Video Transcript
State the type of gland, endocrine
or exocrine, that is described as a gland that secretes hormones directly into the
bloodstream.
To answer this question, we need to
be able to distinguish between two different glands in the human body: endocrine
glands and exocrine glands.
All glands secrete substances with
a specific function. However, the nature of the
substance and the mechanism by which the gland releases them differs, depending on
whether the gland is endocrine or exocrine. Let’s take a look at exocrine
glands first, by examining an exocrine gland you might be familiar with already,
salivary glands.
Different exocrine glands secrete a
variety of substances. For example, the salivary glands
produce and secrete saliva which contains enzymes. These secretions are made via
tubelike structures, called ducts, onto body surfaces that can either be internal or
external.
For example, the salivary glands
secrete saliva via salivary ducts into the mouth, an inner body surface. In the mouth, the enzymes in saliva
can break down large carbohydrates in the food we eat into smaller sugars that are
easier for our body to absorb and use. A different exocrine gland, the
sweat glands, instead secretes sweat via sweat ducts onto an external body surface,
the skin.
Let’s take a look at endocrine
glands next by examining an example, the adrenal glands.
Endocrine glands secrete specific
chemical messengers called hormones. Among the many different hormones
that they can produce and secrete in response to internal and external environmental
changes, the adrenal glands secrete a hormone called adrenaline in response to
intensely stressful situations. These secretions enter the
bloodstream directly from the endocrine cells that produce them. The blood transports these hormones
throughout the entire body so that they can reach their specific target cells to
cause a particular effect.
For example, adrenaline can help to
increase our heart rate among its many other effects, which aids our ability to
fight through or escape from whatever stressful situation triggered its release.
Now, we have enough information to
answer our question correctly. The type of gland that secretes
hormones directly into the bloodstream is an endocrine gland.
