CNS vs. PNS
What is the difference between the central and peripheral nervous systems?
The Central Nervous System (CNS), comprising the brain and spinal cord, is the body’s control centre. The Peripheral Nervous System (PNS) connects the CNS to the rest of the body.
Explain the difference between a nerve and a tract.
Nerves and tracts are both bundles of axons, but differ in location and composition. Nerves are in the PNS, surrounded by connective tissue, and carry both sensory and motor fibres. Tracts are in the CNS, surrounded by glial cells, and usually carry either sensory or motor information.
What is the boundary between the temporal, frontal, and parietal lobes?
The lateral sulcus, or Sylvian fissure, is a deep groove on the brain’s surface that separates the temporal lobe from the frontal and parietal lobes. It covers the insular cortex, which is important for speech, taste, and autonomic functions.
What does the "primary" in "primary motor cortex" and "primary somatosensory cortex" mean?
“Primary” cortical areas are the main entry or exit points for specific sensory or motor functions, directly connected to relevant pathways. The Primary Motor Cortex controls voluntary movement, while the Primary Somatosensory Cortex receives sensory information from the body.
Within the central nervous system, what is meant by an "efferent tract"? What is meant by an "afferent tract"?
Efferent tracts carry signals away from a structure, typically from the cortex to muscles or glands. Afferent tracts carry signals towards a structure, usually bringing sensory information to the cortex.
Identify the three anatomical planes used to study brain "slices" in the cerebral hemispheres.
Sagittal, coronal, and axial planes divide the brain for visualization and imaging.
Explain the difference between nuclei and ganglia.
Nuclei are clusters of neuron cell bodies in the Central Nervous System (CNS), while ganglia are clusters in the Peripheral Nervous System (PNS).
What is the boundary between the frontal and parietal lobes?
The central sulcus, a key anatomical landmark, separates the frontal and parietal lobes. It divides the precentral gyrus (motor cortex) from the postcentral gyrus (somatosensory cortex).
Define the term “subcortical nucleus”.
Subcortical nuclei, clusters of neuron cell bodies beneath the cerebral cortex, process and relay information for movement, emotions, memory, and other brain functions. Examples include the basal nuclei and thalamus.
How does afferent neural information that codes a touch on the arm travel from the spinal cord to the primary somatosensory cortex?
Touch information from the arm travels through the dorsal column–medial lemniscus pathway, synapsing in the medulla, crossing to the opposite side of the brain, and reaching the primary somatosensory cortex.
On the surface of the cerebral hemispheres, what is a gyrus? What is a sulcus?
Gyri are ridges on the cerebral cortex surface, while sulci are grooves between them. Examples include the precentral gyrus, central sulcus, and longitudinal fissure.
Describe the anatomical/cellular components of a synapse.
Synapses are junctions between neurons or neurons and target cells, facilitating communication. They consist of the presynaptic terminal, synaptic cleft, and postsynaptic membrane, with neurotransmitters released from the presynaptic terminal to bind to receptors on the postsynaptic membrane.
Where are head and neck structures located on the somatotopic “map” of the primary motor cortex?
Head and neck structures are represented on the inferior lateral portion of the primary motor cortex, controlling voluntary movements of the face, tongue, jaw, lips, and throat. This organization reflects how the brain controls motor functions based on body regions.
Describe the basal ganglia and state how this group of nuclei is connected to the cortex.
The basal ganglia, located deep within the cerebral hemispheres, control movement, motor learning, and coordination. They regulate voluntary movement initiation and execution through neural circuits connecting the cortex, basal ganglia, and thalamus.
In the human brain, what is the significance of cortical sulci?
Cortical sulci increase surface area, allowing for a larger cerebral cortex and higher cognitive capacity. They also serve as landmarks and can indicate neurological conditions.
Summarize the current understanding of the various functions of Broca’s area.
Broca’s area, located in the frontal lobe, is responsible for speech production and expressive language. Damage to this area can result in Broca’s aphasia, affecting speech clarity and sentence formation.
The insular cortex is hidden; how do you expose it?
The insular cortex, located deep within the brain, is exposed by separating the lateral sulcus and retracting the surrounding frontal, parietal, and temporal lobes.
When discussing descending projection tracts, what are “innervation patterns”? Give two examples of such innervation patterns.
Innervation patterns describe how upper motor neurons connect to lower motor neurons. Examples include contralateral innervation, where one brain hemisphere controls the opposite side of the body, and bilateral innervation, where both hemispheres control the same muscle groups.
Name the four lobes of the cerebral hemispheres and provide one example of a significant function for each lobe.
The brain’s four lobes have distinct functions: frontal (movement, speech), parietal (sensory information), temporal (auditory processing, language), and occipital (visual processing).
Which lobe of the cerebral hemispheres contains Broca's area? Which lobe has Wernicke's area? Which lobe contains the planum temporale?
Broca’s Area, Wernicke’s Area, and the Planum Temporale are crucial for speech, language, and hearing, primarily located in the left hemisphere. Broca’s Area controls speech production, Wernicke’s Area handles language comprehension, and the Planum Temporale aids in auditory and language processing.
What is the internal capsule? In which anatomical plane is the internal capsule shaped like a boomerang?
The internal capsule is a boomerang-shaped band of white matter carrying motor and sensory information between the cerebral cortex and lower brain parts.