Lecture 16 Flashcards
What does CNS stand for?
Central Nervous System.
What does PNS stand for?
Peripheral Nervous System
What are the 2 general classes of cells for both the CNS and PNS?
Neurons and Glia.
Name the 3 general features of the Glia cell in the nervous system.
- provides support for neutrons
- 4 different types
- each have different functions.
Name the 4 different types of Glia cells of the CNS.
- Axoncytes
- Microglia
- Ependymal cells
- Oligocytes
Name the type of Glia cell in the PNS.
Schwann cell.
What are the functions of each of the types of Glia cells in the CNS?
Axoncytes:
- Supplies nutrients to the neutrons.
- Ensheath blood capillaries.
- Transmit information.
Microglia:
- Immune cells of the CNS.
- Engulf microorganisms and debris.
Ependymal cells:
- Line fluid-filled spaces the brain and spinal cord.
- Have cilia (little hairs) that circulate CSF.
Oligodendrocytes:
- Support nerve fibres.
- Ensheath them with myelin.
What is the function of the Glia cell in the PNS?
Schwann cell:
- Supports peripheral nervous fibres (wraps around the axon of the neutron).
- Ensheath them with myelin.
- Similar to Oligodendrocytes (CNS).
What is the myelin sheath made of?
Lipid (fat) wrapped around the axon of the neuron.
Where does the myelin sheath come from?
- Oligodendrocytes (CNS)
- Schwann cells (PNS)
What does the myelin sheath do?
Increases conductive velocity.
What are the 4 components of the a basic neuron structure and what are their functions?
Dendrites:
- Receives information and sends it down into the cell body.
Cell body:
- Contains nucleus and organelles.
- Sums input information (decides whether to pass the information on).
Axon:
- Carries electrical impulse.
- may or may not be myelinated.
Axon Terminal:
- End of the Axon.
- Neurontransmitter release.
What is Ranvier’s node what does it do?
- Located between gaps of myelin.
- Provides an increase in conduction (speed) of the electrical impulse
What is the input zone of a neuron and what structures are involved?
- Dendrites & Cell body
- Receives chemical signals from other neurons.
What is the summation zone of a neuron and what structures are involved?
- Axon hillock
- Decides whether to pass on the information to another neuron.
What is the conduction zone of a neuron and what structures are involved?
- Axon
- Region where the electrical signal is carried along, between brain areas, to and from the spinal cord, or to and from peripheral sensory receptors.
What is the output zone of a neuron and what structures are involved?
- Axon Terminals
- Contacts the input zone of other neurons.
- Release of neurotransmitters (chemical signal).
How does the axon hillock decide whether the information should be passed onto another neuron?
Number of electrical impulses of that same type are received.
Name the 3 types of neurons shapes (morphology).
Multipolar:
- Multiple processes emanate from the cell body.
Bipolar:
- 2 processes emanate from the cell body.
(Pseudo)Unipolar:
- One process emanates from the cell body.
- One end branches into dendrite, and other end branches into an axon.
What is the synapse junction?
The region of communication between 2 neurons (chemical)
What are the 3 energy types the impulses (information) go from?
Electrical (inside the axon) to chemical (between 2 neurons) to electrical again (inside the axon).
What defines the pre-synaptic and post-synaptic neurons?
Pre-Synaptic neuron:
- Before the synapse (transfer of information between 2 neurons).
- Contains synaptic vesicles (packets of neurotransmitters).
- Releases the neurotransmitter (chemical signal) from the axon terminal.
Post-synaptic neuron:
- After the Synapse.
- Contains receptors for the neurotransmitters.
What are the 3 types of Synapse?
- Axondendritic
- Axosomatic
- Axoaxonic
What are the difference between Axondendritic, Axosomatic and Axoaxonic synapses?
Axondendritic - Pre-synaptic neuron contacts the dendrites of the post-synaptic neuron.
Axosomatic - Pre-synaptic neuron contacts the cell body (soma) of the post-synaptic neuron
Axoaxonic - Pre-synaptic neuron contacts the axon of the post-synaptic neuron. (hence going past the Axon hillock and ignoring the decision making phase)
Define Afferent and Efferent flow.
Afferent - information flowing to the brain (ascending).
Efferent - Response from the brain (descending).
What is a group cell bodies called? (CNS)
nucleus (plural: nuclei).
What is a bundle of axons called? (CNS)
Tract.
What are a group of cell bodies in the cerebral cortex called? (CNS)
Grey matter.
What are bundles of axons in the cerebral cortex called? (CNS)
White matter.
What is a group cell bodies called? (PNS)
Ganglion (plural: ganglia).
What is a bundle of axons called? (PNS)
Nerve.
