Chapter 2: Anatomy of Nervous System Flashcards
The two classes of cells that make up nervous system
Neurons and Glia
Neurons
Cells specialized for the reception, integration and transmission of information
What form does information take in neurons?
Electrochemical signals
Glia
Cells that function in support, waste removal, formation of myelin sheath, promotion of neuron growth and guidance
Plasma Membrane
- Lipid bilayer (2 layers of fat)
- Semi-permeable (only some compounds get through)
- Protein channels
Soma
Cell Body
Dendrite Function
Receive information
Axon function
Send information
Dendritic spines
-Points of contacts with other neurons
How do dendritic spines change?
They can grow and retract
Neuron types
Motor and sensory neurons
Motor neuron
Connects to muscle or organ
Sensory neuron
Brings senory information to brain
How many dendrites does a motor neuron have? Less or many?
Many
How many axons does a motor neuron have?
- Only one
- Axon hillock
- Myelin sheath
- Terminal bouton
Are there distinct axons or dendrites in sensory neurons?
There are no true axons or dendrites
Describe each end of sensory neuron
Each end is a combination; myelinated, fast conduction
Where is cell body in sensory neuron?
It is located off to the side
Afferent means __ and which neurons are this
- approach/arrive
- sensory neurons
Efferent means __ and which neurons are this
- Exit
- Motor Neurons
Astrocytes
Remove waste (chemicals and dead neurons)
Microglia
Release nitric oxide (NO) to kill damaged neurons
Radial glia
Used to guide newborn neurons
What do glia produce?
Myelin sheath
Schwann Cell’s location and how many axons they myelinate
- Peripheral Nervous System
- Only one cell
Oligodendrocytes Cell’s location and how many axons they myelinate
- Central Nervous System
- Can cover many axons
Two divisions of nervous system
Peripheral and Central
Dorsal
Top
Ventral
Bottom
Medial
Middle
Lateral
Side
Anterior
Front
Posterior
Back
Saggital cut
Splits left and right hemisphere
Horizontal cut
Splits into dorsal and ventral
Coronal cut
Splits anterior and posterior
Nuclei
Groups of cells that serve a particular function
How do different nuclei communicate?
They form circuits and networks to accomplish functions
Divisions in Central Nervous System
Brain and spinal cord
Divisions in Peripheral Nervous system
Somatic and autonomic
Divisions in somatic
Afferent (sensory) and efferent (motor)
Divisions in autonomic
Sympathetic and Parasympathetic
How many spinal nerves are there and what are they composed of?
- 31 pairs
- each nerve contains sensory and motor axons
How many pairs of cranial nerves are there?
12 pairs
Motor neurons exit from ___ side of spinal cord
ventral
Sensory neurons enter from ___ side of spinal cord
Dorsal
Function of Peripheral Nervous system
Allow communication with external and internal world
External world
Somatic Nervous System
Internal World
Autonomic Nervous system
Nerves
Bundles of axons
Efferent nerves in somatic nervous system control
____
voluntary skeletal muscles
Afferent nerves in somatic nervous system ____________
relay sensory information from the skin