Question 1

Which of the following is NOT an example of the somatic nervous system's contribution to homeostasis?

Accepted Answer

Stimulation of digestive muscles is regulated by the autonomic nervous system, specifically the enteric division. The somatic nervous system controls voluntary movements such as exciting skeletal muscle, maintaining balance, and breathing in and out.

Question 2

In World War I, nerve agents were used in the newly discovered chemical warfare in order to inflict extreme pain and death on a monumental scale. These agents interrupted normal communication at the neuromuscular junction by inhibiting acetylcholinesterase activity. How does this mechanism affect somatic muscle activity?

Accepted Answer

Inhibiting acetylcholinesterase prevents the breakdown of acetylcholine (ACh) in the synaptic cleft, leading to an accumulation of ACh. This results in continuous stimulation of muscles, causing uncontrollable muscle spasms.

Question 3

If you removed the external Ca⁺⁺ at the neuromuscular junction, you would most directly affect which of the following?

Accepted Answer

Removing external calcium ions would most directly affect acetylcholine exocytosis because calcium ions are crucial for the vesicle fusion process that releases neurotransmitters into the synaptic cleft.

Question 4

If the frequency of action potentials in a somatic motor neuron increased, would there be any effect on the activity of the muscle innervated by the motor neuron?

Accepted Answer

An increase in the frequency of action potentials in a somatic motor neuron results in an increase in the release of acetylcholine at the neuromuscular junction. This, in turn, leads to an increase in the contraction strength of the muscle fibers innervated by the motor neuron. Therefore, the activity of the muscle would increase.

Question 5

Which of the following is NOT an example of homeostatic regulation of sexual reproduction by the nervous system?

Accepted Answer

Fertilization of an egg by a sperm is not regulated by the nervous system, but rather by the reproductive system. A) Lactation of breast milk is regulated by the release of hormones controlled by the nervous system. B) Sexual arousal is regulated by the nervous system. D) Expression of sex traits can be regulated by both the nervous and endocrine systems.

Question 6

At the neuromuscular junction, a somatic motor neuron's axon branches to innervate multiple muscle fibers in a muscle.

Accepted Answer

At the neuromuscular junction, a single somatic motor neuron's axon branches to innervate multiple muscle fibers within a muscle, which is known as motor unit.

Question 7

The end-plate potential is a type of graded potential.

Accepted Answer

The end-plate potential is a graded potential that occurs at the neuromuscular junction between a motor neuron and a skeletal muscle fiber. It is a depolarization caused by the release of acetylcholine from the motor neuron, which triggers the opening of ligand-gated ion channels in the muscle fiber's membrane. This depolarization can lead to muscle contraction.

Question 8

Botulinum toxin (Botox) injections are a popular cosmetic treatment because they allow an individual to temporarily reduce visible wrinkles in the skin (usually around the face). What is a probable mechanism of Botox at the neuromuscular junction?

Accepted Answer

Botulinum toxin (Botox) works by inhibiting the release of acetylcholine (ACh) vesicles in the pre-synaptic neuron at the neuromuscular junction. This prevents the generation of an end-plate potential, leading to muscle relaxation by preventing muscle contraction.

Question 9

Which of the following is NOT a way that the nervous system contributes to homeostasis?

Accepted Answer

The somatic nervous system does not regulate the growth of target cells in the body. Instead, growth is primarily controlled by hormones and growth factors. The other choices are all ways that the nervous system contributes to homeostasis, by controlling movement (A), communicating information via action potentials (B), and integrating sensory information with motor commands (D).

Question 10

During a fight-or-flight response, a person can experience vasoconstriction in some blood vessels and vasodilation in others. How is it possible that norepinephrine can produce both vasodilation and vasoconstriction?

Accepted Answer

Different membrane receptors for norepinephrine exist, and activation of different receptor types determines the response of the effector. Some receptors cause vasoconstriction, while others cause vasodilation.

Question 11

Increased autonomic activity to the heart could have what effect on the activity of the heart?

Accepted Answer

Increased autonomic activity to the heart can lead to either an increase or decrease in heart rate, depending on whether the sympathetic or parasympathetic nervous system is more active. The sympathetic nervous system increases heart rate, while the parasympathetic nervous system decreases it.

Question 12

Which of the following drug types might cause uncontrollable muscle seizures?

Accepted Answer

α-latrotoxin causes excitation of pre-synaptic vesicle release, leading to excessive neurotransmitter release and potentially resulting in uncontrollable muscle seizures.

Question 13

The effector(s) of the somatic motor system include(s)

Accepted Answer

The somatic motor system is responsible for voluntary movement of skeletal muscles, therefore the effector of this system is solely skeletal muscle.

Question 14

Increased somatic nervous system activity could have what effect on the activity of skeletal muscles?

Accepted Answer

Increased somatic nervous system activity would lead to an increase in activity of skeletal muscles. This is because the somatic nervous system is responsible for voluntary movement of the skeletal muscles, so increased activity would result in more signals being sent to these muscles to contract and move.

Question 15

Holly just got into a car accident and was T-boned by another driver. Luckily, both drivers escaped with no major injuries and Holly was able to exit her car safely to walk to the side of the road and sit down. When the EMT's arrive, what signs of autonomic nervous system stimulation might they look for in Holly?

Accepted Answer

Sweating palms and large pupils are signs of autonomic nervous system stimulation commonly seen in response to a stressful or threatening situation such as a car accident. Increased heart rate and dilated pupils are also possible signs, but pupil constriction (as seen in choice B) would be unlikely in this scenario. Decreased breathing rate and excessive drooling (choice C) or dangerously low heart rate and excessive tear secretion (choice D) are not typically associated with autonomic nervous system stimulation.

Question 16

Activation of the somatic nervous system is NOT important for which of the following functions?

Accepted Answer

Heart contraction strength is controlled by the autonomic nervous system, specifically the sympathetic division, and not the somatic nervous system. The other options are all functions controlled by the somatic nervous system.

Question 17

The nervous system uses graded and action potentials to communicate with, and regulate most body organs and systems to help maintain homeostasis.

Accepted Answer

The nervous system uses both graded and action potentials to communicate with and regulate most body organs and systems. Graded potentials are used for short-distance signaling, while action potentials are used for longer-distance signaling along axons. This communication helps to maintain homeostasis, or a stable internal environment, by regulating various bodily functions such as heart rate, breathing, and digestion.

Question 18

The graded potentials produced in skeletal muscle fibers are called _____, and they tend to be produced near the _____ of the muscle fiber.

Accepted Answer

The graded potentials produced in skeletal muscle fibers are called end plate potentials, and they tend to be produced near the middle of the muscle fiber at the neuromuscular junction, where the motor neuron releases acetylcholine onto the muscle fiber.

Question 19

Increased somatic nervous system activity has which effect on the motor neurons?

Accepted Answer

Increased somatic nervous system activity leads to an increased release of acetylcholine (ACh) from the somatic motor neuron. This ACh then binds to nicotinic receptors on skeletal muscle cells, leading to muscle contraction. There is no involvement of noradrenaline (NE) in the somatic nervous system.

Question 20

The somatic nervous system has dual innervation of its effectors.

Accepted Answer

The somatic nervous system controls voluntary movements and transmits sensory information to the central nervous system. It does not have dual innervation of its effectors; this characteristic is of the autonomic nervous system, which innervates glands, heart muscle, and smooth muscle with both sympathetic and parasympathetic fibers.

Quiz 10: Autonomic and Somatic Nervous Systems

Which of the following is NOT an example of the somatic nervous system's contribution to homeostasis?

If you removed the external Ca⁺⁺ at the neuromuscular junction, you would most directly affect which of the following?

If the frequency of action potentials in a somatic motor neuron increased, would there be any effect on the activity of the muscle innervated by the motor neuron?

Which of the following is NOT an example of homeostatic regulation of sexual reproduction by the nervous system?

At the neuromuscular junction, a somatic motor neuron's axon branches to innervate multiple muscle fibers in a muscle.

The end-plate potential is a type of graded potential.

Botulinum toxin (Botox) injections are a popular cosmetic treatment because they allow an individual to temporarily reduce visible wrinkles in the skin (usually around the face) . What is a probable mechanism of Botox at the neuromuscular junction?

Which of the following is NOT a way that the nervous system contributes to homeostasis?

During a fight-or-flight response, a person can experience vasoconstriction in some blood vessels and vasodilation in others. How is it possible that norepinephrine can produce both vasodilation and vasoconstriction?

Increased autonomic activity to the heart could have what effect on the activity of the heart?

Which of the following drug types might cause uncontrollable muscle seizures?

The effector(s) of the somatic motor system include(s)

Increased somatic nervous system activity could have what effect on the activity of skeletal muscles?

Activation of the somatic nervous system is NOT important for which of the following functions?

The nervous system uses graded and action potentials to communicate with, and regulate most body organs and systems to help maintain homeostasis.

The graded potentials produced in skeletal muscle fibers are called _, and they tend to be produced near the _ of the muscle fiber.

Increased somatic nervous system activity has which effect on the motor neurons?

The somatic nervous system has dual innervation of its effectors.

Quiz 10: Autonomic and Somatic Nervous Systems

Which of the following is NOT an example of the somatic nervous system's contribution to homeostasis?

If you removed the external Ca++ at the neuromuscular junction, you would most directly affect which of the following?

If the frequency of action potentials in a somatic motor neuron increased, would there be any effect on the activity of the muscle innervated by the motor neuron?

Which of the following is NOT an example of homeostatic regulation of sexual reproduction by the nervous system?

At the neuromuscular junction, a somatic motor neuron's axon branches to innervate multiple muscle fibers in a muscle.

The end-plate potential is a type of graded potential.

Botulinum toxin (Botox) injections are a popular cosmetic treatment because they allow an individual to temporarily reduce visible wrinkles in the skin (usually around the face) . What is a probable mechanism of Botox at the neuromuscular junction?

Which of the following is NOT a way that the nervous system contributes to homeostasis?

During a fight-or-flight response, a person can experience vasoconstriction in some blood vessels and vasodilation in others. How is it possible that norepinephrine can produce both vasodilation and vasoconstriction?

Increased autonomic activity to the heart could have what effect on the activity of the heart?

Which of the following drug types might cause uncontrollable muscle seizures?

The effector(s) of the somatic motor system include(s)

Increased somatic nervous system activity could have what effect on the activity of skeletal muscles?

Activation of the somatic nervous system is NOT important for which of the following functions?

The nervous system uses graded and action potentials to communicate with, and regulate most body organs and systems to help maintain homeostasis.

The graded potentials produced in skeletal muscle fibers are called _____, and they tend to be produced near the _____ of the muscle fiber.

Increased somatic nervous system activity has which effect on the motor neurons?

The somatic nervous system has dual innervation of its effectors.

If you removed the external Ca⁺⁺ at the neuromuscular junction, you would most directly affect which of the following?

The graded potentials produced in skeletal muscle fibers are called _, and they tend to be produced near the _ of the muscle fiber.