How are Type IV hypersensitivity reactions different from all other types (I, II, or III) of hypersentivity reactions?

Smoking is a well-established risk factor for lung cancer, and the pathophysiological process underlying this association involves the exposure of the lungs to carcinogenic agents present in tobacco smoke. Here's why option C is the correct choice:

A) Vasoconstrictive properties of nicotine reduce oxygenation and stimulate metabolism:

While nicotine is a primary addictive component of tobacco smoke and can lead to vasoconstriction, reduced oxygenation, and increased metabolism, these effects primarily contribute to cardiovascular diseases associated with smoking, such as coronary artery disease and stroke, rather than the development of lung cancer.

B) Drug addiction changes the neurochemical messages in the brain causing cravings:

This statement addresses the addictive nature of nicotine and its impact on neurochemistry, leading to cravings and dependence. While addiction is a significant aspect of tobacco use, it does not directly explain the pathophysiological process by which smoking causes lung cancer.

C) Carcinogenic agents in tobacco alter cellular cytology, morphology, and function of the lung:

Correct. Tobacco smoke contains numerous carcinogenic compounds, such as polycyclic aromatic hydrocarbons (PAHs), nitrosamines, and benzene, which can directly damage the DNA of lung cells. This DNA damage can lead to mutations and alterations in cellular cytology, morphology, and function, ultimately contributing to the development of lung cancer.

D) Risk for comorbidities increase incidence of chronic diseases and decrease longevity:

While smoking is associated with an increased risk of various comorbidities and chronic diseases, such as cardiovascular diseases, respiratory diseases, and certain cancers, this option does not specifically address the pathophysiological process of lung cancer development.

A) The drug may be needed to treat a sudden systemic allergic reaction:

While cortisol may play a role in managing allergic reactions by suppressing inflammation, the primary reason for carrying a cortisol kit in Addison's disease is not typically related to managing allergic reactions.

B) Hypertensive crisis requires immediate treatment to prevent a stroke:

Hypertensive crisis may occur in some individuals with Addison's disease due to adrenal insufficiency, but the immediate treatment for this would typically involve fluids and intravenous hydrocortisone rather than carrying a cortisol kit for self-administration.

C) Hyperglycemia may require cortisol to lower the blood glucose level:

Cortisol can indeed influence blood glucose levels, but the need to carry a cortisol kit is primarily related to the management of adrenal insufficiency rather than hyperglycemia alone.

D) Stress increases the body's need for additional replacement hormone:

Correct. Individuals with Addison's disease have insufficient production of cortisol and often also lack aldosterone. During times of stress, such as illness, trauma, or surgery, the body's demand for cortisol increases to help cope with the stress. Inadequate cortisol production during stress can lead to adrenal crisis, a life-threatening condition. Therefore, carrying a cortisol kit allows the individual to promptly administer additional replacement hormone (usually hydrocortisone) during times of stress to prevent adrenal crisis.