Pulmonary Respiration — Chapter 10 Flashcards

1
Q

Function of the pulmonary respiratory system

A
  1. Provides a means of gas exchange between the environment and the body.
  2. Regulation of acid-base balance during exercise.
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2
Q

Definitions – ventilation and diffusion

A

Ventilation – the mechanical process of moving air into and out of lungs.

Diffusion – Process by which O2 moves out of lungs into the blood, and CO2 moves from blood into lungs.

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3
Q

Purpose of the different zones of the respiratory system

A

Divided into 2 functional zones

Conducting Zone:

  1. Conducts (moves) air through the trachea, bronchi, bronchioles, and terminal bronchioles to the respiratory zone.
  2. Humidifies, warms, and filters the air (via mucus and macrophages)
    No exchange of gases b/t lungs and blood here

Respiratory Zone:

  1. Exchange of gases between lungs and blood occurs in alveoli of respiratory bronchioles and in alveolar sacs.
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4
Q

How many alveoli are estimated to exist in the lungs?

A

About 300 million alveoli

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5
Q

Importance of the diaphragm for ventilation

A

Diaphragm initiates the pressure change inside lungs. It stimulates contraction several times per minute.

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6
Q

Active vs. passive phases of ventilation

A

Inspiration (Active)
o Lowering the diaphragm expands the volume of the chest cavity, intrapulmonary pressure is decreased (2-3 mmHg below atmospheric pressure of 760 mmHg or 757 mmHg)

o Create a “vacuum”, allows air to flow into the bronchial passages.

Expiration (Passive)
o Diaphragm relaxes, elastic recoil of the alveoli raises the intrapulmonary pressure (about 763 mmHg)

o Air is forced out of lungs

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7
Q

Average tidal volume and breathing frequency for healthy adult

A

0.5 L x 15 = 7.5 L/min

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8
Q

Alveolar vs. dead-space ventilation

A
  1. Alveolar ventilation (Va) (about 0.35 L out of 0.5 L)
    o Volume of “fresh air” that reaches the respiratory zone each minute.
  2. Dead Space ventilation (Vd) (about 0.15 L out of 0.5 L)
    o Not all air that passes the lips reaches the respiratory zone (remains in conducting zone); this unused ventilation is called dead space ventilation.
     Inflammation = increases Vd
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9
Q

Dalton’s law of partial pressures

A

The total pressure of a gas mixture is = to the sum of the pressure that each gas would exert independently.
o O2 = 20.93  159 mmHg
o CO2 = 0.03  0.3 mmHg
o N2 = 79.04  600.7 mmHg
Total = 100  760 mmHg

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10
Q

Definition of diffusion

A

Random movement of molecules from high to low concentration.
o Gases diffuse from high to low partial pressure

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11
Q

Definition of diffusion

A

Random movement of molecules from high to low concentration.
o Gases diffuse from high to low partial pressure

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12
Q

Fick’s law of diffusion – factors that influence gas movement in the body

A

Rate of gas transfer across tissues depends on :
o Vgas = rate of diffusion
o A = tissue area
o T = tissue thickness
o D = diffusion coefficient of gas
o P1-P2 = difference in partial pressure of the gas on the 2 sides of the tissue

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