Ch.12 Nervous Tissue-final Exam Quiz

The cell body contains the nucleus. The nucleus is the control center of the cell and contains the genetic material, DNA, which regulates the cell's activities. The axon and dendrites are extensions of the cell body that transmit signals to and from other cells. Therefore, the correct answer is the cell body.

The small gap between two successive neurons is called the synaptic cleft. This is the space where communication occurs between neurons. When an electrical signal, known as an action potential, reaches the axon terminal of one neuron, it triggers the release of neurotransmitters into the synaptic cleft. These neurotransmitters then bind to receptors on the dendrite terminal of the next neuron, allowing the signal to be transmitted from one neuron to another. The synaptic cleft plays a crucial role in the transmission of information throughout the nervous system.

The glossy-white appearance of most axons is due to the high lipid content of the myelin sheath. Lipids are a type of fat that make up the myelin sheath, which is a protective covering around the axons. The high lipid content gives the myelin sheath a glossy appearance, resulting in the glossy-white appearance of the axons.

The myelin sheath is formed by Schwann Cells. Schwann cells are a type of glial cell found in the peripheral nervous system. They wrap around the axons of neurons, forming a myelin sheath that acts as an insulating layer. This myelin sheath helps to increase the speed of electrical impulses along the axon, allowing for more efficient transmission of signals. Oligodendrocytes, microglial cells, and astrocytes are all types of glial cells found in the central nervous system, and they do not play a role in forming the myelin sheath in the peripheral nervous system.

Acetylcholine is a common neurotransmitter in the nervous system. It is a chemical messenger that transmits signals between nerve cells and plays a crucial role in various physiological processes such as muscle movement, memory, and learning. Acetylcholine is released from the presynaptic neuron and binds to receptors on the postsynaptic neuron, allowing for the transmission of the nerve impulse. Therefore, acetylcholine is the correct answer as it is a well-known and widely studied neurotransmitter in the human body.

A motor neuron carries impulses from the central nervous system (CNS) to muscles and glands. This is because motor neurons are responsible for transmitting signals that control muscle movement and glandular secretions. They serve as the connection between the CNS and the peripheral nervous system, allowing the brain and spinal cord to communicate with the muscles and glands throughout the body.

The sodium-potassium pump is responsible for maintaining the resting potential of a neuron. It actively transports sodium ions out of the cell and potassium ions into the cell, against their concentration gradients. This creates a higher concentration of sodium ions outside the cell and a higher concentration of potassium ions inside the cell. This concentration gradient is essential for generating and maintaining the electrical potential across the neuron's membrane, allowing it to be in a resting state. Osmosis, pinocytosis, and facilitated diffusion are not directly involved in maintaining the resting potential of a neuron.

The correct answer is dura mater. The dura mater is the tough outermost layer of the meninges, which are the protective membranes surrounding the brain and spinal cord. It is composed of dense, fibrous connective tissue and provides strength and protection to the central nervous system. The arachnoid mater is the middle layer, while the pia mater is the innermost layer of the meninges.

The afferent division of the nervous system is responsible for carrying sensory information from the body to the central nervous system. This includes information such as touch, temperature, pain, and proprioception. Therefore, the correct answer is sensory.

A neurotransmitter is a chemical substance that transmits signals across the synaptic cleft, which is the small gap between two neurons. It carries the signal from the presynaptic neuron to the postsynaptic neuron, allowing for communication between neurons. Sodium ions, potassium ions, and electrons are involved in the electrical signaling within neurons, but they do not directly flow across the synaptic cleft.

The axon is the part of a neuron that carries impulses away from the cell body. It is a long, slender projection that extends from the cell body and transmits electrical signals to other neurons or target cells. The axon plays a crucial role in the transmission of information within the nervous system, allowing for communication between different parts of the body.

During repolarization, potassium ions move outside the neuron. This is because repolarization is the phase in which the membrane potential is restored to its resting state after depolarization. During depolarization, sodium ions move inside the neuron, causing a temporary positive charge inside the cell. To return to the resting state, potassium ions move outside the neuron, repolarizing the membrane and restoring the negative charge inside the cell. This movement of potassium ions outside the neuron helps to reset the neuron for the next action potential.

Microglial cells are a type of glial cell that defends the body against pathogens. They are the immune cells of the central nervous system and play a crucial role in the brain's immune response. When pathogens or foreign substances are detected, microglial cells become activated and release inflammatory molecules to eliminate the threat. They also help in clearing cellular debris and damaged neurons. Therefore, microglial cells are responsible for the defense against pathogens in the body.

Cerebrospinal fluid is produced by ependymal cells. These cells line the ventricles of the brain and the central canal of the spinal cord. They are specialized in the production and regulation of cerebrospinal fluid, which serves important functions such as cushioning and protecting the brain and spinal cord, removing waste products, and providing nutrients to the nervous system.

The resting potential of a neuron refers to the electrical charge difference between the inside and outside of the neuron when it is not actively sending a signal. A negative value indicates that the inside of the neuron is more negatively charged compared to the outside. In this case, the resting potential is measured at -70 millivolts, suggesting that the inside of the neuron is 70 millivolts more negative than the outside.

Glial cells and neurons are the two distinct cell types that form nervous tissue. Glial cells provide support and protection to neurons, while neurons are responsible for transmitting electrical signals in the nervous system. Together, they work in coordination to ensure proper functioning of the nervous system.

Oligodendrocytes are glial cells that myelinate and insulate axons within the central nervous system (CNS). They form the myelin sheath, which is a fatty substance that wraps around the axons, increasing the speed and efficiency of nerve impulse transmission. Unlike neurolemmocytes (Schwann cells), which myelinate axons in the peripheral nervous system (PNS), oligodendrocytes are responsible for myelination in the CNS. Astrocytes provide support and nourishment to neurons, ependymal cells line the ventricles of the brain and spinal cord, and microglial cells are involved in immune defense in the CNS.

The correct answer is meninges. The meninges are the protective membranes that surround the brain and spinal cord. They consist of three layers: the dura mater, arachnoid mater, and pia mater. The meninges provide cushioning and support for the central nervous system, protecting it from injury and infection.

The spinal cord does not belong to the peripheral nervous system. The peripheral nervous system consists of nerves and ganglia that are located outside of the brain and spinal cord. The spinal cord, on the other hand, is a part of the central nervous system, along with the brain. It is responsible for transmitting signals between the brain and the rest of the body.

The tracts of myelinated axons in the CNS are responsible for transmitting signals between different parts of the central nervous system. These axons are coated with a fatty substance called myelin, which gives them a white appearance. Therefore, the correct answer is white matter. Gray matter, on the other hand, consists mainly of cell bodies and unmyelinated axons. Cerebrospinal fluid is a clear liquid that surrounds and cushions the brain and spinal cord, while ventricles are fluid-filled spaces within the brain.

Ependymal cells are the glial cells that help to form cerebrospinal fluid. These cells line the ventricles of the brain and the central canal of the spinal cord, and they are responsible for producing and regulating the flow of cerebrospinal fluid. This fluid provides cushioning and support to the brain and spinal cord, as well as helps to remove waste products and deliver nutrients to these structures. Therefore, ependymal cells play a crucial role in maintaining the overall health and function of the central nervous system.

When a stimulus opens ion channels, it allows sodium ions to flow into the neuron. Sodium ions have a positive charge, so when they enter the neuron, the inside becomes positively charged.

The correct layering of the meninges from the superficial to deep is dura mater, arachnoid mater, pia mater. The dura mater is the outermost layer, followed by the arachnoid mater, and finally the pia mater, which is the innermost layer.

All glial cells have in common that they assist neurons in their respective functions. Glial cells are a type of non-neuronal cells that provide support and protection to neurons in the nervous system. They help in regulating the extracellular environment, providing structural support, insulating neurons, and assisting in the transmission of nerve signals.

An action potential is an electrical signal that is generated by a stimulus. It is the initial event that triggers the depolarization and subsequent repolarization of a neuron. The stimulus can be any external or internal event that excites the neuron and leads to the generation of an action potential. Therefore, the correct answer is "stimulus".

Astrocytes are the most abundant glial cells in the central nervous system (CNS). They play a crucial role in supporting and maintaining the neurons. Astrocytes provide structural support, regulate the extracellular environment, and contribute to the blood-brain barrier. They also play a role in neurotransmitter regulation and synaptic function. Astrocytes are involved in various physiological processes, including energy metabolism, ion homeostasis, and neuroprotection. Therefore, astrocytes are the correct answer as they are the most abundant glial cells in the CNS and have multiple essential functions.

The space between the arachnoid and pia maters is known as the subarachnoid space. This space is filled with cerebrospinal fluid, which acts as a cushion and provides protection to the brain and spinal cord. The subarachnoid space also contains blood vessels and plays a crucial role in the circulation of cerebrospinal fluid.

Saltatory conduction is the correct answer because it refers to the process of an action potential "jumping" or rapidly propagating from one node of Ranvier to the next along a myelinated axon. This mode of conduction allows for faster transmission of the electrical signal compared to continuous conduction, where the action potential travels along the entire length of the axon. The myelin sheath insulates the axon, preventing ion leakage and forcing the action potential to "leap" between nodes, increasing the speed and efficiency of signal transmission.

The ventricles of the brain contain cerebrospinal fluid. Cerebrospinal fluid is a clear, colorless fluid that surrounds and protects the brain and spinal cord. It acts as a cushion, providing mechanical support and shock absorption for the brain. Cerebrospinal fluid also helps to remove waste products and deliver nutrients to the brain.

The somatic sensory division of the nervous system is responsible for conducting impulses from the skin, joints, skeletal muscles, and special senses. This division is involved in processing sensory information from these areas and relaying it to the brain for interpretation and response. It allows us to feel sensations such as touch, temperature, pain, and proprioception, which is the sense of body position and movement.

During depolarization, the neuron's membrane potential becomes less negative as sodium ions move inside the neuron. This occurs due to the opening of sodium channels in the neuron's membrane. The influx of sodium ions results in the reversal of the membrane potential, causing an action potential to be generated and propagated along the axon. This movement of sodium ions inside the neuron is crucial for the transmission of electrical signals in the nervous system.

The neuron conducting an impulse from the stomach wall to the CNS would be classified as a visceral sensory neuron. Visceral sensory neurons are responsible for transmitting sensory information from the internal organs to the central nervous system. In this case, the impulse from the stomach wall would be sensed by the visceral sensory neuron and transmitted to the CNS for processing and interpretation.

The spinal cord is divided into different segments, and each segment gives rise to a pair of spinal nerves. There are a total of 31 segments in the spinal cord, which means there are 31 pairs of spinal nerves. Therefore, the correct answer is 31.

Acetylcholinesterase plays the role of breaking down acetylcholine at a synapse. Acetylcholine is a neurotransmitter that is released by the presynaptic neuron and binds to receptors on the postsynaptic neuron, transmitting the signal. However, to prevent continuous stimulation, acetylcholinesterase breaks down acetylcholine into choline and acetate, terminating the signal transmission. This allows for proper regulation and control of synaptic communication.

The somatic motor division of the nervous system is responsible for voluntary control over skeletal muscles. This division sends signals from the brain and spinal cord to the skeletal muscles, allowing us to consciously control our movements. Unlike the autonomic motor division, which controls involuntary actions such as heartbeat and digestion, the somatic motor division allows us to move our muscles at will. Therefore, the correct answer is somatic motor.

A nerve is a cablelike bundle of parallel axons. This means that it consists of multiple axons that are running parallel to each other, similar to the cables in a cable bundle. Nerves are found throughout the body, both in the central nervous system (CNS) and the peripheral nervous system (PNS). They can carry both sensory and motor information, meaning they transmit signals from both the sensory organs to the CNS and from the CNS to the muscles and glands. Therefore, the statement that a nerve carries only sensory information or is found only in the CNS is incorrect.

Sodium ions are found on the outside of the neuron membrane and contribute to a positive resting potential. This is because the concentration of sodium ions is higher outside the neuron compared to the inside. The neuron maintains this concentration gradient through the action of the sodium-potassium pump, which actively transports sodium ions out of the cell. The accumulation of positive sodium ions outside the cell creates a positive resting potential, which is essential for the generation of action potentials and the transmission of nerve impulses.

The cardiac, vasomotor, and respiratory centers are responsible for regulating heart rate, blood pressure, and breathing respectively. These centers are located in the medulla oblongata, which is the lower part of the brainstem. It controls vital functions and connects the spinal cord to the higher brain structures. The medulla oblongata plays a crucial role in maintaining homeostasis and coordinating involuntary actions necessary for survival.

Interneurons are responsible for integrating information by retrieving, processing, storing, and deciding how the body responds to stimuli. They act as a bridge between sensory neurons and motor neurons, transmitting signals between them. Unlike sensory neurons that detect stimuli and motor neurons that carry out responses, interneurons are involved in complex processes of information processing and decision-making within the nervous system. They play a crucial role in coordinating and integrating signals to produce appropriate responses to external stimuli.

Astrocytes are a type of glial cell that play a crucial role in forming and maintaining the blood-brain barrier. They have specialized structures called endfeet that wrap around blood vessels in the brain, creating a physical barrier that prevents substances from freely entering or leaving the brain. Astrocytes also regulate the transport of nutrients and waste products between the blood and brain tissue, providing support and protection to the neurons. Therefore, astrocytes are the correct answer as they actively contribute to the formation of the blood-brain barrier.

Calcium ions trigger the release of a neurotransmitter from the presynaptic neuron vesicles. When an action potential reaches the presynaptic terminal, it causes voltage-gated calcium channels to open. This allows calcium ions to enter the neuron. The influx of calcium ions leads to the fusion of neurotransmitter-containing vesicles with the presynaptic membrane, releasing the neurotransmitter into the synaptic cleft. This neurotransmitter then binds to receptors on the postsynaptic neuron, allowing for the transmission of the signal across the synapse.

A bundle of parallel axons in the central nervous system is called a tract. Nerves are responsible for transmitting signals between different parts of the body and the brain. They are made up of multiple axons, which are long, slender projections of nerve cells that carry electrical impulses. Nerves can be found throughout the body and play a crucial role in coordinating movement, sensation, and other functions.

The transmission across a synapse typically occurs from the axon of one neuron to the dendrite of another neuron. This is because the axon of a neuron sends out electrical signals called action potentials, which travel down the axon and reach the synapse. At the synapse, neurotransmitters are released from the axon terminal and bind to receptors on the dendrite of the receiving neuron, allowing the transmission of the signal. While there are rare cases where transmission can occur in the opposite direction, the most common and typical direction is from axon to dendrite.

Interneurons are a type of neuron that transmit signals between sensory neurons and motor neurons. They are found entirely within the central nervous system (CNS) and play a crucial role in processing and integrating information. Therefore, the correct answer is "to the CNS" because interneurons carry impulses from one part of the CNS to another, facilitating communication and coordination within the nervous system.

The correct answer is the anterior horns. The anterior horns of the spinal cord contain the cell bodies of lower motor neurons. Upper motor neurons from the brain synapse with these lower motor neurons in the anterior horns, allowing for the transmission of signals from the brain to the muscles. This connection is essential for motor control and movement.

Neuroglia, also known as glial cells, are non-neuronal cells that provide support and protection for neurons in the nervous system. They do not transmit electrical signals like neurons but play essential roles in maintaining the health and function of neurons. The other options, sensory neurons, motor neurons, and interneurons, are all types of neurons that transmit electrical signals to process and transmit information in the nervous system.  Sources and related content

Guillain-Barre syndrome is the correct answer because it is a disorder of the peripheral nervous system that is characterized by muscle weakness starting in the distal limbs and progressing to involve proximal muscles. Parkinson's disease, multiple sclerosis, and amyotrophic lateral sclerosis do not match the given description.

A ganglion is a cluster of neurosomas in the PNS. Neurosomas are the cell bodies of neurons, and ganglia are collections of these cell bodies. Ganglia are found outside of the central nervous system (CNS) and are responsible for coordinating and regulating the activities of peripheral nerves. They play a role in sensory processing, motor control, and autonomic functions.

Oligodendrocytes are glial cells that produce myelin, a fatty substance that insulates axons and speeds up nerve impulse conduction, in the central nervous system (CNS). Schwann cells perform a similar function in the peripheral nervous system (PNS).

The action potential consists of depolarization, which is the phase where the membrane potential becomes less negative, and repolarization, which is the phase where the membrane potential returns to its resting state. Resting potential refers to the stable, negative charge of the cell membrane when it is not transmitting signals. Therefore, the correct answer is depolarization and repolarization.