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Kirsten Berg p.5 Nervous system - Coggle Diagram
Kirsten Berg p.5 Nervous system
Major functions of the nervous system
sensory functions
detect internal and external changes
travels from receptors sensory neurons
sensory receptors
transports into the CNS
motor functions
nerve impulses conducted along motor neurons to effectors
effectors = muscle and glands respond from CNS decisions
Integrative function
processing information is basis for decision making
coordination of sensory into the CNS
thinking. movement, interal process of physiology
Major divisions and subdivisions of the nervous system
Subdivisions
peripheral nervous system
sensory fibers connect for PNS to sensory receptors to CNS
Autonomic fiber connects to viscera
somatic fibers connects to skin and skeletal muscles
Central nervous syetem
spinal cord
Brain
Tissues
Neuroglia
cell that support neurons
fills space, structurally supports, protect and insulate neurons
doesnt generate or conduct nerve impluses
CNS
Oligodendroctyes
forms myelin sheath around axon in brain and spinal cord
Microglia
Small cells
Functions as phagoctyes for bacterial cells, cellular debris and produce scar tissue for injury
Classification of neurons
Bipolar neuron
2 process extending from the cell body
dendrite and 1 axon
found in special senses ( eyes, nose & ears)
Unipolar neurons
splits into two part functions
1 axon
one process extending from call body: outside cell body
Multipolar neuron
Most neurons in cell bodies are multipolar
Many dendrites and 1 axon arising from the body
Sensory neurons
usually unipolar
some bipolar
Impulses from the peripheral recptors to CNS
Afferent
Interneurons neurons
Cell bodies of some internerons aggregate in nuclie
Multipolar laying with CNS
Forms links between other neurons
Motor neurons
Multipolar neurons
conducts impulses from CNS to peripheral neurons
Connective Tissue Coverings
Epineurium
outer covering of nerves
Perineurium
covering around fascicles of nerve fibers
bundles
Endoneurium
covering around individuals nerve fibers
axons
Major parts and functions of the brain
4 main parts
cerebrum
largest portion
higher mental function and sensory and motor functions
diencephalon
controls homeostatic
process sensory input
Brainstem
coordinates and regulates visceral actions
Connects to the NS
cerebellum
coordinates muscle activity
largest and most complex portion of the NS
4 lobes
Parietal
speech
Occipital
visual and sensory information
Frontal
common sense
Tempral
hearing
Major parts and functions of the spinal cord
gray matter
butterfly shaped core
houses inter-neurons and neuron cell bodies
white matter
bundles of myelinated nerve fibers
posterior and anterior horns
upper and lower wings of gray matter
lateral horn between
31 segments each connected to the spinal nerve
Cauda equina ( horse tail)
spinal cord tapers to a point inferiority
spinal nerve in lumber and sacral areas
at the base of the brain
dorsal root ganglia
cell bodies of sensory neurons that enter spinal cord
outside the spinal cord
Central canal
middle of the gray matter contains cerebrosinal fluid
lumbar enlargement
thicken at the bottom region
rises to nerves for the lower limbs
Functions
ascending tracks
transmits to and from the brain
tranmits impulses to and from brain
descending tracts
carry motor info from the brain to muscles and glands
house spinal reflexes
Spinal reflexes
controlled by reflex arc
passes through the spinal cord
Cervical enlargement
had nerves to upper limbs
thicken area at the top of spinal cord
Action potential & the Nerve Impulse
Action potenical either happends or doesnt
occurs when charges reaches -55mv
neurons are all the same strength
reaches cells and responds by going back to repolarization
impulse conduction
continuous conduction
conducts impulses over the entire length of there membranes
occurs in unmyelinated axons
Saltatory conduction
myelin sheath insulates axons rom ion movment across the call membrane
impulses from node of ranvier to the next because sodium and potassium channels only occur at the nodes
occurs in myelinated axons
Cranial nerves
2nd pair from the thalamus
twelve pairs of underside of brain
in order from superior to inferior
sensory and motor fiber
some are sensory all the way
others primarily motor
1st pair arise from cerebrum
Spinal nerves
1st pair are mixed nerves
Numbered sequence
lumbar nerve
5 pairs
sacral nerve
5 pairs
cervical nerves
8 pairs
coccygeal nerve
thoracic nerves
12 pairs
31 pairs
Two roots
ventral root
Motor
dorsal root
sensory
houses the cell bodies sensory neurons entering spinal cord
Neurotransmitters
stores and relases from synaptic cleft
action depend on the type of receptors in synapse
communication accoplished by chemical reaction
more than 100 neurotransmitters
some nerouns can produce 1 to 2 types of transmitter some produce more than 2
Amino acids, neuroptides and acetycholine
relases in response to a nerve impulse
diffuse across the cleft and bind to receptors on the membrane of the postsynaptic neurons
Compare & contrast the autonomic nervous system
Sympathetic divison
axons leave spinal nerves, proceeds into sypathici ganalia
short preganglionic fibers arises from neurons in gray matter in thoracic and lumbar regions
axons exit spinal cord from the ventral roots
synapse with posthanglionic neurons , long axons returns to spinal nerves and propceeds to viceral effectors
fight or flight
Parasympathetic divison
long preganglionis fibers arise from brainstem and sacral region
extends outward in cranial or sacral nerves
synapse in terminal ganglia on or close to visceral effectors organ
rest and digest
Reflex arc
central nervous system
Recpetors
Motor/ efferent neurons
sensory or afferent neurons
Effectors = mucsle and glands