Test Your Knowledge On Neuroanatomy Questions

The choroid plexus within the ventricles secretes CSF. The choroid plexus is a network of blood vessels located within the ventricles of the brain. It produces cerebrospinal fluid (CSF), which is a clear, colorless fluid that surrounds and protects the brain and spinal cord. CSF helps to cushion the brain against injury, remove waste products from the brain, and provide nutrients to the brain cells.

Schwann cells have multiple functions in the nervous system. They play a crucial role in myelinating axons, which helps to increase the speed and efficiency of nerve impulse conduction. Additionally, they hold multiple axons together, providing structural support. Schwann cells also contribute to the maintenance of extracellular chemical balance in the nervous system and are involved in some metabolic processes along with neurons. Therefore, the given answer accurately describes the functions of Schwann cells.

Acetylcholine (ACH) is the correct answer because it is the neurotransmitter responsible for transmitting signals from the motor neurons to the muscle fibers at the neuromuscular junction. It binds to the receptors on the muscle fibers, causing them to contract and initiate muscle movement. GABA is a neurotransmitter that primarily inhibits neuronal activity in the brain, and cortices refer to the outer layer of the brain.

Pyramidal cells and Purkinji cells are both output (projection) neurons. Pyramidal cells are found in the cerebral cortex and are known for their pyramid-shaped cell bodies. They are the primary excitatory neurons in the cortex and play a crucial role in various cognitive functions. Purkinji cells, on the other hand, are located in the cerebellar cortex. They receive input from granule cells and are responsible for transmitting information from the cerebellar cortex to other parts of the brain and spinal cord. These two types of neurons are involved in relaying information and transmitting signals to other areas of the nervous system.

The correct answer is the internal capsule white matter tract. The internal capsule is a bundle of nerve fibers that runs between the thalamus and the cerebral cortex, and it separates the putamen and caudate nucleus, which are both part of the basal ganglia. The white matter in the internal capsule contains myelinated axons, which allows for efficient transmission of signals between different regions of the brain. Therefore, the internal capsule white matter tract is responsible for separating the putamen and caudate.

The fibres with the fastest conduction velocity are Group A/Alpha fibres. This is because Group A/Alpha fibres are myelinated, meaning they have a protective covering called myelin sheath that allows for faster conduction of electrical signals. In contrast, Group B/Beta fibres and Group C/C-fibres are unmyelinated or have thinner myelin sheaths, resulting in slower conduction velocities. Therefore, Group A/Alpha fibres have the fastest conduction velocity among the given options.

Myelinated fibers in the peripheral nervous system are characterized by spiral wrappings of Schwann cell membranes around axons, which are periodically interrupted by nodes of Ranvier. This arrangement allows for the rapid conduction of nerve impulses along the axons. The Schwann cell membranes act as insulation, preventing the leakage of electrical signals and ensuring efficient transmission. The nodes of Ranvier are gaps in the myelin sheath where the axon is exposed, allowing for the efficient propagation of the electrical signal from one node to the next.

The lenticular nucleus of the basal ganglia consists of the putamen and globus pallidus. The putamen is a large structure located in the lateral part of the lenticular nucleus, while the globus pallidus is located medially. These two structures play important roles in motor control and are involved in the regulation of movement.

The maintenance of balance and control of head and eye movements is associated with the vestibulocerebellum, specifically the floculonodular lobe and uvula. This region of the cerebellum receives input from the vestibular system, which is responsible for detecting changes in head position and movement. The vestibulocerebellum then helps coordinate and adjust muscle activity to maintain balance and stabilize gaze.

Microglia are a type of immune cell found in the central nervous system (CNS). They play a crucial role in immune function within the CNS by monitoring and protecting the brain and spinal cord from infections and inflammation. Microglia act as the first line of defense against pathogens and are responsible for phagocytosis, releasing inflammatory molecules, and promoting tissue repair. Unlike other cells in the CNS, microglia are derived from the immune system and have the ability to migrate to sites of injury or infection. Therefore, microglia have the greatest role in immune function within the CNS.

The layer of connective tissue continuous with dura at the exit of a spinal nerve is the arachnoid. The arachnoid is one of the three layers of the meninges, which are the protective coverings of the brain and spinal cord. It is located between the dura mater and the pia mater. The arachnoid forms a loose, delicate membrane that surrounds the spinal nerves as they exit the spinal cord, providing support and protection.

The climbing fibres entering the cerebellum arise from the contralateral inferior olivary nucleus. The inferior olivary nucleus is located in the medulla oblongata and is responsible for transmitting sensory information from the spinal cord and brainstem to the cerebellum. The climbing fibres receive input from various sources, including the spinal cord, and play a crucial role in motor control and coordination. They form synapses with Purkinje cells in the cerebellar cortex, allowing for the integration of sensory and motor information in the cerebellum.

Nociception is the perception of pain. It is a function that involves both afferent and efferent fibers. Afferent fibers transmit sensory information from the body to the central nervous system, while efferent fibers transmit motor commands from the central nervous system to the muscles and organs. In the context of nociception, fast pain fibers are specifically involved in the transmission of sharp, localized pain signals. Therefore, the correct answer is "Afferent and efferent fibers - fast pain fibers."

Increased pressure with the posterior cranial fossa can lead to herniation of the cerebellar tonsils. The posterior cranial fossa is a space at the back of the skull that houses the cerebellum. When there is an increase in pressure within this space, such as in cases of brain swelling or hydrocephalus, the cerebellar tonsils can be pushed downward through the foramen magnum (the opening at the base of the skull). This can compress the brainstem and cause various neurological symptoms, potentially leading to serious complications if not treated promptly.

The fastigial nucleus receives input predominantly from the Purkinji cells of the vermis. The Purkinji cells are a type of neuron located in the cerebellar cortex, specifically in the vermis region. These cells are responsible for receiving input from various sources and transmitting it to the deep cerebellar nuclei, including the fastigial nucleus. Therefore, the correct answer is Purkinji cells of the vermis.

The Brodmann number assigned to the lateral postcentral gyrus is 3, 1, and 2. Brodmann numbers are a system used to divide the cerebral cortex into different areas based on their cytoarchitecture. The lateral postcentral gyrus is part of the primary sensory cortex and is responsible for processing somatosensory information, such as touch, pressure, and temperature, from the opposite side of the body.

The spinothalamic pathway is responsible for carrying pain and temperature information from the body to the brain. This pathway consists of a chain of neurons that transmit these sensory signals from the spinal cord to the thalamus, which then relays the information to the appropriate areas of the brain for processing and perception. Unlike the ascending sensory pathway, which carries other types of sensory information such as touch and proprioception, the spinothalamic pathway specifically focuses on pain and temperature sensations.

The correct answer is located on the lateral surface of the frontal lobe. It contains the primary motor area. This is because the precentral gyrus, also known as the primary motor cortex, is indeed located on the lateral surface of the frontal lobe. It is responsible for initiating voluntary motor movements and controlling the muscles of the body.

The correct answer is the Spino-cerebellum (Ant. and Post. Lobe). The spino-cerebellum is responsible for controlling limb and trunk movement. It receives input from the spinal cord and helps to coordinate and fine-tune movements of the limbs and trunk. The anterior and posterior lobes of the cerebellum are specifically involved in this control.

Fibres I have the largest axon diameter compared to Fibres II and Fibres III. This means that the nerve fibres in category I have a thicker axon, which allows for faster conduction of electrical signals. The larger diameter reduces resistance to the flow of ions, resulting in faster transmission of nerve impulses.

Neocortical layer V is known to primarily project to subcortical regions. This means that the neurons in this layer send their axons to areas located beneath the cortex, such as the thalamus, basal ganglia, and brainstem. These projections play a crucial role in various functions, including motor control, sensory processing, and regulation of arousal and attention.

The correct answer is the pineal gland, habenular nuclei, and posterior commissure. The epithalamus is a region of the diencephalon that includes these structures. The pineal gland is responsible for producing melatonin, a hormone that regulates sleep-wake cycles. The habenular nuclei are involved in the regulation of emotional and reward-related behaviors. The posterior commissure is a bundle of nerve fibers that connects the left and right sides of the brain. Together, these structures play important roles in various physiological and behavioral processes.

Anxiety can often increase gamma discharge, which in turn leads to an increase in reflex response. This means that when a person is anxious, their reflexes may become more sensitive and reactive.

The centromedial nucleus of the thalamus is located medial to VPL/VPM (ventral posteriomedial/ventral postereolateral). This means that it is situated closer to the midline of the brain compared to VPL/VPM.

The correct answer is the first option: Basket cells, granule cells, golgi cells, stellate cells. These are all examples of interneurons, which are a type of neuron that connects other neurons within the central nervous system. They are responsible for processing and integrating information, and they play a crucial role in regulating and coordinating neural activity.

A simple stretch reflex involves both extrafusal and intrafusal fibers. Extrafusal fibers are responsible for generating force and producing movement in skeletal muscles, while intrafusal fibers are specialized muscle fibers found within muscle spindles, which are sensory receptors that detect changes in muscle length. The interaction between these two types of fibers is crucial for the stretch reflex, where a sudden stretch in a muscle activates the intrafusal fibers, which in turn activate the extrafusal fibers to contract and resist the stretch.

Protoplasmic astrocytes are a type of astrocyte, a star-shaped glial cell found in the brain and spinal cord. They are primarily located in the grey matter tissues of the central nervous system. Grey matter is responsible for processing information in the brain, and astrocytes play a crucial role in supporting and regulating neuronal activity. Therefore, the presence of protoplasmic astrocytes in grey matter tissues is essential for maintaining the proper functioning of the brain.

The correct answer is Tentorium cerebelli/preoccipital notch. The cerebellum is separated from the occipital lobe by the tentorium cerebelli, which is a fold of dura mater. The preoccipital notch is a specific area within the tentorium cerebelli where the cerebellum is separated from the occipital lobe.

The cell bodies of preganglionic sympathetic neurons are located in the grey matter of the thoracic and upper lumbar segments of the spinal cord. This is where the preganglionic neurons originate and send their axons out to synapse with postganglionic neurons in the sympathetic ganglia. From there, the postganglionic neurons innervate various target organs and tissues in the body to mediate sympathetic responses.

The medial geniculate nucleus is associated with auditory function. It is a part of the thalamus and receives auditory information from the inferior colliculus. It then relays this information to the auditory cortex in the temporal lobe. The lateral geniculate nucleus, on the other hand, is associated with visual function, receiving information from the optic tract and relaying it to the visual cortex. The superior geniculate nucleus is also associated with visual function, specifically processing visual information related to the perception of motion.

The correct answer is reduced perfusion, often subsequent to thrombus or embolism. Cerebrovascular accidents, or strokes, occur when there is a disruption in blood flow to the brain. This can be caused by a thrombus (blood clot) or an embolism (a clot that travels from another part of the body). These blockages reduce the perfusion, or blood supply, to the brain, leading to a stroke. Hemorrhages, on the other hand, occur when there is excessive bleeding in the brain, which is not the main cause of the majority of strokes. Increased perfusion, as mentioned in the third option, is also not a common cause of strokes.

The thalamic nuclei most commonly associated with the somatosensory function are the Ventral posterior nucleus (VPL/VPM). These nuclei receive sensory information from the body and relay it to the primary somatosensory cortex. The VPL nucleus specifically receives information from the body, while the VPM nucleus receives information from the face and head. Together, they play a crucial role in processing and transmitting sensory information related to touch, temperature, pain, and proprioception. The other options mentioned, Ventral superior nucleus (VPL/VPS) and Hypothalamic nucleus (VPM/VPS), are not primarily associated with somatosensory function.

The middle cerebellar peduncle is the correct answer because it is the main pathway through which information is brought into the cerebellum. It contains the majority of the fibers that transmit sensory and motor information from the cerebral cortex to the cerebellum. The superior cerebellar peduncle primarily carries efferent fibers from the cerebellum to other parts of the brain, while the inferior cerebellar peduncle mainly carries afferent fibers from the spinal cord and brainstem to the cerebellum.

The sympathetic-effector junction uses noradrenaline as the neurotransmitter. Noradrenaline is released by sympathetic nerve endings and acts on target organs to activate the sympathetic response. It binds to adrenergic receptors on the target organ, leading to various physiological effects such as increased heart rate, dilation of blood vessels, and mobilization of energy stores. Acetylcholine, on the other hand, is the neurotransmitter used at the parasympathetic-effector junction. Adrenaline is also a catecholamine neurotransmitter but is primarily released by the adrenal glands into the bloodstream as a hormone, rather than being used as a neurotransmitter at the sympathetic-effector junction.

The mammillothalamic tract is a neural pathway that connects the mamillary body, located in the hypothalamus, to the anterior thalamus. This tract is involved in the relay of information between these two structures, playing a role in memory and learning processes. The connection between the mamillary body and the anterior thalamus is important for the integration of emotional and memory-related information.

When the internodal distance within a myelin sheath increases, it means that the gaps between the myelin segments become larger. This does not affect the conduction of the nerve impulse because the myelin sheath still provides insulation and speeds up the transmission of the signal. However, an increase in internodal distance may lead to an increase in the number of Schwann cells. Schwann cells are responsible for producing the myelin sheath, so an increase in their number would be necessary to maintain the integrity of the myelin sheath despite the larger gaps between segments.

The dorsomedial hypothalamic nucleus is responsible for regulating the circadian rhythm. It receives input from the suprachiasmatic nucleus (SCN), which is considered the master clock of the body. The SCN receives information about light and darkness from the retina and sends signals to the dorsomedial hypothalamic nucleus to synchronize the body's internal clock. This nucleus plays a crucial role in maintaining the sleep-wake cycle and coordinating various physiological processes throughout the day.

The changes in the substantia nigra that are frequently associated with Parkinson's disease include the death of dopaminergic neurons in the pars compacta, which is responsible for motor control. This loss of dopaminergic neurons leads to a decrease in dopamine levels in the brain, resulting in the motor symptoms characteristic of Parkinson's disease, such as tremors, rigidity, and bradykinesia.

The axon hillock is a specialized part of the neuron's cell body that connects to the axon. It is responsible for summing both inhibitory postsynaptic potentials (IPSPs) and excitatory postsynaptic potentials (EPSPs). This summation of potentials determines whether or not an action potential will be generated and propagated down the axon. The axon hillock acts as a crucial integration site for incoming signals from other neurons, allowing the neuron to make decisions about whether to transmit information to other cells.

The Golgi tendon organ (GTO) is a proprioceptive sensory receptor located within the tendons of skeletal muscle. Its primary function is to detect changes in muscle tension or force during contraction, providing feedback to regulate muscle activity and prevent excessive force generation.

Parkinson's disease is characterized by a hypokinetic disorder involving the basal ganglia. It is a progressive neurological disorder caused by the death of dopaminergic neurons in the pars compacta of the substantia nigra. This leads to symptoms such as rigidity, slow movements, and reduced mobility.

The correct answer explains the two main features or characteristics of graded membrane potentials. Firstly, it states that graded membrane potentials allow a cell to function as a battery, providing power to operate various "molecular devices" embedded in the membrane. This suggests that graded membrane potentials are involved in energy production and utilization within the cell. Secondly, it mentions that graded membrane potentials are used for transmitting signals between different parts of a cell, specifically in electrically excitable cells like neurons. This implies that graded membrane potentials play a crucial role in cellular communication and signal transmission.

Muscle spindles are sensory receptors located within the muscle. They are responsible for detecting changes in the length of the muscle. These receptors provide feedback to the central nervous system about the position and movement of our body parts. When the muscle lengthens or shortens, the muscle spindles are activated and send signals to the brain, allowing us to have a sense of body position and movement.