Respiration during Exercise (1) Flashcards

1
Q

What is the primary purpose of the respiratory system?

A

To maintain arterial blood-gas homeostasis

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2
Q

maintenance of arterial blood-gas
homeostasis is accomplished by a 4-step process. What are the 4 steps?

A
  1. Pulmonary ventilation
  2. Alveolar gas exchange
  3. Gas transport
  4. Systemic gas exchange
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3
Q

What does the epiglottis do?

A

Separates the upper and lower respiratory tracts.

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4
Q

The lungs are enclosed within membranes called..?

A

Pleura

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5
Q

Is intrapleural pressure > or < than atmospheric pressure?

A

Intrapleural pressure < atmospheric pressure, which prevents the alveoli from collapsing

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6
Q

There are ~23 airway generations. What is the main bronchi?

A

The main bronchi is Z1; the conducting zone extends to the terminal bronchioles (Z16)

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7
Q

In terms of the airways, where does gas exchange occur?

A

Gas exchange occurs in the respiratory zone (Z17-23)

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8
Q

Where does pulmonary gas exchange take place?

A

Across the pulmonary capillary

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9
Q

How do O2 and CO2 move between air and blood?

A

Simple diffusion (high to low partial pressure)

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10
Q

There are 2 types of alveolar cell (pneumocytes), what are they?

A

o Type I cells cover ~95% of the internal
surface of the alveolus and are critical for gas exchange
o Type II cells release surfactant—a molecule that lowers the surface tension (like soap) - without surfactant alveoli would collapse.

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11
Q

What is the volume of gas passing through a sheet dependent upon?

A
  1. Surface area (A)
  2. Thickness (T)
  3. Diffusion coefficient (D)
  4. Pressure gradient (alveolar to arterial)
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12
Q

Alveolar gas has a diffusion path to the erythrocyte and includes 5 layers, what are these ?

A
  1. Surfactant (not shown)
  2. Alveolar epithelium (EP)
  3. Interstitium (IN)
  4. Capillary endothelium (EN)
  5. Plasma

The blood-gas barrier is very thin (0.3 μm) and has a vast surface area (50-100 m2) making it ideal for gas exchange/diffusion (Fick’s law)

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13
Q

The mechanics of breathing is concerned with the movement of air into and out of the lungs by changes in..?

A

pressure, flow and volume
contraction length = change in volume
contraction velocity = change in flow
contraction force = change in pressure

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14
Q

What does the bucket handle motion do?

A

increases the transverse (lateral) diameter of the thorax during
inspiration

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15
Q

What does the pump handle motion of the ribs do?

A

increases the anteroposterior diameter of the thorax during inspiration

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16
Q

What muscle is responsible for the majority of pulmonary ventilation at rest?

A

Diaphragm contraction (expiration is passive)

17
Q

During exercise, what muscle are the diaphragm assisted by?

A

external intercostal muscles, scalenes,
sternocleidomastoid and many others in
order to increase pulmonary ventilation 10 20-fold above resting levels

18
Q

When expiration become active, contraction of what muscles happen?

A

contraction of the rectus abdominis, internal intercostal muscles and external oblique (among others)

19
Q

What is Ohm’s law?

A

o Current = voltage/resistance, applied to breathing
o Airflow is dependent upon a pressure gradient and airway resistance

20
Q

What is Poiseuille’s law?

A

o Resistance is dependent upon length and radius of a tube
o Radius is raised to the fourth power, thus the major determinant of airway resistance

21
Q

What is the difference between a volume and a capacity?

A
  • A volume is one segment
  • A capacity is two or more segments
22
Q

What is ‘dead space’?

A

Not all air breathed reaches the alveoli; the volume of air not participating in gas
exchange is called dead space.

23
Q

What is forced vital capacity ?

A

the maximum volume air that can be forcefully expired after a maximum inspiration

COPD is characterised by increased airway resistance and a reduced FEV1/FVC