Chapter 3 Flashcards
What are the characteristics of neurons?
- … that they share with other cells?
- … that make them unique?
Neurons have a cell membrane, they are enclosed by a lipid bilayer that regulates the movement or substances in and out, they have a nucleus (genetic material (DNA)), organelles such as mitochondria (energy production), endoplasmic reticulum (protein synthesis), and Golgi apparatus (protein modification).
they are unique because they can generate electrical signals called action potentials in response to stimuli (excitability), they communicate with other neurons through synapses, and they have dendrites and axons for receiving and transmitting electrical signals.
What is the cellular anatomy of neurons?
- what are the various parts? What are they responsible for?
- what classes exist and what are they based on?
Dendrites: receive electrical signals
Soma (cell body): integrate incoming signals
Axon: transmits electrical signals away from the cell body to other neurons or muscles
Axon Hillock:where action potential is initiated
Myelin Sheath: insulating layer that speeds up the signal transmission
Nodes of Ranvier: gaps in the myelin sheath where action potentials are regenerated
Axon Terminals: released neurotransmitters into synapses
There are three classes, multipolar, bipolar, and unipolar and they ate based on how many dendrites extend from the cell body
What are the cellular functions of glia?
- what classes exist and what does each class do?
Glia support and protect neurons. There are 6 classes:
Astrocytes: provide structural support and maintain the BBB
Oligodendrocytes (CNS): produce myelin sheath for axons in the CNS - faster electrical signal transmission
Schwann Cells (PNS): produce myelin sheath for axons in the PNS - faster electrical signal transmission
Microglia: immune cells in the CNS
Ependymal Cells: Line the ventricles of the brain and the central canal of the spinal cord, helps produce CSF
Satellite Cells (PNS):provide support, regulate extracellular environments, and mediate metabolic exchanges between neurons and the environment.
Action potential
A rapid electrical signal that travels along the axon of a neuron, allowing for communication between neurons
Active zone
The area in a neurons axon terminal where synaptic vesicles release neurotransmitters into the synapse
Astrocytes
Glial cells in the CNS that provide structural support, regulate the BBB, and maintain the chemical environment around neurons
Axon
A long projection of a neuron that transmits electrical impulses away from the cell body to other neurons or muscles.
Axon hillock
The region where the axon joins the cell body, often the site where action potentials are initiated
Axon terminal
The endpoint of an axon where neurotransmitters are released into synapses to communicate with other neurons
Bipolar cell
A type of neuron with one dendrite and one axon, commonly found in sensory systems like the retina
Cell body
The part of the neuron that contains the nucleus and organelles, responsible for maintaining the cell and integrating incoming signals
Cell membrane
A lipid bilayer surrounding the neuron that regulates the movement of ions and molecules in and out of the cell
Dendrites
Branch-like extensions of a neuron that receive signals from other neurons
Electron microscopy
A powerful imaging technique that uses electrons to visualize structures at a very high resolution
Endoplasmic reticulum
An organelle involved in protein and lipid synthesis; rough ER is studded with ribosomes for protein synthesis
Ependymal cells
Glial cells that line the ventricles in the brain and produce CSF
Glia
Non-neuronal cells in the nervous system that provide support, protection, and nourishment to neurons
Glial fibrillary acidic protein (GFAP)
A protein found in astrocytes, used as a marker for identifying these glial cells
Golgi apparatus
An organelle that modifies, sorts, and packages proteins for secretion or delivery to other parts of the cell
Golgi stain
A staining technique used to visualize individual neurons by selectively staining a small percentage of cells
Hydrophilic
Having an affinity for water; often describes molecules that dissolve in water
Hydrophobic
Repelled by water; describes molecules that do not dissolve in water (LIPIDS)
Interneuron
A neuron that connects sensory and motor neurons within the CNS, facilitating communication between them
Messenger RNA
A type of RNA that carries genetic information from DNA to ribosomes for protein synthesis
Microglia
Immune cells in the CNS that remove debris and dead cells, acting as the brains macrophages
Microtubules
Cylindrical structures in the cytoskeleton that provide support and aid in intracellular transport
Motor neuron
A neuron that carries signals from the CNS to muscles, initiating movement
Multiple sclerosis
A neurodegenerative disease in which the immune system attacks the myelin sheath, leading to impaired nerve function
Multipolar cell
A type of neuron with multiple dendrites and a single axon, common in the CNS
Nerves
Bundles of axons in the peripheral nervous system that transmit signals between the CNS and the rest of the body
Neurofilaments
Intermediate filaments in the cytoskeleton of neurons that provide structural support
Neurogenesis
The process by which new neurons are formed in the brain
Neuron doctrine
The theory that the nervous system is made up of discrete, individual cells (neurons) that communicate via synapses
Neurons
The basic functional units of the nervous system, responsible for transmitting electrical and chemical signals
Nodes of Ranvier
Gaps in the myelin sheath along an axon where action potentials are regenerated, speeding up signal transmission
Nucleus
The organelle in the cell body that contains the neurons genetic material (DNA)
Oligodendrocytes
Glial cells in the CNS that form the myelin sheath around axons
Plasticity
The ability of the nervous system to adapt and change in response to experience or injury
Reticular theory
An early, disproven theory that the nervous system was a continuous network rather than composed of individual neurons
Ribosomes
Cellular structures that facilitate protein synthesis by translating messenger RNA into proteins
Schwann cells
Glial cells in the peripheral nervous system (PNS) that form the myelin sheath around axons
Sensory neuron
A neuron that carries signals from sensory receptors to the CNS
Soma
Another team for the cell body of a neuron, where the nucleus and most organelles are located
Synapse
The junction between two neurons where communication occurs through neurotransmitter release
Terminal bouton
The small swelling at the end of an axon terminal where neurotransmitters are released into the synapse
(Trans) Membrane potential
The voltage difference across a cell membrane, crucial for the generation of action potentials in neurons
Tripartite synapse
A concept where the synapse includes not only the pre- and post synaptic neurons but also astrocytes, which modulate synaptic activity
Trophic factors
Molecules that support the growth, survival, and differentiation or neurons
Unipolar cell
A neuron with a single process that branches into two parts, common in sensory neurons
Vesicles
Small membrane-bound sacs in the axon terminal that contain neurotransmitters, which are released during synaptic transmission
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