CH15+Autonomic+Nervous+System PDF

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Autonomic Nervous System To complete this worksheet, select: Module: Regulation Activity: Animations Title: Autonomic Nervous System Introduction 1.

What is the sensory function of the Autonomic Nervous System (ANS)? Unconsciously perceives visceral sensations or emotions.

2. What is the function of the hypothalamus and spinal cord relative to the ANS? It is the control center of the ANS.________________________________________________________

3. Name some of the effectors regulated by the ANS. Smooth muscle, cardiac muscle, exocrine and endocrine glands, and adipose tissue.

4. a.

Identify the two ANS divisions.

Sympathetic and Parasympathetic

b. Define dual innervation and explain its function . It is the phenomenon of regulating a single effector by both divisions. The function of the dual innervation is to balance an autonomic effector’s function.

5. Contrast ANS and somatic motor pathways. The difference is the amount of motor neurons for each pathway (ANS has 2 motor neurons, Somatic has one), presence and location of ganglia, and number and type of neurotransmitters.

Motor Pathways: Preganglionic and Postganglionic Neurons 6. Describe somatic motor neuron structure for stimulating an effector such as a skeletal muscle.

A single motor neuron excites the effector.

7. Unlike the SNS, two ANS motor neurons carry action potentials to effectors. Describe the location and function of each of them. Note their myelination differences, too. a.

Preganglionic Neuron – Synapses with cell bodies of a non-myelinated postganglionic neuron. Preganglionic Neurons are Myelinated neurons and are located in the spinal cord.

b. Postganglionic Neuron -Synapses with preganglionic neurons. This action potential is a non-myelinated neuron that’s located at the autonomic ganglion. _______________________ Motor Pathways: Ganglia 8. Describe the role of acetylcholine at the ganglia. It diffuses across the synaptic cleft and generates an action potential on the postganglionic neuron. The action potential then continues to travel along the axon of the postganglionic neuron towards the effector.

9. a.

Describe the location of parasympathetic motor ganglia

It’s located within or close to the effector organs which connects with the preganglionic neurons from 4 cranial nerves and the sacral segments of the spinal cord, also known as “craniosacral division”

b. Describe the pattern that establishes a stimulation connection to only a single parasympathetic effector. The parasympathetic ganglion has only a few postganglionic neurons, which are usually providing stimulation to only one effector._________________________________

10. a.

Describe the location of sympathetic motor ganglia . Are located near the spinal cord or major abdominal arteries. They are connected with preganglionic motor neurons from the thoracic and lumbar segments of the spinal cord. This is also known as the “thoracolumbar division”

b. Describe the pattern that establishes a stimulation connection to MANY sympathetic effectors. Has many postganglionic neurons that usually provide stimulation to many effectors.

Motor Pathways: Neurotransmitters 11. How are autonomic neurons classified? Depends on the type of neurotransmitter that is released into a synapse.

12. Identify the neurotransmitter , the deactivation enzyme, a.

cholinergic neurons – Release acetylcholine (ACh). Deactivated rapidly from the synapse by____________ acetylcholinesterase.

b. andregenic neurons – Release norepinephrine. Deactivated slowly by monoamine oxidase (MAO)

13. Identify the ANS neurons that are cholinergic. All sympathetic and parasympathetic preganglionic neurons_______________________________________ All parasympathetic postganglionic neurons___________________________________________________ Only sympathetic postganglionic neurons that stimulate sweat glands

14. Contrast the functions of postsynaptic receptors. a.

nicotinic receptors – always depolarize (excite) a cell when activated

b. muscarinic receptors -may depolarize (excite) or hyperpolarize (inhibit) a cell when activated

15. a.

Identify the ANS neurons that are adrenergic. Most sympathetic postganglionic neurons______________________________________

b. What affect does norepinephrine (NE) have on postsynaptic membranes? NE binds with receptors on the postsynaptic cell membrane and either depolarizes (excites) or hyperpolarizes (inhibits) the cell.

Physiological Effects of the ANS 16. Describe hypothalamus role within the ANS.

Coordinates the activity of sympathetic and parasympathetic divisions of the ANS to insure a more efficient and balanced response_____________________________

17. a.

When does the sympathetic division of the ANS respond and stimulate its effectors? It dominates during medical emergencies, embarrassment, exercise, and emotional reactions. The response of the sympathetic division to these stimuli is a suite of effector functions known as the “Fight or Flight” or “alarm reaction”

b. Identify some sympathetic responses. Pupil dilation______________________________________________________________________ Increased heart rate (force of contraction and blood pressure),________________________________ Bronchodilation of airways in lung_______________________________________________________ Vasoconstriction of vessels supplying blood to urinary, digestive, and reproductive organs,_____________ Vasodilation of vessels supplying skeletal muscles, cardiac muscles and liver________________________ Increased blood glucose from liver and fatty acids and glycerol from adipose cells___________________ c.

How are these responses appropriate for the sympathetic “fight or flight” response? They provide a rapid mechanism that promote increased nutrients and oxygen support for increased metabolism and activity in organs needed to resist stress. _____________

d. Name three reasons why the effects of sympathetic stimulation are longer lasting and more widely spread than parasympathetic stimulation. 1.) Motor pathways diverge to more effectors________________ 2.) Norepinephrine is deactivated more slowly than acetylcholine__ 3.) Norepinephrine secreted from the adrenal medulla during times of stress, increases and spreads the overall effect fo NE that is released as a neurotransmitter

18. a. Explain why the parasympathetic division is sometimes called the “rest and digest” reaction. The parasympathetic division becomes dominant when a person is relaxed, well fed or sleepy. The response suites the rest and digest reaction___________ b. Identify some parasympathetic responses. Decreased heart rate (force of contraction and blood pressure___________________________ Bronchoconstriction of airways in lung (opposite of sympathetic response) ___________________ Vasodilation of vessels supplying blood to urinary, digestive, and reproductive organs___________ Vasoconstriction of vessels supplying skeletal muscles, cardiac muscles and liver_______________ c.

Define the SLUDD responses.

Salivation, lacrimation, urination, digestion, defecation are all increased d. In general, define the function of parasympathetic responses. Provides a rapid mechanism to promote the maintenance of normalcy, decreases energy consumption, and increases energy conservation________________________________________________________...