Chapter 10: Nervous System

The myelin sheath is the correct answer because it is the fatty insulating material that surrounds the axons. It is produced by specialized cells called glia and plays a crucial role in speeding up the transmission of electrical signals along the axons. The myelin sheath acts as an insulator, preventing the loss of electrical signals and allowing for efficient communication between neurons. The other options, glia, choroid plexus, and sarcolemma, are not directly involved in the insulation of axons.

The subarachnoid space is a space located between the arachnoid mater and the pia mater, two of the meninges that surround the brain and spinal cord. It is filled with cerebrospinal fluid (CSF), which acts as a cushion to protect the brain and spinal cord from injury. CSF also helps to regulate the chemical environment of the central nervous system and remove waste products. Therefore, the correct answer is cerebrospinal fluid.

Injury to the occipital lobe is most likely to cause loss of vision because the occipital lobe is responsible for processing visual information. It receives and interprets signals from the eyes, allowing us to see and perceive the world around us. Therefore, damage to this area can result in a loss or impairment of vision.

The subarachnoid space contains cerebrospinal fluid. This space is located between the arachnoid mater and the pia mater, which are two of the three layers that make up the meninges, the protective membranes surrounding the brain and spinal cord. Cerebrospinal fluid is produced in the ventricles of the brain and circulates through the subarachnoid space, providing cushioning and support to the central nervous system.

The corpus callosum is a bundle of nerve fibers that connects the right and left cerebral hemispheres of the brain. It allows for communication and coordination between the two hemispheres, enabling them to work together and share information. This connection is essential for various cognitive functions, including language processing, perception, and problem-solving.

Dendrites are the branching structures that carry information toward the cell body of a neuron. They receive signals from other neurons or sensory receptors and transmit them to the cell body, where the signals are integrated and processed. Dendrites play a crucial role in the communication between neurons, as they receive and transmit electrical and chemical signals, allowing for the transmission of information throughout the nervous system.

The midbrain, pons, and medulla oblongata are collectively referred to as the brain stem. The brain stem is responsible for many vital functions such as controlling breathing, heart rate, and blood pressure. It also serves as a pathway for nerve fibers to transmit signals between the brain and the spinal cord. The brain stem plays a crucial role in maintaining basic bodily functions and is essential for survival.

Endorphins are natural morphine-like substances that can reduce anxiety and induce a sense of well-being. They act as neurotransmitters in the brain and are released in response to various stimuli such as exercise, laughter, and certain foods. Endorphins work by binding to opioid receptors in the brain, which then leads to a decrease in pain perception and an increase in feelings of pleasure and happiness. These natural chemicals play a crucial role in regulating mood and are often referred to as the body's natural painkillers.

The pituitary gland is located beneath the hypothalamus. The hypothalamus is a small region of the brain that plays a crucial role in regulating various bodily functions, including the release of hormones from the pituitary gland. The hypothalamus and the pituitary gland work together to control processes such as growth, reproduction, and metabolism. Therefore, it is logical that the pituitary gland would be situated beneath the hypothalamus to facilitate communication and coordination between these two important structures.

Broca's area is the correct answer because it is a motor speech area located in the frontal lobe of the brain. It is responsible for the production of speech and plays a crucial role in the coordination of the muscles involved in speech production. Damage to Broca's area can result in a condition called Broca's aphasia, characterized by difficulty in speaking fluently while comprehension remains intact. The other options, such as the brain stem, the pons, and the diencephalon, are not specific motor speech areas and do not accurately answer the question.

Acetylcholinesterase is the enzyme responsible for breaking down acetylcholine in the body. Acetylcholine is a neurotransmitter that plays a crucial role in the transmission of nerve impulses. By breaking down acetylcholine, acetylcholinesterase helps to regulate its levels and prevent excessive stimulation of the nervous system. Dopamine and norepinephrine are other neurotransmitters that have different functions in the body, but they do not directly destroy acetylcholine. Therefore, the correct answer is acetylcholinesterase.

The cerebellum is one of the four major areas of the brain. It is responsible for coordinating voluntary movements, balance, and posture. It receives information from the sensory systems, the spinal cord, and other parts of the brain, and then integrates this information to fine-tune motor activity. The cerebellum plays a crucial role in motor control and motor learning, and damage to this area can result in difficulties with coordination and movement.

The correct answer is cerebrum. The frontal, temporal, occipital, and parietal lobes are all parts of the cerebrum, which is the largest and most highly developed part of the brain. It is responsible for higher cognitive functions such as thinking, memory, perception, and voluntary movement. The cerebrum plays a crucial role in our ability to process information and make decisions.

The occipital lobe is responsible for processing visual information and contains the primary visual cortex. This area of the brain is crucial for interpreting and making sense of visual stimuli. It plays a key role in visual perception, including the recognition of shapes, colors, and movement. Damage to the occipital lobe can result in visual impairments, such as difficulty recognizing objects or faces, and can impact overall visual perception.

The arachnoid mater is the middle layer of the meninges, which are protective membranes that surround the brain and spinal cord. It gets its name from its spiderweb-like appearance. The arachnoid mater is located between the outer dura mater and the inner pia mater. It is a thin, delicate membrane that helps cushion and protect the brain and spinal cord from injury.

The correct answer is synapse. A synapse is the name for the space or junction between the axon of one neuron and the dendrite of another neuron. It is a crucial site for communication between neurons, where electrical or chemical signals are transmitted from one neuron to another.

Astrocytes are a type of glial cell in the central nervous system that play a crucial role in supporting and protecting neurons. They provide structural support to neurons, regulate the extracellular environment by removing excess neurotransmitters and ions, and help to form the blood-brain barrier. The blood-brain barrier is a protective barrier that prevents harmful substances from entering the brain, and astrocytes contribute to its formation by regulating the permeability of blood vessels in the brain. Therefore, the statement "support and protect the neurons and help to form the blood-brain barrier" accurately describes the functions of astrocytes.

The temporal lobe is a region in the brain that contains the primary auditory cortex. This means that it is responsible for processing and interpreting auditory information, such as sound and language. The primary auditory cortex plays a crucial role in our ability to perceive and understand sounds, making the temporal lobe an important area for auditory processing.

A neuron is the type of nervous tissue that conducts a nerve impulse. Neurons are specialized cells that transmit electrical signals in the form of nerve impulses throughout the body. They have a unique structure that allows them to receive, process, and transmit information. Neurons are the basic building blocks of the nervous system and play a crucial role in communication within the body.

The hypothalamus is a structure located in the diencephalon region of the brain. It plays a crucial role in regulating various physiological processes in the body. It controls the release of hormones from the anterior pituitary gland, which in turn affects many functions such as growth, metabolism, and reproduction. The hypothalamus also helps maintain water balance by controlling thirst and urine production. It regulates appetite by influencing feelings of hunger and fullness. Additionally, it plays a role in controlling body temperature and the autonomic nervous system, which controls involuntary bodily functions such as heart rate and digestion.

The corpus callosum is a thick band of nerve fibers that connects the right and left hemispheres of the brain. It allows for communication and coordination between the two hemispheres, enabling them to work together and share information. This connection is crucial for various cognitive functions such as language processing, perception, and problem-solving. Without the corpus callosum, the brain would not be able to integrate information from both hemispheres effectively, leading to impaired functioning.

The Na+/K+ ATPase pump plays a crucial role in maintaining the resting membrane potential in neurons. It actively transports three sodium ions out of the cell and two potassium ions into the cell, against their concentration gradients. This creates an electrochemical gradient, with more sodium outside and more potassium inside the cell. This gradient is essential for the generation of an action potential, as it allows for the rapid influx of sodium ions and efflux of potassium ions during depolarization and repolarization phases. Therefore, the purpose of the Na+/K+ ATPase pump is to establish the Na+ and K+ gradients necessary for the development of an action potential.

Broca's area is a region in the brain that is responsible for motor speech. It plays a crucial role in the production of speech and language. Damage to this area can result in difficulties in forming words and sentences, a condition known as Broca's aphasia. This explanation aligns with the given statement that Broca's area is concerned with motor speech.

The medulla oblongata is a part of the brainstem that connects the brain to the spinal cord. It is responsible for controlling vital functions such as breathing, heart rate, and blood pressure. The medulla oblongata descends as the spinal cord, meaning it continues downwards from the brainstem into the spinal column. This allows for the transmission of signals between the brain and the rest of the body, enabling the coordination of various bodily functions.

The arachnoid mater is a membrane that is part of the meninges, which are the protective layers that surround and cushion the brain and spinal cord. The meninges consist of three layers: the dura mater, the arachnoid mater, and the pia mater. The arachnoid mater is located between the dura mater and the pia mater, and it is named for its spider-web-like appearance. It helps to protect the brain and spinal cord from injury and infection.

Dendrites are the structures that bring information toward the cell body. They are branched extensions of the neuron that receive signals from other neurons and transmit them to the cell body. Dendrites play a crucial role in integrating and processing incoming signals, allowing the neuron to make decisions on whether to transmit the signal further or not. Axons, on the other hand, transmit information away from the cell body, while nodes of Ranvier are gaps in the myelin sheath that help in the rapid conduction of electrical signals along the axon. Axon terminals are the end points of the axon where the signal is transmitted to other neurons or target cells.

Parkinson's Disease is a neurodegenerative disorder that is caused by a deficiency of dopamine within the basal ganglia. Dopamine is a neurotransmitter that plays a crucial role in movement and coordination. When there is a deficiency of dopamine in the basal ganglia, it leads to the characteristic symptoms of Parkinson's Disease, such as tremors, rigidity, and difficulty with movement. The loss of dopamine-producing cells in the brain is responsible for this deficiency, and it is believed to be caused by a combination of genetic and environmental factors.

Excessive opioids depress the medulla oblongata, which is responsible for regulating breathing. This leads to a decrease in respiratory function, resulting in respiratory depression.

Ganglia are clusters of cell bodies that are located outside the central nervous system. They are found in the peripheral nervous system and play a crucial role in coordinating and transmitting signals between different parts of the body. Ganglia are responsible for functions such as sensory perception, motor control, and autonomic processes.

White matter is called "white" because of the presence of the myelin sheath. The myelin sheath is a fatty substance that surrounds and insulates the nerve fibers in the brain and spinal cord. This insulation gives the white matter its white color. The myelin sheath helps in the efficient transmission of electrical signals between different regions of the brain and spinal cord. It acts as an insulator, preventing the electrical signals from leaking out and speeding up the transmission of information.

The nodes of Ranvier are gaps in the myelin sheath that surrounds the axons of neurons. These nodes are located along the postsynaptic membrane and play a crucial role in increasing the speed of the action potential. The myelin sheath acts as an insulator, preventing the dissipation of the electrical signal as it travels along the axon. However, the action potential needs to be regenerated periodically to maintain its strength. The nodes of Ranvier allow for the rapid and efficient regeneration of the action potential, allowing it to propagate more quickly along the axon.

The ventricles are called the lateral, third, and fourth. The ventricles are interconnected cavities within the brain that are filled with cerebrospinal fluid. They play a crucial role in protecting and cushioning the brain, as well as providing nutrients and removing waste products. The lateral ventricles are the largest and are located in the cerebral hemispheres. The third ventricle is located in the diencephalon, and the fourth ventricle is located between the brainstem and the cerebellum.

Saltatory conduction refers to the rapid jumping of action potentials from one node of Ranvier to another along a myelinated axon. Nodes of Ranvier are the small gaps in the myelin sheath where the axon is exposed. These nodes play a crucial role in increasing the speed of conduction by allowing the action potential to "leap" from one node to the next, rather than propagating along the entire length of the axon. Therefore, nodes of Ranvier are most closely related to saltatory conduction.

Saltatory conduction is the term that describes the hopping of the action potential along the axon from one node of Ranvier to the next. This process occurs in myelinated axons, where the myelin sheath acts as an insulating layer, allowing the action potential to jump from one node to another. This mechanism speeds up the transmission of the nerve impulse, making it more efficient compared to continuous conduction. Depolarization refers to the change in membrane potential during the initiation of an action potential, while repolarization is the return of the membrane potential to its resting state after depolarization. Myelination, on the other hand, is the process of forming the myelin sheath around axons.

The precentral gyrus is a region in the brain that is primarily responsible for controlling voluntary movements. It is part of the motor cortex and plays a crucial role in coordinating and executing motor functions. Therefore, the word "motor" best describes the precentral gyrus.

The correct answer is convolutions, or gyri. The surface of the cerebrum is not smooth, but rather folded into elevations called convolutions or gyri. These gyri increase the surface area of the cerebrum, allowing for more neurons and connections, and therefore increasing its processing power. The folds also help to fit the large cerebrum into the limited space of the skull. Fissures are deep grooves that separate the gyri, while sulci are shallower grooves. Foramen, on the other hand, refers to a hole or opening in a bone.

The depression between the convolutions of the cerebrum is called sulci.

Depolarization is the correct answer because it refers to the first phase of the action potential where the cell's membrane potential becomes less negative. This is caused by the inward movement of sodium ions through ion channels, which leads to a rapid change in the electrical charge across the cell membrane. Depolarization is an essential step in the propagation of nerve impulses and plays a crucial role in transmitting signals throughout the nervous system.

Neurotransmitters such as acetylcholine (ACh) are stored within the axon terminals. Axon terminals are the end points of the axon, where the neurotransmitters are stored in vesicles. When an action potential reaches the axon terminal, these vesicles release the neurotransmitters into the synapse, allowing them to bind to the postsynaptic receptors and transmit signals to the next neuron. Therefore, the axon terminals play a crucial role in the transmission of signals between neurons.

Ependymal cells in the choroid plexus are responsible for the formation of cerebrospinal fluid (CSF). CSF is a clear fluid that circulates around the brain and spinal cord, providing cushioning and support to these structures. It also helps in the removal of waste products and provides a medium for the transport of nutrients and chemical messengers. Ependymal cells line the ventricles of the brain and have cilia that help in the movement of CSF. Therefore, their main function is to produce and regulate the flow of CSF in the central nervous system.

The primary somatosensory area and the primary motor area are separated by the central sulcus. The central sulcus is a prominent groove that runs across the surface of the brain, dividing the frontal lobe from the parietal lobe. The primary somatosensory area is located in the parietal lobe and is responsible for processing sensory information from the body, while the primary motor area is located in the frontal lobe and is involved in the initiation and control of voluntary movements. The central sulcus acts as a boundary between these two areas, with the primary somatosensory area located posteriorly and the primary motor area located anteriorly.

Broca's area is located in the frontal lobe of the brain. This area is responsible for the production of speech and language comprehension. It plays a crucial role in the coordination of the muscles involved in speech production. Damage to Broca's area can result in a condition called Broca's aphasia, characterized by difficulty in speaking fluently while comprehension remains intact. Therefore, the correct answer is frontal.

The frontal lobe is responsible for personality development and emotional and behavioral expression. It is also involved in carrying out the "executive" functions, such as decision-making, problem-solving, and planning. This lobe is located at the front of the brain and is crucial for higher cognitive functions and social behavior. It helps regulate emotions, control impulses, and coordinate complex movements.

The limbic system is often referred to as the "emotional brain" because it plays a crucial role in regulating emotions and emotional responses. It is responsible for processing and experiencing emotions, as well as forming and retrieving memories. The limbic system includes several structures such as the amygdala, hippocampus, and hypothalamus, which are involved in various emotional and memory-related functions.

The precentral gyrus is the primary motor area of the brain. It is responsible for initiating voluntary movements. Located in the frontal lobe, it plays a crucial role in coordinating and executing motor functions. This area contains specialized nerve cells called motor neurons, which send signals to the muscles, enabling us to perform various movements. The precentral gyrus is an essential component of the motor cortex and is involved in the control and coordination of voluntary muscle activity throughout the body.

The medulla oblongata descends into the vertebral cavity through the foramen magnum. The foramen magnum is a large opening at the base of the skull through which the spinal cord passes. It connects the brain with the spinal cord and allows for the passage of nerves and blood vessels.

The refractory period is the term applied to the inability of a neuron to accept a stimulus while the neuron is still depolarized. During this period, the neuron is temporarily unresponsive and unable to generate an action potential. This is important for maintaining the proper timing and directionality of nerve impulses, preventing them from overlapping or firing too rapidly. The refractory period allows the neuron to reset and return to its resting state before it can be stimulated again.

The correct answer is the resting membrane potential. The inside of an unstimulated neuron is negative due to the outward leak of potassium ions. This creates an electrical charge across the cell membrane, known as the resting membrane potential. It is the baseline electrical state of the neuron when it is not actively transmitting signals.

The postcentral gyrus is located in the parietal lobe. This region of the brain is responsible for processing sensory information from the body, such as touch, temperature, and pain. It is involved in the perception and interpretation of these sensory inputs, allowing us to have a sense of our body's position and movement in space. The postcentral gyrus plays a crucial role in somatosensory processing and is essential for our ability to perceive and interact with the world around us.

The primary motor area is located on the frontal lobe anterior to the central sulcus. It is responsible for the initiation and control of voluntary movement. This area contains neurons that send signals to the muscles, allowing us to perform various motor tasks. Damage to the primary motor area can result in difficulties with movement and coordination.