click below
click below
Normal Size Small Size show me how
Stack #53760
Chapter 13-Autonomic nervous system
Question | Answer |
---|---|
Central nervous system | made up of the brain & spinal cord |
Afferent nerves | CNS receives signals from sensory receptors throughout the body that are transmitted to the spinal cord & brain |
Efferent nerves | CNS processes these signals & controls body repsonses by sending signals through efferent nerves |
Peripheral nervous system | efferent & afferent nerves are known collectively as PNS |
Motor nervous system | efferent system is divided into the motor nervous system, which controls skeletal muscle contractions & the autonomic nervous system |
Autonomic nervous system | helps regulate such body functions as heart rate, BP, thermal control, light regulation by the eyes & many other activities |
Neurons | each nerve of the CNS & PNS is actually composed of a series of segments called neurons |
Synapse | the junction between one neruon & the next is called a synapse |
Neurotransmitters | the transmission of nerve signals or impulses occurs because of the activity of chemical substances called neurotransmitters(transmitters of nerve impulses) |
Autonomic nervous system | with the exception of the skeletal muscle, the autonomic nervous system controls most tissue function, also called the involuntary nervous system because we have little or no control over it. |
norepinephrine | one of the two major neurotransmitters of the autonomic nervous system (acetylcholine) |
acetylcholine | one of the two major neurotransmitters of the autonomic nervous system (norepinephrine) |
cholinergic fibers | the nerve endings that liberate acetylcholine are called cholinergic fibers |
adrenergic fibers | those that secrete norepinephrine are called adrenergic fibers |
cholinergic | meds that cause effects in the body similar to those produced by acetylcholine are called cholinergic or parasympathominetic drugs because they mimic the action produced by stimulation of parasympathetic division of the autonomic nervous system |
Adrenergic | meds that cause effects similar to those produced by the adrenergic neurotransmitter are called adrenergic, or sympathomimetic drugs |
Anticholinergic agents | agents that block or inhibit cholinergic activity are called anticholinergic agents |
Drug Class: Adrenergic Agents (actions) | the adrenergic nervous system may be stimulated by two broad classes of drugs: catecholamines & noncatecholamines. The body's naturally occurring neurotransmitter catecholamines & norepinephrine, epinephrine & dopamine |
Norepinephrine | secreted primarily from nerve terminals |
Epinephrine | primarily from the adrenal medulla |
Dopamine | at selected sited within the brain, kidneys & GI tract |
Autonomic nervous system | subdivided into alpha, beta & dopaminergic receptors |
Alpha-1 | stimulation of alpha-1 causes vasoconstriction of blood vessels |
Alpha-2 | appear to serve mediators of negative feedback, preventing further release of norepinephrine |
Beta-1 | stimulation of beta-1 causes an increase in the heart rate |
Beta-2 | stimulation of beta-2 receptors causes relaxation of smooth muscle in the bronchi(bronchodilation), uterus(relaxation), & peripheral arterial blood vessels(vasodilation) |