Question

05. In metabolically active tissue, how does hemoglobin respond in comparison to its action in a less metabolically active environment?

a. it releases more O₂.

b. it releases less O₂.

c. it releases more CO₂.

d. it releases less CO₂.

e. the response depends on the tissue.

06. Which of the following conditions would increase the rate of oxygen diffusing from the alveolar space in the lungs into the blood?

a. increasing the binding rate of O₂ to hemoglobin.

b. decreasing the partial pressure of O₂ in the lung.

c. increasing the partial pressure of O₂ in the blood.

d. decreasing the hematocrit.

e. increase partial pressure of CO₂ in the lung.

07. Which of the following is characteristic of the mammalian lung?

a. the trachea and bronchi are particularly short.

b. ventilation is tidal.

c. exhalation relies on muscle-mediate compression of the pleural cavity.

d. crosscurrent air and blood flow.

e. air and blood flow in opposite directions.

08. Which of the following underlies lung expansion during inhalation?

a. the diaphragm contracts upward.

b. the shoulder girdle moves upward.

c. the volume of the pleural cavity increases.

d. lung tissue actively stretches.

e. the lung tissue rebounds from exhalation.

Answer 1

5. It release more oxygen

• Bohr effect describes hemoglobin’s lower affinity for oxygen secondary to increases in the partial pressure of carbon dioxide and decreases in blood pH.
• This lower affinity, in turn, enhances the unloading of oxygen into tissues to meet the oxygen demand of the tissue.

6. Increase the binding rate of oxygen to haemoglobin

• The partial pressure of oxygen with in alveoli is higher than partial pressure of oxygen in blood
• This create pressure gradient and diffusion of oxygen take place from alveoli to blood.
• Partial pressure of carbon dioxide higher in blood than alveoli  
• Hence carbon dioxide diffuse from blood to alveoli and exhaled
• Oxygen get diffused into blood and taken into tissues

7. Ventilation is tidal

Tidal volume is the lung volume representing the normal volume of air displaced between normal inhalation and exhalation when rest

• The flow of air is in the opposite direction from blood flow, and gas exchange takes place much more efficiently. This type of breathing enables birds to obtain the requisite oxygen, even at higher altitudes where the oxygen concentration is low.
• crosscurrent air and blood flow seen in bird lungs
• In man the trachea is about 15 centimetres long and 2 to 3 centimetres in diameter.

8. the volume of the pleural cavity increases.

• When we  inhale your diaphragm contracts and moves downward.
• This increases the space in your chest cavity, and your lungs expand into it.
• The muscles between your ribs also help enlarge the chest cavity.
• They contract to pull your rib cage both upward and outward when you inhale.