What is meant by chromatolysis?
Definition of chromatolysis : the dissolution and breaking up of chromophil material (such as chromatin) of a cell and especially a nerve cell.
What causes chromatolysis?
Chromatolysis is the dissolution of the Nissl bodies in the cell body of a neuron. It is an induced response of the cell usually triggered by axotomy, ischemia, toxicity to the cell, cell exhaustion, virus infections, and hibernation in lower vertebrates.
What is central Chromatolysis?
Central chromatolysis (arrow) occurs when the normal aggregations of rough endoplasmic reticulum and associated ribosomes, known as Nissl substance, in the neuronal perikaryon disperse as a response to injury. It signifies the acceleration of neuronal protein synthesis in the face of cellular injury.
Is chromatolysis reversible?
Chromatolysis is also reversible in CNS neurons.
What is the function of Neurofibrils?
Neurofibrils are bundles of neurofilaments that extend into the dendrites and axon, and provide internal support to them….The cell body.
| Structures | Functions |
|---|---|
| Neurofibrils | Determine shape of neuron |
| Microfilaments | Help to form and retract cell processes; assist in cellular transport |
What is axonal hillock?
In nervous system: Axon. …at a region called the axon hillock, or initial segment. This is the region where the plasma membrane generates nerve impulses; the axon conducts these impulses away from the soma or dendrites toward other neurons.
Is chromatolysis irreversible?
Where is neurofilament located?
cytoplasm of neurons
Neurofilaments (NF) are classed as type IV intermediate filaments found in the cytoplasm of neurons. They are protein polymers measuring 10 nm in diameter and many micrometers in length.
What is the difference between chromatolysis and Wallerian degeneration?
Axonal reaction / central chromatolysis / Wallerian degeneration: When the axon of a neuron is cut or damaged, the axon and its myelin sheath undergo degeneration distal to the lesion (Wallerian degeneration). The sequence of events that takes place in the cell body is known as central chromatolysis or axonal reaction.
What are collateral sprouts?
Collateral sprouting is a process in which the surviving (intact) motor axons send axon terminals (sprouts) to the denervated muscles in an attempt to reinnervate these muscle fibers and restore muscle power.
Is Chromatolysis irreversible?
What does Wallerian degeneration feel like?
What are the symptoms of Wallerian Degeneration? Symptoms of Wallerian degeneration (peripheral nerve disease) include neuropathic (nerve) pain, pain associated with certain stimuli, spontaneous pain, and sensory deficits, such as tingling, weakness, and paralysis.
What is Pseudounipolar?
A pseudounipolar neuron is a type of neuron which has one extension from its cell body. This type of neuron contains an axon that has split into two branches; one branch travels to the peripheral nervous system and the other to the central nervous system.
Where is neurofibrils found?
large neurons
Neurofibrils are best seen in large neurons, but are present in almost all (Fig. 21G). With metallic-impregnation, they are thin, interlacing, silver-loving threads (up to 2 μm in diameter) running through the cytoplasm and extending into dendrites and axon.
What are Ranvier’s nodes?
The nodes of Ranvier are characterized by short (1um), specialized regions in the axonal membrane that are not insulated by myelin. Although it is bare of myelin at the node, the axon is in direct contact with the microvilli of the Schwann cells in the PNS, or with processes of astrocytes in the CNS (Figure 1).
What is nissl body?
Nissl bodies (also called Nissl granules Nissl substance or tigroid substance) are discrete granular structures in neurons that consist of rough endoplasmic reticulum, a collection of parallel, membrane-bound cisternae studded with ribosomes on the cystosolic surface of the membranes.
What does a neurofilament look like?
Neurofilaments (NF) are classed as type IV intermediate filaments found in the cytoplasm of neurons. They are protein polymers measuring 10 nm in diameter and many micrometers in length. Together with microtubules (~25 nm) and microfilaments (7 nm), they form the neuronal cytoskeleton.
What is the Neurofibril?
Neurofibrils are bundles of neurofilaments that extend into the dendrites and axon, and provide internal support to them. Neurofibrils are numerous and run parallel to each other.