5 points about chicken experiment
- testes removed and reimplanted into abdomen
- OR testes removed and NOT reimplanted
- Reimplanted roosters were just like ones where testes not removed
- conclusion that hormonal signal need not be into blood and has widespread effects
hormones are
substances secreted from endocrine glands and the brain
neurotransmitters are
substances released by nerve cells in the brain and peripheral nervous system
neuropeptides are
substances released from neurons and endocrine glands
cytokines are released by
cells of the immune system
methods of communication between cells
- intracrine 2. autocrine 3. paracrine 4. neurocrine 5. endocrine 6. neuroendocrine
intracrine communication
cell producing messengers and communicating within itself
autocrine communication
chemical messengers sent out into interstitial fluid and acts externally on itself and other cells (that are of the same cell type)
paracrine communication
chemical messengers are released externally to neighboring cells of a different type
neurocrine communication
diffuse a short distance and affect a different type of cell
endocrine communication
chemical messengers travel from endocrine cells into the bloodstream to distant locations in body
neuroendocrine communication
chemical messengers do not diffuse across synapse but rather are secreted directly into the bloodstream coming from a neural cell. looks like neuron acts like gland
types of chemical messengers
- phyto hormones 2. true hormones 3. neurohormones 4. neurotransmitters 5. pheromones 6. parahormones 7. prohormones 8. growth factors 9. cytokines 10. adipokines 11. vitamins
phytohormones are
plant hormones ie. kinins, auxins, gibberellins.
factoid about phytohormones
similar to human hormones and may influence the human neuroendocrine system
true hormones are
chemical messengers synth in endocrine glands and secreted into bloodstream
endocrine glands have no
ducts
true hormones do what?
act on specific target cell receptors and cause biochemical action in target cells
neurohormones are
hormones which are released by neurosecretory cells via the p. pit into circulation OR via portal system into A. pit
neurotransmitters are
messengers that are released by presynaptic nerve cells into the synapse and stimulate postsynaptic receptors
pheromones are
volatile chemical messengers synthesized in exocrine glands secreted into environment
exocrine glands have
ducts
pheromones do what
act on other individuals, usually of same spp through olfaction or gustatory means and alters behaviour in that animal
primer effects
effects of pheromones on neuroendocrine system
releaser effects
effects of pheromones on behaviour
parahormones are
hormone like substances that are not produced in endocrine glands but have some of the same properteies of hormones
examples of parahormones
histamine, prostaglandins, vit D
prohormones can be either
large peptide molecules or steroid molecules converted into bioactive steroids
growth factors are
hormone-like substances which promote growth of body/b rain tissue (ie NGF/EGF)
cytokines are
hormone like factors released from cells of immune system
cytokines regulate
activity of immune system
adipokines are
hormones secreted from fat cells eg. leptin
vitamins are
chemical messengers that regulate metabolism, growth, and development in the body
vitamin D is syth in X and has Y properties
in body; hormone-like
problems with definition of hormones
- not all regulators are hormones 2. different quantities 3. some not synthesized in true endocrine glands 4. some secrete into csf and blood stream 5. some have specific targets or act on many cells 6. some have specific functions, others general