Introduction to the CNS and functional localisation of the Cerebrum Flashcards
Describe the main components of the CNS
Brain:
- cerebrum handles higher brain functions such as reasoning, sensory perception, and voluntary movement
- cerebellum coordinates balance, posture, and fine motor skills
- brainstem controls basic life-sustaining functions such as breathing, heart rate, and sleep
Spinal cord:
Divided into gray matter and surrounding white matter, with gray matter containing nerve cell bodies and horns, and white matter consisting of longitudinal tracts of
myelinated axons
Conduit between the peripheral nervous system and the brain, receiving sensory information from various organs and transmitting it to reflex centres or higher brain centres
thin, cylinder-like structure within the vertebral canal
Describe the internal structure of the spinal cord
Gray matter:
Dorsal (posterior) horns -contain sensory neurones, receive signals from PS receptors
Ventral (anterior) horns -contain motor neurones that send signals to muscles
Lateral horns - neurones of ANS
White matter:
Myelinated axons connecting brain to body
Dorsal (posterior) columns - carry sensory info to brain
Ventral (anterior) columns - carry motor command
Lateral columns - carriers both sensory and motor signals
Central canal - contains CSF providing cushioning
Spinal nerves:
Emerge from the spinal cord through the intervertebral foramina.
Each spinal nerve is connected to the spinal cord by:
Dorsal Root: Contains sensory (afferent) neurons.
Ventral Root: Contains motor (efferent) neurons.
Describe association fibres
Connect different regions within the same hemisphere
Arcuate Fasciculus - connects Broca’s Area and Wernicke’s Area, crucial for language comprehension and speech production.
Cingulum - links regions of the limbic system, important for emotion and memory.
Superior Longitudinal Fasciculus - connects the frontal, parietal, occipital, and temporal lobes for higher order cognitive functions
Describe the functional areas of the brain and the link between them
Describe the main regions of the brainstem
Describe commissural Fibres
Connect corresponding regions of the two cerebral hemispheres
Corpus Callosum - largest commissural fibre bundle, enabling communication between the left and right hemispheres
Anterior Commissure - connects the temporal lobes and is involved in pain sensation and olfactory processing
Posterior Commissure - links areas of the midbrain, important for visual reflexes
Describe projection fibres:
Connect the cerebral cortex to lower brain regions and the spinal cord
Internal Capsule: A dense bundle of fibres carrying motor (descending) and sensory (ascending) information between the cerebral cortex and subcortical structures like the brainstem and spinal cord.
Corona Radiata: Radiating fibres that extend between the internal capsule and the cortical regions.
Corticospinal Tracts: Descending motor fibres that travel from the motor cortex to the spinal cord to control voluntary movements.
