Video Transcript
Complete the following sentence. Hormones are primarily released from the blank glands in the human body.
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 release substances with a specific function. However, the nature of this substance and the mechanism by which they are released
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 secrete 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 and fill in the blank
in the statement. The type of gland that releases hormones in the human body is an endocrine gland.
