Nerve Tissue Cytology Flashcards
What is the main organelle found in the soma of a neuron?
The nucleus, surrounded by rough endoplasmic reticulum (Nissl bodies)
What is the function of Nissl bodies?
Protein synthesis, crucial for neurotransmitter production
What is the cytoskeletal framework in neurons composed of?
Microtubules, neurofilaments, and actin filaments
What is the role of microtubules in neurons?
They facilitate axonal transport of organelles and vesicles
What are the two types of axonal transport?
Anterograde (away from the soma) and retrograde (toward the soma)
Which motor proteins are involved in axonal transport?
Kinesin for anterograde transport and dynein for retrograde transport
What is transported via fast axonal transport?
Vesicles, organelles, and synaptic components
What is transported via slow axonal transport?
Cytoskeletal elements and soluble proteins
What are the major components of a synapse?
Presynaptic terminal, synaptic cleft, and postsynaptic terminal
What organelle is abundant in the presynaptic terminal?
Synaptic vesicles, which store neurotransmitters
How are neurotransmitters released into the synaptic cleft?
By exocytosis, triggered by calcium influx
What are the main features of astrocytes?
Star-shaped cells with numerous processes that interact with neurons and blood vessels
What cytoplasmic inclusions are found in oligodendrocytes?
Lipid-rich myelin, which they use to insulate axons
What distinguishes microglia cytologically?
Small cells with elongated nuclei and processes that can transform into macrophage-like cells during injury
What do ependymal cells have on their apical surface?
Cilia and microvilli, aiding in the circulation and absorption of cerebrospinal fluid (CSF)
What is the cytological process of myelination?
Schwann cells (PNS) or oligodendrocytes (CNS) wrap their plasma membranes around axons to form a multilayered sheath
What proteins are critical for myelin compaction?
Myelin basic protein (MBP) and proteolipid protein (PLP)
What is the role of the node of Ranvier?
It allows saltatory conduction by concentrating ion channels
What organelles are prominent in the neuron for energy production?
Mitochondria, especially in axons and synaptic terminals
Which organelle is responsible for recycling neurotransmitters?
Endosomes within the presynaptic terminal
What is the role of the Golgi apparatus in neurons?
Packaging of neurotransmitters into synaptic vesicles
What are lipofuscin granules?
Cytoplasmic inclusions found in aging neurons, representing lysosomal degradation products
What is the significance of neuromelanin?
It is a dark pigment found in certain neurons, such as in the substantia nigra, linked to dopamine metabolism
What are Lewy bodies and what do they indicate?
Cytoplasmic inclusions composed of α-synuclein, associated with Parkinson’s disease
What role do neurofilaments play in neurons?
They provide structural support and maintain the shape of axons and dendrites
What happens when tau proteins in microtubules become hyperphosphorylated?
They form tangles, which are hallmarks of Alzheimer’s disease
Which stain is used to visualise Nissl bodies?
Cresyl violet stain
What does a Golgi stain highlight?
The entire morphology of a neuron, including dendritic and axonal processes
Which stain is used to identify myelin in tissue?
Luxol fast blue
