Topic 5 - Nervous System Flashcards
A subdivision of the nervous system that consists of the brain and the spinal cord.
Central Nervous System (CNS)
A subdivision of the nervous system that consists of all nervous tissue outside of the brain and spinal cord.
Peripheral Nervous System (PNS)
Some different functions of the _______ system include:
- Sensory detection and input
- Integrative processing, storing and analyzing of sensory info for decision making
- Motor output
Nervous
_________ contain a lot of receptor sites for receiving chemical messages from other cells.
Dendrites
Fine processes in which the end of an axon divides into.
Axon Terminals
The swollen ends of some axon terminals.
Synaptic End Bulbs
A multilayered lipid and protein covering that speeds up signal conduction.
Myelin
Axons coated in myelin.
Myelinated Axons
The longest cells in the body that possess electrical excitability. They can respond to a stimulus and convert it to an action potential.
Neurons
Any change in the internal or external environment that is strong enough to stimulate an action potential.
Stimulus
An electrical signal that allows neurons to communicate with each other. They travel along the cell membrane of a neuron that allows them to communicate over small or large distances at different speeds.
Action Potential (AP)
What are the 3 structural classifications of neurons?
1) Multipolar
2) Bipolar
3) Unipolar
Neurons with several dendrites and one axon. Includes most neurons in the brain and spinal cord, as well as all motor neurons.
Multipolar
Neurons with one main dendrite and one axon. Generally these neurons are associated with sight and hearing.
Bipolar
Sensory neurons in the PNS with one point of attachment. The peripheral axon has sensory receptors and the central axon has axon terminals.
Unipolar
What are the 3 functional classifications of neurons?
1) Sensory Neurons
2) Motor Neurons
3) Interneurons
Neurons that are mostly classified as unipolar and contain either sensory receptors at the dendritic ends or are located just after sensory receptors that are separate cells. Once activated by a stimulus, the AP forms and propagates along the axon and is conveyed into the CNS. They travel together in the spinal and cranial nerves.
Sensory (aka. Afferent) Neurons
Neurons that are classified as multipolar and the AP propagates away from the CNS to effectors.
Motor (aka. Efferent) Neurons
The cells and organs that carry out an action (e.g. muscle fibres, glands).
Effectors
Neurons that are mostly classified as multipolar and are located primarily in the CNS between sensory and motor neurons. They integrate/process information from sensory neurons and if a motor response is required, the specifics of the response are formulated and relevant motor neurons are activated.
Interneurons (aka. Association Neurons)
The site of communication between two neurons or between a neuron and another type of cell.
Synapse
What are 2 types of synapses?
1) Electrical
2) Chemical
Synapses where APs conduct directly between the plasma membranes of adjacent cells through gap junctions. They produce fast communication and allow for synchronization of function (e.g. muscles of the heart).
Electrical Synapses
The more common type of synapse that allows your body to fine tune communication (slower) and can be found in skeletal muscle. When the AP reaches the end of the pre-synaptic neuron, it causes the release of a NT that diffuses across the synaptic cleft and binds to the post-synaptic neuron.
Chemical Synapses
The neuron sending the signal in a chemical synapse.
Pre-Synaptic Neuron
The neuron receiving the signal in a chemical synapse.
Post-Synaptic Neuron
The space between the communicating neurons in a chemical synapse.
Synaptic Cleft
A chemical protein released by the pre-synaptic neuron to affect (excite/inhibit) the post-synaptic neuron(s) or effector. Similar to a lock and key system.
Neurotransmitter (NT)
If the neurotransmitter is __________, continuation of the AP is more likely.
Excitatory
If the neurotransmitter is __________, continuation of the AP is less likely.
Inhibitory
A neurotransmitter found in the PNS/CNS that is excitatory at the neuromuscular junction.
Acetylcholine (ACh)
A neurotransmitter found in the CNS that is inhibitory.
Gamma-Aminobutyric Acid (GABA)
A neurotransmitter that can be excitatory or inhibitory, depending on the receptor. It generates emotional responses, addictive behaviours and skeletal muscle tone.
Dopamine
A neurotransmitter that can be excitatory or inhibitory, depending on the receptor. Related to sensory perception, temperature regulation, mood, sleep and appetite.
Serotonin
The 4 types of _________ in the CNS are:
- Astrocytes
- Oligodendrocytes
- Microglia
- Ependymal Cells
Neuroglia
A type of neuroglia cell that helps form the blood-brain barrier and provide nutrients to neurons. They have a star-like appearance.
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, consists of tight junctions and has a thick basement membrane.
Blood-Brain Barrier (BBB)
A type of neuroglia cell that forms and maintains the myelin sheath of CNS neurons.
Oligodendrocytes
A type of neuroglia cell that are considered phagocytotic cells (similar to macrophages) that remove debris and phagocytize microbes.
Microglia
A type of neuroglia cell that lines the cavities of the brain and spinal cord that produce and assist in circulation of cerebrospinal fluid.
Ependymal Cells
A clear, colourless fluid that circulates around the brain and spinal cord that protects these structures from injury.
Cerebrospinal Fluid (CSF)
A type of neuroglia cell that encircles axons in the PNS and form the myelin sheath. They are also involved in the regeneration of PNS axons and are the only type of neuroglia in the PNS.
Schwann Cells
Some structures found in the __________ nervous system include:
- Cranial nerves & their branches
- Spinal nerves & their branches
- Ganglia
- Enteric plexuses
- Sensory receptors
Peripheral
A cluster of neuronal cell bodies in the CNS.
Nucleus
A cluster of neuronal cell bodies in the PNS.
Ganglion
A bundle of axons in the CNS that interconnect neurons in the spinal cord and brain.
Tract
A bundle of axons in the PNS.
Nerve
Nerves that connect the spinal cord to the periphery.
Spinal Nerves
Nerves that connect the brain to the periphery.
Cranial Nerves
Collections of cell bodies and unmyelinated nerve fibres in the CNS.
Grey Matter
Collections of myelinated axons in the CNS.
White Matter
A structure encased in the vertebrae that consists of white matter surrounding an inner core of grey matter. It extends from the bottom part of the brain stem to L2.
Spinal Cord