Video Transcript
Which of the following best
explains the key difference between an endocrine and an exocrine gland? (A) Exocrine glands secrete
substances via ducts, whereas endocrine glands secrete substances directly into the
bloodstream. Or (B) endocrine glands secrete
substances via ducts, whereas exocrine glands secrete substances directly into the
bloodstream.
This question asks us about the
difference between endocrine and exocrine glands. All glands within the body release
a substance with a specific function. But the substances they release and
the mechanism by which the glands release them is what differentiates the different
types of glands.
Endocrine glands secrete hormones
directly into the bloodstream. Hormones are chemical messengers
that travel throughout the body via the blood to cause specific effects. For example, an endocrine gland
called the thyroid gland releases a hormone called thyroxine into the blood, with
various target cells and effects. Thyroxine plays a number of roles,
such as stimulating brain development, physical growth, and even regulating our
metabolism.
Exocrine glands produce and secrete
substances, such as enzymes, via tubelike structures called ducts onto body
surfaces. For example, the salivary glands
secrete a substance called saliva through salivary ducts onto the inner surface of
our mouths. Saliva contains enzymes that break
down large carbohydrates in our food into smaller simple sugars.
Using this information, we can
deduce that the answer that best explains the key difference between an endocrine
and an exocrine gland is (A). Exocrine glands secrete substances
via ducts, whereas endocrine glands secrete substances directly into the
bloodstream.
