Cerebrum 1
Which neuron type is the most characteristic of the cerebral cortex and has a triangular cell body with a single apical dendrite?
Pyramidal neuron.
Which layer of the cerebral cortex is also called the molecular layer and contains mainly dendrites, axons, and synapses with few neuronal cell bodies?
Layer I
How many layers does the cerebellar cortex have? Name them.
Three layers — Molecular layer, Purkinje cell layer, Granular layer.
What is the main cell type found in the Purkinje cell layer?
Purkinje neurons, arranged in a single row.
What are the two main divisions of the ANS?
Sympathetic and parasympathetic.
Which type of glial cell is responsible for producing myelin in the subcortical white matter of the cerebrum?
Oligodendrocytes.
Which cortical layer receives the majority of thalamocortical sensory input and is especially well-developed in the primary sensory cortex?
Layer IV
Which fibers synapse on the dendrites of Purkinje cells?
climbing fibers (from inferior olive) and parallel fibers (from granule cells).
What neurotransmitter do Purkinje cells release? Excitatory or inhibitory?
GABA, so they are inhibitory.
What is the main neurotransmitter at sympathetic postganglionic synapses?
Norepinephrine (NE).
What type of fiber tract connects the two cerebral hemispheres, and what is the major example of such a tract?
Commissural fibers
Example: Corpus callosum
Which layer of the neocortex contains large pyramidal neurons, including Betz cells, and serves as the main source of motor output from the cortex?
Layer V (Internal Pyramidal Layer).
What are mossy fibers, and where do they terminate?
Mossy fibers are major excitatory inputs (from pontine nuclei, spinal cord, vestibular nuclei).
They terminate in the cerebellar glomeruli of the granular layer.
Which cerebellar layer contains stellate and basket cells, and what is their function?
Molecular layer; they provide inhibitory interneuron control of Purkinje cells.
Name the neurotransmitter exception in sympathetic system.
Sympathetic fibers to sweat glands release ACh, not NE.
What are the main structural components of the cerebrum’s white matter, and which type of glial cell is essential for maintaining fast signal conduction within these fiber tracts?
The cerebrum’s white matter is composed primarily of myelinated axons organized into association, commissural, and projection fibers.
The glial cell essential for maintaining fast signal conduction is the oligodendrocyte, which produces the myelin sheath around these axons, enabling rapid and efficient nerve impulse transmission.
What two types of neurons dominate the external granular layer (Layer II) and what is their main functional role within the cortex?
Dominant neurons: Small granule (stellate) cells and some small pyramidal neurons.
Main role: Local intracortical communication, receiving and distributing signals within the cortex.
What is the functional significance of parallel fiber–Purkinje cell synapses?
They carry divergent, weak excitatory (glutamatergic) input and help encode timing, coordination, and fine-tuning of movement.
What is a cerebellar glomerulus composed of?
Mossy fiber terminal, granule cell dendrites, and Golgi cell axon terminals, all surrounded by glial sheath.
What is the “fight-or-flight” physiological triad?
↑HR, ↑BP, ↑blood glucose.
Why are association, commissural, and projection fibers all necessary for normal brain function in the cerebrum?
Because association fibers connect areas within one hemisphere, commissural fibers link the two hemispheres, and projection fibers connect the cortex with subcortical structures. Together they allow the cerebrum to integrate information and communicate with the rest of the CNS.
How do Layers III and VI differ in their roles in cortical communication?
Layer III sends corticocortical fibers to other cortical areas, while Layer VI sends corticothalamic fibers back to the thalamus.
Describe the difference between “simple spikes” and “complex spikes” in Purkinje cells.
Simple spikes: High-frequency; generated by parallel fibers (granule cells).
Complex spikes: Low-frequency, large waveform; generated by climbing fibers (inferior olive); induce long-term depression (LTD).
Provide the output pathway of the neocerebellum starting from Purkinje cells.
Purkinje cells → Dentate nucleus → Superior cerebellar peduncle → Contralateral red nucleus & VL thalamus → Motor and premotor cortex.
Describe the two-neuron chain of the ANS.
Preganglionic neuron (CNS) → ganglion → postganglionic neuron → effector.