According to the Bohr effect, which of the following results from increased CO2 production in tissues?

A. Bronchioles: Bronchioles, labelled as C, are small-diameter airway passages that branch from the secondary (lobar) bronchi and lead to the alveolar ducts. They lack cartilage and are composed mainly of smooth muscle, which allows them to constrict or dilate to regulate airflow resistance and distribution within the lungs.

B. Left primary bronchus: The left primary bronchus, labelled as H, is a major airway that branches directly from the trachea and enters the left lung. It is wider, shorter, and more vertical on the right side than the left, but on the left, it angles more horizontally due to the heart’s position. It contains cartilage rings to maintain patency and directs airflow into the left lung.

C. Primary bronchi: Primary bronchi refer collectively to the right and left main bronchi that originate from the trachea. They are reinforced with cartilage and lined with ciliated epithelium and mucus-secreting cells to trap particles and propel mucus upward, protecting the lower respiratory tract from inhaled debris and pathogens.

A. Elevated oxygen levels in the blood: Abnormalities in oxygen delivery typically result in reduced oxygen availability, not elevated levels. Hyperoxia is uncommon in pathological states and does not reflect impaired tissue oxygenation.

B. Enhanced tissue repair: Adequate oxygen is necessary for tissue repair, but abnormalities in delivery compromise this process rather than enhance it. Insufficient oxygen impairs cellular metabolism, collagen synthesis, and wound healing.

C. Hypoxia, which can lead to cell death and organ damage: Inadequate oxygen delivery causes hypoxia, limiting aerobic metabolism and ATP production. Prolonged hypoxia damages cells and can progress to organ dysfunction or failure, making it the primary consequence of impaired oxygen transport.

D. Increased metabolic activity: Reduced oxygen delivery decreases, rather than increases, cellular metabolic activity. Cells may switch to anaerobic metabolism, generating less energy and producing lactic acid, which can further impair tissue function.