volume + expiratory reserve volume

Question 44

Increased residual volume can indicate...

Answer 44

loss in elastic tissue and decrease recoil, resulting in increased retention of air of expiration.

Question 45

Healthy individuals with good lung function can expire approximately ________% of their vital capacity in 1 second.

Answer 45

80%

Question 46

Increased depth of breathing (increased tidal volume) will increase alveolar ventilation more effectively than increasing ______________________.

Answer 46

respiratory rate

Question 47

The _________________ controls both inspiration and expiration and contains the dorsal respiratory group neurons and the ventral respiratory group neurons.

Answer 47

medullary respiratory center

Question 48

Neurons of the dorsal respiratory group appear to integrate information from the peripheral stretch receptors and the chemo-receptors and communicate the information to the __________________.

Answer 48

ventral respiratory group

Question 49

The ventral respiratory group contain _________ neurons that excite the diaphragm and external intercostals resulting in the V and P changes to occur for inspiration.

Answer 49

inspiratory

Question 50

Within the ventral respiratory center is a rhythm generator composed of __________ that set basal/quiet breathing rates.

Answer 50

pacemaker cells

Question 51

Once inspiratory muscle contraction and inspiration has occurred, signals to the spinal motor cortex ______ and the external intercostals and diaphragm relax = passive expiration.

Answer 51

cease (stop)

Question 52

Cycle of breathing is composed of approximately ___ seconds of inspiration and _____ seconds in expiration with ________ breaths/minute = eupnea

Answer 52

2 seconds of inspiration 3 seconds in expiration 12-15 breaths/minute

Question 53

During severe hypoxia, the ventral respiratory group generates "_________" to try increase O2 intake.

Answer 53

gasping

Question 54

The ventral respiratory group contains expiratory neurons that are most active when...

Answer 54

increased ventilation is required (increased metabolism and activity).

Question 55

With increased ventilation, the ventral respiratory group expiratory neurons send signals to the expiratory muscles (internal intercostals and the rectus abdominus and the external abdominal obliques), resulting in contraction of these muscles and...

Answer 55

increases release of air from the lungs.

Question 56

The pontine respiratory centers found within the pons, modify the activity of the ________.

Answer 56

medulla

Question 57

Impulses from the pontine centers to the ventral respiratory group influence the transition between...

Answer 57

inspiration and expiration

Question 58

Some ventilation is under voluntary control (ex. coughing, singing) and controlled by centers in the thalamus and cerebral cortex of the central nervous system which sends input to the ________________.

Answer 58

pontine respiratory centers

Question 59

Rhythm for respiration may be set by several processes, list these processes:

Answer 59

1) specialized inspiratory neurons that act as pacemaker neurons 2) reciprocal inhibition of the interconnected neuronal networks in the medulla - most likely there are 2 sets of pacemaker neurons that inhibit each other and cycle the inhibition to set the rhythm.

Question 60

Inspiratory depth is altered by...

Answer 60

how actively the respiratory center stimulates the motor neurons serving the respiratory muscles.

Question 61

Increased depth of each breath results in increased _____________.

Answer 61

ventilation

Question 62

Rate of respiration = ___________________________.

Answer 62

how long the inspiratory center is active or how quickly it is switched off.

Question 63

Suppression of the __________ center can occur with: sleeping pills, morphine, and alcohol.

Answer 63

inspiratory

Question 64

Complete suppression of the inspiratory center = _________________.

Answer 64

cessation of breathing (apnea)

Question 65

Respiratory centers require "input" from receptors that monitor ____________ such as the central and peripheral chemo-receptors.

Answer 65

blood chemistry

Question 66

Central chemo-receptors are located throughout the brain stem and in the medulla, they respond to changes in the brain ________________.

Answer 66

extracellular fluid

Question 67

Increases in blood CO2 above the normal 40 mmHg (hypercapnia) stimulates the central chemo-receptors via increased blood H+ levels, increased carbonic acid, increased free H+, which in turn results in increased ________________.

Answer 67

ventilation

Question 68

Increased free H+ results in _____________ blood pH, which stimulates the central chemo-receptors to send information to the respiratory regulatory centers.

Answer 68

decreased

Question 69

Stimulation of the central chem-receptors due to decreased blood pH results in increased ventilation (increased depth and rate) which will result in increased release of ________ from the body.

Answer 69

CO2

Question 70

Peripheral chemo-receptors help maintain ventilation when the ________________ have become hypoxic and unable to function.

Answer 70

central chemo-receptors (brain centers)

Question 71

Carotid body chemo-receptors are located in the bifurcation of each carotid artery, these are the main _____________ sensors.

Answer 71

oxygen

Question 72

The carotid body chemo-receptors primarily monitor changes to _______________ , which will stimulate the peripheral chemo-receptors resulting in increased respiratory rate and depth of breathing.

Answer 72

arterial O2

Question 73

Oxygen levels need to drop significantly to 60 mmHg or below before ventilation changes occur. true or false?

Answer 73

true

Question 74

Aortic body chemo-receptors are found in the aortic arch, and monitor ______ blood released from the left ventricle.

Answer 74

O2 rich

Question 75

_________ chemo-receptors are sensitive to changes in arterial O2 levels.

Answer 75

Aortic body chemo-receptors

Question 76

Pulmonary receptors are located in the lungs and respond to...

Answer 76

a variety of irritating factors (smoke, pollutants, excess mucus, dust, pollen)

Question 77

__________ receptors communicate with the respiratory centers to initiate coughing.

Answer 77

Pulmonary receptors

Question 78

Dyspnea=

Answer 78

shortness of breath

Question 79

Tachypnea=

Answer 79

rapid breathing

Question 80

Bradypnea=

Answer 80

abnormally slow respiratory rate

Question 81

Apnea=

Answer 81

no inspiration/expiration

Question 82

Hyperventilation=

Answer 82

increased clearance of CO2 through increased respiratory rate = decreased arterial CO2 and possible alkalosis (increased pH, decreased H+)

Question 83

Hypoventilation=

Answer 83

inadequate CO2 clearance through decreased repiratory rate = increased arterial CO2 and possible acidosis (decreased pH, increased H+)

Question 84

Cheyne-Stokes Breathing=

Answer 84

periodic breathing with rise and fall patterns separated by periods of apnea = result of impaired central feedback mechanisms (need to accumulate large arterial concentrations of CO2 to trigger expiration)