the cns and pns Flashcards
Nervous system tissue 2 basic cell types
- Glial cells (neuroglia) – supporting cells which are not excitable (5 times more abundant than neurons)
- Neurons (nerve cells) – cells within the nervous system that transmit information
glial cells/ neuroglia function
non-neuronal cells in the nervous system that support, protect, and nourish neurons, maintaining homeostasis and forming myelin.
Neuroglia in the CNS
Astrocytes
Microglial cells
Ependymal cells
Oligodendrocytes
Neuroglia in the PNS
Satellite cells
Schwann cells
function of dendrites, cell body, and axon
Dendrites:
Receptive region
Cell body/soma:
Acts as part of the receptive region
Axon:
Conducting region
what are the connective tissues surrounding a peripheral nerve (PNS)
- Endoneurium: Surrounds a single nerve fibre.
- Perineurium: Surrounds a nerve fascicle.
- Epineurium: Surrounds the entire peripheral nerve.
where is the primary somatosensory cortex located and function
parietal lobe
* Located at the postcentral gyrus, in the parietal lobe of each hemisphere
* Receives information from sensory receptors in skin/muscles/joints
where is the primary motor cortex located and function
frontal
* Located at the precentral gyrus in the frontal lobe of each hemisphere
* Responsible for conscious control of skeletal muscle movement
grey matter
Have a high density of neuronal cell bodies (soma), non-myelinated axons, synapses, dendrites and glial cells.
White matter
Have a high density of myelinated axons and glial cells (schwann cells and oligodendrocytes.
how many cranial nerves and spinal nerves
Cranial nerves
* 12 pairs of cranial nerves
Spinal nerves
* 31 pairs of spinal nerves
what are microglia
Microglia are resident immune cells of the brain (CNS) that act as the brain’s “macrophages”.
Astrocytes
Astrocytes – Support and nourish neurons.
Microglial cells
Microglial cells – Defend against pathogens.
Ependymal cells
Ependymal cells – Produce and circulate cerebrospinal fluid.
Oligodendrocytes
Oligodendrocytes – Form myelin in the CNS.
Satellite cells
Satellite cells – Support neurons in the PNS.
Schwann cells
Schwann cells – Form myelin in the PNS.
