Final answer:
Weather conditions do not influence insulin needs for diabetic patients, whereas vomiting, pregnancy, and exercise do. Insulin injections decrease blood sugar after a high-glucose meal and are necessary in diabetes due to the lack of sufficient insulin production.
Step-by-step explanation:
The question is addressing factors that could potentially affect the required dose of insulin for individuals with diabetes. Among the given options, weather conditions do not directly influence the amount of insulin a diabetic patient needs. The other factors, such as vomiting (a), pregnancy (c), and exercise (d), can indeed impact blood glucose levels and thus the need for insulin.
To clarify, insulin injections are used to help manage blood glucose levels. When a person eats a meal, especially one high in glucose, blood sugar levels rise. In response, insulin is needed to facilitate the transport and storage of glucose, thereby helping to decrease the blood sugar levels (d). However, in diabetic individuals, whose pancreases are under-producing insulin (b), this process is impaired, leading to the requirement for insulin injections. It's also important to note that insulin does not stimulate the breakdown of glycogen into glucose, nor does it stimulate the kidneys to reabsorb glucose back into the bloodstream; instead, it enables cells to take in glucose from the blood.
Negative feedback mechanisms that normally maintain blood glucose homeostasis cannot proceed in diabetic individuals due to inadequate or ineffective insulin production, which is why they need external insulin (a). Vomiting can affect insulin needs because it alters blood sugar levels by eliminating food intake that would normally elevate blood sugar. Pregnancy affects insulin needs due to changes in hormone levels and weight, which can increase insulin resistance. Exercise affects insulin needs by increasing glucose uptake by muscles, potentially lowering blood sugar levels and thereby altering insulin requirements.