Which statement about the human gas exchange system is not...

Which statement about the human gas exchange system is not true? a. During inhalation, a subatmospheric pressure exists in the space between the lung and the thoracic wall. b. Smoking one cigarette can immobilize the cilia lining the airways for hours. c. The respiratory control center in the medulla responds more strongly to changes in arterial $\mathrm{O}_{2}$ concentration than to changes in arterial $\mathrm{CO}_{2}$ concentration. d. Without surfactant, the work of breathing is greatly increased. e. The diaphragm contracts during inhalation and relaxes during exhalation.

Which statement about the human gas exchange system is not true?
a. During inhalation, a subatmospheric pressure exists in the space between the lung and the thoracic wall.
b. Smoking one cigarette can immobilize the cilia lining the airways for hours.
c. The respiratory control center in the medulla responds more strongly to changes in arterial $\mathrm{O}_{2}$ concentration than to changes in arterial $\mathrm{CO}_{2}$ concentration.
d. Without surfactant, the work of breathing is greatly increased.
e. The diaphragm contracts during inhalation and relaxes during exhalation.

Key Concepts

Pleural Pressure Dynamics

This concept involves understanding how the negative pressure, or subatmospheric pressure, in the pleural cavity between the lung and thoracic wall assists in lung expansion during inhalation. It is crucial in explaining how the lungs inflate as the chest wall expands.

Mucociliary Clearance

This refers to the function of the cilia lining the airways, which play a vital role in removing debris and pathogens from the respiratory tract. Impairment of ciliary function, such as by smoking, can lead to decreased clearance and increased risk of respiratory infections.

Respiratory Chemoreception and Control

This key concept covers how the respiratory control centers, particularly in the medulla, monitor blood gas levels through chemoreceptors. Normally, these centers are more sensitive to carbon dioxide changes than oxygen, making CO2 the primary driver of respiratory rate adjustments.

Surfactant Function

Surfactant is a substance that reduces surface tension within the alveoli, thereby preventing their collapse and reducing the work of breathing. Its presence ensures efficient gas exchange and mechanical stability during respiration.

Diaphragm Mechanics

The diaphragm plays a central role in breathing through its contraction and relaxation. During inhalation, the diaphragm contracts, increasing the thoracic cavity volume, and during exhalation, it relaxes, reducing the volume, thereby facilitating the movement of air in and out of the lungs.

Transcript

00:01 Okay, more to answer this question we have to talk about the lungs mechanics.

00:05 First, remember that if this is your trachean, bronchial, and your lungs, in order for you to breath or for air to gush inside of your respiratory air, the pressure in the atmosphere has to be greater than the pressure here in the land.

00:30 Because remember that oxygen or air is going to move from higher concentrations to lower concentrations so in order for air to gushing at the atmospheric pressures has to be greater than the pressure inside of the lungs okay also in order to control ventilation or respiration okay it means remember that that normal respiratory weight wages from 16 to 20 breath per minute.

01:04 Okay, so we have central chemo -gceptors and peripheral chemogeceptors.

01:16 The central chemo -ggeceptors are located in the medulla, while the peripheral chemo -giceptors are located in the carotid body and also in the aortic.

01:30 Arch okay those and the locations of the peripheral and the central chemo receptors in the central chemo receptors are more more sensitive to changes in carbon dioxide while the peripheral chemogeceptors are more sensitive to changes in oxygen pressure okay so also remember that if this is one albulous okay, the alveolus, when we inhale, it is going to expand.

02:04 It's going to become bigger, okay? it is direct when we inhale.

02:09 And when we exhale after inhaling, it is going to get to it to its normal shape, practically.

02:18 The alveoli is never going to get like this, like this, like it.

02:25 Why? because there is something here called surface.

02:33 Okay normally an alveoli without surfactant here there is going to be a pressure attention okay that is going to attract this side to this side in the same here the same here it is going to be a surface tension okay so in order to prevent this some cells pneumocytes type 2 are going to produce a surfactant okay and and this surfactant is going to prevent this is going to decrease the surfacitation in other words okay in order to prevent lung or alveoli collapsing okay because when your albiolai is going to be collapsed it is going to be like this for example imagine imagine this is collapse it is like a like a balloon try to stick your a balloon with water and then try to to to deflate it and then deflate it and you will see that the two sides this side and this side are going to be to be very sticky together because of the tension okay so it is going to be very hard to separate this side from this side so this is why we have to prevent alveoli collapsing and this is why we have surface station okay so let's see the answers now the options option a says that during inhalation a sub -atmospheric pressure exists in the space between the lung and the thoracic wall.

04:04 And this is true because if this is your lung, and this is your chest wall, then between the thoracic wall and the lungs, there is a space that is called the plural space...

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