Special pathology - neurology Flashcards
Neuropathophysiology refers to
pathophysiological conditions that affect the nervous system
groups of neuronal cell bodies in the peripheral nervous system are called?
while those in the CNS are called?
ganglia
in the central nervouse system, they’re called nuclei
describe an Axon (3)
one long nerve fibre
enclosed in a myelin sheath (lipoprotein)
carries nerve impulses away from the cell body
describe Dendrites (2)
multiple branched protoplasmic extensions of a nerve cell
carry impulses to the cell body
Action potentials are (3)
-described and measured as an electrical parameter
-evoked in nerve and muscle cells in response to stimulation
-associated with the cellular and cellular membrane metabolism (membrane potential)
2 fundamental activities of neurons
- modulate and effectively transmit chemical and electric signals from one neuron to another via synapses in the CNS
- or from one neuron to a muscle cell via junctional complexes, myoneural junctions, or motor end plates in the PNS
what are glial cells
supportive cells of the nervous system
name 4 macroglial cells
Astrocytes
Oligodendrocytes
Shwann cells
Ependymal cells
what are Microglial cells
resident phagocytic cells of the nervous system that regulate brain development, maintenance of neuronal networks, and injury repair.
principal manifestation of the activity of the central nervous system is the
reflex
function of astrocytes
Astrocytes regulate synaptic transmission and plasticity, protect neurons against toxic compounds, and support metabolically to ensure their optimal functioning.
function of oligodendrocytes
are highly specialized neural cells whose function is to myelinate central nervous system axons.
Myelin sheaths are extraordinarily large extensions of the oligodendrocyte cell membrane
function of schwann cells
play a vital role in maintaining the peripheral nervous system, and come in two types either myelinating or non-myelinating Schwann cells.
Both play a pivotal role in the maintenance and regeneration of axons of the neurons in the PNS.
function of ependymal cells
play a critical role in cerebrospinal fluid (CSF) homeostasis, brain metabolism, and the clearance of waste from the brain
Immuno-privilege of the CNS means?
adaptive immunity and inflammation are highly controlled
Central nervous system (CNS) immune privilege is an experimentally defined phenomenon. Tissues that are rapidly rejected by the immune system when grafted in sites, such as the skin, show prolonged survival when grafted into the CNS.
haematoencephalic barrier =
Blood-brain barrier is between endothelial cells of capillaries and astrocytes.
purpose is to protect against toxic substances in the blood, supplies brain tissues with vital nutrients, and filters harmful compounds from the brain back to the bloodstream.
hemato-liquor barrier =
Blood-CSF barrier of the CNS is formed by tight junctions between neighboring choroid plexus epithelial cells
to preserve homeostasis within the cerebral compartment so that the complex neural integrative functions of the CNS can operate optimally.
Cerebrospinal fluid originates
in the ventricles of the brain
-fills and surrounds the brain and the spinal cord
-provides a mechanical barrier/buffer against physical damage
-nutrient delivery and waste removal system for the brain
- the fluid is constantly flowing/circulating and renewing itself
Encephalitis
inflammation of the brain
Encephalopathy
(degenerative) disease process of the brain
(syndrome)
Myelitis
Inflammation of the spinal cord
Myelopathy
(degenerative) disease process of the spinal cord
Neuropathy
disease process of the nerve
Myopathy
disease process of the muscles
upper motor neuron
Motor neurons with axons residing solely in the CNS that control lower motor neurons.
lower motor neuron
Large multipolar neurons in the brainstem and ventral horns of the spinal cord with axons extending into the PNS.
difference between upper and lower motor neurons
The upper motor neurons originate in the cerebral cortex and travel down to the brain stem or spinal cord, while the lower motor neurons begin in the spinal cord and go on to innervate muscles and glands throughout the body.
which cells of the CNS are most sensitive to injury
Neurons are the most sensitive to injury, whereas glial and other cells are more resistant to injury.
Neurons with the highest metabolic rate, such as some neurons in the cerebral cortex, will die 6 to 10 minutes after the cessation of blood flow after cardiac arrest.
neurons > oligodendroglia > astrocytes > microglia > blood vessels
why are neurons so vulnerable?
- small energy stores, depend heavily on an intact blood flow to supply oxygen and nutrients
- neurons do not have regeneration
If nerve fibers in the CNS are cut by transection of the cord, what is the result?
no or little regeneration of nerve fibers results:
- paralysis
- neurologic deficit