Chapter 14: Breathing and Exchange of Gases

Q11Written answer

Define the oxygen dissociation curve. Can you suggest any reason for its sigmoidal pattern?

Show solutionHide solution

Worked solution

Ans. The oxygen dissociation curve is a graph showing the percentage saturation of oxyhemoglobin at various partial pressures of oxygen.

Oxygen Dissociation Curve

The curve shows us the equilibrium of oxyhemoglobin and hemoglobin at different partial pressures.
The partial pressure of oxygen in the lungs is high, so hemoglobin binds to oxygen and forms oxyhemoglobin.
Tissues have low levels of oxygen, so oxyhemoglobin releases oxygen in tissues to form hemoglobin.
The sigmoid form of the dissociation curve is due to the binding of oxygen to hemoglobin. As the first oxygen molecule binds to hemoglobin, the binding affinity of the second oxygen molecule increases. The hemoglobin then attracts more oxygen.

Q12Written answer

Have you heard about hypoxia? Try to gather information about it, and discuss it with your friends.

Show solutionHide solution

Worked solution

Ans. Hypoxia is a condition characterized by insufficient or decreased oxygen supply to the lungs and caused by various extrinsic factors such as decreased pO2, insufficient oxygen, etc. The different types of hypoxia are;-.

Hypoxemic hypoxia

In this hypoxia, there is a decrease in the oxygen content of the blood due to the low oxygen partial pressure in the arterial blood.

Anaemic hypoxia

This hypoxia results in a decrease in haemoglobin concentration.

Stagnant or ischemic hypoxia

This type of hypoxia results in a lack of oxygen in the blood due to poor circulation. It occurs when a person is exposed to a cold temperature for a long period of time.

Histotoxic hypoxia

In this type of hypoxia, the tissues cannot use oxygen, which occurs with carbon monoxide or cyanide poisoning.

Common symptoms of hypoxia include:

Shortness of breath
Rapid breathing
Rapid heart rate
Lethargy
Confusion
Anxiousness
Slurred speech

Q13Written answer

Distinguish Between

(a) IRV and ERV

Inspiratory Reserve Volume (IRV)	Expiratory Reserve Volume(ERV)
This is defined as the maximum volume of the air that can be breathed in after a normal inspiration.	It is the maximum volume of air that can be exhaled i.e released out after a normal expiration.
It is approx 2500-3500 ml in human lungs.	It is approx 1000-1100 ml in human lungs.

(b) Inspiratory Capacity and Expiratory Capacity

Inspiratory Capacity (IC)

Expiratory Capacity (EC)

It is defined as the volume of the air that can be inhaled easily after a normal expiration.

It is defined as the volume of air that can be exhaled easily after a normal inspiration.

It comprises inspiratory reserve volume and tidal volume.

IC = TV + IRV

It comprises expiratory reverse volume and tidal volume.

EC = TV + ERV

(c) Vital Capacity and Total lung Capacity

Vital Capacity (VC)	Total lung Capacity (TLC)
It is defined as the maximum volume of air that can be exhaled easily after a maximum inspiration. It includes IC and ERV.	It is defined as the volume of air in the lungs after maximum inspiration. It includes IC, ERV, and residual volume.
It is approximately 4000 mL in the human lungs.	It is approximately 5000 – 6000 mL in the human lungs.

Show solutionHide solution

Worked solution

Solution coming soon.

Q14Written answer

What is Tidal volume? Find out the Tidal volume (approximate value) for a healthy human in an hour.

Show solutionHide solution

Worked solution

Ans. Tidal volume is defined as the volume of air that is inspired or expired during normal respiration. It is approximately 6000 to 8000 mL of air per minute.

The hourly tidal volume for a human with a good health is calculated as shown below:

Tidal volume = 6000 to 8000 mL/minute

Tidal volume in an hour = 6000 to 8000 mL ×(60 min)

= 3.6 x10 5 ml to 4.8x10 5 ml

Therefore, the hourly tidal volume for a human with good health is around

3.6 x10 5 ml to 4.8x10 5 ml.

My Cart

Your Cart 0

Textbook exercises