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Balliet Sys Phys ex1
NYCC Systems Physiology chapters 45 and 60 exam I - Balliet
Question | Answer |
---|---|
how do neurons communicate? | chemical synapses and electrical synapses (gap junctions) |
what is the vehicle neurons use to communicate? | chemical transmitters -more than 50 have been identified! |
neuronal communication is always ____-way. | one (one direction) |
why is neuronal communication always in one direction only? | allows signals to be directed toward specific goals |
chemical substances which function as synaptic transmitters | neurotransmitters |
small molecules which act as rapidly acting transmitters | neurotransmitters |
3 kinds of neurotransmitters | neuropeptides (thank you, Dr. Candace B. Pert!), hypothalamic releasing hormones, pitutitary peptides |
neuropeptides, hypothalamic releasing ________, and pituitary peptides are three kinds of neurotransmitters | hormones (ergo, neuropeps,pituitary peps and hormones) |
Acetylcholine, Norepinephrine, Dopamine, Serotonin, GABA, Glycine, Glutamate, Nitric Oxide are all small molecules that are derived from? | amino acids and are rapidly acting (ionotropic) |
which of the neurotransmitters are small molecules and are derived from amino acids (and their derivatives)? | the Rapidly Acting small molecules of a.a.'s and their derivatives: Ach, DA, 5-HTP, NE, GABA, Gly, Glu, NO |
more potent than small molecule (a.a.) neurotransmitters and cause more prolonged actions (metabotropic): | neuropeptides! |
list the neuropeptides (3) | endorphins, enkephalins, VIP (vasoactive intestinal polypeptide) |
TRH, GHRH, CRH, GnRH? | Thyrotropin-releasing hormone, Growth-releasing hormone, Corticotropin releasing hormone are all hypothalamic releasing hormones (neurotransmitters from the hypothalamus so are, by definition, hormones) |
ACTH, Prolactin, Vasopressin, Oxytocin, LH, FSH, TSH | Pituitary peptides (anything related to sex, getting buff to have sex, releasing eggs to have sex, getting ready to have sex, prolonging sex, all these are pituitary peptides so we can tell each other when we are ready to have sex. |
anything that has "-releasing hormone" on the end of it is derived from the | hypothalamus |
anything that is about sex is a peptide from the ? | pituitary gland |
contain neurotransmitter substances to excite or inhibit postsynaptic neuron | PREsynaptic vesicles |
provide energy to synthesize NT (neurotransmitter) for release at the synapse | mitochondria |
causes membrane depolarization and subsequent emptying of small number of vesicles into the synaptic cleft - this excites or inhibits the postsynaptic neuron. | action potential |
An action potential causes ___________________ in order that the vesicles may be emptied into the synaptic cleft and then excite or inhibit the postsynaptic membrane. | membrane DEPOLARIZATION |
type of channel in the pre-synaptic membrane | Voltage~#~gated channels |
If the presynaptic channel contains voltage-gated channels because they are relying on an ion to set them free, what does the post-synaptic membrane contain? | Ligand-gated channels, because they are waiting for the neurotransmitter to cross |
what is necessary for Ca++ to be able to enter the presynaptic membrane | depolarization of the membrane by an action potential |
what ion comes into the presynaptic membrane and when? | Ca++. after the membrane has been depolarized by an action potential |
what induces the release of the neurotransmitter enclosed in synaptic vesicles at the presynaptic membrane? | Ca++ influx after membrane depolarization via an action potential |
how is NT released into the synaptic cleft? | Ca++ enters presynaptic membrane upon depolarization (a.p.) and vesicles fuse with membrane, then exit via exocytosis into the synaptic cleft |
what kind of channels does the presynaptic membrane contain? | voltage gated CALCIUM channels! |
where are voltage gated Calcium channels found in neurotransmission? | in the presynaptic membrane |
what kind of channel does the postsynaptic membrane contain? | ligand gated channels which are made of Receptor proteins, waiting for the NT |
postsynaptic receptors (ligand-gated channel proteins) contain 2 things: | binding component & an ionophore component |
2.Channel formers[2] that introduce a hydrophilic pore into the membrane, allowing ions to pass through while avoiding contact with the membrane's hydrophobic interior | ionophore (wikipedia) |
describe the ligand-gated postsynaptic receptor BINDING COMPONENT | binding component sticks out into cleft and binds to the transmitter (think of it as a trawler) |
describe the ligand-gated postsynaptic IONOPHORE component | extends from the exterior into the interior of the post-synaptic structure. Ionophore either OPENS the channel or activates a 2ND MESSENGER system |
an ionophore component of the ligand gated channel in the postsynaptic membrane does one of two things: | either opens the channel or activates a second messenger |
an chemical compound (eg, NT) that bins to a specific site on a receptor | a ligand (For that receptor) |
ions can only move ____________ the concentration gradient. | with |
AMP - the "A" does what? | activates! |
Cation channels allow ______ & ______ to pass. | Ca++ and Na+ |
Anion channels allow ________ to pass. | Cl- |
Transmitters that open Na++ channels _________ the postsynaptic neuron! | excite! (salt is exciting!) |
Transmitters that open Cl- channels ___________ the postsynaptic neuron. | inhibit (-negativity makes for more negativity-) |
When potassium goes out of the postynaptic neuron, what happens? | inhibition (because the cell is losing K+ and so becoming more negative or hyperpolarized) |
About 75% of the second messenger activators are transduced with ___________-coupled receptors. | G protein |
activation of these receptors on the postsynaptic cell initiates a cascade of events that leads to an increase in cAMP, the Phosphorylation, then altered cell activity. | G-protein linked 7-pass transmembrane ligand-gated receptors (haha remember neuropharmacology? Well, it's baaaaacccckkkk!) |
what happens in the nucleus of the postsynaptic cell when a G-protein coupled receptor is activated? | transcription, translation, expression |
G-protein coupled receptor activation starts a cascade that begins with an increase in _______. | cAMP |
the increase of which can have metabotropic/long term effects and is the first target of the G-protein coupled receptor activation inside the cell | cAMP |
can cause prolonged changes in the activity of neurons (seconds to months) | second messenger activators (like cAMP that cause protein Phosphorylation) |
example of a process which requires long term changes in neuronal activity | memory (long term memory potentiation) |
what is the benefit of a second messenger system (would nature have installed them in 75% of the ligand-gated channels if there weren't some greater benefit? No.) | opens a membrane channel for a SPECIFIC ion species like Na+ or K+ and KEEPS IT OPEN for a longer period of time than seen with typical ligand-gated channels. |
what 2 purines always become cyclic as the result of 2nd messenger G-protein coupled receptor activation? | adenosine (cAMP) and guanosine (cGMP) |
stimulate specific metabolic machinery in the neuron (activated by the 2nd messenger sys): | cAMP or cGMP (the cyclic purines of 2nd messenger systems) |
Once cAMP or cGMP causes phosphorylation, then __________ are activated which initiate biochemical reactions in the post-synaptic neurons. | enzymes |
the second messenger system activates ______________ and _________ synthesis that may alter the metabolism or morphology of the cell. | gene transcription, protein synthesis |
second messenger activation may cause these 2 results in the nucleus | gene transcription, protein synthesis |
4 possible results of the 2nd messenger system when the alpha subunit is displaced: | 1-open channel and keep it open longer, 2-increase cAMP or cGMP, 3-turn off allosteric enzymes, 4-gene transcription and make more |
the 3 special characteristics of synaptic transmission: | fatigue, post-tetanic facilitation, synaptic delay |
fatigue of synaptic transmission | exhaustion of the stores of transmitter in synaptic terminals. Protective against excessive firing. |
example of a substance that causes fatigue of synaptic transmission | capsacin exhausts substance-P vesicles so deadens excitability |
spikes for sleep cycle, psychomotor skill retention, and LTP | Ca++ |
Another special characteristic of synaptic transmission, besides fatigue and synaptic delay, is? | post-tetanic facilitation: enhanced responsiveness following repetitive stimulation (yes, think of that if you need to remember this and always tell your lover you are in a state post-tetanic facilitation) |
enhanced responsiveness following repetitive stimulation | post-tetanic facilitation via Ca++ buildup in the presynaptic terminals |
where does and what does build up in order to bring about post-tetanic facilitation? | Ca++ in the presynaptic terminals |
The build up of calcium in the presynaptic terminals causes more vesicular release of _______________, and therefore the state of post-tetanic facilitation. | neurotransmitter (meaning more calcium means more NT after the calcium has built up) |
"tetanic" or "tetany" is always associated with | Ca++ |
A special characteristic of synaptic transmission, besides fatigue (numbness due to max let of NT), post-tetanic facilitation (Ca++ at presyn mem causes more NT release), there is also ________ __________. | synaptic delay: from the delay between episodes of neurotransmission, one can calculate the number of neurons in the circuit |
the process of neurotransmission takes time; from the delay can calculate the number of neurons in a circuit. Called? | synaptic delay |
Three states that can affect neuronal activity, either exciting or inhibiting: | acidosis (coma), alkalosis (seizure), hypoxia (unconsciousness) |
depresses neuronal activity. pH change from 7.4 to 7.0 usually will induce coma. | effect of acidosis |
increases neuronal excitability - pH changes from 7.4 to 8.0 and usually will induce seizures | effect of alkalosis |
Interruption of brain blood flow for 3-7 seconds can lead to unconsciousness | effect of hypoxia |
portion of the nervous system that controls most visceral functions | ANS |
where are centers of organization for ANS? (5) | brain stem, spinal cord, hypothalamus, Limbic system (of cerebral cortex transmits signals to spine, brain and brain stem), Visceral reflexes |
short on sympathy | ANS is short on preganglionic sympathetic. Can figure other 3 relations from this one (long on sympathetic postganglionic, long on parasympathetic preganglionic, short on parasympathetic postganglionic) |
short on sympathy is the only one you need to know - other 3 can be figured out from this one | ANS: preganglionic sympathetic are short |
spinal level origins of sympathetic nervous system | T1-L2 |
Sympathetic nervous system (T1-L2) afferents first pass the ___________________horn of spinal cord then synapse on one of 3 locations: | intermediolateral horn, 1-sympathetic chain ganglia, 2-pass up or down then synapse, 3-synapse in a peripheral ganglia |
3 locations an efferent sympathetic preganglionic can synapse from its intermediolateral horn start: | 1- sympathetic chain gang, 2-pass up or down then synapse, 3-synapse in peripheral gang |
where do sympathetic preganglionic cell bodies live? | intermediolateral cell column (horn) |
After a short sympathetic preganglionic fiber leaves the intermediolateral horn, where can it go? | sympathetic chain ganglia, up or down to synapse, or to the peripheral ganglia |
How do short sympathetics leave the chain ganglia? | via the grey rami |
In what kind of fibers do the long postganlionic sympathetics travel when they leave the sympathetic chain ganglia? | small C-fibers |
the long postganglionic sympathetics traveling inside small C-fibers towards what destinations? | blood vessels, sweat glands, piloerector muscles of hair |
sympathetic nerve fibers comprise ____ of the total fibers inside a skeletal nerve | 8% |
what organ has specialized sympathetic tissue? | adrenal medulla - special because pregang sympathetics go all the way to the medulla without synapsing anywhere! |
what is special about the fibers to the adrenal medulla? | they function and originate as ready-made post ganglionic sympathetic tissue |
products of adrenal medulla | hormones: norepinephrine and epinephrine |
The sympathetic nervous system stems from spinal levels T1-L2. From where does the parasympathetic system come? | Cranial nerves III, VII, IX and X (3.7.9.10) and sacral plexus S2-S4 |
Ophthalmic, Facial, Glossopharyngeal, Vagus | (3.7.9.10) the parasympathetic nervous system origin, with S2-S4 |
besides cranial nerves 3.7.9.10, where does the parasympathetic n.s. come from? | S2-S4 |
What nerve contains 75% of the parasympathetic nerve fibers? | VAGUS! |
75% of us want to go to Vagus! | Vagus nerve contains 75% of parasympathetic nerve fibers |
Where do parasympathetic nerve cell fibers synapse? | short trip to post-ganglionic nerve cell bodies located in the viscera |
where are the parasympathetic postganglionic nerve cell bodies? | viscera |
sympathetic preganglions release ___________, while sympathetic postganglions release ___________. | acetylcholine, norepinephrine |
excepting postganglionic sympathetics, what do all other ANS fibers release? | acetylcholine (sympathetic postgang is NE) |
acetylcholine requires an ______________, while norepinephrine (postgang sympathetics) require _________ fiber type. | cholinergic for Ach, Adrenergic for NE |
where do you guess ADRENERGIC fibers for NE come from? | adrenal medulla |
2 components of acetylcholine | Acetyl-CoA + Choline |
enzyme that digests Ach | acetylcholinesterase |
is choline from Ach recycled, trashed, or decomposed? | REcycled! Choline is transported back to the nerve ending to be used again and again. |
What does acetylcholinesterase do with Ach? | recycles the choline from the Acetyl-CoA and uses the choline over and over again (puts it back into the nerve ending) |
NE, used by postganglionic parasympathetics, is a cholinergic compound. How is it synthesized? | Tyrosine to Dopa, Dopa to dopamine, dopamine to noreprinephrine |
what is the cycle of NE | tyrosine, dopa, dopamine, NE |
What happens to NE? | 80-90% is reuptake. The last is broken down: diffused into blood, MAO (nerves), or Catechol-O-methyl transferase (most tissues) |
___________________ is synthesized by a series of enzymatic steps in the adrenal medulla and postganglionic neurons of the sympathetic nervous system from the amino acid tyrosine | norepinephrine |
From locus coeruleus... As such it provides an endogenous anti-inflammatory agent in the microenvironment around the neurons, glial cells, and blood vessels in the neocortex and hippocampus | norepinephrine |
Up to 70% of ____________ projecting cells are lost in Alzheimer’s Disease. | NE |
The synthesis of norepinephrine depends on the presence of tyrosine, an amino acid found in proteins such as meat, nuts, and eggs. Dairy products such as cheese also contain high amounts of tyrosine. | |
(the amino acid is named for "tyros," the Greek word for cheese). | tyrosine |
The host of physiological changes activated by a stressful event are unleashed in part by activation of a nucleus in the brain stem called the locus ceruleus. This nucleus is the origin of most __________pathways in the brain. | norepinephrine |
what kind of receptors are at the synapses between the preganglionic and postganglionic neurons of both parsymp and sympathetic systems? | nicotinic(everybody smokes at this stage!) |
what receptors are found at the end of sympathetic postganglion synapses? | adrenergic receptors |
what receptor is found at the postganglionic parasympathetic synapse? | cholinergic/muscarinic receptors (rest & digest at the end of the day with a glass of muscadine wine) |
anyway, what the prof is trying to say is that ____________ receptors are found between pre- and post-ganglionic synapses for both sympathetic and parasympathetic. And... | Nicotinic (both para and sympa in middle), adrenergic at end of sympathetic for NE while cholinergic/muscarinic receptors at end of parasympathetic for Ach. |
where is Ach NOT used in the parasympathetic and sympathetic pathways? | only at the end of the sympathetic postganglions - they are adrenergic receptors for NE, not ach. |
kind of receptors that detect NE and E | adrenergic in the postgang symp path |
Norepinephrine stimulates mainly ________ adrenergic receptors. | alpha, and sometimes beta |
What stimulates both alpha and Beta adrenergic receptors? | epinephrine (E) |
What stimulates mostly alpha adrenergic receptors? | NE |
kind of receptors located in blood vessels that have both alpha and beta adrenergics | epinephrine |
where are alpha adrenergic receptors located | blood vessels |
what does both NE and E do to alpha adrenergic blood vessels? | causes vasoconstriction |
Alpha receptors are: | in blood vessels, cause vasoconstriction, and respond to both E and NE |
There are two kinds of Beta receptors: | Beta 1 and Beta 2 receptors for Epinephrine |
activation of these receptors causes an increase in heart rate and contractility | Beta-1 receptors (epinephrine) |
activation of these receptors causes bronchial dilation, dilation of blood vessels in skeletal muscles (totally different from alpha that vasoconstrict!), calorigenesis and glycoenolysis. | Beta-2 receptors (epinephrine) |
The heart is more important than the lungs so it is beta-___? | 1 |
Beta 2 receptors do not cause an increase in | heart rate. They cause bronchial dilation, vasodilation in skeletal muscles, calorigenesis, and glycogneolysis |
how does the autonomic nervous system affect the eye | sympathetic is pupillary dilation, parasymp is pupillary constriction and accomodation (focusing) of the lens |
parasympathetic stimulation of the glands of the body causes | nasal, lacrimal, salivary and GI glands to kick on |
sympathetic stimulation of the glands of the body causes | sweat glands (cholinergic/Ach) and aponcrine/armpit glands (adrenergic/NE and E) to open |
sweat glands have _________ receptors | cholinergic (Ach) |
tell me what sympathetic does to the GI, heart and systemic blood vessels | very little effect on GI, increases heart rate and contractility, causes vasoconstriction of vessels |
the adrenal medulla is a large ________ ganglion | sympathetic |
when stimulated, the adrenal medulla releases __________ (80%) and ___________ (20%) into the blood. | epinephrine (80%) and NE |
what nt does the adrenal medulla (the big sympathetic ganglion) release primarily? | Ep (80%) |
the adrenal medulla functions to cause prolonged activity of the substances E & NE. This stimulates ____________ & _____________ rates. | heart (cardiovascular) and metabolic |
large sympathetic ganglion that helps the body deal with stress | adrenal medulla |
Both para- and sympathetic systems have a base(al) rate from which to increase or decrease in activity by a single system. Sympathetic normally causes ~50% increase in ___________. | vasoconstriction |
What can change the diameter of a blood vessel | "tone" increase or decrease (tense or relaxed, sympathetic or parasympathetic, vasoconstriction or vasodilation = all the same things) |
what kind of tone provides background GI activity? | parasympathetic |
you already know about the sympathetic response. | fight or flight |
what kind of drugs act on the adrenergic effector organs | sympatho-mimetic (mime the sympathetic) |
Cholinergic effector organs are acted on by ______________ drugs. | parasympatho-mimetic (mime the parasympathetics) |
an antihistamine/nasal decongestant phenylephrine _________ adrenergic receptors | stimulates (alpha) |
a heart UNblocking drug Isoproterenol ____________ adrenergic receptors | stimulates (alpha) |
an asthma drug Albuterol _________ adrenergic receptors | stimulates (alpha) |
ephedrine, tyramine (some hard cheeses and wine -where tyrosine gets its name), and amphetamine cause the release of ____________ from the nerve endings | Norepinephrine |
an adrenergic drug does one of 5 things to one or two neurotransmitters: | blocks synthesis of, blocks storage of, blocks release of, blocks receptor of, blocks transmission of norepinephrine and epinephrine |
a drug that blocks synthesis, storage, release, transmission, or receptors for NE and E (alpha for NE, alpha and beta for E) is called an | adrenergic blocker |
what is a common condition for which adrenergics that block synthesis, storage, release, transmission or receptors of NE or E is perscribed? | high blood pressure (anti-adrenergic would vasodilate/relax vessels) |
besides high blood pressure and pheochormocytoma, what is a condition that adrenergics are perscribed for? | chronic pain! |
what are common conditions a cholinergic drug would be perscribed for? Why? | glaucoma, myasthenia gravis, insecticide poison antidote - to cycle up or down Ach system and its muscarinic receptors |
cholinergic drugs activate | muscarinic receptors (ie, pliocarpine for glaucoma) |
anti-cholinesterase drugs prevent the breakdown of | acetylcholinesterase, like neostigmine for myasthenia gravis |
Anti-muscarinic drugs block the action of ___________ on the ___________ effector organs | acetylcholine, mucarinic (heart), like Atropine for insecticide poisoning |
What drug can stimulate both postganglionic sympathetic and parasympathetic neurons? | nicotine |
causes stron sympathetic vasoconstriction in abdominal organs and limbs | nicotine |
increases stomach acid, causes parasympathetic stimulation of GI activity (ie, secretions) | nicotine |
slows heart rate parasympathetically | nicotine |