Chemical Messengers z Neurotransmitters z Hormones z Neurohormones

Chemical Messengers z. Neurotransmitters z. Hormones z. Neurohormones 1

Types of Neurotransmitters z. Acetylcholine z. Serotonin z. Norepinephrine z. Dopamine z. Endorphins z. GABA z. Glutamate 2

Acetylcholine z. Found in neuromuscular junction z. Involved in muscle movements 3

Alzheimer’s Disease z Deterioration of memory, reasoning and language skills z Symptoms may be due to loss of ACh neurons 6

Serotonin z. Involved in sleep z. Involved in depression y. Prozac works by keeping serotonin in the synapse longer, giving it more time to exert an effect 7

Norepinephrine z. Arousal z“Fight or flight” response 8

Dopamine z. Involved in movement, attention and learning z. Dopamine imbalance also involved in schizophrenia z. Loss of dopamine- producing neurons is cause of Parkinson’s Disease 9

Parkinson’s Disease z Results from loss of dopamine-producing neurons in the substantia nigra z Symptoms include: ydifficulty starting and stopping voluntary movements ytremors at rest ystooped posture yrigidity ypoor balance 10

Parkinson’s Disease z. Treatments: y. L-dopa ytransplants of fetal dopamineproducing substantia nigra cells yadrenal gland transplants yelectrical stimulation of the thalamus to stop tremors 11

Endorphins z Control pain and pleasure z Released in response to pain z Morphine and codeine work on endorphin receptors Involved in healing effects of acupuncture 12

Endorphins z. Runner’s high feeling of pleasure after a long run is due to heavy endorphin release 13

Gamma-Aminobutyric Acid (GABA) z. Main inhibitory neurotransmitter z. Benzodiazepines (which include tranquilizers such as Valium) and alcohol work on GABA receptor complexes 14

Huntington’s Disease z Involves loss of neurons in striatum that utilize GABA z Symptoms: yjerky involuntary movements ymental deterioration 15

Glutamate z. Major excitatory neurotransmitter z. Too much glutamate (and too little GABA) associated with epileptic seizures 16

Hormones Hormonal communication z. Chemical messengers secreted into bloodstream Endocrine cells Bloodstream Target cells 17

Hormones vs. Neurotransmitters z Distance traveled between release and target sites yhormones travel longer distances yneurotransmitters - travel across a synaptic cleft (20 nm) z Speed of communication yhormones - slower communication yneurotransmitters - rapid, specific action 18

Hormones z. Released by organs, including the stomach, intestines, kidneys and the brain z. Also released by a set of glands called the endocrine system 19

Endocrine System z Consists of hormone-releasing glands z Includes: y hypothalamus y y y y pituitary gland adrenal glands thyroid gland parathyroid glands pineal gland pancreas ovaries and testes 20

Hypothalamus and Hormones z. Hypothalamus releases hormones or releasing factors which in turn cause pituitary gland to release its hormones 21

Pituitary Gland z“Master endocrine gland” z. Produces hormones that control hormone production in other endocrine glands 22

Pituitary Gland z. Also produces growth hormones z. Too little pituitary activity produces dwarfism z. Too much leads to gigantism 23

Pituitary Gland z. Also involved in breastfeeding z. Produces prolactin ystimulates milk production z. Produces oxytocin yinvolved in milk release 24

Adrenal Glands z Involved in stress response z Hormones released include: yepinephrine (a. k. a. adrenaline) ynorepinephrine (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 25 enable adaptation to stress.

Endocrine Glands z Thyroid gland - metabolism z Pineal gland - sleep and wakefulness z Pancreas - regulates blood sugar level z Ovaries and testes - secrete sex hormones such as testosterone and estrogen 26