Chapter One: Chemical Messengers Flashcards
Neuroendocrinology
The study of how the brain controls the endocrine sysyems
Hormones
a) chemical messengers which are biologically effective in minute quantities
b) synthesized in ductless or endocrine glands
c) secreted into the blood stream
d) act on specific target cell receptors
e) exhibit specific physiological action on the target cell
Neurohormones
Hormones released by hypothalamic neurosecretory cells via the posterior pituitary into circulation OR via the portal system into the anterior pituitary
Neurotransmitters
Released by presynaptic nerve cells into a synapse where they stimulate receptors on a postsynaptic nerve cell
Pheromones
Chemical messengers
Synthesized in exocrine glands
secreted into the outside environment, not the bloodstream
Act on other individuals through olfaction/gustatory receptors
Alter behaviour or the neuroendocrine systems
Parahormones
Hormone-like chemical messenger which is generally not produced in an endocrine gland, but has all of the qualifications of a true hormone
E.g., histamine, prostoglandins
Prohormones
Large peptide molecules which get spliced into hormones
Growth Factors
Hormone-like substances which promote growth of body or brain tissue
Cytokines
Hormone-like factors released from lymphocytes, macrophages and other cells of the immune system which regulate immune activity e.g., interleukins
Adipokines
Hormone class secreted from fat (adipose) cells e.g., leptin
Vitamins
Chemicals which regulate metabolism, growth, and development in the body (vitamins can be synthesized in the body)
Intracrine signaling
Hormones synthesized and used in the same cell
Autocrine communication
Hormones act on the cells that secrete them by exiting and reentering the cell
Paracrine communication
Hormones act on adjacent cells
Neurocrine communication
Close range communication between neurons
Endocrine communication
Hormones are released into the bloodstream and act on cells at distant sites
Neuroendocrine communication
Neuropeptides are released from presynaptic neurons into the synapse and act on postsynaptic receptors in the CNS and peripheral nervous system
Phytohormones
Plant hormones - auxin, gibberellins
Neuropeptides
Hormonal or non-hormonal peptide that acts as a neuroregulator
Neuromodulator
Chemical messenger (neuropeptide) that is released by brain cells to act on neurons and modulate their response to a neurotransmitter
