Exemplar Problems

Question:

Define the following:

(a) Exocrine gland

(b) Endocrine gland

(c) Hormone

Answer:

(a) Exocrine Gland:

• Definition: Exocrine glands are glands that produce and secrete substances onto an epithelial surface by way of a duct.

• Characteristics: These glands have ducts that carry their secretions to the specific site. The secretions may be released onto the skin or into body cavities.

• Examples: Sweat glands, salivary glands, and glands within the gastrointestinal tract like the pancreas (which secretes digestive enzymes).

(b) Endocrine Gland:

• Definition: Endocrine glands are ductless glands that produce and secrete hormones directly into the bloodstream.

• Characteristics: The hormones released by endocrine glands travel through the blood to reach their target organs or cells, where they exert their specific effects.

• Examples: Pituitary gland, thyroid gland, adrenal glands, and pancreas (which also functions as an endocrine gland by secreting insulin and glucagon).

(c) Hormone:

• Definition: A hormone is a chemical messenger that is secreted by glands in the endocrine system and transported by the bloodstream to target organs or cells, where it exerts regulatory influences on various bodily functions.

• Characteristics: Hormones are involved in regulating a wide range of physiological processes including growth, metabolism, and reproduction. They act at very low concentrations and have specific effects on the activity of cells that are often distant from their site of production.

• Examples: Insulin (regulates blood glucose levels), adrenaline (involved in the body’s fight-or-flight response), and estrogen (involved in reproductive and sexual development).