PNS Ws Flashcards
WHta is a schwann cell?
Myelinating cell of PNS + support cells of peripheral neurons.. Can be myelinating or non-myelinating. Functional analogues of oligodendrocytes in the CNS.
WHta is. LMN?
Motor neurons that directly innervate muscle eg, a motor neurons of ventral horn.
WHat is a somatic motor unit
motor unit defined as an a motor neuron and all of the myofibres that it innervates. Frequently, different motor units, of different subtypes, function together to coordinate contraction of given muscle. All the a motor neurons and fibres it innervates is motor unit.
What is a dorsla root ganglion
Spinal ganglion. Collection of neuronal cell bodies of pseudouniplolar primary somatosensory neurons in turnk.
What is a myelin basic protein
believed to be important in process of myelination of nerve sin NS. Protein that sticks together membrane that’s wrapped dupon one another.
What is a perineuriam
Layer of CT within a nerve that surrounds a nerve fascicle. Within it lies the endoneurum, composed of endoneural bundles of CT(mostly collagen) and endoneural fluid of pns (CSF).
WHat is a growth cone
Specialised motile tip of an axon of a growing or regenerating neuron.
Henry head area
Head areas- areas of skin exhibiting reflex hyperesthesia and hyperalgesia due to visceral disease. Head lines- bands of cutaneous hyperesthesia associated with acte or chronic inflammation of viscera.
Do the nerve sin CNS/PNS regenerate
CNS axons do not spontaneously regenerate after injury in adult mammals. PNS axons readily regenerate, allowing recovery of function after PNS nerve damage.
Peirherla nerve labelled
![](https://s3.amazonaws.com/brainscape-prod/system/cm/373/926/047/a_image_thumb.png?1645356096)
Whats happening in these axons
![](https://s3.amazonaws.com/brainscape-prod/system/cm/373/926/050/q_image_thumb.png?1645356124)
Degeneration becomes visible via blebbing about 40hours after injury. Degeneration occurs proximally and distally.
![](https://s3.amazonaws.com/brainscape-prod/system/cm/373/926/071/q_image_thumb.png?1645356151)
Regrowth almost perfect with same patterns synapse/ growth
What can you conclude about the organisation of motor endplates after nerve lesion?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/373/926/080/q_image_thumb.png?1645356172)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/373/926/086/q_image_thumb.png?1645356182)
Mycobacterium leprae. Hansen disease- leprosy. Macrophages are filled with acid fast bacilli (“globi”)
A poorly formed granuloma is seen around a peripheral nerve within the dermis. The bacilli (Mycobacterium leprae) grow best just below body temperature, preferring the cooler skin and peripheral nerves. Hypopigmented patches or macular lesions with decreased sensation develop on the face, extremities, and trunk. Nodular disfiguring lesions occur with one form in which many macrophages are filled with numerous acid-fast bacilli (“globi”) (◄). In the tuberculoid form with more robust immune response, the acid-fast organisms are sparse. Seen here is the “borderline” form, with some organisms and some epithelioid cells. It is possible to control with drug therapy.
![](https://s3.amazonaws.com/brainscape-prod/system/cm/373/926/101/q_image_thumb.png?1645356199)
Peripheral nerve with axonal sprouting. Clusters of regrowing axons.
Here is a cross-section of a peripheral nerve following transection (axonotmesis), with clusters of regrowing axons (▼) surrounded by the basement membrane of a Schwann cell. Such small clusters of thinly myelinated fibers represent axonal sprouting. With ongoing disease from neuropathies, degeneration and regeneration may coexist.