Video Transcript
Endocrine glands are often located
away from their target cells or organs in the body. Which system do most hormones use
to reach their target cells or organs? (A) The nervous system, (B) the
lymphatic system, (C) the blood circulatory system, (D) the digestive system.
To answer this question, we will
need to review what the endocrine system is and recall how it communicates with the
target cells and organs in the human body.
The endocrine system is a
communication system that consists of a series of glands located throughout the
human body. The main endocrine glands of the
human body are the pineal gland, the hypothalamus, the pituitary gland, the thyroid
gland, the thymus gland, the pancreas, the adrenal glands, and the ovaries in
females and the testes in males. These endocrine glands use hormones
to communicate and coordinate responses to different stimuli.
Endocrine glands secrete hormones,
which are chemical messengers that travel via the bloodstream to their target cells
or organs. The secreting cells in endocrine
glands produce the hormones which then move directly into the blood vessels. Once in the bloodstream, hormones
are able to move throughout the body using the circulatory system until they reach
their target cells or organs. Since hormones need to travel to
their target organs via the circulatory system, this type of communication can be
slow. However, while the response of
hormones is slow, the effects of hormones are long-lasting. So hormones are able to act on
their target organs anywhere in the body since they’re secreted into the
bloodstream. But this type of response is
slow.
With this information, we are able
to answer the question. Most hormones use the blood
circulatory system to reach their target cells or organs.
