Chapter 1: Nerve Cells Flashcards
What is a Neuron?
Neurons are highly specialized cells that possess electrical excitability and function to process and transmit cellular signals.
Neurons receive information and transmit it to other cells
What does the shape of a neuron determine?
It’s connection with other neurons and its contribution to the nervous system
What do neurons vary in?
Size, shape and function
What are Purkinje cells?
Cells that carry info primarily about body movement
How are Purkinje cells arranged?
They are aligned like dominos forming a 2-D grid.
What do Purkinje cells do?
Cell output permits comparison of ongoing movement and sensory feedback derived from it.
Thus, generates an error correction signal that can modify movements already begun
What do Glial cells do?
They provide support and protection for neurons by
- Surround
- Hold in place
-Supply nutrients and oxygen
-Insulate
-Form myelin
-destroy and remove decay and debris
-clearance of neurotransmitters
-crucial to development (synaptic plasticity and genesis)
What is the ratio of glial cells to neurons in cerebral gray matter?
3 glial cells to every 2 neurons
Otherwise its a 1:1 ratio
What do astrocytes do?
Astrocytes synchronize the activity of the axon by wrapping around the presynaptic terminal and taking up chemicals released by the axon
By surrounding a connection between neurons, an astrocytes shields it from chemically circulating around.
Also, by taking up ions and transmitters and then releasing them back, an astrocyte helps synchronize, close neurons, enabling them to send messages in waves.
They are important for rhythm — like your breathing
Astrocytes also dilate blood vessels to bring nutrients to the brain.
What do microglia do?
Remove waste material and other microorganisms that may be harmful to the neuron
They act as part of the immune system removing viruses and fungi from the brain
After brain damage they proliferate, removing damaged and dead neurons
They also contribute to learning by removing the weakest synapses
What do oligodendrocytes (cns) and Schwann cells (pns) do?
Build the myelin sheath that surrounds vertebrate axons of the brain and spinal cord
They also supply the axon with nurture to necessary for proper functioning
Radial glia
Guide the migration of neurons and the growth of axons and dendrites during embryonic development
They differentiate into neurons after
What did Camilo Golgi invent?
The procedure of staining Neuronal cells using silver chromate fixed to the neuronal membrane
What did Santiago Ramon y Cajal discover?
Used Golgis cell staining technique to demonstrate that the individual cells comprising the nervous system remained separate but connected to each other by small zones later called synapses
The theory was called the neuron doctrine
When did golgi and cajal receive a nobel prize?
In 1906 for their studies of the structure of the nervous system
Ironically Golgi defended the theory that nerve cells are merged during his speech
What’s different about Neurons versus other cells
Neuronal cells are similar to other cells of the body, but have a distinctive shape
What is a dendrite?
Sensory branching fibers lined with synaptic receptors responsible for bringing in info from other neurons
What is the soma?
The cell body contains the nucleus, mitochondria, ribosomes and other structures found in other cells
Axon
(Motor) Thin fiber of a neuron responsible for transmitting neural impulses away to other neurons, glands, or muscles (myelin sheath, nodes or rancher, terminal buttons)
What are dendrites connected to?
Dendrites are connected to the soma (Cell body)