Clinical Neuroanatomy & Neurophysiology - SLP 501

Practice flashcards for SLP 501 covering neuroscience fundamentals, historical contributors, neuron functional anatomy, cellular respiration, gene expression, neuroglia types, and nerve injury/regeneration principles.

What is the central rationale for speech-language pathologists and audiologists to study neuroscience?

Clinical interventions in CSD aim to change a client's behavior, perception, or cognitive state, which inherently alters the anatomy, structure, and operation of their nervous system.

What area of the brain did Paul Broca identify in 1861, and what clinical impairment is associated with lesions to this area?

Paul Broca identified Broca's area (Brodmann's area 44 & 45). Lesions here cause Expressive aphasia, most commonly resulting from an stroke/infarct of the superior division of the left middle cerebral artery (MCA).

What area did Carl Wernicke identify in 1874, and what type of aphasia results from a lesion in this region?

Carl Wernicke identified Wernicke's area (Brodmann's area 22). Lesions here cause Receptive aphasia, commonly caused by an infarct of the inferior division of the left middle cerebral artery (MCA).

What language pathway is damaged when a patient presents with conduction aphasia?

The arcuate fasciculus.

What were Wilder Penfield's major contributions to understanding cortical organization?

He mapped the cerebral cortex during brain surgeries and established the somatotopic organization represented by the sensory and motor homunculi in primary somatosensory cortex (S1) and primary motor cortex (M1).

According to Alexander Luria (1973), what are the three functional units of the brain?

1. The unit for regulating tone, waking, and mental states; 2. The unit for receiving, analyzing, and storing information; 3. The unit for programming, regulation, and verification of activity.

Which of Luria's three functional units of the brain is highlighted in red in this diagram?

The unit for receiving, analyzing, and storing information.

What are the four primary structural features of a typical neuron?

The soma (cell body), dendrites, axon, and presynaptic terminal.

What are the four functional zones of a neuron?

An input site, an integration site, a conduction segment, and an output site.

What three fundamental activities must each neuron perform within a neural network?

1. Receive input (excitatory or inhibitory); 2. Integrate input (at the axon hillock to alter baseline electrical state); 3. Form an output (transmission at the synapse).

What morphological classification of neuron is found in retinal ganglion cells?

Bipolar neuron.

What morphological classification of neuron is found in tactile primary afferents of spinal and trigeminal nerves?

Pseudounipolar neuron.

What structural type of neuron categorizes motoneurons?

Multipolar neuron.

What are the metabolic processes of ATP hydrolysis and phosphorylation within neuronal mitochondria?

Hydrolysis reduces ATP to ADP to release energy for metabolic processes; phosphorylation converts ADP back to ATP by absorbing energy.

What are the two major steps of gene expression in neurons, and where do they occur?

Transcription occurs in the nucleus (RNA polymerase creates mRNA from DNA), and translation occurs at the ribosome (tRNA matches anticodons to mRNA codons to build an amino acid chain).

What are the three structural types of synaptic contacts between neurons?

Axosomatic, axodendritic, and axoaxonic synapses.

What is the primary functional role of microglia in the nervous system?

Microglia serve as the immune cells and 'sanitation workers' of the brain, clearing necrotic cells, waste products, and pathogens via phagocytosis, exhibiting both pro- and anti-inflammatory activity.

Which specific glial cells produce myelin in the Central Nervous System (CNS) versus the Peripheral Nervous System (PNS)?

Oligodendrocytes produce myelin in the CNS, whereas Schwann cells produce myelin in the PNS.

What are the primary functions of astrocytes in the central nervous system?

Astrocytes form the structural support for CNS neurons, maintain the blood-brain barrier (BBB), regulate extracellular $K^+$ and glutamate levels around synapses, provide metabolic support, and form scar tissue following injury.

What is the function of ependymal cells in the ventricular system?

They line the spinal cord central canal and brain ventricles, participate in producing cerebrospinal fluid (CSF), and form tight junctions with capillaries in the choroid plexus to contribute to the blood-brain barrier.

What are the roles of satellite cells in the Peripheral Nervous System (PNS)?

They surround neuron cell bodies in ganglia and regulate extracellular neurotransmitter levels.

How does the population size of neuroglia compare to neurons, and can glia divide in adulthood?

There are $40\text{--}50\times$ more glial cells than neurons in the CNS, and glia are capable of mitotic cellular division throughout adult life.

What is chromatolysis, and what is its timeline following axonal injury?

Chromatolysis is the swelling and destruction of the cell body microanatomy in the proximal aspect of an injured neuron; it begins $12\text{--}24\text{ hours}$ after injury and reaches maximum effect at $20\text{ days}$.

What is Wallerian degeneration, and what is its timeline in an injured neuron?

Wallerian degeneration is the swelling and deterioration of the distal segment of a damaged axon; deterioration starts within $12\text{--}20\text{ hours}$, target muscle denervation occurs in $2\text{--}3\text{ days}$, and microglial debris clearance takes $3\text{--}6\text{ months}$.

At what rate do peripheral nerves regenerate following injury?

Peripheral nerves regenerate at a rate of $3\text{--}4\text{ mm/day}$.

Why is nerve regeneration effective in the PNS but generally ineffective in the CNS?

PNS axons regenerate effectively due to the supportive environment and composition provided by Schwann cells; CNS re-growth is not orderly and typically results in scarring.

What are the primary types of glial cell tumors listed in the lecture notes?

Astrocytoma, ependymomas, schwannomas, meningiomas, medulloblastomas, glioblastoma, and oligodendrogliomas.