Topic 5 Nervous system / neuroglia Flashcards
Role of the neuroglia?
Support, nourish and protect neurons
With injury and/or disease, neuroglia multiply to fill the spaces formerly occupied by neurons
What are the 4 types of neuroglia of the CNS?
Astrocytes
Obligodendrocytes
Microglia
Ependymal cells
These neuroglia cells help form the blood brain barrier (BBB);
Provide nutrients to neurons
Astrocytes
A specialized barrier that prevents the passage of materials from the blood and the brain (and its surrounding fluid)
It protects the brain from harmful substances
thick basement membrane, tight junctions
Blood-brain barrier
Neuroglia cells that form/ maintain the myelin sheath of CNS neurons
Obligodendrocytes
Obligo=a few
Dendro=tree
Phagocytotic cells (similar to tissue macrophages);
They remove debris, phagocytize microbes from CNS
Activated with disease or damage taken place
Microglia
*only in CNS like immune system cell
They line the cavities of the brain and spinal cord (secrete)
They produce and assist in the circulation of cerebrospinal fluid (CSF)
Ependymal cells
Def.
A clear, colourless fluid that circulates around the brain and spinal cord.
It protects the brain and spinal cord from injury
Cerebrospinal fluid CFS
*acts as buffer for brain, help to protect from damage
Type of neuroglia…
Cells that encircle axons in the Peripheral nervous system
They form the myelin sheath of PNS axons
Are involved in the regeneration of PNS axons
Schwann cells
*only located in the Peripheral nervous system (PNS)
Structures of the nervous system…
CNS is comprised of 2 parts
Brain and spinal cord
Structures of the nervous system…
The peripheral nervous system comprises (5)
Cranial nerves and their branches Spinal nerves and their branches Ganglia Enteric plexuses (digestive system) Sensory receptors(skin)
Def.
A cluster of neuronal cell bodies in the CNS
Nucleus
Plural nuclei
Def.
A cluster of neuronal cell bodies in the PNS
Ganglion
Plural ganglia
Def.
a bundle of axons in the CNS
Tract
*tracts interconnect neurons in the spinal cord and brain
Def.
A bundle of axons in the PNS
Nerve
Type of nerve that connects the spinal cord to the periphery
Spinal nerve
Type of nerve that connects the brain to the periphery
Cranial nerve
Def.
Collections of cell bodies and unmyelinated nerve fibres in the CNS
Grey matter
Def.
collections of myelinated axons in the CNS
White matter
Encased in the vertebrae (bones & spine)
Extends from the bottom part of the brain stem to the 2nd lumbar vertebra (L2)
Spinal cord
At L2 the spinal cord tapers into a structure called ?
Conus medullaris
The roots of the spinal nerves below the conus medullaris is called
Cauda equina
Like horses tail
Spinal cord structure…
White matter surrounds the inner core of grey matter
There are 2 grooves that divide the white matter into right and left. What are they
Anterior median fissure and the posterior sulcus.
Def.
A small tube in the Sinal Cord that contains the CSF (cerebral spinal fluid)
Central canal
Spinal cord structure…
Each side is decided into regions called horns
Grey matter
What horns related to grey matter have axons of incoming sensory neurons and interneurons?
Posterior horn
Aka dorsal horn
What horns related to great matter have motor nuclei ?
Anterior horn
Aka ventral horn
What horn related to grey matter is present in thoracic, upper lumbar, sacral portions, they contain the sympathetic nuclei
Lateral horn
Each side is divided into regions called columns
White matter
White matter is divided into 3 regions
Anterior (aka ventral) columns
Posterior (aka dorsal) columns
Lateral columns
White matter…
Each column contains bundles of axons that have a common origin or destination -these are known as?
Sensory and motor
These tracts consist of axons that conduct APs toward the brain
Sensory
Aka ascending
These tracts consist of axons that conduct APs away from the brain
Motor
Aka descending
