Identify which of the following actions isare mediated by be

Identify which of the following actions is/are mediated by beta-2 receptors? In the blank provide, write Yes for those biological responses that are mediated by the beta-2 receptor and No for those that are not mediated by the beta-2 receptor. increased heart rate: _____ contraction of vascular smooth muscle (of blood vessels flowing to skeletal muscle): _____ contraction of vascular smooth muscle (of blood vessels flowing to the skin): _____ dilation of airways: _____ Fill in the blank: A woman who is taking atropine for a gastrointestinal disorder notices that her pupils are dilated. This has occurred because atropine blocks _____ receptors on the _____ muscle of the iris. Which of the following is/are characteristic of the parasympathetic nervous system? Fill blank with a YES response for each of the following that is/are characteristic of the parasympathetic nervous system but not of the sympathetic nervous system? Otherwise, put a NO in the blank. Ganglia in or near target tissues _____; nicotinic receptors on postganglionic neurons_____; muscarinic receptors on some target tissues _____; Beta-1 receptors on some target tissues _____; Cholinergic preganglionic neurons _____; Propranolol causes a decrease in heart rate because it _____ (stimulates/deactives) the _____ receptors in the sinoatrial node of the heart.

Solution

1. A increased heart rate yes

B.Contraction of vascular smooth muscle flowing to skeletal muscle - no

C. Contraction of vascular smooth muscle flowing to skin - no

D. Dilation of air ways- yes

Beta 2 receptors agonists cause smooth muscle relaxation causing vasodilation in muscles and liver, dilation of bronchial passages etc. They are primarily used to treat asthma, pulmonary disorder COPD. Its adverse effects cause tachycardia ( increased heart rate)