Module 3 RQ Flashcards
What does it mean to be “an exogenous catecholamine”?
versions of natural occurring catecholamines in the body that are administered to the patient. Some examples that are used during emergency situations are epinephrine and norepinephrine that treat problems such as allergic reactions
What are the two noradrenergic neurons are important for the uptake of catecholamines. These transporters, and more are important for uptake, synthesizing, metabolism, and release of catecholamines based on the need in the body
Dopamine transporter (DOT) at dopaminergic neurons and norepinephrine transporter (NET)
What are the three mechanisms by which sympathomimetics operate?
Drugs acting directly on adrenoreceptors, indirectly by activating the release of nonadrenaline from nerve endings and using both mechanisms at once
Produce a ‘reasonable, thorough, and convincing” explanation for the relatively short T1/2 of endogenous circulating catecholamines.
Endogenous circulating catecholamines have a short half-life because they are inactivated or broken down by MAO (monoamine oxidase) and COMT (catechol-O- methyltransferase) enzymes. Once these enzymes break down catecholamines they are taken up by various transporters in the body, one being adrenergic receptors. They are then packaged and removed from the bloodstream
What in the world does it mean to have something administered “parenterally”?
Parenterally administration is when medications are given IV (in the blood). This is because they are absorbed more quickly and have a faster rate of action than when medications are given other routes
what does it mean to ‘titrate to clinical effect.”
Titrate to clinical effect is when medications are started at a low dose and increased to see when
the clinical effect is helpful to the patient and how the body reacts
What are the two non-selective sympathomimetic catecholamines
The drugs epinephrine(adrenaline) synthesized by the adrenal medulla
Why is the drugs epinephrine (adrenaline) synthesized by the adrenal medulla considered to be the two non-selective sympathomimetic catecholamines
This is because it can be administered, intra-muscular, subcutaneous, and intravenously in emergency situations. But, during non-emergent cases it is recommended to give an intramuscular injection
What is the main drug used during cardiac events, such as cardiac arrest
Epinephrine
Why is Epinephrine considered to be the main drug used during cardiac events such as cardiac arrest
This is because alpha-1 adrenoreceptor agonist increases arterial blood pressure and coronary perfusion during CPR. It is given in the blood, so medication can travel to other organs and have a greater half-life. If you were to give Epi IM, you would lose some effect of your drug and decrease T1/2 because of breakdown, leading to a less effective drug. If medication, especially Epi given IV during an emergency, it can lead to a faster response
Explain what it means that the systemic effects of Epi are dose dependent.
Dose dependent, to me, means that effects are different based on the amount given and the effects it can have on the animal
This drug when given in small amount you will have beta effects on the body. Bronchodilation, increases heart rate, increase cardiac output, and higher oxygen consumption. Example of this would a decrease in vascular resistance as diastolic pressure decreases on splanchnic arterioles. At higher rates of infusion or given in a bolus form alpha effects will take over. For example, vasoconstriction on blood vessels will cause systemic vascular resistance to increase
Epinephrine
When the neurotransmitter __________ binds to vascular smooth muscle it uses the beta-2 receptor. This causes an increase in adenylyl cyclase causing an increase in cAMP leading to the production of protein kinase A. This kinase phosphorylates the myosin- light-chain-kinase leading to vasodilation of blood vessels. This allows for diastolic pressure to decrease and overall causing issues like heart rate to decrease
Norepinephrine
Explain why cardiac output may fall subsequent with administration of noradrenaline.
Norepinephrine can cause cardiac output to fall because of increased afterload and higher oxygen consumption in the heart. NE is seen in low systemic vasculature resistance during events such as post cardiac bypass and sepsis. NE increases systolic and diastolic pressure and causes pulmonary artery and central venous pressures to increase. Since afterload is the amount of pressure it takes the heart to eject the blood, and these pressures increasing, the effect would be cardiac output decreases
What is the splanchnic circulation?
The splenic circulation is composed of the gastric system, small intestine, colon, pancreas, liver, and spleen. The celiac, superior, and inferior mesenteric arteries supply blood to these organs. This system is important for regulation of cardiac output and can store blood for when it is needed
