Nervous System Flashcards
What is the neuroglia of the CNS?
Astrocytes, Ependymal cells, Microglia, Oligodendrocytes
What is the function of astrocytes?
- Forming a supporting framework for blood vessels and neurons.
- Assists in the formation of tight junctions between endothelial cells of the capillaries
- Respond to tissue damage in the CNS
What is the function of ependymal cells?
- Line the central cavities of the brain and spinal cord
What is the function of microglial cells?
- Monitor the health of surrounding neurons
- Phagocytose microorganisms, infection, trauma or inflammation
What is the function of oligodendrocytes?
- Cover axons which form an insulating sheath around them
What is the neuroglia of the PNS?
- Schwann cells
- Satellite cells
What is the function of Schwann cells?
- Form myelin sheath around axons to insulate
- Also called neurolemmocytes
What is the function of satellite cells?
- Provide support and nutrition to cell bodies in ganglia
- Protect cell bodies from harmful substances
What are the characteristics of the cell membrane that allow a membrane potential to be generated?
- Differences in ionic concentration across the cell membrane (particularly sodium and potassium).
- Permeability of the cell membrane to ions.
What are non-gated ion channels?
Ion specific channels. Also known as leak channels. The cell membrane has more K+ leak ion channels compared to Na+ leak channels.
What are gated ion channels?
Channels that require signals to open them. Ligand-gated, voltage-gated, and other-gated.
What is depolarisation?
When the membrane potential becomes more positive
What is hyperpolarisation?
When the membrane potential becomes more negative
What is repolarisation?
When the membrane potential returns to normal
What is graded potential?
Short-lived, localised changes in membrane potential. Often occurs in dendrites or the cell body of a neuron. Graded potentials are decremental meaning they are not able to transfer information over long distances.
What is a reflex?
An automatic response to a stimulus. Can be somatic or autonomic, and are homeostatic.
What are the types of reflexes?
Stretch (monosynaptic), golgi tendon, withdrawal
What are the five regions of the spinal cord?
Cervical, thoracic, lumbar, sacral, and coccygeal
What many pairs of spinal nerves are there?
31
How many pairs of cranial nerves are there?
12