Respiratory 3: cycle +mechanics Flashcards Preview

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Flashcards in Respiratory 3: cycle +mechanics Deck (25)
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1
Q

Define respiration

A

To extract oxygen fro the air and together with the cardiovascular system transport it to respiring tissues
2. To remove carbon dioxide from respiring tissues and exhaust into the atmosphere

2
Q

As respiration evolved from diffusion in protozoa, to lungs in reptiles and mammals what were the main factors that drove the change

A

There was increase in the size of the tissue, therefore distance for diffusion increased.
Increase metabolic rate means more gas needed

3
Q

List the main muscles associated with breathing and their nervous innervation

A

Diaphragm is innervated by phrenic nerve which comes from phrenic motor nucleus (C3-C5)
-The internal (exp) and external (insp) intercostal muscles are innervated by the internal and external intercostal nerves that come from the intercostal motor neurones (T1-L1)

-The abdominal muscles are innervated by the abdominal nerve which comes from the abdominal motor neurones (T7-L1)

4
Q

Where do the nerves that innervate the muscles for breathing go to from the spinal cord

A

These motor neurons are excited by the brainstem (medulla oblongata +pons) which makes a neural rhythm to control expiration and inspiration to occur not at the same time. However there is the ability to voluntarily adjust breathing

5
Q

When are the abdominal muscles involved breathing

A

During active expiration. (eg cough, laugh, exercise) Doesn’t contract at rest.

6
Q

What is the intra pleural pressure vs the intra pulmonary pressure

A

The intra pleural pressure is the pressure inside the pleural cavity outside the lung and the intra pulmonary pressure is the pressure within the lung, within the respiratory zone prob

7
Q

How does the respiratory volume , intra pulmonary pressure and intra pleural pressure change during inspiration

A

The pleural pressure decreases from a negative pressure to an even more negative pressure. This causes the intra pulmonary pressure to go from atm down to negative pressure. This causes air to move from higher pressure (atm) to lower pressure, increasing volume of air in lungs. As volume increase to a peak the pulmonary pressure rises back up to atm (in a cup shape) .

8
Q

How does the respiratory volume , intra pulmonary pressure and intra pleural pressure change during exspiration

A

The intra pleural pressure starts to rise from its most negative point back to becoming less negative as air leaves. This causes the pulmonary pressure to become more positive relative to atm. This means that air moves out so the volume decreases from the peak of the bell curve back down to 0.

9
Q

Why is it important for the pleural cavity to have a negative pressure in regards

A

This means that the visceral and parietal membranes stick together joining the chest wall to the lungs. This means that the lung doesn’t collapse

10
Q

What is Pneumothorax

A

Thoracic puncture wound where air rushes into the chest and there is a loss of the negative pressure of the pleura. The lung moves away from the chest wall and deflates and its hard to maintain those changes in pressure to inflate the lungs

11
Q

How does the lungs inflate

A

As the diaphragm and intercostal muscles contract they increase the volume of the intra pleural space and this also increase the volume of the intra pulmonary space This means that the pressure of the intra pleural space decreases. As a result the atm tries to equalise the pressure by pushing air inside the lungs.

12
Q

How is lung volume measured

A

With spirometer where the oxygen volume in a floating drum (floating in water) is attached to a tube to breathe into means that while breathing you can push the drum up and down and measure the volume

13
Q

What is the difference between a respiratory volume and capacity

A

Volume is measured whereas capacity is calculated from the measured values

14
Q

What is the tidal volume

A

This is the normal resting volume that comes in when you breath (peak to trough)

15
Q

What is the inspiratory reserve volume vs the expiratory reserve volume

A

Inspiratory reserve is the maximum volume that can be inhaled after the peak of the normal tidal breath. Whereas expiratory reserve is the maximum volume that can be expired after the expiration of a tidal breath

16
Q

What is the residual volume

A

The volume of air left in lungs after maximum effort exhaling because its trapped underneath collapsed air ways due to expiration forces. It cannot be blown out

17
Q

Compare the inspiratory capacity and the functional residual capacity

A

Inspiratory capacity is tidal volume + inspiratory reserve volume

Functional residual capacity is the expiratory reserve volume and the residual volume. Thisi also known as the resting point of the lung before the next breathing in.

18
Q

What is the vital capacity

A

Expiratory reserve volume + inspiratory capacity. This the total volume of air that can be inhaled and exhaled.

19
Q

What is Total lung capacity and what parts are measurable

A

The vital capacity (can measure) + residual volume (can’t measure).

20
Q

What is minute ventilation

A

This is the respiratory volume over a certain time. (Time derivative)

=the number of tidal respiratory cycles over time (minute) (frequency) x the tidal volume.

21
Q

What is hyperventilation vs hypoventilation

A

Breathing greater than 6L/min is hyperventilation and Breathing less than 6L/min is hypoventilation

22
Q

What is alveolar ventilation, how calculated and why important

A

This is the rate of ventilation within the respiratory zone -> actually contributing to respiration.
Va = minute ventilation - dead space ventilation (the air inside the conducting zone (2.2mL/kg/ 0.15 L)

23
Q

How is special residual volume measured

A

An inert gas that doesn’t enter the blood (eg Helium) is put inside the drum of spirometer instead of oxygen. It is allowed to equilibriate inside the person and therefore C1V2 = C2 (V1 +V2) can be used to find V2 = total lung capacity which can be used to calculate residual volume.

24
Q

How is lung health found from vitalographs

A

It measures the rate at which you can blow out a maximum expiratory volume. The forced expiratory volume in 1 second is compared to the forced vital capacity (total amount of air you can blow out). If there is a ratio of 80% then healthy

25
Q

What would be the ratio % of the FEV1 to FVC for an asthmatic

A

It is more difficult to breathe out as more resistance. You cannot blow out as much and not as fast so both FEV1 and FVC would be small