Intro part 1; Neurons & Glial cells Flashcards
a-motor neurons are also known as what?
Lower Motor Neurons
Cuteaneous neurons are described as what?
surface level (skin) sensory neurons
What are Pyramidal neurons?
major brain neurons that link parts of the brain to other parts.
What are the 3 components of the neuron?
- Soma / body
- Dendrites
- Axon
what is the function of the dendrites?
they receive incoming signals from other neurons
; communication via chemical and bio electricity
What is the function of the Soma?
it is the metabolic centre of the neuron
What is the function of the Axons?
they convey information to other neurons and cells; away from soma
Dendrites and Axons are referred to as what?
Neurites
Which part of the neuron initiates the mode of communication?
Initial Segment
What is the function of the Myelin Sheath?
Electrical insulation; confines all electric events to the axon
- increases the speed of AP transmission
What is the Schwann cell’s role in a neuron?
It is the cell that produces myelin (not the neuron itself)
What is the Collateral Axon?
A major branch that increases innervation to other cells (amount is not constant)
What is the Node of Ranvier, and what is its function?
It is the exposed area of the axon between myelin sheaths, increasing the speed of action potential propagation
What are presynaptic terminals?
enlargements at the ends of axon branches
What characterizes a multipolar neuron?
It has many dendrites and one axon; motor neurons fall into this category, with dendrites receiving approximately 10,000 inputs
What characterizes a bipolar neuron, and where is it found?
It has one dendrite and one axon,
found in the retina and olfactory epithelium
What is a pseudo-unipolar neuron, and how does it function?
It has no axons or dendrites
functions with one process in the periphery and another transmitting to the CNS, such as in somatosensory neurons
What is the function of sensory receptors in pseudo-unipolar neurons?
They generate bioelectrical signals in response to sensory stimuli
What is the function of sensory neurons?
Carry info from the periphery to the CNS,
about the external and internal state of life, including motor coordination.
How are Interneurons characterized?
relay interneurons: long axons for long-distance communication
local interneurons: short axons connecting nearby neurons
What are the most numerous type of neuron?
Interneuron
What are the Functional Categories of Neurons?
- Sensory Neurons
- Interneurons
- Motor Neurons
What is the function of motor neurons?
They carry information out of the CNS (efferent)
What are glial cells, and why are they important?
They are neurons’ supporting cells
What are astrocytes, and what is their role?
Star-shaped cells that provide structural support, regulate K+ levels, and maintain homeostasis
What is the role of microglial cells?
Protect neurons by absorbing toxic substances and acting as phagocytes to remove bacteria and damaged cells
What is the primary function of oligodendrocytes and Schwann cells?
They both produce myelin; oligodendrocytes in the CNS and Schwann cells in the PNS
How do astrocytes improve neuron functionality? (3)
- by separating neurons and synapses
- by regulating extracellular potassium
- by absorbing neurotransmitters from synaptic spaces
What additional role do astrocytes play in neuron repair?
They release growth factors that trigger the development of new neurons and synapses
Where are Schwann cells located, and what is their function?
In the PNS
- they produce myelin to insulate axons and prevent AP decay
How does myelination by Schwann cells enhance neural communication?
By increasing speed and efficiency of AP propagation and clustering Na+ channels at nodes
What is unique about oligodendrocytes compared to Schwann cells? (2)
- Oligodendrocytes are in the CNS (schwann cells are in PNS)
- Oligodendrocytes can myelinate multiple axons (up to 30),
(schwann cells can only myelinate single axons)
What signals oligodendrocytes to increase myelination?
ATP and adenosine release from active neurons
(high activity of these indicate importance + need for myelin )
What is the initial segment in a neuron responsible for?
initiates the mode of communication
What is the role of capillaries in neural function? (2)
- provides oxygen and nutrients to the brain
- removes metabolic waste
What is the function of ventricles in the brain?
hollow regions where fluid flows, ensuring appropriate fluid balance
What is the function of ependymal cells?
Line the ventricles ;
help maintain appropriate fluid balance in the brain
True or False: glial cells convey bioelectricity.
False: they do not, as they do not have neurites
How do microglial cells protect the CNS?
Protect the CNS from oxidative and mild cell-damaging stress
- secrete cytokines to modulate the inflammatory response.
How does myelination affect axon diameter?
Myelinated axons tend to have larger diameters
