Nagelhout chpt 29 Flashcards
first step- organization
this is a bit of review and basics
The central nervous system consists of?
the brain and spinal cord
….. wanted to start this off niiiiiiiice and easy
The peripheral nervous system consists of?
Cranial nerves, spinal nerves and their receptors
somatic and autonomic
Two primary cell types for the CNS?
neurons and glial (neuroglial)
Neurons are classified as (4)
Unipolar, bipolar, psudounipolar, and multipolar
Where are unipolar neurons found?
Only in lower invertebrates
Where are bipolar neurons found?
retina, ear, and olfactory mucosa
Where are psudounipolar neurons found?
dorsal root ganglia and cranial ganglion cells
enables sensory impulses to travel from the dendrite directly o the axon without passion through the cell body
What about Multipolar neurons?
constitute the majority of the CNS neurons.
they have multiple dendritic processes but only ONE axon.
What is the gray matter of the CNS composed of?
neuron cell bodis
What is the white matter of the CNS composed of?
myelinated axons
Neurons are classified into their specific functions. Name them (3)
motor, sensory, and interneurons.
Motor neurons are what type, and do what?
multipolar and innervate and control effector tissues like the muscles and glands
Sensory neurons are what type and do what?
Psuedounipolar and receive exteroceptive, interoceptive, or proprioceptive input
Interneurons are what type and do what?
psuedounipolar and connect adjacent neurons.
Neuron membranes….. what is it made from? and is it hydrophilic or phobic?
bilaminar lipoprotein made from phospholipids
inner hydrophobic membrane and the membrane in contact with the ECF is polar hydrophilic
glial cells…. what are the four types?
astrocytes, oligodendrocytes, microglial and ependymal
how are glial cells different?
smaller, outnumber the neuron cells, and lack both the dendritic and axonal processes
As a whole what is the role of the glial cell?
maintenance of proper ionic environment, modulation of nerve cell electrical conduction, control of reuptake of neurotransmitters, and repair after neuronal injury
Astrocytes- what are they responsible for?
Predominant cell
Provide structural neuronal support, group and pair neurons and nerve terminals, regulate the metabolic environment, and are active in repair after injury.
2 types of astrocytes….
fibrous found in white matter
protoplasmic found in gray matter.
What important barrier is the astrocyte responsible for?
The contact of the cerebral endothelium by astrocytes is believed to be essential to the development of the blood brain barrier.
Oligodendrocytes
form the myelin sheath of axons in brain and spinal cord, and are capable of myelenating more that one axon.
down side to the oligodendrocyte?
cannot regenerate after injury :(
Why is myelin so important?
myelin increases velocity without increases size of an axon. without it we would be just giant axons….
Schwann cells… don’t forget about them….
modified glial cells that myelin ate the PNS. Can only myelin ate ONE axon.
What is a node of Ranvier?
site of electrical impulse propagation
What is Saltatory conduction?
how impulses travel from one node of ranvier to another.
What is Wallerian degeneration?
distal degeneration of axon after peripheral nerve injury
What do schwann cells do in the case of peripheral nerve injury?
Within one week of initial injury, schwann cells proliferate to for a tube (like scaffolding) to direct axon regeneration.
What are microglial cells responsible for?
they proliferate and become large macrophages to phagocytize neuronal debris.
What are ependymal cells responsible for?
line the roof of the 3rd and 4th ventricles of the brain and the central spinal canal. the for the cuboidal epithelium (the choroid plexus) which secretes our CSF.
