What does the term 'endocrinology' refer to?

Endocrinology specifically refers to the branch of medicine that focuses on the study of glands and hormones. This field involves understanding how these glands, such as the thyroid, pituitary, and adrenal glands, produce hormones that regulate various bodily functions, including metabolism, growth, development, tissue function, and mood, among others. By examining the hormonal imbalances or disorders, endocrinologists can diagnose and treat conditions such as diabetes, thyroid diseases, and hormonal imbalances.

The other fields referenced in the other options focus on different systems of the body—hematology relates to blood and its disorders, immunology pertains to the immune system, and cardiology deals with the heart. Each of these disciplines has its unique focus and methodologies distinct from those of endocrinology.