Autonomic and Somatic Nervous Systems

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Questions and Answers

What is the primary effect of sympathetic nerves when body temperature rises?

Decrease in metabolic rate

Dilation of cutaneous blood vessels (correct)

Constriction of blood vessels

Inhibition of sweat glands

What mechanism is stimulated by the sympathetic division to help raise blood pressure?

Vasodilation of blood vessels

Increase in heart rate

Renin release from kidneys (correct)

Decreased blood glucose levels

What happens to blood glucose levels during the fight or flight response?

They remain unchanged

They are regulated by parasympathetic fibers

They decrease to conserve energy

They increase due to glycogen breakdown (correct)

Which drug acts as a nicotinic cholinergic receptor antagonist?

Succinylcholine Signup and view all the answers

Which type of autonomic receptor do epinephrine and norepinephrine primarily bind to?

Beta-adrenergic receptors Signup and view all the answers

What is a significant role of the sympathetic division?

Facilitates the fight or flight response Signup and view all the answers

How do the sympathetic and parasympathetic divisions generally operate?

They oppose each other's actions Signup and view all the answers

What is the primary function of drugs like scopolamine in relation to the ANS?

To act as a muscarinic receptor antagonist Signup and view all the answers

What is the primary difference in the neuron structure between the autonomic nervous system and the somatic nervous system?

The autonomic system uses preganglionic and postganglionic neurons. Signup and view all the answers

Which neurotransmitter is predominantly released by the postganglionic fibers of the sympathetic division?

Norepinephrine Signup and view all the answers

What effect does the sympathetic division typically have on digestion?

It inhibits digestion. Signup and view all the answers

Which of the following receptors are exclusively excitatory?

Nicotinic receptors Signup and view all the answers

What is a characteristic of the parasympathetic division's preganglionic fibers?

They are long and terminate in or near the effector organ. Signup and view all the answers

Which physiological response is primarily associated with the sympathetic nervous system?

Increased heart rate and blood pressure. Signup and view all the answers

The effect of acetylcholine on the heart is primarily to:

Reduce cardiac contraction to slow heart rate. Signup and view all the answers

Which of the following is a function of the autonomic nervous system?

Innervates glandular tissues. Signup and view all the answers

Which division of the autonomic nervous system is responsible for the 'rest and digest' response?

Parasympathetic division Signup and view all the answers

In what situation do the sympathetic and parasympathetic divisions work cooperatively?

In reproductive functions. Signup and view all the answers

Study Notes

Autonomic Nervous System

The autonomic nervous system (ANS) regulates internal body functions unconsciously, adjusting to meet needs like fight-or-flight or rest-and-digest.
The ANS is typically divided into two parts that oppose one another: sympathetic and parasympathetic.
Sometimes they work together to balance bodily functions.
The sympathetic nervous system (SNS) prepares the body for action ("fight or flight").
The parasympathetic nervous system (PNS) calms the body and helps with "rest and digest".

Neuron Chain

The autonomic nervous system uses a two-neuron chain.
The first neuron (preganglionic) has its cell body in the central nervous system (CNS).
The preganglionic axon synapses with the second neuron (postganglionic) in an autonomic ganglion.
The postganglionic axon synapses with the target organ.

Somatic Nervous System

The somatic nervous system operates consciously by directly innervating skeletal muscle.
It uses single neurons extending from the CNS to the muscle.
It primarily uses acetylcholine (ACh).

Neurotransmitters

Acetylcholine (ACh): a neurotransmitter used by both the parasympathetic and somatic systems.
Norepinephrine (NE): a neurotransmitter used by the sympathetic system; effects depend on receptor type.
Epinephrine (adrenaline): a neurotransmitter used by the sympathetic system; effects depend on receptor type.

Sympathetic Nervous System (Fight-or-Flight)

Originates from thoracic and lumbar spinal cord.
Short preganglionic neurons, long postganglionic neurons.
Ganglia near spinal cord.
Increases heart rate, blood pressure, respiration, and other functions associated with alertness and energy expenditure.
Decreases digestion.
Dilates pupils (mydriasis)

Parasympathetic Nervous System (Rest-and-Digest)

Originates from the brain and sacral spinal cord.
Long preganglionic neurons, short postganglionic neurons.
Ganglia near effector organ.
Decreases heart rate, blood pressure, respiration.
Increases digestion.
Constricts pupils (miosis).

Receptor Types

Cholinergic receptors receive acetylcholine (ACh).
Nicotinic receptors: always excitatory
Muscarinic receptors: can be excitatory or inhibitory
Adrenergic receptors bind norepinephrine (NE) and epinephrine (E).
Alpha receptors, Beta receptors: effects vary.

Drugs and the ANS

Drugs can alter ANS function for various needs (e.g., anesthesia, treating asthma).
Drugs can be agonists (mimicking the effect of a neurotransmitter) or antagonists (blocking the receptor from engaging with a neurotransmitter).

Regulation/Control

The autonomic nervous system regulates body temperature, blood pressure, heart rate, etc.
It helps maintain homeostasis; a dynamic balance.
Sympathetic and parasympathetic activities work together or oppose one another depending on the need.

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Description

Explore the intricacies of the autonomic and somatic nervous systems in this quiz. Understand how these systems regulate body functions, including the interplay between the sympathetic and parasympathetic divisions. Test your knowledge on neuron chains and muscle innervation.