Alveoli

Q. In heat transfer, which method is based on gravitation?

1. Natural convection
2. Conduction
3. Radiation
4. All of the above

Q. Which of the following is not part of the conducting zone of the respiratory system?

1. Oral cavity
2. Trachea
3. Bronchioles
4. Alveolar sacs

Q.

The alveoli are lined by simple squamous epithelium which is coated with a thin film of lecithin, a phospholipid. What purpose does this serve?

1. Lecithin reduces the friction between the millions of alveoli in the lungs

2. Lecithin protects against infections

3. Lecithin increases the surface tension and prevents the alveoli from bursting

4. Lecithin lowers the surface tension and prevents the alveoli from collapsing

Q. A body initially at ${80}^{\circ }\text{C}$ cools to ${64}^{\circ }\text{C}$ in $5$ minutes and to ${52}^{\circ }\text{C}$ after another $5$ minutes. The temperature of the surroundings is

1. ${15}^{\circ }\text{C}$
2. ${16}^{\circ }\text{C}$
3. ${20}^{\circ }\text{C}$
4. ${25}^{\circ }\text{C}$

Q. What are the types of cells present in the alveoli?

1. pneumocytes
2. acinocytes
3. alveocytes
4. macrophages

Q. A body cools from ${60}^{\circ }\text{C}$ to ${50}^{\circ }\text{C}$ in $10$ minutes. If the room temperature is ${25}^{\circ }\text{C}$ then the temperature of the body at the end of the next $10$ minutes will be

1. ${38.50}^{\circ }\text{C}$
2. ${40.25}^{\circ }\text{C}$
3. ${42.86}^{\circ }\text{C}$
4. ${45.75}^{\circ }\text{C}$

Q. When placed in air at ${30}^{\circ }C,$ the temperature of a body decreases from ${60}^{\circ }C\text{to}{50}^{\circ }C$ in ten minutes. After next ten minutes, its temperature will be-

1. Less than ${40}^{\circ }C$
2. ${40}^{\circ }C$
3. More than ${40}^{\circ }C$
4. Not definite

Q.

A unique feature common to the alveoli of lungs and the villi of the intestine is that both

1. Have ciliated columnar epithelium

2. Are suited for diffusion of gases

3. Provide a large surface area

4. Have a rich supply of blood vessels and lymph ducts

Q. A continuous flow water heater (geyser) has an electrical power rating $=2\text{kW}$ and efficiency of conversion of electrical power into heat $=80\%$. If water is flowing through the device at the rate of $100\text{cc/sec}$, and the inlet temperature is ${10}^{\circ }C$, the outlet temperature will be

1. ${12.2}^{\circ }C$
2. ${13.8}^{\circ }C$
3. ${20}^{\circ }C$
4. ${16.5}^{\circ }C$

Q. If the temperature of the surrounding is increased keeping all other parameters constant, then the rate of heat transfer from a comparatively hotter body due to convection will

1. not change
2. increase
3. decrease
4. first increases then decreases

Q.

The plateau portion of the $O_2-Hb$ curve________

1. Is in the blood-PPO₂ range that exists at the pulmonary capillaries.

2. Means that hemoglobin becomes almost nearly saturated in the lungs unless the pulmonary capillary PPO₂ falls below 60 mmHg.

3. Is in the blood-PPO₂ range that exists at the systemic capillaries.

4. Both (b) and (c) above are correct.

5. Both (a) and (b) above are correct.

Q.

Because of the steep portion of the $O_2-Hb$ curve_______

1. There is a good margin of safety in O₂-carrying capacity of the blood.

2. A small drop in systemic capillary PPO₂ in a metabolically active tissue automatically makes large amounts of O₂ available, because O₂ is released from hemoglobin as a result of a big drop in percent hemoglobin saturation.

3. O₂ loading is still almost normal even when alveolar PPO₂ falls up to 40%.

4. More O₂ is physically dissolved in the systemic capillaries than in the pulmonary capillaries.