1. Chemical Messengers
Neurotransmitters
Hormones
Neurohormones

2. Types of Neurotransmitters
Acetylcholine
Serotonin
Norepinephrine
Dopamine
Endorphins
GABA
Glutamate
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3. Acetylcholine Found in neuromuscular junction
Involved in muscle movements

4. Alzheimer’s Disease
Deterioration of memory, reasoning and language skills
Symptoms may be due to loss of ACh neurons

5. Serotonin Involved in sleep Involved in depression
Prozac works by keeping serotonin in the synapse longer, giving it more time to exert an effect

6. Norepinephrine
Arousal
“Fight or flight” response

7. Dopamine Involved in movement, attention and learning
Dopamine imbalance also involved in schizophrenia
Loss of dopamine- producing neurons is cause of Parkinson’s Disease

8. 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

9. Parkinson’s Disease Treatments: L-dopa
transplants of fetal dopamine-producing substantia nigra cells
adrenal gland transplants
electrical stimulation of the thalamus to stop tremors

10. Endorphins Control pain and pleasure Released in response to pain
Morphine and codeine work on endorphin receptors Involved in healing effects of acupuncture

11. Endorphins
Runner’s high - feeling of pleasure after a long run is due to heavy endorphin release

12. Gamma-Aminobutyric Acid (GABA)
Main inhibitory neurotransmitter
Benzodiazepines (which include tranquilizers such as Valium) and alcohol work on GABA receptor complexes

13. Huntington’s Disease
Involves loss of neurons in striatum that utilize GABA
Symptoms:
jerky involuntary movements
mental deterioration

14. Glutamate Major excitatory neurotransmitter
Too much glutamate (and too little GABA) associated with epileptic seizures

15. Hormones Chemical messengers secreted into bloodstream
Hormonal communication
Endocrine
cells
Blood-
stream
Target
Chemical messengers secreted into bloodstream

16. 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

17. Hormones
Released by organs, including the stomach, intestines, kidneys and the brain
Also released by a set of glands called the endocrine system

18. Endocrine System Consists of hormone-releasing glands Includes:
hypothalamus
pituitary gland
adrenal glands
thyroid gland
parathyroid glands
pineal gland
pancreas
ovaries and testes

19. Hypothalamus and Hormones
Hypothalamus releases hormones or releasing factors which in turn cause pituitary gland to release its hormones

20. Pituitary Gland “Master endocrine gland”
Produces hormones that control hormone production in other endocrine glands

21. Pituitary Gland Also produces growth hormones
Too little pituitary activity produces dwarfism
Too much leads to gigantism

22. Pituitary Gland Also involved in breastfeeding Produces prolactin
stimulates milk production
Produces oxytocin
involved in milk release

23. Adrenal Glands Involved in stress response Hormones released include:
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
enable adaptation to stress.
Involved in stress response
Hormones released include:
epinephrine (a.k.a. adrenaline)
norepinephrine (a.k.a. noradrenaline)

24. 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