Chapter 3 - Synapse Flashcards
Neuronal Signaling
neuron cell sends neurotransmitters that are received by protein receptors on target cell
Neuronal Signaling
neuron cell sends neurotransmitters that are received by protein receptors on target cell
Endocrine Signaling
hormones are sent from endocrine cell into bloodstream. if cell has receptor for hormone, it will affect that cell.
Paracrine Signaling
cell releases chemical in local environment to cells nearby. binds with receptor proteins on local target cells
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
Synpase
zone in which neuron communicates with another neuron, muscle, or gland
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
Postsynaptic membrane
contains receptor proteins
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*
Metabotropic effect
neurotransmitter temporarily binds with receptor protein coupled to G-protein (GTP-binding-protein), which activates second messenger cascade inside the cell
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
Second Messenger
cyclic AMP
cAMP
activates cyclic-nucleotide-gated ion channels; activates protein kinases (open and close ion channels, affect certain intracellular biochemical reactions, affect gene expression)
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
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
What decays over space and time?
Graded potentials - EPSPs and IPSPs
Spacial Summation
EPSPs and IPSPs delivered simultaneously at different locations on cell sum together
Temporal Summation
EPSPs and IPSPs delivered close in time can sum together
Types of Neurotransmitters
Acetylcholine, Monoamines, Amino Acids, Peptides, ATP and Adenosine, and Nitric Oxide
Monoamines
have1 amine group, made primarily from amino acids
Catecholamines
dopamine, norepinephrine, epinephrine (all part of same synthetic pathway)
Catecholamines
dopamine, norepineph
Endocrine Signaling
hormones are sent from endocrine cell into bloodstream. if cell has receptor for hormone, it will affect that cell.
Paracrine Signaling
cell releases chemical in local environment to cells nearby. binds with receptor proteins on local target cells
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
Synpase
zone in which neuron communicates with another neuron, muscle, or gland
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
Postsynaptic membrane
contains receptor proteins
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*
Metabotropic effect
neurotransmitter temporarily binds with receptor protein coupled to G-protein (GTP-binding-protein), which activates second messenger cascade inside the cell
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
Second Messenger
cyclic AMP
cAMP
activates cyclic-nucleotide-gated ion channels; activates protein kinases (open and close ion channels, affect certain intracellular biochemical reactions, affect gene expression)
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
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
What decays over space and time?
Graded potentials - EPSPs and IPSPs
Spacial Summation
EPSPs and IPSPs delivered simultaneously at different locations on cell sum together
Temporal Summation
EPSPs and IPSPs delivered close in time can sum together
Types of Neurotransmitters
Acetylcholine, Monoamines, Amino Acids, Peptides, ATP and Adenosine, and Nitric Oxide
Monoamines
have1 amine group, made primarily from amino acids
Histamine
some make you drowsy, involved with sleep circuits
Catecholamines
dopamine, norepineph
Serotonin
5-hydroxytryptamine
What’s an inhibitory neurotransmitter amino acid?
Gamma-aminobutyric acid (GABA), glutamate, glycine
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
ATP and Adenosine
ATP fuels metabolic reactions in cell, Adenosine part of ATP
acetylcholinesterase (protein)
bound to postsynaptic membrane and catalyzes breakdown of acetylcholine
Monoamine Oxidase (MAO)
deaminates norepinephrine and serotonin. found in variety of cells
Catechol-O-Methyltransferase (COMT)
inactivates catecholamines. Broad specificity and found in variety of cells. important in kidney and liver. found in presynaptic terminals
Uptake by Glia
Glia contain transporter proteins that help remove neurotransmitters that have diffused away from synaptic cleft
Agontist
Chemical that mimics effects of neurotransmitter
Antagonist
Chemical that suppresses the effects of neurotransmitter
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
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
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.
Cocaine
blocks reuptake of DA, NE, and 5-HT (serotonin). most behavioral effects thought to be related to effects on dopamine. “crashing” occurs
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)
Lysergic Acid diethylamide (LSD)
stimulates 5-HT2 receptors, hallucinogenic drug
Tetrahydrocannabinol (THC)
active ingredient in marijuana. Binds w/ canabanoid receptors found in hippocampus, basal ganglia, and cerebellum (almost completely absent in medulla).
Anandamine and sn-2-arachidonylglycerol
endogenous neurotransmitters floating around in brain
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
Opiates
derived from opium poppy plant. include morphine and heroin. stimulate opioid receptors
Hormones
Chemical signals released into circulation by endocrine glands and affect specific target cells: peptide and steroids (derived from cholesterol)
2 lobes of pituitary gland
anterior lobes and posterior lobes
posterior pituitary
neurons send axons down to pituitary stalk, axon terminals end within pituitary stalk.
2 important hormones produced from axons from hypothalamus
vasopression and oxytocin; made in hypothalamus and released into poterior pituitary
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
negative feedback loop
thyroxine and triodothyronine released from thyroid glands; stimulates growth and metabolism
hypothalamus
contains TSH, stimulates cells that hold TSH, release TSH, goes throughout body but only stimulates thyroid gland, releases thyroxine and triiodothyronine
TSH
releasing hormone released into circulation, goes directly into anterior pituitary
Central Nervous System
brain, spinal cord
Peripheral Nervous System
somatic and autonomic
somatic portion
carries information to and from sensory receptors and muscles. primarily efferent
autonomic portion
mediates internal body adjustments through its influence over glands, cardiac muscle, and smooth muscle. primarily efferent
Sagittal plane
left to right side
coronal plane
front to back
horizontal
upper brain and lower brain
anterior
rostral
posterior
caudal
dorsal
toward top of back of brain
ventral
lower, towards the belly
medial
toward midline
lateral
away from midline
