Download Endocrine System

Chemical Messengers
Neurotransmitters
Hormones
Neurohormones
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Types of
Neurotransmitters
Acetylcholine
Serotonin
Norepinephrine
Dopamine
Endorphins
GABA
Glutamate
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Acetylcholine
Found in
neuromuscular
junction
Involved in
muscle
movements
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Alzheimer’s Disease
Deterioration of
memory,
reasoning and
language skills
Symptoms may
be due to loss of
ACh neurons
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Serotonin
Involved in sleep
Involved in depression
Prozac works by keeping serotonin
in the synapse longer, giving it
more time to exert an effect
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Norepinephrine
Arousal
“Fight or flight” response
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Dopamine
Involved in movement, attention
and learning
Dopamine imbalance also
involved in schizophrenia
Loss of dopamine- producing
neurons is cause of Parkinson’s
Disease
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Parkinson’s Disease
Results from loss of dopamine-producing
neurons in the substantia nigra
Symptoms include:
difficulty starting and stopping voluntary
movements
tremors at rest
stooped posture
rigidity
poor balance
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Parkinson’s Disease
Treatments:
L-dopa
transplants of fetal dopamineproducing substantia nigra cells
adrenal gland transplants
electrical stimulation of the
thalamus to stop tremors
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Endorphins
 Control pain and
pleasure
 Released in response
to pain
 Morphine and codeine
work on endorphin
receptors Involved in
healing effects of
acupuncture
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Endorphins
Runner’s high feeling of
pleasure after
a long run is
due to heavy
endorphin
release
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Gamma-Aminobutyric Acid
(GABA)
Main inhibitory neurotransmitter
Benzodiazepines (which include
tranquilizers such as Valium) and
alcohol work on GABA receptor
complexes
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Huntington’s Disease
Involves loss of
neurons in
striatum that
utilize GABA
Symptoms:
jerky involuntary
movements
mental
deterioration
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Glutamate
Major excitatory neurotransmitter
Too much glutamate (and too
little GABA) associated with
epileptic seizures
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Hormones
Hormonal communication
Chemical
messengers
secreted into
bloodstream
Endocrine
cells
Bloodstream
Target
cells
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Hormones vs.
Neurotransmitters
Distance traveled between release and
target sites
hormones travel longer distances
neurotransmitters - travel across a
synaptic cleft (20 nm)
Speed of communication
hormones - slower communication
neurotransmitters - rapid, specific action
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Hormones
Released by organs, including the
stomach, intestines, kidneys and
the brain
Also released by a set of glands
called the endocrine system
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Endocrine System
 Consists of hormone-releasing glands
 Includes:
 hypothalamus
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pituitary gland
adrenal glands
thyroid gland
parathyroid glands
pineal gland
pancreas
ovaries and testes
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Hypothalamus and
Hormones
Hypothalamus releases
hormones or releasing factors
which in turn cause pituitary
gland to release its hormones
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Pituitary Gland
“Master endocrine gland”
Produces hormones that control
hormone production in other
endocrine glands
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Pituitary Gland
Also produces growth hormones
Too little pituitary activity
produces dwarfism
Too much leads to gigantism
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Pituitary Gland
Also involved in breastfeeding
Produces prolactin
stimulates milk production
Produces oxytocin
involved in milk release
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Adrenal Glands
 Involved in stress
response
 Hormones released
include:
epinephrine
(a.k.a.
adrenaline)
norepinephrine
(a.k.a.
noradrenaline)
Shadowy figure
Brain interprets stimulus
as fearsome.
Hypothalamus secretes
corticotropin-releasing
factor into blood portal
path to anterior pituitary.
Anterior pituitary secretes
corticotropin, carried by
blood to the adrenal gland.
Adrenal secretes cortisol
and other hormones.
The adrenal hormones act
on various tissues to
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enable adaptation to stress.
Endocrine Glands
Thyroid gland - metabolism
Pineal gland - sleep and wakefulness
Pancreas - regulates blood sugar level
Ovaries and testes - secrete sex
hormones such as testosterone and
estrogen
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