The Nervous System Flashcards
Central Nervous System (CNS)
Brain, Spinal Cord
Peripheral Nervous System (PNS)
cranial nerves, spinal nerves, ganglia, sensory receptors, enteric plexuses in small intestines
The Nervous system is divided into:
the Central Nervous System and the Peripheral Nervous System
The Peripheral Nervous System is divided into:
The Motor (Efferent) and Sensory (Afferent) divisions
The Motor (Efferent) division is divided into:
Somatic (voluntary) and Autonomic (involuntary)
the autonomic division is divided into:
the sypmathetic (fight or flight) and parasympathetic (rest & digest)
Sensory (Afferent)
sensory information arrives at spinal cord
Motor (Efferent)
information exists the spinal cord
Somatic (voluntary)
the motor commands go to the skeletal muscles
Sympathetic (fight or flight)
to do with anything that requires a lot of energy
Parasympathetic (rest and digest)
to do with anything when you relaxing. keeps body’s energy as low as possible
Functional Cells
Neurons
Support Cells
Glial Cells (Neuroglia)
Neurons Structure
Dendrites: information comes into neuron through dendrites
Head of neuron: called soma
Tail of neuron: called axon
Nucleus:
Junction between neuron head and tail: axon hillock
End of axon: called axon terminal
Myelin Sheath: electrically insulates the axon of the neuron and increases the speed of the impulse.
Node or Ranvier:
Oligodendrocyte:
Neurons
- electrically excitable
- cannot multiply or divide
- 50% of nervous system cells
Neuroglia
- not electircally excitable
can multiply and divide - 50% of nervous system cells
Process of Myelination
Preserves the integrity and intensity of the signal down the axon [neuron tails] and increases the speed of transmission.
The myelin sheaths electrically insulate the axon of a neuron and increases the speed of the impulse.
Cranial Nerves
- emanate from the brain
- 12 pairs
Spinal Nerves
- motor and sensory functions
- 31 pairs
- dorsal roots: contain sensory neurons
- ventral roots: contain motor neurons
Types of Neurons
Multipolar: most common
Bipolar neuron: in eyes
Pseudo-unipolar or unipolar (sensory neuron): sensory neurons carry info from skin to spinal cord
Glial Structure:
Schwan Cell (PNS): provides covering on axon of neuron called myelin sheath Oligodendrocytes (CNS):
Process of Myelination
Preserves the integrity and intensity of the signal down the axon [neuron tails] and increases the speed of transmission.
The myelin sheaths electrically insulates the axon of the neuron and increases the speed of the impulse
Types of Neurons
- Multipolar - most common located in brain & spinal cord
- Bipolar: located in eye, inner ear, olfactory area
- unipolar: sensory receptors for touch, pressure, pain, & temp
