exam 2: SHORT ANSWER Flashcards
chapter 5:Radial Glia in Neural Development:
Location: Radial glia are primarily found in the developing cerebral cortex.
Role: They act as scaffolding for migrating neurons during neural development, guiding their movement from the ventricular zone to their final destinations in the cortex.
Signals for Cell Migration: Chemokines and other signaling molecules, like Reelin, are crucial for the directional migration of neurons along the radial glial fibers.
chapter 5: Death Genes and Apoptosis:
Death genes regulate apoptosis by encoding proteins that initiate and execute the cell death program.
Key players include the Bcl-2 family (which includes pro-apoptotic and anti-apoptotic proteins) and caspases (which are proteases that carry out the death program).
When a cell receives pro-apoptotic signals, Bcl-2 proteins promote the release of cytochrome c from mitochondria, activating caspases that lead to cellular breakdown.
chapter 6: Conversion of Light Waves in Photoreceptors:
Phototransduction occurs in the outer segments of photoreceptors (rods and cones).
When light hits photopigments (like rhodopsin in rods), it causes a conformational change that activates a G-protein (transducin).
This leads to a cascade of events that ultimately decrease cGMP levels, causing cGMP-gated ion channels to close. As sodium ions stop entering the cell, the membrane hyperpolarizes, leading to a decrease in neurotransmitter release.
chapter 6: role of retinal cells
Bipolar Cells: Connect photoreceptors to ganglion cells, integrating signals and contributing to the formation of on-center/off-surround and off-center/on-surround receptive fields.
Horizontal Cells: Provide lateral inhibition, enhancing contrast and refining the visual signal.
Ganglion Cells: Receive input from bipolar cells and send visual information to the brain, coding the type of receptive field (on or off)
chapter 6: visual pathway
From Retina to Primary Visual Cortex:
Retinal Ganglion Cells → Optic Nerve → Optic Chiasm (where some fibers cross) → Optic Tract → Lateral Geniculate Nucleus (LGN) of the Thalamus → Optic Radiation → Primary Visual Cortex (V1).
Chapter 7: Olfactory Receptor Cells:
Structure: Olfactory receptor cells are bipolar neurons located in the olfactory epithelium. They have cilia that extend into the mucus layer for odorant detection.
Axon Projection: Their axons project to the olfactory bulb, where they synapse on mitral and tufted cells.
Auditory Pathway Structures
Cochlea → Auditory Nerve → Cochlear Nucleus (brainstem) → Superior Olivary Complex → Inferior Colliculus → Medial Geniculate Nucleus (thalamus) → Auditory Cortex.
somatosensory cortex
Location: The somatosensory cortex is located in the postcentral gyrus of the parietal lobe.
Representation: The body surface is represented topographically (homunculus). If a person has their left hand amputated, the corresponding area in the cortex may shrink or be taken over by adjacent areas, demonstrating neural plasticity.
Chapter 8: Proprioceptive receptors:
Types:
Muscle Spindles: Detect stretch and changes in muscle length, firing more during muscle stretch.
Golgi Tendon Organs: Detect tension in muscles, firing more during muscle contraction.
Firing Patterns: Their activity indicates the state of the muscle (relaxed, contracted, stretched) based on the amount of stretch or tension.
chapter 8: Cortex Areas in Pyramidal System
Primary Motor Cortex (M1): Initiates voluntary movements.
Premotor Cortex: Involved in planning and coordinating movements.
Supplementary Motor Area (SMA): Engaged in the preparation and organization of complex movements.
chapter 8: Movement Disorders and Basal Ganglia Dysfunction:
Parkinson’s Disease: Characterized by tremors, rigidity, and bradykinesia due to loss of dopaminergic neurons in the substantia nigra, affecting movement initiation.
Huntington’s Disease: Involves involuntary movements (chorea) and cognitive decline, resulting from degeneration of the striatum and imbalance of neurotransmitter systems, particularly the loss of GABAergic neurons.
