Cells of the Nervous System Flashcards
Where are the myelinated axons located in the spinal cord?
White matter
Where are the cell bodies of neurons in the spinal cord?
Grey matter
Where does the PNS form from?
The neural crest
Where does the CNS form from?
The neural tube
What are the two types of astrocyte?
Protoplasmic astrocytes
Fibrous astrocytes
What are protoplasmic astrocytes and where are they found?
Short branching processes found in gray matter.
What are fibrous astrocytes and where are they found?
Long unbranched processes found in white matter.
What are the functions of astrocytes?
- Support neurons
- Support and stimulate formation of the blood brain barrier
- In the embryo astrocytes secrete chemical signals that stimulate growth and connections in neurons.
- Maintenance of the chemical environment needed for the generation of nerve impulses.
- Role in learning and memory by influencing the formation of neural synapses.
What do oligodendrocytes do?
Responsible for forming and maintaining the myelin sheath around CNS axons.
What do microglial cells do?
Function as phagocytes, phagocytozing microbes and damaged nervous tissue.
Where are ependymal cells located?
Ependymal cells line the ventricles of the brain and the central canal of the spinal cord.
What is the function of ependymal cells?
Monitor and assist in the circulation of CSF. Ependymal cells also form the blood cerebro-spinal fluid barrier.
What type of cells are ependymal cells?
Columnar with microvilli and cilia
What are the two types of glial cells in the PNS?
Schwann cells and satellite cells
Where are schwann cells found?
Encircling PNS axons
Where are oligodendrocytes found?
Encircling CNS axons
What is the function of schwann cells?
Myelinate axons speeding up nerve transmission and participate in axon regeneration.
Where are satellite cells found?
Surrounding the cell bodies of PNS neurons
What do satellite cells do?
Provide structural support and regulate exchange of material between neuronal cell bodies and interstitial fluid.
Where are bipolar neurons found?
Found in the retina of the eye, the inner ear and the olfactory area.
What do unipolar neurons usually function as?
Sensory receptors that detect touch, pressure, pain and thermal stimuli.
What type of neurons are sensory neurons?
Unipolar neurons
What type of neurons are motor neurons?
Multipolar neurons
What type of neurons are interneurons?
Multipolar neurons
What do interneurons do?
Connect sensory and motor neurons to one another.
Which type of neuron is the most abundant in the CNS?
Multipolar neurons
Where in the CNS are oligodendrocytes located?
White matter
What can diffuse across the blood brain barrier?
Lipid soluble substances such as O2, CO2, steroid hormones, alcohol, nicotine and water can diffuse acorss the lipid bilayer.
What is the outer nucleated cytoplasmic sheath of the schwann cell called?
Neurolemma
What are the gaps between the myelin sheaths?
Nodes of Ranvier
How would you describe the cross sectional histology of the cerebellar cortex?
Stripes
What is the specialised somatosensory receptor of the skin?
Merkel cell
What does the Meissner receptor detect?
Touch - movement
Where are Meissner receptors?
Skin