Study Guide: Final Exam
Chapter 45: Hormones and the Endocrine System
Comparing the nervous and endocrine system, hormones released by the endocrine system are usually
slower but provides longer-lasting responses to stimuli such as stress.
There are 3 types of chemical pathways:
Endocrine, low blood glucose (stimulus to a receptor protein on an endocrine cell, production of a
hormone, release into blood vessel, target effectors, response)
Neurohormone, suckling (stimulus to sensory neuron in the brain, neurosecretory cell in hypothalamus
produces a hormone which is released into the blood, target effectors and response)
Neuroendocrine, a combination of the two (stimulus to the brain via a sensory neuron, neurosecretory cell
produces a hormone, released into blood, this hormone interlocks into a receptor protein on an endocrine
cell, another hormone is released into the blood, target effectors, response)
The three steps involved in a signal transduction pathway are reception, signal transduction and response.
Receptors may be present in the nucleus where gene expression may be affected (lipid soluble, or it may
be present on the membrane (water soluble) where a signal transduction pathway occurs and leads to a
change in cytoplasmic function.
An endocrine gland is a ductless gland that secretes hormones directly into the interstitial fluid, from
which they diffuse into the blood stream. Exocrine glands are
that secrete their products into
(duct glands). They are the counterparts to
, which secrete their products (
directly into the
Hormones are chemical signals that are released into the blood stream and communicates regulatory
messages within the body. Endocrine glands are glands that secrete hormones directly into the blood
stream. A target cell is the site where a hormone acts. A target cell receptor can be either on the surface
(water soluble proteins or amines) or in the nucleus (lipid-soluble steroids).
The three basic types of chemical messengers are proteins and peptides, amines, and steroids. Proteins,
peptides and amines are water soluble (need a receptor), but steroids are not (penetrate the membrane
A hormone can be thought of as a long distance chemical messenger, conveying information via the
bloodstream to target cells throughout the body. A local regulator transmits information to target cells
near the secreting cells. Chemicals called pheromones carry messages between different individuals of a