Chapter 41 - Chemical Signals in Animals Flashcards
Insulin
Decrease blood glucose level
Secreted by: beta-cells in pancreas
Antagonistic to glucagon
Glucagon
Glucagon
Increases blood glucose level
Secreted by: alpha-cells in pancreas
Tropic hormone
stimulates other endocrine gland to secrete hormones
(target cells are other endocrine glands)
Non-tropic hormone
directly causes response by binding to specific receptor
e.g. PEG - Prolactin, Endorphin, Growth hormones
Endocrine
- intercellular communication
- ductless gland
- receptors on target cells
- secreted into bloodstream
e. g. hormone
Exocrine
- extracellular communication
- gland with duct
e.g. sweat, sebum, digestive enzyme
Epinephrine (adrenaline)
= norepinephrine = adrenaline = noradrenaline
nor = methyl group absent
hydrophilic amine hormone
- belongs to catecholamine (two hydroxy phenols and amine)
- neurotransmitter
- produced in: adrenal medulla
- role: fight/flight response - raises blood glucose level, acts on pancreas, smooth muscle, digestive system
5 types of intercellular communication
1) Endocrine signaling
2) Paracrine signaling (local)
3) Autocrine signaling (local)
4) Synaptic signaling
5) Neuroendocrine signaling
Endocrine signaling
- local
- signal molecule: hormone
- secreting cell: endocrine gland
- route: blood stream to target cell with specific receptor
Paracrine signaling
- local
- signal molecule: local regulator
- secreting cell: neighbor cells
- route: interstitial fluid
e. g. cytokines, growth factors (polypeptides)
Autocrine signaling
- local
- signal molecule: local regulator
- secreting cell: they themselves are target cells
- route: interstitial fluid
e. g. cytokines, growth factors (polypeptides)
Synaptic signaling
- nervous system (neuron to neuron)
- signal molecule: neurotransmitter
- secreting cell: neurons (nerve cells)
- route: movement across synapse
e. g. inhibitory/excitatory neurotransmitters
Neuroendocrine signaling
- nervous system (neuron to bloodstream)
- signal molecule: neurohormones
- secreting cell: neurosecretory cells
- route: blood stream to target cell with receptor
e. g. oxytocin, ADH, TRH
ADH
antidiuretic hormone, vasopressin
produced in: hypothalamus
stored in : posterior pituitary gland
role: promotes retention of water by kidneys
TRH
TRH
Thyrotropin Releasing Hormone
tropic hormone
Prostaglandin
- local regulator (paracine, autocrine signaling)
- modified fatty acid
- found in prostate gland
- also in semen (cause contraction of uterine wall)
- promotes inflammation, pain sensing
Aspirin
painkiller
-blocks prostaglandin synthesis
(prostaglandin increases inflammation and immune response)
Ibuprofen
painkiller
-blocks prostaglandin synthesis
(prostaglandin causes inflammation)
Cytokines
polypeptides
enhance immune response
Nitrogen Oxide (NO)
- local regulator
- acts as neurotransmitter
-promotes vasodilation of blood vessel in penis (increases strength & duration of erection)
polypeptide (local regulator)
cytokines
growth hormones
Chemical classes of local regulators
1) prostaglandin
2) polypeptide
3) gas
Chemical classes of hormones
1) Polypeptide
2) amine
3) steroid
Polypeptide hormone
- most abundant
- hydrophilic
- binds to membrane receptors
e. g. insulin