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Phrenic muscles contract to increase the volume of the thoracic chamber resulting in inspiration.

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Important Questions on Breathing and Exchange of Gases

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Biology>Human Anatomy and Physiology-I>Breathing and Exchange of Gases>Mechanism of Breathing

Select the correct events that occur during inspiration.

(a) Contraction of diaphragm
(b) Contraction of external intercostal muscles
(c) Pulmonary volume decreases
(d) Intrapulmonary pressure increases

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Biology>Human Anatomy and Physiology-I>Breathing and Exchange of Gases>Mechanism of Breathing
Explain the process of inspiration under normal conditions.
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Biology>Human Anatomy and Physiology-I>Breathing and Exchange of Gases>Mechanism of Breathing
Which of the following sequences is correct to initiate inspiration?
(i) The contraction of external intercostal muscles raises the ribs and sternum.
(ii) Volume of thorax increases in the dorso-ventral axis.
(iii) Intrapulmonary pressure decreases.
(iv) Diaphragm contraction.
(v) Air rushes into lungs.
(vi) Volume of thorax increases in the anterior-posterior axis.
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Biology>Human Anatomy and Physiology-I>Breathing and Exchange of Gases>Mechanism of Breathing
Inspiration occurs when there is a negative pressure in the lungs with respect to atmospheric pressure. This negative pressure is achieved when
EASY
Biology>Human Anatomy and Physiology-I>Breathing and Exchange of Gases>Mechanism of Breathing
Exhalation is the process of expulsion of air through the respiratory tract. Which figure illustrates the process of exhalation?
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Biology>Human Anatomy and Physiology-I>Breathing and Exchange of Gases>Mechanism of Breathing
Involuntary breathing is controlled by the
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Biology>Human Anatomy and Physiology-I>Breathing and Exchange of Gases>Mechanism of Breathing
Which of the following statements about the mechanism of ventilation/breathing is incorrect?
MEDIUM
Biology>Human Anatomy and Physiology-I>Breathing and Exchange of Gases>Mechanism of Breathing
Select the incorrect statement w.r.t. the mechanism of breathing?
MEDIUM
Biology>Human Anatomy and Physiology-I>Breathing and Exchange of Gases>Mechanism of Breathing
Distinguish between inspiratory capacity and expiratory capacity.
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Biology>Human Anatomy and Physiology-I>Breathing and Exchange of Gases>Mechanism of Breathing
The ventilation movements of the lungs in mammals are governed by
HARD
Biology>Human Anatomy and Physiology-I>Breathing and Exchange of Gases>Mechanism of Breathing

Given below is a list of different steps (i-vi) involved in respiration.
(i) Utilisation of O2 by the cells for catabolic reactions.
(ii) Transport of gases by the blood.
(iii) Pulmonary ventilation by which atmospheric air is drawn in and CO2 is released out.
(iv) Release of resultant CO2 .
(v) Diffusion of O2 and CO2 between blood and tissues.
(vi) Diffusion of gases ( O2 and CO2 ) across alveolar tissues.

Select an option which has the correct sequence of all the steps.

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Biology>Human Anatomy and Physiology-I>Breathing and Exchange of Gases>Mechanism of Breathing
During expiration, the diaphragm becomes
MEDIUM
Biology>Human Anatomy and Physiology-I>Breathing and Exchange of Gases>Mechanism of Breathing
Distinguish between vital capacity and total lung capacity.
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Biology>Human Anatomy and Physiology-I>Breathing and Exchange of Gases>Mechanism of Breathing
The given figure illustrates the changes in lung volume during the process of breathing.
Question Image
The change from II to III indicates the:
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Biology>Human Anatomy and Physiology-I>Breathing and Exchange of Gases>Mechanism of Breathing
Intercostal muscles are attached to:
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Biology>Human Anatomy and Physiology-I>Breathing and Exchange of Gases>Mechanism of Breathing
According to Boyle's law, the product of pressure and volume is a constant. Hence,
MEDIUM
Biology>Human Anatomy and Physiology-I>Breathing and Exchange of Gases>Mechanism of Breathing
Which of the following changes occur in diaphragm and intercostal muscles when expiration of air takes place?
EASY
Biology>Human Anatomy and Physiology-I>Breathing and Exchange of Gases>Mechanism of Breathing
The amount of air exchanged in breathing can be measured with a
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Biology>Human Anatomy and Physiology-I>Breathing and Exchange of Gases>Mechanism of Breathing
Read the following statements (A – D).

(A) The movement of air in and out of the lungs is carried out by creating a pressure gradient between the lungs and atmosphere.
(B) Inspiration can occur if the pressure within the lungs is more than the atmospheric pressure.
(C) Expiration takes place when the intrapulmonary pressure is lesser than the atmospheric pressure.
(D) The diaphragm and a specialized set of intercostal muscles in between the ribs help in the generation of such pressure gradients for breathing.

How many of the following statements are correct?
MEDIUM
Biology>Human Anatomy and Physiology-I>Breathing and Exchange of Gases>Mechanism of Breathing
Distinguish between IRV and ERV.