Resp. 2 - Resp cycle and dynamics of vent

Question 1

Spirometry

Answer 1

• The drum is calubrated and as the person breathes, it measures how much air enters and leaves

Question 2

Lung volumes

Answer 2

• Tidal volume
• Expiratory reserve volume
• Inspiratory reserve volume
•

Question 3

• Tidal volume →

Answer 3

the volume of air moved IN OR OUT of the respiratory tract (Breathed) during each ventilatory cycle.

Question 4

• Expiratory reserve volume →

Answer 4

the additional volume of air that can be forcibly exhaled following a normal expiration; it can be accessed simply by expiring maximally to the Maximum Voluntary Expiration.

Question 5

• Inspiratory reserve volume →

Answer 5

the additional volume of air that can be forcibly inhaled following a normal inspiration; it can be accessed simply by inspiring maximally, to the Maximum Possible Inspiration

Question 6

Residual volume →

Answer 6

the volume of air remaining in the lungs after a Maximal Expiration; it cannot be expired no matter how vigorous or long the effort; RV cannot be measured with a spirometry test; RV = FRC - ERV

(Always a small volume of air remaining in the lungs – prevents collapsing of the alveoli)

Question 7

Capacities:

Answer 7

• Vital capacity (VC)
• Inspiratory capacity (IC)
• Functional Residual Capacity (FRC)
• Total Lung Capacity (TLC)

Question 8

• Vital capacity (VC) →

Answer 8

the maximal volume of air that can be forcibly exhaled after a Maximal Inspiration; VC = TV + IRV + ERV

Question 9

• Inspiratory capacity (IC) →

Answer 9

the maximal volume of air that can be forcibly inhaled; IC = TV + IRV

Question 10

• Functional Residual Capacity (FRC) →

Answer 10

the volume of air remaining in the lungs at the end of a normal expiration; FRC = RV + ERV

Question 11

• Total Lung Capacity (TLC) →

Answer 11

the volume of air in the lungs at the end of a Maximal Inspiration; TLC = FRC + TV + IRV = VC + RV

Question 12

What can we not measure with the spirometer

Answer 12

• We cannot measure residual volume with the spirometry test and as a result we cannot measure all the capacities that have residual volume as a component of the capacity itself.

Question 13

Inspiration:

Answer 13

CNS sends an excitatory drive to the muscles of inspiration (diaphragm) → muscles contract = increase in the thoracic volume → intrapleural pressure becomes more negative → transpulmonary pressure (which is dependent on the intrapleural pressure) increases → increase in lung volume → decrease the alveoli pressure → alveoli pressure will be smaller than the atmospheric pressure → a difference in pressure generates movement of gas → gas will move from a region of high pressure to a region of low pressure → alveolar pressure is smaller so air will move from the atmosphere into the lungs

Question 14

Expiration:

Answer 14

Relaxation of the inspiratory muscles → chest wall recoils (goes back to its resting state) → intrapleural pressure moves back to a pre-inspiratory value→ as transpulmonary pressure is equal to the alveolar pressure minus the intrapleural pressure, the transpulmonary pressure will also will be reduced as the intrapleural pressure returns to pre-inspiratory values → as transpulmonary pressure is also linked to lung volume, lungs recoil and a reduce volume, generating compression of the gas molecules inside the alveoli → increase in alveolar pressure so it is greater than the atmospheric pressure → air will move from a region of high pressure to a region of low pressure, flowing out of the lungs to the environment

Question 15

All points follow Boyles Law, accept for 2 points in inspiration and 2 in expiration, where they follow ideal gas law, this is because at these point your chnaging the # of mol. of gas at these points

Answer 15

• point B where vol. INC. and aveolar press. INC.

* point D where vol. DEC. as aveolar press. DEC.

Question 16

The types of ventilation measurements

Answer 16

• Minute ventilation (Vf) = RR x Vt
• Alveolar ventilation (Va) = PPx(vt-Vd)
• DEADSPACE ventilation (Vd)

Question 17

Tachypnea:

Answer 17

rapid breathing (rate) / shallow breathing / hyperventilation

• no alveolar ventilation = no gas exchange
• reduced tidal volume, increased rate

Question 18

Deep breathing

Answer 18

High tidal volume, low rate = very high alveolar ventilation = lots of gas exchange

Question 19

Hyperpnea:

Answer 19

any increase in breathing rate and/or depth (e.g., exercise)

Question 20

• Compliance gives indication of

Answer 20

stiffness or rigidity of structure

• LOW COMPLIENCE = stiff / rigid (not good, cuz takes more E to expand it)
• HIGH COMPLIENCE = less stiff, requires less E to inflate or deflate.

Question 21

Formula for compliance

Answer 21

C= DELTA V / DELTA P

DELTA P = Ptp

Ptp = Pa = Pip

Question 22

lung compliance:

Answer 22

• determined by both dynamic and static properties
• Occurs in the absence or presence of airflow
• Measure of elasticity

Question 23

• The proprieties of the lung are diff when you expire VS inspire, that’s why the curves aren’t exactly the same, this is called

Answer 23

hysteresis.

Hysteresis curve gives info on COMPLIENCE. Now we have lung COMPLIENCE during inflation or expiration.

Question 24

If the curve is more to the right, tends to be

Answer 24

Less compliant

Question 25

Is inflation or expiration have more compliance

Answer 25

• Inflation curve is less compliant. at point 2, only 25% lung capacity
• Expiration curve is more compliant, at point 2, its at around 80% lung capacity.

Question 26

What determines compliance

Answer 26

Surface tension

Question 27

Why is there less surface tension during deflation then inflation

Answer 27

Deflation contains more surfactin

Question 28

• When the lungs were INFLATED with liquid, the hysteresis was

Answer 28

eliminated, and all the curves shift to the left = greater compliance, its more compliant then expiration because the liquid inside eliminated surface tension.

Question 29

What do you need for surface tension to exist?

Answer 29

• you need an air-water interface for surface tension to exist.

That’s why when u inflate lung with liquid, ST is gone.

Question 30

a measure of the attracting forces acting to pull a liquid’s surface molecules together at an air-liquid interface

Answer 30

• would cause alveoli to collapse as they contain liquid

- produce elastic recoil of lungs

Question 31

Surfactant is a

Answer 31

phospholipid, has hydrophilic head, oriented towards water, and hydrophobic tails that’s orientated away from water.

Question 32

How does surfactant work?

Answer 32

The overall effect of positioning the surfactant at the interface is that it breaks the strong attractive forces that occur between the molecules of water at the
surface

Question 33

Does emphysema give more or less compliance and why?

Answer 33

More compliance

• due to smoke = destroy lung tissue = elasticity
• Inhalation = easy. Exhalation = hard

Question 34

Does fibrosis give more or less compliance and why?

Answer 34

Less compliant

= stiff lungs require more E to inhale

• more surface tension and less surfactant
• overproduction of callogen

Question 35

Increased resistance in the tissues does what to airflow

Answer 35

Is decreases airflow, therefore, when R INC, it takes a lot more E to move the same V of air into and out of the lungs.