Nervous system Physiology Part 2 Flashcards
What are the primary functions of the soma and dendrites of a neuron?
To receive information from the synapse and generate/integrate local potential changes.
Where on a neuron is the action potential typically generated?
The initial segment.
What is the main role of the axon in a neuron?
To transmit impulses to the nerve endings.
What is the primary function of the nerve endings (axon terminals)?
To release synaptic transmitters
Are neuroglia neuronal or non-neuronal cells?
Non-neuronal cells.
What are the main functions of neuroglia in the nervous system?
To maintain homeostasis, form myelin, and provide support and protection for neurons.
How many types of neuroglia are found in the central nervous system (CNS)?
Four types.
How many types of neuroglia are found in the peripheral nervous system (PNS)?
2 types
Name the four main types of neuroglia found in the central nervous system (CNS).
Astrocytes, Oligodendrocytes, Microglia, and Ependymal cells.
What is the general function of astrocytes in the CNS?
Astrocytes provide structural and metabolic support for neurons, contribute to the blood-brain barrier, and help regulate the chemical environment of the CNS.
They also secrete Neurotrophic factors
They also take up K+ neurotransmitters
What is the role of microglia in the CNS?
Microglia act as scavengers removing debris and pathogens
What is the function of ependymal cells?
Create barriers between compartments
Name the two main types of neuroglia found in the peripheral nervous system (PNS).
Schwann cells and Satellite cells.
What is the general function of satellite cells in the PNS?
Satellite cells support cell bodies
What is the functional difference between oligodendrocytes and Schwann cells regarding myelin formation?
Oligodendrocytes can myelinate multiple axons in the CNS, while each Schwann cell typically myelinates only one segment of a single axon in the PNS.
Define a synapse.
A synapse is a junction that mediates information transfer from one neuron to the next or from a neuron to an effector cell.
What are the two main classes of synapses?
Electrical synapses and chemical synapses.
What is the primary structural component of an electrical synapse?
Gap junctions.
What are connexons and what is their function in electrical synapses?
Connexons are protein channels that intimately connect the cytoplasm of adjacent neurons, allowing ions and small molecules to flow directly from one neuron to the next.
These neurons are electrically coupled, and transmission across
these synapses is very rapid.
Is the transmission of information at an electrical synapse typically unidirectional or bidirectional?
Bidirectional
What is the key characteristic of signal transmission at a chemical synapse?
Interaction between the cells occurs via chemical intermediaries known as neurotransmitters.
Is the transmission of information at a chemical synapse typically unidirectional or bidirectional?
Unidirectional
What happens at the chemical synapse?
•Action potential arrives at axon terminal
•Voltage-gated Ca≥* channels open
•Ca2+ enters the presynaptic neuron
•Ca2+signals to neurotransmitter vesicles
•Vesicles move to the membrane and dock
•Neurotransmitters released via exocytosis
•Neurotransmitters bind to receptors
•Signal initiated in postsynaptic cell
