The Autonomic Nervous System 265- A fall in cyclic AMP within the target cell occurs when
norepinephrine binds to which of adrenergic receptors?
a. a 1 c. b 1
b. a 2 d. b 2 - A drug that serves as an agonist for a 2 receptors can be used to
a. increase the heart rate.
b. decrease the heart rate.
c. dilate the bronchioles.
d. constrict the bronchioles.
e. constrict the blood vessels.Test Your Understanding
- Compare the sympathetic and parasympathetic systems in
terms of the location of their ganglia and the distribution of
their nerves. - Explain the anatomical and physiological relationship between
the sympathetic nervous system and the adrenal glands. - Compare the effects of adrenergic and cholinergic
stimulation on the cardiovascular and digestive systems. - Explain how effectors that receive only sympathetic
innervation are regulated by the autonomic system. - Distinguish between the different types of adrenergic receptors
and state where these receptors are located in the body. - Give examples of drugs that selectively stimulate or block
different adrenergic receptors and give examples of how
these drugs are used clinically. - Explain what is meant by nicotinic and muscarinic ACh
receptors and describe where these receptors are located in
the body. - Give examples of drugs that selectively stimulate and block
the nicotinic and muscarinic receptors and give examples of
how these drugs are used clinically.
Test Your Analytical Ability
- Shock is the medical condition that results when body
tissues do not receive enough oxygen-carrying blood. It
is characterized by low blood flow to the brain, leading to
decreased levels of consciousness. Why would a patient
with a cervical spinal cord injury be at risk of going
into shock?- A person in shock may have pale, cold, and clammy
skin and a rapid and weak pulse. What is the role of the
autonomic nervous system in producing these symptoms?
Discuss how drugs that influence autonomic activity might
be used to treat someone in shock. - Imagine yourself at the starting block of the 100-meter dash
of the Olympics. The gun is about to go off in the biggest
race of your life. What is the autonomic nervous system
doing at this point? How are your organs responding? - Some patients with hypertension (high blood pressure) are
given beta-blocking drugs to lower their blood pressure.
How does this effect occur? Explain why these drugs are not
administered to patients with a history of asthma. Why might
drinking coffee help asthma? - Why do many cold medications contain an alpha-adrenergic
agonist and atropine (belladonna)? Why is there a label
warning for people with hypertension? Why would a person
with gastritis be given a prescription for atropine? Explain
how this drug might affect the ability to digest and absorb
food.
Test Your Quantitative Ability
Refer to table 7.3 (chapter 7, p. 180) to obtain axon diameters
and conduction rates. Given that a rate of 1 m/sec is equal to
2.24 mph, answer the following questions.- What is the fastest rate (in m/sec and mph) that pain
information can be transmitted? - How much faster is sensory information from a muscle
transmitted than pain information? - Calculate the maximum rate of conduction (in mph) of
preganglionic autonomic axons. - Calculate the rate of conduction (in m/sec and mph) of a
postganglionic axon of average thickness. - How much faster does a somatic motor axon of average
thickness conduct action potentials compared to a
postganglionic autonomic axon of average thickness?
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