Chapter 3 - Synapse Flashcards Preview

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Flashcards in Chapter 3 - Synapse Deck (83):
1

Neuronal Signaling

neuron cell sends neurotransmitters that are received by protein receptors on target cell

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Neuronal Signaling

neuron cell sends neurotransmitters that are received by protein receptors on target cell

3

Endocrine Signaling

hormones are sent from endocrine cell into bloodstream. if cell has receptor for hormone, it will affect that cell.

4

Paracrine Signaling

cell releases chemical in local environment to cells nearby. binds with receptor proteins on local target cells

5

Contact-dependent signaling

signaling cell has molecule on the surface of the cell, that whole cell binds/stimulates target cell that has receptor for that molecule

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Synpase

zone in which neuron communicates with another neuron, muscle, or gland

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Synaptic cleft

~ 0.02 micrometers wide; really small but big enough for charge to travel across space; transmission across cleft is chemical by way of neurotransmitter fiber axon

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Postsynaptic membrane

contains receptor proteins

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Ionotropic effect

Neurotransmitter temporarily binds with membrane surface receptor site on protein channel that directly opens/closes a ligand-gated channel *need to know gradients for direction of flow*

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Metabotropic effect

neurotransmitter temporarily binds with receptor protein coupled to G-protein (GTP-binding-protein), which activates second messenger cascade inside the cell

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Ionotropic vs Metabotropic

Ionotropic: fast (10ms), short lived (30ms), longer lasting (seconds, minutes, hours), modulates the excitability of cells and strength of synaptic connections. important in learning and memory

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Second Messenger

cyclic AMP

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cAMP

activates cyclic-nucleotide-gated ion channels; activates protein kinases (open and close ion channels, affect certain intracellular biochemical reactions, affect gene expression)

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Excitatory Postsynaptic Potential (EPSP)

graded depolarization in postsynaptic cell caused by Na+ entering cell as a result of neurotransmitter molecules binding with their receptor sites on the postsynaptic membrane

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Inhibitory Postsynaptic Potential (IPSP)

graded hyperpolarization in post synaptic cell caused by K+ leaving cell or Cl- entering cell as a result of (concentration gradient) neurotransmitter molecules binding with their receptor sites on post synaptic membrane

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What decays over space and time?

Graded potentials - EPSPs and IPSPs

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Spacial Summation

EPSPs and IPSPs delivered simultaneously at different locations on cell sum together

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Temporal Summation

EPSPs and IPSPs delivered close in time can sum together

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Types of Neurotransmitters

Acetylcholine, Monoamines, Amino Acids, Peptides, ATP and Adenosine, and Nitric Oxide

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Monoamines

have1 amine group, made primarily from amino acids

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Catecholamines

dopamine, norepinephrine, epinephrine (all part of same synthetic pathway)

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Catecholamines

dopamine, norepineph

23

Endocrine Signaling

hormones are sent from endocrine cell into bloodstream. if cell has receptor for hormone, it will affect that cell.

24

Paracrine Signaling

cell releases chemical in local environment to cells nearby. binds with receptor proteins on local target cells

25

Contact-dependent signaling

signaling cell has molecule on the surface of the cell, that whole cell binds/stimulates target cell that has receptor for that molecule

26

Synpase

zone in which neuron communicates with another neuron, muscle, or gland

27

Synaptic cleft

~ 0.02 micrometers wide; really small but big enough for charge to travel across space; transmission across cleft is chemical by way of neurotransmitter fiber axon

28

Postsynaptic membrane

contains receptor proteins

29

Ionotropic effect

Neurotransmitter temporarily binds with membrane surface receptor site on protein channel that directly opens/closes a ligand-gated channel *need to know gradients for direction of flow*

30

Metabotropic effect

neurotransmitter temporarily binds with receptor protein coupled to G-protein (GTP-binding-protein), which activates second messenger cascade inside the cell

31

Ionotropic vs Metabotropic

Ionotropic: fast (10ms), short lived (30ms), longer lasting (seconds, minutes, hours), modulates the excitability of cells and strength of synaptic connections. important in learning and memory

32

Second Messenger

cyclic AMP

33

cAMP

activates cyclic-nucleotide-gated ion channels; activates protein kinases (open and close ion channels, affect certain intracellular biochemical reactions, affect gene expression)

34

Excitatory Postsynaptic Potential (EPSP)

graded depolarization in postsynaptic cell caused by Na+ entering cell as a result of neurotransmitter molecules binding with their receptor sites on the postsynaptic membrane

35

Inhibitory Postsynaptic Potential (IPSP)

graded hyperpolarization in post synaptic cell caused by K+ leaving cell or Cl- entering cell as a result of (concentration gradient) neurotransmitter molecules binding with their receptor sites on post synaptic membrane

36

What decays over space and time?

Graded potentials - EPSPs and IPSPs

37

Spacial Summation

EPSPs and IPSPs delivered simultaneously at different locations on cell sum together

38

Temporal Summation

EPSPs and IPSPs delivered close in time can sum together

39

Types of Neurotransmitters

Acetylcholine, Monoamines, Amino Acids, Peptides, ATP and Adenosine, and Nitric Oxide

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Monoamines

have1 amine group, made primarily from amino acids

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Histamine

some make you drowsy, involved with sleep circuits

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Catecholamines

dopamine, norepineph

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Serotonin

5-hydroxytryptamine

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What's an inhibitory neurotransmitter amino acid?

Gamma-aminobutyric acid (GABA), glutamate, glycine

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Peptides

Chains of amino acids; endorphins, subtance P, neuropeptide Y, angiotensin II; made in cell and transported to terminal, packaged into vessicles, or leak out of end bulb with proper stimulus

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ATP and Adenosine

ATP fuels metabolic reactions in cell, Adenosine part of ATP

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acetylcholinesterase (protein)

bound to postsynaptic membrane and catalyzes breakdown of acetylcholine

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Monoamine Oxidase (MAO)

deaminates norepinephrine and serotonin. found in variety of cells

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Catechol-O-Methyltransferase (COMT)

inactivates catecholamines. Broad specificity and found in variety of cells. important in kidney and liver. found in presynaptic terminals

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Uptake by Glia

Glia contain transporter proteins that help remove neurotransmitters that have diffused away from synaptic cleft

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Agontist

Chemical that mimics effects of neurotransmitter

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Antagonist

Chemical that suppresses the effects of neurotransmitter

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Neuroactive Effect of Drugs that affect Neurotransmitters in following ways:

Cause vessicles to leak, increase release, decrease reuptake, blocking breakdown into inactive chemical, directing stimulating or blocking postsynaptic receptors

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Subtypes

numerous given for given neurotransmitter; neurotransmitter binds with all subtypes; serve different functions in neuron and often differently distributed in brain; serotonin has 15 known subtypes

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Amphetamine (speed)

displaces NE and DA (dopamie) from vesicles allowing them to leak out of the nerve terminal. "Crashing" occurs several hours after administration due to depletion of NE and DA stores bc of loss from diffusion away from synpatic cleft.

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Cocaine

blocks reuptake of DA, NE, and 5-HT (serotonin). most behavioral effects thought to be related to effects on dopamine. "crashing" occurs

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Methylphenidate (Ritalin)

prescribed for ADD; blocked reuptake of DA (dopamine) but with much slower kinetics (less potency) than coaine, affects are more gradual and less severe. increases release of serotonin (5-HT)

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Lysergic Acid diethylamide (LSD)

stimulates 5-HT2 receptors, hallucinogenic drug

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Tetrahydrocannabinol (THC)

active ingredient in marijuana. Binds w/ canabanoid receptors found in hippocampus, basal ganglia, and cerebellum (almost completely absent in medulla).

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Anandamine and sn-2-arachidonylglycerol

endogenous neurotransmitters floating around in brain

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Nicotine

stimulates nicotinic acetylcholine receptors on skeletal muscles and in brain. found on domaminergic neurons in areas of brain known to be involved with processing "reward". active ingredient in cigarettes

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Opiates

derived from opium poppy plant. include morphine and heroin. stimulate opioid receptors

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Hormones

Chemical signals released into circulation by endocrine glands and affect specific target cells: peptide and steroids (derived from cholesterol)

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2 lobes of pituitary gland

anterior lobes and posterior lobes

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posterior pituitary

neurons send axons down to pituitary stalk, axon terminals end within pituitary stalk.

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2 important hormones produced from axons from hypothalamus

vasopression and oxytocin; made in hypothalamus and released into poterior pituitary

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anterior pituitary

other cells release releasing hormone, gets released into circulation that goes directly in anterior pituitary; cells in anterior pituitary store and release certain hormones directly into circulation

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negative feedback loop

thyroxine and triodothyronine released from thyroid glands; stimulates growth and metabolism

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hypothalamus

contains TSH, stimulates cells that hold TSH, release TSH, goes throughout body but only stimulates thyroid gland, releases thyroxine and triiodothyronine

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TSH

releasing hormone released into circulation, goes directly into anterior pituitary

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Central Nervous System

brain, spinal cord

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Peripheral Nervous System

somatic and autonomic

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somatic portion

carries information to and from sensory receptors and muscles. primarily efferent

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autonomic portion

mediates internal body adjustments through its influence over glands, cardiac muscle, and smooth muscle. primarily efferent

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Sagittal plane

left to right side

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coronal plane

front to back

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horizontal

upper brain and lower brain

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anterior

rostral

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posterior

caudal

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dorsal

toward top of back of brain

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ventral

lower, towards the belly

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medial

toward midline

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lateral

away from midline