Intro to Neuro Flashcards

Question

What is gray matter?

Answer 1

Gray matter: areas of the brain that is concentrated with cell bodies, dendrites, and synapses. If the collection of cell bodies is relatively discrete, it is known as a nucleus, while if it is an extensive layer, it I known as a cortex.

Answer 2

Nucleus: a discrete collection of cell bodies Ganglion: usually a collection of neuronal cell bodies outside of the CNS. An example where this is not the case is the basal ganglia, which are masses of gray matter in the cerebral hemispheres. Cortex: an extensive, layered region of gray matter covering part of the CNS surface

Answer 3

Tract: a discrete collection of fibers (myelinated axons). Tracts usually have two-part names. The first part refers to where the neuron cell bodies are located; the second part refers to where the axons terminate. So, a thalamicortical tract would originate in the thalamus and terminate in the cortex.

Answer 4

Fasciculus: Latin for “little bundle”; refers to a bundle of axon fibers Lemniscus: Greek for “ribbon”; refers to a flat tract of axons Peduncle: Latin for “little foot”, described fibers collected together on their way into or out of someplace (i.e., a type of tract; contains axons)

Answer 5

Motor neurons for skeletal muscle (efferent) have a cell body in the CNS. The cell body is located in the spinal cord, and the axon leaves the spinal cord gray matter in the ventral root. From there, the muscle is directly innervated; there are no more connections.

Answer 6

• Nerves for smooth muscle, cardiac muscle, and glands also contain a cell body in the CNS; however, the axon of this cell will synapse to another neuron that will then innervate the smooth muscle, cardiac muscle, and glands. The clusters of neurons are known as autonomic ganglia; thus the autonomic nervous system requires a preganglionic neuron and a postganglionic neuron. o The sympathetic nervous system has its ganglia outside but near the spinal cord. o The parasympathetic nervous system has its ganglia near the organ it innervates

Answer 7

• Cerebral Cortex: covers the surface of the cerebral hemispheres. Higher functions (learning, memory, language, abstract thinking, planning), perception, voluntary movement o Frontal lobe: movement, personality, foresight, insight o Parietal lobe: somatic sensation, orientation and directed attention o Temporal lobe: auditory cortex, higher-order visual functions, learning and memory o Occipital lobe: vision

Answer 8

• Basal ganglia: lenticular and caudate nuclei are the major components. Basal ganglia is a collective term applied to certain masses of gray matter in the cerebral hemispheres. Damage to these areas can cause changes in muscle tone, involuntary movements, and difficulty initiation or stopping movement (generally motor functions)

Answer 9

• Limbic system: involved in drive-related behavior, emotions, and some forms of memory. Hippocampus and amygdala are part of this system.

Answer 10

o Thalamus: major relay station by which specific information reaches the cortex o Hypothalamus: control center for the autonomic nervous system and for drive-related behavior (hunger, thirst, temperature regulation, neuroendocrine control, etc.)

Answer 11

• Brainstem o Attachment for cranial nerves III-XII; processes their incoming information, handles cranial nerve reflexes, and with motor commands for the cranial nerves o Long tract function: since the brainstem is between the cerebral cortex and the spinal cord, long tracts must -pass through it (for example, a spino-thalamic tract) o Ascending Reticular Activating System regulates our state of consciousness and are important to the sleep-wake cycle o Contains midbrain, pons, medulla

Answer 12

• Cerebellum o The cerebellum is not involved at all with the sensory system. Instead, the cerebellum uses sensory information to design movement and to adjust movement. Cerebellar lesions therefore cause movement disorders.

Answer 13

o Processes incoming information from the body o Reflex arcs o Contains motor neurons to control skeletal muscle o Houses many long tracts that either originate or terminate here

Answer 14

Wallerian degeneration: after an axon is severed, the distal process will degenerate due to lack of signal transmission.

Answer 15

eripheral Nervous System: Following transection of a peripheral nerve, macrophages clean up the debris and stimulate PNS glial cells (Schwann cells) to secrete growth factors and guidance molecules. Sometimes the axons successfully regenerate down their old basal lamina tubes, get re-myelinated, and reestablish synaptic contacts. Central Nervous System: If a CNS pathway is transected, microglia moves in to get rid of the degenerating distal processes. The glia proliferates and forms a scar that impedes regeneration. There are not many growth factors in the brain, and the glia