Cells of the Nervous System Flashcards
The communicating system of the body
Nervous System
Sensory Input =
Motor Output =
Afferent information
Efferent information
Nervous system composed of the brain and spinal cord, is the common command system
Nervous system composed of the cranial and spinal nerves. Communication between body and CNS
Central Nervous System (CNS)
Peripheral Nervous System (PNS)
Excitable cells that transmit electrical signal or action potentials
Neurons
In the CNS, supporting cells are called
In the PNS, supporting cells are called (2)
neuroglia
Schwann Cells and Satellite Cells
Do neurons usualy replicate?
No
Is the metablism of neurons high or low?
What do they require a supply of?
Highly metabolic
Require continuous and constant supply of oxygen and glucose
The soma of the neuron, contains the nucleus and nucleolus with usual organielles
Cell body
What organelle is missing in the neuron?
Why?
Mitotic Spindle
Neurons (most) do not divide
Receptive regions of the neuron that bring the message towards the body
Dendrite
The impulse generating and conducting region of the cell, can be short or long
Axon
Point that generates the AP in the neuron
Axon hillock
Groups of axons that travel together are called
Tracts
The axon branches near its end and the ends enlarge slight as, where NTs are released from into synapse
Terminal bouton
The covering of the axon
Myelin Sheath, Neurilemma
What cells is myelin made of?
Schwann Cells
The sheath of Schwann cells is called
Neurilemma
The space between Schwann cells helps to increase transmission
Node of Ranvier
What role does myelin play in cell communication?
Insulation
One Schwann cell can accompany 15 or more axons
!
99% of neurons are bipolar, unipolar, or multipolar?
Multipolar
What is a multipolar cell?
Has many connections
Neuron with two processes, one on each side in the cell body
Bipolar
Neuron with one process which divides like a T
Pseudo-unipolar
Most sensory neurons are bipolar, unipolar, or multipolar?
Where are they located?
Unipolar
Outside the nervous system in ganglia
Motor neurons are bipolar, unipolar, or multipolar?
Where are they located?
Multipolar
In CNS (grey matter)
Do supporting cells conduct an action potential?
No.
What is the ratio of supporting cells to neurons?
10:1
Type of neuroglia (in CNS) that exchange between capillaries and neurons. Most abundant type of neuroglial cell.
Control Chemical movement and ion concentration
ex: Take up neurotransmitters
Astrocyte
Type of neuroglia that is phagocytic, it monitors the health of neurons. Small cells with long processes.
Phagocytic - takes up chemicals that are detremental to cell’s health
Microglial Cells
Type of neuroglial cells that help form and circulate the CSF.. Have a squamous or cuboidal shape
Are ciliated.
Ependymal Cells
Type of neuroglial cells that form the myelin sheath in the CNS.
Fewer branches than astrocytes.
One of them can help form myelin of many cells
Oligodendrocyte
Supporting cell of the PNS that surrounds the cell bodies of neurons in ganglia and are supportive to neurons
Satellite Cells
Supporting cell of the PNS that forms the myelin sheath in the PNS
Schwann Cells
Dorsal Root Ganglion contain what kind of cells?
What surrounds them?
Pseudo-unipolar
Satellite Cells
Factor affecting conduction velocity that states the largre the diameter the faster a current will occur. THere is less resistance
Axon Diameter
Factor affecting conduction velocity that myelinated axons conduct impulses faster than unmyelinated axons
Myelin Sheath
Type of conduction that occurs when axons conduct APs immediately adjacent to one another because they are unmyelinated, this is called
Continuous Conduction
Type of conduction that occurs when action potentials only generated at nodes of Ranvier (of myelin) it is called
Saltatory Conduction
What are nerve fibers classified by?
Diameter and degree of myelination
A somatic sensory and motor nerve fiber.
It has the largest diameter and degree of myelination. Very fast conducting
Group A
A nerve fiber that innervates the viscera and pain fibers from the skin; lightly myelinated
Come from body wall/limbs not viscera
Group B
Nerve fibers that are visceral and play some role in pain and touch.
Have the smallest diameter, are unmyelinated, and are the slowest conducting.
Incapable of saltatory conduction
Group C
The outermost layer of connective tissue that covers entire nerve
Epineurium
Middle layer of connective tissue that covers the bundles, or fascicles, which are bundles of nerve processes
Perineurium
Inner layer of connective tissue of nerves that covers the individual processes of a neuron
Endoneurium
