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ANS and receptors
Physiology Test 2
Question | Answer |
---|---|
Which nervous system controls vegetative functions? | autonomic nervous system (why a head injury pt is called a "vegetable") |
What is the other name for the sympathetic nervous system? | thoracolumbar system (b/c it begins in thoracic segments and 1st 3 or 4 segments of lumbar spinal cord) |
What is the nickname for the sympathetic nervous system? | fight or flight |
What is the other name for the parasympathetic nervous system? | craniosacral system (b/c it begins in cranial nerves III, VII, IX, and X or sacral region of spinal cord) |
What is the nickname for the parasympathetic nervous system? | rest and digest |
What are the lengths of the pre and postganglionic fibers of the sympathetic nervous system? | preganglionic=short; postganglionic=long |
What are the lengths of the pre and postganglionic fibers of the parasympathetic nervous system? | cranial nerve X: preganglionic=long and postganglionic=short; cranial nerve III, VII, and IX: pre and post are about same length |
What is the preganglionic NT of the sympathetic NS? | ACh |
What is the preganglionic NT of the parasympathetic NS? | ACh |
What is the preganglionic receptor of the sympathetic NS? | nicotinic |
What is the preganglionic receptor of the parasympathetic NS? | nicotinic |
What is the postganglionic NT of the sympathetic NS? | norepi |
What is the postganglionic NT of the parasympathetic NS? | ACh |
What is the postganglionic receptor of the sympathetic NS? | alpha or beta |
What is the postganglionic receptor of the parasympathetic NS? | muscarinic |
What is the effect of stimulation of alpha receptors? | vasoconstriction |
What is the effect of stimulation of beta receptors? | vasodilation |
What is a collection of nerve cell bodies in the CNS called? | nuclei |
What is a collection of nerve cell bodies outside the CNS called? | ganglia |
What is the parasympathetic ganglion from cranial nerve III called and what does is control? | ciliary ganglion: iris, ciliary body |
What are the parasympathetic ganglions from cranial nerve VII called and what do they control? | sphenopalatine ganglion: lacrimal gland; chorda tympani nerve: sublingual and submaxillary salivary gland |
What is the parasympathetic ganglion from cranial nerve IX called and what does it control? | otic ganglion: parotid glands |
What is unique about the parasympathetic ganglion from cranial nerve X? | most widely distributed cranial nerve (sends fibers everywhere); the preganglionic fibers are very long and don't synapse until right at or in the effector organ (terminal ganglia) |
Which cranial nerve has terminal ganglia? | X |
Which cranial nerve is the most widely distributed cranial nerve? | X |
What are 3 examples of catecholamines? | dopamine, norepi, epi |
Isoprot-renal is a catecholamine that has an affinity for which receptor(s)? | only beta |
Epinephrine is a catecholamine that has an affinity for which receptor(s)? | both alpha and beta |
Norepinephrine is a catecholamine that has an affinity for which receptor(s)? | only alpha |
A sympathetic preganglionic fiber has what 3 options of where to form a ganglia? | 1)paravertebral ganglia, 2)cervical ganglia, 3)prevertebral ganglia |
Describe paravertebral ganglia. | run out of the spinal cord and synapse with a postganglionic fiber at the same level |
What is the highest ganglion of the paravertebral ganglia? | stellate ganglion |
Describe cervical ganglia. | run out of the spinal cord, enter the paravertebral chain ganglia and run up or down a few ganglionic levels and synapse with a postganglionic fiber at a different level |
What are 3 examples of cervical ganglia? | superior, middle, and inferior cervical ganglia |
Describe prevertebral ganglia. | run out of the spinal cord, enter the paravertebral chain ganglia and run out of the ganglia and run all the way to certain ganglia in the abdominal cavity, and then synapse with a sympathetic postganglionic fiber |
Prevertebral preganglionic fibers are (long or short?) | long |
What is an example of prevertebral ganglia and what does it innervate? | splanchnic nerves which innervate the celiac and superior and inferior mesentery ganglion |
In the somatic motor system, describe the pathway of the alpha motor neuron. | originates in the ventral horn, exits the ventral root to the skeletal muscle |
In the sympathetic motor system, describe the pathway of the neurons. | Pregang. fiber orig.in the lateral horn,axon exits ventral root&enters spinal nerve.Exits spinal nerve via white ramus in2 paravertebral chain gang.where it synapses w/ postgang.fiber which then enters the spinal cord via gray ramus then2effector organ |
What is the name of the large belly of the bladder? | detrusor |
What type of cell is found only in the bladder? | transitional epithelium (subject to transitional cell carcinoma); when bladder begins to fill, transitional epithelium presses flat as bladder expands |
What is the "trigone"? | triangle formed by 2 openings for ureters and 1 opening for urethra |
What can happen when the trigone is stimulated? | uncontrolled urination |
What effect does the sympathetic NS have on the eye? | 1)accommodation of vision for far vision, 2)pupillary dilation |
What effect does the parasympathetic NS have on the eye? | 1)accommodation for near vision, 2)pupillary constriction |
What effect does the sympathetic NS have on the salivary glands? | 1)decreased watery secretion, 2)increased mucus secretion, 3)decreased enzyme (amylase) secretion |
What effect does the parasympathetic NS have on the salivary glands? | 1)increased watery secretion, 2)decreased mucus secretion, 3)increased enzyme (amylase) secretion |
What effect does the sympathetic NS have on the lungs? | 1)bronchodilation, 2)decrease mucus secretion (open airways) in trachea and bronchi |
What effect does the parasympathetic NS have on the lungs? | 1)bronchoconstriction, 2)increased mucus production |
What effect does the sympathetic NS have on the heart? | all aspects of cardiac output are increased |
What effect does the parasympathetic NS have on the heart? | all aspects of cardiac output are decreased |
What effect does the sympathetic NS have on the GI tract? | decreased motility, peristalsis, secretions; blood flow is shunted to other areas |
What effect does the parasympathetic NS have on the GI tract? | increased motility |
What effect does the sympathetic NS have of the urinary bladder? | trigone may be stimulated and cause uncontrollable urination |
What effect does the parasympathetic NS have on the urinary bladder? | detrusor and trigone areas are stimulated to contract |
Urination is a (sympathetic or parasympathetic?) process? | parasympathetic (if you are stressed, it will be harder to urinate) |
What effect does the sympathetic NS have on the genitalia? | ejaculation is a sympathetic process |
What effect does the parasympathetic NS have on the genitalia? | erection is a parasympathetic process |
What effect does the sympathetic NS have on defication? | none |
What effect does the parasympathetic NS have of defication? | defication is a parasympathetic process |
True or False: All organs have dual innervations (sympathetic and parasympathetic) and are trying to have homeostasis/equilibrium. | True |
True or False: Any high degree of stress cause throw us into a sympathetic overdrive. | True |
What is the effect of parasympathetic override? | extreme relaxation (romantic evening, the act of defication) |
What is considered the 6th sense? | proprioception |
True or False: Muscle spindles are part of proprioception. | True |
Define proprioception. | Positional info; how our body is oriented in a given space or time; also, sensing stretch in our muscles |
In what body system will you find muscle spindles? | skeletal system (we call them skeletal muscles b/c their origin and insertion sites are on the skeletal system by tendons) |
Skeletal muscle movement is (voluntary or involuntary?) | voluntary |
What are the contraction units of muscle cells? | actin and mycin |
True or False: Bundles of muscle fibers are relatively small and cannot contract very powerfully. | False: they are relatively large and can contract very powerfully |
Where do skeletal muscle fibers receive their innervation from? | alpha motor neuron terminal releases ACh to a nicotinic receptor causing contraction |
What are the 2 types of skeletal muscle fibers? | 1)extrafusal fibers 2)intrafusal fibers |
What are extrafusal fibers? | large and long; only job is contraction; receive alpha motor neuron |
What are intrafusal fibers? | muscle spindles within the connective tissue sacs; job is to sense stretch |
What are the 2 types of intrafusal fibers? | 1)nuclear bag fiber 2)nuclear chain fiber |
What is a nuclear bag fiber? | type of intrafusal fiber; senses stretch; nuclei are bundled up in the center of the fiber |
What is a nuclear chain fiber? | type of intrafusal fiber; senses stretch; nuclei are lined up along the fiber |
What are annulospiral fibers? | afferent fibers that coil around the muscle spindles to sense stretch |
What are 2 functions of the muscle spindles/intrafusal fibers? | 1)make split second motor corrections (recruit more extrafusal fibers if something weighs more than expected) 2)protect the muscle (must drop object if all extrafusal fibers are activated to keep muscle from tearing) |
What can increase the sensitivity of the annulospiral fibers? | efferent motor neurons on the muscle fibers (in a normal patient, the effect motor neurons have the sensitivity set just right; some patients need meds to alter the contraction) (similar process in tendon=Golgi apparatus) |
What are the 2 types of cholinergic receptors? | nicotinic and muscarinic |
Which type of receptor is found on the NMJ for skeletal muscles? | nicotinic |
What are the agonists for nicotinic cholinergic receptors found on the NMJ? | ACh and nicotine |
What is an antagonist for nicotinic cholinergic receptors found on the NMJ? | d-tubocurare |
What are the 2 places where nicotinic receptors are found? | 1)NMJ for skeletal muscles, 2)ANS post-ganglionic neuron |
What are the agonists for nicotinic cholinergic receptors found on the ANS post-ganglionic neuron? | ACh and nicotine |
What are the antagonists for nicotinic cholinergic receptors found on the ANS post-ganglionic neuron? | benzohexonium & tetraethylammonium (NOT curare) |
Which nicotinic receptors are antagonized by curare? | the ones located on the NMJ of skeletal muscles |
Where are muscarinic cholinergic receptors located? | parasympathetic effector organs such as glands, blood vessels, GI tract, heart, etc |
What are the agonists for muscarinic cholinergic receptors? | ACh and muscarine (mushroom poison) |
What are the antagonists for muscarinic cholinergic receptors? | atropine, scopolamine, pirenzipine |
How many subtypes of muscarinic receptors are there? | 5 (M1, M2, M3, M4, M5) |
Where are M1 muscarinic receptors located? | stomach and salivary glands |
Where are M2 muscarinic receptors located? | heart |
Where are M3 muscarinic receptors located? | smooth muscle such as in bronchi |
Where are M4 muscarinic receptors located? | CNS |
Where are M5 muscarinic receptors located? | CNS |
Which muscarinic receptors are associated with cognitive functions? | M5 |
What kind of effect can decreased ACh function/defective cholinergic neurons on the M5 receptor cause? | senility |
What are receptors for epi and norepi called? | noradrenergic/adrenergic receptors |
What organ/gland is responsible for releasing epi/adrenalin in fight or flight response? | adrenal gland |
What type of tissue makes up the adrenal medulla? | modified sympathetic postganglionic tissue |
How does the modified sympathetic postganglionic tissue of the adrenal medulla release epi/norepi? | the preganglionic sympathetic nerves fire to it and the cells themselves release large amounts of epi (80%) and norepi (20%) into the bloodstream |
Once in the bloodstream, epi/norepi are no longer called neurotransmitters, they are now called... | hormones |
Epi binds to what type of receptor? | adrenergic |
Norepi binds to what type of receptor? | noradrenergic |
What are some examples of subtypes of adrenergic receptors? | alpha 1, alpha 2, beta |
Alpha1, alpha2, and beta receptors are (internal or external?) | external-- stick out on top of the cell, so they must have a way to transfer signals to the inside of the cell when stimulated externally (G proteins) |
______________ are internal transducing proteins associated with the external (alpha1, alpha2, and beta) receptors that cause the effect inside the cell. | G proteins |
What are the names of the G proteins 3 globular subunits? | alpha, beta, and gamma (all hooked together) |
During its inactive state, the G protein has a molecule of ___________. | guanasine diphosphate (GDP) |
What are the 3 versions of G proteins? | Gi, Gs, Gq |
What is the overall function of the Gi protein? | inhibitory to cellular processes |
Which receptor is Gi protein most associated with? | alpha 2 |
Describe the process by which Gi protein inhibits cellular processes. | 1)GDP is replaced w/ GTP, which displaces the subunits, and alpha comes off. 2)inactivates adenylate-cyclase (enzyme that usually turns ATP into cAMP) 3)inactivation of Ca2+ influx 4)smooth muscle relaxation and inability to release ACh |
Which enzyme is inhibited by Gi protein? | adenylate-cyclase |
What are the 2 ultimate effects of the Gi protein? | 1)inhibition of NT (ACh) release, 2)smooth muscle contraction (in rare cases such as GI sphincters) |
What is the overall function of the Gs protein? | stimulatory for intracellular actions |
Which receptor is Gs protein most associated with? | beta |
Describe the process by which Gs protein stimulates intracellular activity. | 1)stimulates beta receptors, 2)adenylate-cyclase changes ATP to cAMP 3)heart muscle contraction, smooth muscle relaxation, glycogenolysis (breakdown of glucose) |
Which enzyme is stimulated by Gs protein? | adenylate-cyclase |
Which are the 3 ultimate effects of the Gs protein? | 1)heart muscle contraction, 2)smooth muscle relaxation, 3)glycogenolysis (breakdown of glucose) |
Which receptor is Gq protein most associated with? | alpha1 |
Describe the process by which Gq protein works. | 1)GDP is replaced by GTP (which has a lot of energy), 2)alpha subunit comes off 3)activation of intracellular enzyme called phospholipase C 4)PIP2 comes out of membrane and changes to IP3 and DAG 5)calcium influx 6)smooth muscle contraction |
What is the ultimate effect of Gq protein? | smooth muscle contraction |
From which amino acid are epi and norepi made from? | tyrosine |
What is the ultimate effect of activation of alpha1 receptor? | smooth muscle contraction |
Which G protein does alpha 1 receptor bind to? | Gq |
Alpha 1 receptors are typically (pre or post?) synaptic receptors. | postsynaptic |
What is the ultimate effect of activation of alpha2 receptor? | decreased NT release; and in rare cases (GI sphincter) smooth muscle contraction |
Which G protein does alpha 2 receptor bind to? | Gi |
Alpha 2 receptors are typically (pre or post?) synaptic receptors. | presynaptic |
Where are beta1 receptors found? | only on contractile fibers in the heart |
What do beta1 receptors do? | increase the force of myocardial contraction |
Where are beta2 receptors found? | everywhere except heart |
What effect does the activation of beta2 receptors have on blood vessels? | vasodilation |
What effect does the activation of beta2 receptors have on the liver? | glycogenolysis |
What are some examples of alpha receptor antagonists? | alpha1=(phentolamine, phenoxybenzamine, prazosin); alpha2=yohimbine (used for erectile dysfunction by antagonizing alpha2 receptors to cause vasodilation) |
What are some examples of beta receptor antagonists? | propranolol, metoprolol, atenolol(only beta1), timolol |
Serotonin (5HT) receptors have how many subtypes? | at least 7 |
Which amino acid is the precursor of serotonin (5HT)? | tryptophan |
What are 4 functions for serotonin (5HT)? | 1)social engagement, 2)mood and emotion, 3)decreases appetite, 4)induces sleep |
How can serotonin levels be manipulated by medication to treat depression? | MAO inhibitors destroy norepi, epi, and dopa; more serotonin allowed to accumulate in the synapse |
Where is serotonin made? | median raphe (part of midbrain) |
Where is serotonin found? | hypothalamus, cerebrum, and limbic system |
How many subtypes of dopamine receptors are there? | 5 (D1, D2, D3, D4, D5) |
Which of the subtypes of dopamine receptors are inhibitory? | D1 and D5 (aka: D1 family) |
Which of the subtypes of dopamine receptors are stimulatory? | D2, D3, and D4 (aka: D2 family) |
What are the 3 main dopaminergic pathways? | 1)nigrostriatal tract, 2)mesolimbic tract, 3)infundibular tract |
Where does the nigrostriatal dopaminergic pathway run? | from substantia nigra to corpus striatum |
Which dopaminergic tract is associated with Parkinsonism? | nigrostriatal tract (too little dopamine) |
Where does the mesolimbic dopaminergic tract run? | from midbrain to limbic system |
Which dopaminergic tract is involved in psychosis/schizophrenia? | mesolimbic tract (excessive dopamine release) |
How do antipsychotic medications (that target the mesolimbic dopaminergic tract) work? | dopamine receptor antagonists (help w/ positive symptoms like hallucinations, disordered thinking, paranoia; but no help w/ negative symptoms like social withdrawal and shyness) |
What are some side effects of antipsychotic drugs that target the mesolimbic dopaminergic tract? | parkinsonian symptoms, motor ticks (extrapyramidal symptoms), gynecomastia (breast enlargement), gynecorrhea (milk production) |
Where does the infundibular dopaminergic tract run? | from hypothalamus to median eminence of the infundibulum |
The infundibulum is essentially the stalk that attaches the ______________ to the ____________. | hypothalamus to the pituitary gland |
Dopamine travels down the infundibular tract and (promotes or inhibits?) the release of prolactin. | inhibits; toward the end of pregnancy, there is less dopamine release to allow for the production of milk |
What are the 3 ways to terminate neurotransmitters? | 1)neuronal reuptake, 2)MAO (enzyme), 3)COMT (Catecholamine Oxygen Methyl Transferase) |
Which neurotransmitter cannot be terminated by COMT and why? | serotonin (5HT), because it is not a catecholamine |
___________ bind to receptors on or in the cells and produce a biological response. | Ligands |
What are some examples of ligands. | hormones, NT, drugs, toxins, chemicals |
What are some ligands that bind to external receptors? | peptide hormones (insulin, GH, PrL, FSH, LH, TSH); NT (catecholamines like NE, E, DA; ACh, 5HT, histamine) |
What are some ligands that bind to internal receptors? | steroid hormones (cortisol, aldosterone, testosterone, E/P), vitamin D, small molecular weight proteins (T3/T4, retinol) |
What is another name for internal receptors? | cytosolic receptors |
What are 3 ways that a ligand can pass through the membrane after attaching to an external receptor? | 1)seven-pass/serpentine, 2)one-pass, 3)pore/channel |
Explain the mechanism of seven-pass/serpentine. | ligand passes in and out of membrane 7X; has an external binding domain and an internal binding domain (which makes the cell internally respond);the internal binding domain is the G protein(acts as the transducer enzyme and causes a change in the cell) |
Explain the mechanism of one-pass. | ligand passes through the membrane only once; G protein is the internal binding domain here, too (like in 7-pass) |
What is an example of a pore/channel receptor. | nicotinic receptor on a Na channel that binds the ligand ACh |
Describe the process from the point that the ligand binds to the G protein to the cellular effect. | G protein binds --> cAMP --> kinases --> phosphorylate protein --> cellular effect |
Once formed, how is CGMP/CAMP broken down? | phosphodiesterase inactivates CAMP/CGMP |
What effect do phosphodiesterase inhibitors have? | prolongs the cellular actions of cGMP (d/t the inhibition of phosphodiesterase which breaks down CAMP/CGMP) |
What are some examples of phosphodiesterase inhibitors? | caffeine, xanthines, viagra |
How are the phosphorylated enzymes and proteins deactivated? | phosphatase |
How do the different subtypes of dopamine receptors affect cAMP? | D1&D5 increase cAMP; D2,D3&D4 decrease cAMP |
GABA receptors are found next to ________________ channels and next to ________________ receptors. | chloride ion channels, and benzo receptors |
Describe the properties of GABA A receptors. | 1)associated with chloride ion channels, 2)hyperpolarization, 3)neurons, 4)main inhibitory NT in CNS |
Describe the properties of GABA B receptors. | 1)K+ ion effect, 2)metabotropic |
Benzos are most associated with GABA (A or B?) receptors? | GABA A |
What are 2 examples of GABA agonists? | 1)baclophen, 2)gabapentin (anti-seizure, muscle relaxants, and anti-spasmodics) |