1.
A somatic motor neuron carries
Correct Answer
C. Motor commands to the skeletal muscles
Explanation
A somatic motor neuron carries motor commands to the skeletal muscles. This means that it is responsible for transmitting signals from the central nervous system (CNS) to the muscles that are under voluntary control. These motor commands initiate muscle contraction and allow for voluntary movement of the body.
2.
Most synapses are found in the:
Correct Answer
A. The CNS
Explanation
The correct answer is the CNS (central nervous system). The CNS consists of the brain and spinal cord, where most of the synapses are located. Synapses are the junctions between neurons where signals are transmitted, and they play a crucial role in the communication and processing of information within the nervous system. Ganglia are clusters of nerve cell bodies found outside the CNS, and while they contain synapses, they are not as abundant as in the CNS. White matter refers to the regions of the nervous system that contain myelinated axons, and while it does contain synapses, they are not the primary location. The PNS (peripheral nervous system) consists of nerves outside the CNS, and while it contains synapses, they are not as numerous as in the CNS.
3.
Which of the following is NOT a characteristic of neurons
Correct Answer
D. Ability to survive without oxygen
Explanation
Neurons require a constant supply of oxygen to function properly. They have a high metabolic rate and are highly dependent on oxygen for energy production. Therefore, the ability to survive without oxygen is not a characteristic of neurons.
4.
Ganglia represent groups of:
Correct Answer
C. Neuron body cells
Explanation
Ganglia represent groups of neuron body cells. Ganglia are clusters of nerve cell bodies found outside the central nervous system. These cell bodies are responsible for receiving, integrating, and transmitting information within the nervous system. Axons and dendrites are extensions of neurons, while synapses are the junctions where neurons communicate with each other. Therefore, the correct answer is neuron body cells.
5.
The majority of neurons in the body are:
Correct Answer
A. Multipolar
Explanation
The majority of neurons in the body are multipolar. This means that they have multiple processes extending from the cell body, including one axon and multiple dendrites. Multipolar neurons are the most common type of neurons and are involved in transmitting information between different parts of the body. They are found in the brain, spinal cord, and throughout the peripheral nervous system.
6.
Which of the following structures is found only in the PNS and not in the CNS
Correct Answer
C. A ganglion
Explanation
A ganglion is a structure found only in the peripheral nervous system (PNS) and not in the central nervous system (CNS). Ganglia are clusters of nerve cell bodies located outside the CNS. They play a crucial role in transmitting sensory information from the periphery to the CNS and coordinating motor responses. In contrast, tracts, white matter, and gray matter can be found in both the PNS and CNS. Tracts refer to bundles of axons that connect different regions of the CNS, while white matter and gray matter are types of tissue found in both the brain and spinal cord.
7.
Interneurons are found only in the:
Correct Answer
B. CNS
Explanation
Interneurons are specialized neurons that connect sensory and motor neurons within the central nervous system (CNS). They are responsible for transmitting signals between different parts of the CNS, allowing for complex processing and integration of information. Therefore, interneurons are found only in the CNS, making the correct answer choice the CNS.
8.
Which cells provide the myelin sheaths for the neurons in the CNS
Correct Answer
D. Oligodendrocytes
Explanation
Oligodendrocytes are the cells that provide the myelin sheaths for the neurons in the CNS. Myelin sheaths are fatty coverings that insulate and protect the axons of neurons, allowing for faster and more efficient transmission of electrical signals. Schwann cells, on the other hand, provide myelin sheaths for neurons in the peripheral nervous system. Astrocytes are a type of glial cell that support and nourish neurons, while microglial cells are involved in immune responses in the CNS.
9.
Which of the following is the correct order of the components in a reflex arc:
Correct Answer
A. Receptor, sensory neuron, integration center, motor neuron, effector
Explanation
The correct order of the components in a reflex arc is receptor, sensory neuron, integration center, motor neuron, effector. This sequence represents the flow of information in a reflex arc. The receptor detects a stimulus, which is then transmitted to the integration center through the sensory neuron. The integration center processes the information and sends a signal to the motor neuron. Finally, the motor neuron carries the signal to the effector, which is the muscle or gland that responds to the stimulus.
10.
White matter represents
Correct Answer
C. Myelinated axons traveling together in the CNS
Explanation
White matter represents myelinated axons traveling together in the CNS. Myelinated axons are nerve fibers that have a protective covering called myelin, which is white in color. These axons are responsible for transmitting signals between different regions of the central nervous system (CNS), including the brain and spinal cord. The white matter gets its name from the appearance of these myelinated axons, which give it a white color. Therefore, the correct answer is myelinated axons traveling together in the CNS.
11.
Action potentials travel along the
Correct Answer
A. Axon membrane
Explanation
Action potentials are electrical signals that transmit information within the nervous system. These signals are generated in the axon hillock, which is located at the junction between the cell body and the axon. From there, the action potential travels along the axon membrane, which is the outer covering of the axon. This is where the depolarization and repolarization of the membrane occur, allowing the action potential to propagate along the length of the axon and eventually reach the synaptic terminals. Therefore, the correct answer is the axon membrane.
12.
The peripheral nerve fibers that would measure the degree of stretch in a the biceps brachii muscle and its tendons would be an example of a:
Correct Answer
A. General somatic sensory
Explanation
The peripheral nerve fibers that measure the degree of stretch in the biceps brachii muscle and its tendons would fall under the category of general somatic sensory. This is because these nerve fibers are responsible for sensing and relaying information about the stretch and position of muscles and tendons in the body. General somatic sensory fibers are involved in providing sensory information from the skin, muscles, and joints to the central nervous system.
13.
All of the following are characteristics of the dendrites except that they
Correct Answer
B. Always conduct action potentials
Explanation
Dendrites are the branch-like extensions of a neuron that receive signals from other neurons. They play a crucial role in transmitting these signals towards the cell body, where the information is processed. However, dendrites do not always conduct action potentials. Action potentials are electrical impulses that are generated and propagated along the axon of a neuron, not the dendrites. Therefore, the statement "always conduct action potentials" is incorrect when referring to dendrites.
14.
Myelin on axons functions to:a. make axons live longer b. store nutrients (fat) for use of the neuronc. cover the nodes of Ranvier d. speed the rate of impulse conduction and insulate the axon
Correct Answer
D. D
Explanation
Myelin on axons functions to speed the rate of impulse conduction and insulate the axon.
15.
Unmyelinated axons area. thicker than myelinated axons b. are not associated with Schwann cellsc. conduct impulses more slowly than myelinated axons d. occur the PNS only
Correct Answer
C. C
Explanation
Unmyelinated axons conduct impulses more slowly than myelinated axons. This is because myelin, which is produced by Schwann cells, acts as an insulating layer around the axon, allowing for faster conduction of electrical impulses. In the absence of myelin, the electrical impulses have to travel along the entire length of the axon, resulting in slower conduction. Unmyelinated axons can be found in both the peripheral nervous system (PNS) and the central nervous system (CNS).
16.
Which of the following immediately encloses a single neuron?a. endoneurium b. perineurium c. fascicle d. indoneurium
Correct Answer
A. A
Explanation
The endoneurium immediately encloses a single neuron.
17.
A man walking barefoot steps on a piece of glass. His foot jerks upwards in which type of reflexa. somatic, polysynaptic, withdrawal b. visceral, monosynaptic, stretchc. somatic, monosynaptic, withdrawal d. visceral, polysynaptic, withdrawa
Correct Answer
A. A
Explanation
When a man steps on a piece of glass, his foot jerking upwards is a reflex action known as withdrawal reflex. This reflex is somatic because it involves the skeletal muscles of the foot. It is also monosynaptic because it only involves a single synapse between the sensory neuron and the motor neuron. Therefore, the correct answer is a) somatic, monosynaptic, withdrawal.
18.
Gray matter in the CNS contains all of the following excepta. neuronal cell bodies b. neuroglia c. dendrites d. fiber tracts
Correct Answer
D. D
Explanation
Gray matter in the CNS contains neuronal cell bodies, neuroglia, and dendrites. Fiber tracts, on the other hand, are located in the white matter of the CNS.
19.
The chemical substance that is released at the axon terminal is called aa. hormone b. neurotransmitter c. synaptic vesicle d. nissl body
Correct Answer
B. B
Explanation
Neurotransmitter is the correct answer because it is the chemical substance that is released at the axon terminal. Neurotransmitters are released from synaptic vesicles and they transmit signals across a synapse from one neuron to another. Hormones are chemical messengers that are released into the bloodstream and have a more widespread effect on the body. Synaptic vesicles are small sacs within the axon terminal that store neurotransmitters. Nissl bodies are specialized structures found in the cell body of neurons that are involved in protein synthesis.
20.
In the spinal cord, the cell bodies of most interneurons line in thea. sensory ganglia b. PNS c. dorsal half of gray matter d. ventral half of white matter
Correct Answer
C. C
Explanation
In the spinal cord, the cell bodies of most interneurons are located in the dorsal half of the gray matter. The gray matter is the region of the spinal cord that contains cell bodies, while the white matter contains nerve fibers. Interneurons are responsible for relaying signals between sensory and motor neurons, and their location in the dorsal half of the gray matter allows for efficient integration and processing of sensory information before transmitting it to motor neurons.