Chapter 11: Nervous System Flashcards
What 3 things does the nervous system do?
- Sensory input: protects environment
- Integration: processes input
- Motor output: respond
What does the CNS consist of?
Brain and spinal cord
Integrative and control centers
What does the PNS consist of?
Cranial nerves and spinal nerves
Communication between CNS and rest of the body
What does the sensory division consist of?
Somatic and visceral sensory nerve fibers
Transmits info to the CNS
What does the motor division consist of?
Motor nerve fibers
Transmits info away from the cns
What does the somatic nervous system consist of?
Somatic motor (voluntary) Conducts impulses from CNS to skeletal muscles
What does the ANS consist of?
Visceral motor (involuntary) Conducts impulses from CNS to cardiac and smooth muscles and glands
What are the 2 principal cell types in the nervous system?
- Neuroglia (glial cells): supporting cells
2. Neurons: excitable cells that transmit information
Why is the nervous system fragile?
There is no connective tissue so it is held together by cells
What are astrocytes?
CNS
The most abundant, versatile, and branched glial cells.
Cling to neurons, synaptic endings, and capillaries.
Support and brace neurons.
Help determine capillary permeability.
Regulate environment of the neurons and presence of neurotransmitters.
Holds the CNS together by wrapping around other structures that are present in the nervous system.
What are microglia?
CNS. Small cells with thorny processes. Migrate toward injured neurons. Phagocytize microorganisms and neuronal debris. Rough equivalent of macrophage.
What are ependymal cells?
CNS.
Line the central cavities of the brain and spinal column.
Separate CNS interstitial fluid from cerebrospinal fluid.
Produce CSF at choroid plexuses.
Sometimes connected by tight junctions; sometimes have cilia.
Play a key role in synthesis of cerebral spinal fluid and reabsorption in the spinal cord.
What are oligodendrocytes?
CNS
Branched cells.
Processes wrap around multiple axons in CNS, forming insulating myelin sheaths.
Multiple sclerosis (demylination in the CNS).
Produce myelin.
This makes communication faster and serve as a means of protection against physical injury and the scaffolding in the repair of axons.
What are satellite cells?
PNS.
Equivalent of astrocytes.
Surround neuron cell bodies in the PNS.
Regulate conditions present in the soma.
What are Schwann cells?
PNS.
Equivalent to oligodendrocytes and do almost everything they do.
Very small cells.
Surround peripheral nerve fibers and form myelin sheaths.
Vital to regeneration of damaged peripheral nerve fibers.