Neurophysiology Practice Quiz Questions And Answers

The nervous system is responsible for generating responses in the body. It receives and processes information from the environment and sends signals to various parts of the body, allowing it to respond to stimuli. This includes both voluntary actions, such as moving a muscle, as well as involuntary actions, such as the beating of the heart or the release of hormones. The nervous system plays a crucial role in coordinating and controlling the body's actions and responses.

Sensory neurons are responsible for carrying signals from sensory receptors towards the brain. These neurons are specialized to detect and transmit sensory information such as touch, temperature, pain, and other sensory stimuli. They have long dendrites that receive signals from sensory receptors and transmit them to the central nervous system, including the brain. This allows us to perceive and interpret the various sensations we experience in our environment.

Schwann cells are responsible for forming the myelin sheath around axons in the peripheral nervous system. These cells wrap around the axons multiple times, creating layers of myelin that insulate and protect the axons. This myelin sheath helps to increase the speed and efficiency of nerve signal transmission. Schwann cells are found only in the peripheral nervous system, while oligodendrocytes are responsible for myelinating axons in the central nervous system. Microglia are immune cells in the central nervous system, and astrocytes have various functions such as providing support and maintaining the blood-brain barrier.

The resting membrane potential of a neuron is the electrical charge difference across the cell membrane when the neuron is at rest. It is typically around -65 millivolts. This negative charge is maintained by the unequal distribution of ions inside and outside the cell, with more negatively charged ions inside the cell. This difference in charge allows the neuron to generate and transmit electrical signals when stimulated. Therefore, the resting membrane potential of a neuron is closer to -65 millivolts.

The axon is the part of the neuron that sends signals to the next neuron. It is a long, slender projection that extends from the cell body of the neuron. The axon carries electrical impulses, known as action potentials, away from the cell body and transmits them to other neurons or target cells. This allows for communication between neurons and is essential for the functioning of the nervous system.

Hyperpolarization refers to a state in which the membrane potential becomes more negative than the resting potential. This occurs when there is an increase in the outflow of positive ions or an influx of negative ions, making it more difficult for the neuron to reach the threshold for firing an action potential. As a result, hyperpolarization inhibits the generation of an action potential and decreases the likelihood of neuronal activity.

When Na+ channels are opened on a cell, it means that the channels are allowing Na+ ions to flow into the cell. This is because Na+ ions have a higher concentration outside the cell compared to inside, and when the channels are opened, the ions move down their concentration gradient, rushing into the cell.

The correct answer is "Left-arm is weaker and shorter." This is an example of lower motor neuron dysfunction because weakness and atrophy of muscles in a specific limb, such as the left arm, can occur when there is damage or dysfunction in the lower motor neurons that innervate those muscles. This can result in weakness, decreased muscle tone, and reduced muscle bulk in the affected limb. Inability to fly and inability to learn a language are unrelated to lower motor neuron dysfunction.

Damage to the cerebellum can result in impaired coordination of movement. The cerebellum is responsible for fine-tuning motor movements and ensuring their smooth execution. When it is damaged, individuals may experience difficulties with balance, posture, and precise control of voluntary movements. This can manifest as unsteady gait, tremors, and difficulties with tasks that require coordination and precision, such as writing or playing an instrument. In contrast, inability to speak and memory loss are not directly associated with damage to the cerebellum.

Oligodendrocytes are a type of glial cell in the central nervous system that play a crucial role in myelination. They form myelin sheaths around axons in the brain, which helps to insulate and increase the speed of electrical impulses. Additionally, oligodendrocytes have the ability to myelinate multiple axons at once, making them more efficient in their function. In addition to myelination, oligodendrocytes also provide physical support to neurons, helping to maintain the structural integrity of the brain. Therefore, the correct answer is "all of the above."

Astrocytes are a type of glial cells in the central nervous system (CNS) that provide physical support to neurons. They play a crucial role in maintaining the structural integrity of the brain and spinal cord by forming a network of supportive structures. This support includes providing a framework for neuronal migration during development, regulating the extracellular environment, and forming the blood-brain barrier. Astrocytes also help in the repair and regeneration of damaged neural tissue. Therefore, the correct answer is that astrocytes provide physical support to neurons.

EPSPs (Excitatory Post-Synaptic Potentials) are graded potentials that result from the depolarization of the postsynaptic membrane in response to neurotransmitter binding. When multiple EPSPs occur close together in time and space, they can summate or combine their effects, potentially reaching the threshold for generating an action potential. This phenomenon is known as temporal and spatial summation. Therefore, the statement "EPSPs can summate to produce action potentials" is true.

EPSP's, or excitatory post-synaptic potentials, are local potentials that depolarize the cell. When a neuron receives an excitatory input, it causes a small depolarization in the cell membrane, making it more likely to generate an action potential. EPSP's are important in the process of signal transmission between neurons, as they contribute to the overall excitability of the cell.

The medulla is a structure that is part of the rhombencephalon, which is also known as the hindbrain. The rhombencephalon is one of the three primary divisions of the brain and is responsible for controlling vital functions such as breathing, heart rate, and blood pressure. The medulla, located at the base of the brainstem, plays a crucial role in regulating these essential bodily functions. Therefore, the correct answer is Medulla.

Sweating is considered a basic nervous system function because it is controlled by the autonomic nervous system. The autonomic nervous system regulates involuntary bodily functions, such as sweating, in response to changes in body temperature or emotional stress. Sweating helps to regulate body temperature by cooling the body through evaporation. This process is controlled by the sympathetic division of the autonomic nervous system, which activates sweat glands when necessary. Therefore, sweating is a fundamental function of the nervous system in maintaining homeostasis and responding to external stimuli.