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11 Cards in this Set
- Front
- Back
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Alpha 1 Receptors
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Found: vascular smooth muscle of skin, skeletal muscle and splanchnic region, sphincters of GI and bladder and radial muscle of Iris
Activation: leads to contraction of these areas Mechanism: Activation of Phospholipase C increasing IP3 |
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Alpha 2 Receptors
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-Inhibitory
Found: presynaptic adrenergic and cholinergic nerve terminals and in the GI tract. - Alpha 2 found sympathetic post ganglionic are called autoreceptor and when activated inhibit further release of norepinephrine - Alpha 2 present on parasympathetic post terminals are heteroreceptors and they inhibit release of ach post synaptically Mechanism: inhibition of cAMP |
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Beta 1 Receptors
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Found: Heart (AV, SA and ventricular muscle), Salivary gland, adipose and kidney
Effects: increase heart rate and contractility Mechanism: activation of adenylyl cyclase which increases cAMP |
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Beta 2 Receptors
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Found: in Vascular smooth muscle of skeletal muscle, walls of GI tract and bladder and in the bronchioles and activation leads to relaxation or dilation
Mechanism simliar to Beta 1 with increase in adenylyl cyclase. |
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Nicotinic Receptors
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Found: on the motor end plate of skeletal muscle, on all post ganglionic of sympathetic and parasympathetic and on chromafin of adrenal medulla.
Mechanism: G proteins act directly to open ion channels. |
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Muscarinic
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Found: all the effector organs of the parasympathetic (heart, GI, bronchioles, bladder and male sex organs). And found in sympathetic sweat glands.
Mechanism: can work as Alpha 1 worked or with G protein acting directly on ion channels. |
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Sympathetic
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•Pre in thoracolumbar spine
•T1-L3 •Leave cord from ventral motor roots -Go to pre vertebral ganglia or paravertebral -Prevertebral ganglia include superior cervical , celiac, superior and inferior mesenteric •Norepinephrine at target (alph and beta 1 and 2) •Ach for sweat glands •Increase heart rate and respiratory rate •Increased metabolic rate •Increases mental activity |
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Norepinephrine (sympathetic)
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•Dilates
-Bronchi -Bladder and contricts the sphincter -Iris (radial muscles increases the radius) -Bowel wall and tightens sphincters •Decreases secretion -Low volume high viscosity •Heart increases •Exception: sweating -Uses ach too -And ejaculation •Constricts blood vessels in the skin (alpha 1) •Skeletal muscles is dilated by beta 2 -Alpha 1 constricts during rest |
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Adrenal Medulla
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•big sympathetic ganglion
•makes 80% epi and 20% norepi •travel in splanchinic nerve •no synapse in sympathetic chain •don’t die if you lose it •no protein effect of catecholamines •cortisol for permissive effect: -synthesis of catecholamines -increases on vasculature (contraction) •pheochromocytoma -tumor of adrenal medulla -wont kill you right away and retains normal function -switches product to norepinephrine -episodic hypertension -palpitation headache and panic -best intial test: urine catecholamines and metanephrines -treat with alpha blockers |
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Parasympathetic
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•rest and digest
•originates in CN III, VII, IX, X •sacral S2-S4 •long pre short post •storage sites in varicosities •nicotinc at ganglia •muscarinic at effector organs. •Exceptions -VIP transmitters -NO transmitters |
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Effects not Paired between Sympathetic and Parasympathetic
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•Vasculature (only symp)
-Alpha 1 constricts skin, splanchnic flow and resting muscle -Beta 2 dilates exercising muscle •Gastric and pancreatic secretion (ach increase only para) •Sweat: symp increases with ach •Lacrimal: ach only para •Liver: symp only: increases gluconeogenesis (beta 2 stimulation) •Adipose: lipolysis Beta3 only •Kidney: renin secretion is beta 1 only |
