Nervous system organization Flashcards
What are the main roles of the nervous system?
Gathers, interprets, and transmits info between tissues
Main role of CNS + structures
- brain receives/processes sensory info, coordinates response, store memories, thoughts and emotions
- spinal cord: conduct signal to and from brain + reflexes
What is CSF and where is it found
- brain and spinal cord
- cushioning/shock absorber, nutrient transport
- blood barrier since blood doesn’t touch brain
Types of matter in brain/spinal cord
- White: myelinated parts of neurons - axons
- Grey: unmyelinated and places where connections form - dendrites, axon terminals, synapses
- More grey matter = more connections = smarter… so more wrinkles in brain = smarter
Main role of PNS + structures
- sensory receptors: take in stimuli (towards CNS)
- motor output: respond to signals caused by stimuli (away from CNS)
Somatic NS
branch of PNS -> motor neurons
- voluntary mvmt
Autonomic NS
branch of PNS -> motor neurons
autonomic: involuntary
sympathetic NS
branches of PNS -> motor neurons -> autonomic
- fight or flight
parasympathetic NS
branches of PNS -> motor neurons -> autonomic
- rest or digest
Notes about nerve SIGNALS
binary and one-way
What are nerves composed of and what do they generally do?
NEURONS carry electrical impulses called action potentials in ONE DIR.
What are glial cells?
Glial cells are non-neurotic cells that provide support… ex:
- Schwann cells: produce myelin
- Astrocytes: supports nerve network, nutrient supply
Dendrites
- The receiving end of a neuron
- Info can come from MULTIPLE neurons, or sensory cells
Cell Body
contains most organelles and mitochondria (ATP needed for Na/K pump, in synapses to package neurotransmitters into vesicles and reuptake of NRTMs)
Axon
Long trunk of neuron where action potential takes place. The connection btw cell body and axon is the AXON HILLOCK
Action potentials
Quick flips of Na+ and K+ in and out the axon through “organized diffusion”
Myelin
A set of fatty acids secreted by Schwann ells to insulate axons electrical signal
–> similar to rubber outside of electrical wires
Nodes of Ranvier
Gaps of exposed axon not covered by myelin
Axon terminals
End of neuron where axon branches off into other nerves, glands, or muscles
synaptic cleft
Space between neuron or sensory cell and a neuron. Pre-synaptic cell and Post synaptic cell surround synapse.
What are reflex arcs
- simple neural circuits controlled by spirnal cord (NOT BRAIN)
Reflex arc pathway
(draw and label)
sensory neuron -> interneuron -> motor neuron
- Sensory cell is affected by stimulus
- release neurotransmitters to sensory neuron in PNS
- Action potential in sensory neuron
- NRTM go to interneuron in CNS
- CNS interprets impulse
- NRTM to to motor neuron in PNS
- motor neuron affect muscles and causes contraction
draw and label a neuron diagram
draw and label tree diagram of nervous systems
