A&P ANS Study Guide

List the catecholamines

epinephrine and norepinephrine

Define and give examples of sympathomimetics, sympatholytics, parasympathomimetics and parasympatholytics

sympathomimetics = enhance sympathetic activity (ephedrine stimulates norepinepherine release) sympatholytics = suppress sympathetic activity (beta blockers reduce blood pressure) parasympathomimetics = enhance parasympathetic activity (pilocarpine reduces pressure in the eye to treat glaucoma) parasympatholytics = suppress parasympathetic activity (atropine dilates the eye for examination)

List the ANS component of a visceral reflex arc and the number of neurons involved

2 neurons span the distance from CNS to effectors; a presynaptic neuron in the spinal cord and a postsynaptic neuron in the peripheral ganglion

What effect does an ANS reflex have on a effector

ANS modifies effector activity, rather than causing it

Characterize the adrenal glands

Adrenal glands sit at the end of each kidney and secrete steroid hormones to stimulate a fight or flight reflex

Describe what is meant by autonomic tone and give an example

Autonomic tone is the normal rate of activity caused by a balance of the sympathetic and parasympathetic divisions (blood pressure would be too low or too high if either division had complete control)

Define biofeedback and visceral reflexes

Biofeedback is conscious control over the ANS. Visceral reflexes are automatic responses to stimuli in the viscera

Explain how caffeine functions as a stimulant

Caffeine binds to adenosine receptors which normally bind with adenosine to cause a sleepy feeling

List the effectors of the ANS

Cardiac muscles and smooth muscles

List the 3 major collateral ganglia

Celiac, superior mesenteric ganglion, inferior mesenteric ganglion

Compare cholinergic and adrenergic fibers

Cholinergic fibers secrete acetylcholine while adrenergic fibers secrete norepinephrine

Explain how cocaine use affects dopamine

Cocaine prevents the reuptake of dopamine, increasing the concentration of dopamine for a short period of time but long term use may deplete the body of dopamine

List the organs that are controlled by the ANS

Glands, circulatory system, and digestive system

Explain the treatments and management of clinical depression

Medication may be prescribed to raise serotonin levels (SSRI's or MAO inhibitors)

Characterize the pathways of SNS preganglionic fibers

Myelinated nerves take signals to the white communicating ramus

Compare neuronal convergence and divergence

Neuronal convergence = a single cell receives information from multiple neurons Neuronal divergence = a single nerve sends signals to multiple cells

Contrast nicotinic and muscarinic receptors - where they are located and the effects of ACh

Nicotinic receptors are found in skeletal muscles and are excitatory when ACh is present. Muscarinic receptors are found in cardiac and smooth muscles and can be excitatory or inhibitory

Describe the anatomy of the parasympathetic nervous system

Originate on the pons of the cranium and vertebrae S2-S4 and travel down to the inferior hypogastric plexus

Explain the pathway of ANS stimulation and response

Receptors detect a stimuli -> afferent neurons carry sensory signals to CNS -> efferent neurons carry motor signal from CNS to ANS -> effectors modify activity in the ANS

Describe the functions of the ANS

Regulates unconscious processes that maintain homeostasis

List and describe 3 routes of the SNS to effectors

Spinal nerve route = effectors in the body walls are innervated by neurons from the spine, controls sweat glands and muscular blood vessels Sympathetic nerve route = effectors in the head and thoracic cavity are innervated by neurons from the SNS to form a plexus (multiple routes), control salivary glands, the heart, and the iris Splanchnic nerve route = effectors in the abdominal cavity are innervated by splanchnic nerves, controls the urinary system

Define splanchnic nerves

Splanchnic nerves send signals to, and receive signals from, the visceral organs and blood vessels

Explain the role of the adrenal glands in the SNS response

Stimulate a complimentary fight or flight reflex

Compare the adrenal cortex and medulla

The cortex secretes steroid hormones and the medulla secretes neurotransmitters

Characterize the enteric nervous system

The enteric nervous system is the nervous system of the digestive organs which work almost autonomously

List examples of central control of autonomic function

The hypothalamus aids in sympathetic reactions, the spinal cord controls the skeletal sphincters of defecation

Illustrate paravertebral ganglia and how many associated with each spinal cord region

The paravertebral ganglia run parallel to the spinal cord and connect to form the sympathetic nervous system; 3 cervical, 11 thoracic, 4 lumbar, 4 sacral, and 1 coccygeal

List and characterize the divisions of ANS and their alternate names

The sympathetic division (thorocolumbar) division prepares the body for physical activity (fight or flight) while the parasympathetic division (craniosacral) prepares the body for relaxation (rest and digest)

Describe the anatomy of the sympathetic nervous system

The sympathetic nervous system stems from the horns of vertebrae T1-L2 and connect with other nerves to form the communicating rami

List another name for the ANS and describe how that name exemplifies it's function

The visceral motor system because it controls the movements (motor) of the visceral organs (viscera)