Central Nervous System: Brain and Spinal Cord Flashcards
What is a group of neuron cell bodies in the CNS called?
Nucleus
What is a group of nerve fibers traveling in parallel called? (only in CNS)
Tract
What is a nerve fiber?
An axon with or without a myelin sheath; present in both CNS and PNS
What is gray matter?
An area of the CNS where neuron cell bodies are located; no myelin
What is white matter?
An area of the CNS where axons are present (no cell bodies); myelinated
What is the soma (or perikaryon)?
A neuron cell body (conducting); present in CNS and PNS
What are glial cells?
Non-conducting support cells of the CNS
What are stains that allow for the visualization of myelinated fibers?
Myelin stains; do not react with cell bodies or dendrites.
What stains allow for visualization of nerve fibers and cell bodies?
Silver stains
What stain allows for visualization of the cell body, axon, and dendrites in their entirety?
Golgi stain
What stains allow for the visualization of RER and Nissl bodies, therefore showing the shape and size of cell bodies?
Nissl stains
Define meninges.
Connective tissue covering of the brain and spinal cord; composed of dura mater, arachnoid mater, and pia mater.
Describe the dura mater.
Tough, outer layer of the meninges; composed of dense irregular connective tissue
Describe the arachnoid mater.
Transparent, middle layer of the meninges; thin, delicate connective tissue lined with simple squamous epithelium
Describe the subarachnoid space.
Separates the arachnoid from the pia mater; stores and moves CSF around the outside of the brain and spinal cord
Describe the pia mater.
Delicate inner layer of the meninges; thin layer of connective tissue lined with simple squamous epithelium; has direct contact with neural tissue
What are the four principal functions of the spinal cord?
Conduction: sensory information ascends and motor commands descend
Neural integration: processing of information from diverse sources
Locomotion: central pattern generators coordinate simple repetitive movements
Reflexes: involuntary stereotyped response to stimuli
Describe the cervical enlargement?
Widening of the spinal cord from C2-C7; gives rise to nerves of the upper limbs.
Describe the lumbosacral enlargement?
Widening of the spinal cord between vertebrae between T10-T12; gives rise to the nerves of the pelvic region and lower limbs; superior to the medullary cone.
Describe the medullary cone?
Tapering off of the spinal cord at L1, giving rise to the nerve root bundles of the cauda equina
Describe the cauda equina?
Nerve roots given off by the medullary cone that occupy the vertebral canal from L2-S5; innervates the pelvic organs and lower limbs
Describe the dorsal (posterior) and ventral (anterior) horns of the spinal cord.
Compose the gray matter of the spinal cord; the dorsal horn is typically composed of afferent sensory neurons that ascend the spinal cord to the brain; the ventral horn is typically composed of efferent motor neurons that descend the spinal cord from the brain.