What is the Nervous System Made of? Flashcards
What is the nervous system?
Collections of cells, glia, synapses, cerebrospinal fluid, and the resulting circuits of precisely arranged/connected cells
Cells
Neurons
Glia
supporting cells of the nervous system, “housekeeping” cells
Synapses
the connections made between neurons
Cerebrospinal fluid
salty water (lots)
How does behavior arise?
from coordination of these cells/neurons, even if they are few in number
Sensory Neurons
receive input
Motor neurons
move the body
Facilitating neurons
the “in between” neurons
The more neurons means…
the more complex circuits and the more complex functions
neurons
the building blocks of the nervous system and the element of processing information, give rise to behavior
What aspects of the nervous system are shared across all species?
peripheral ganglia and closely related species share brain and spinal cord similarities in mammals
Camillo Golgi
-Nobel prize in 1906
-Staining technique to stain
neurons in their entirety –
axons and dendrites
-Gave clear descriptions of
cerebellum, hippocampus,
spinal cord, olfactory bulb
Ramony Cajal
-Nobel prize in 1906
-Dendritic spines
-Axonal growth cone
Parts of a neuron
-input zone
-integration zone
-conduction zone
-output zone
Input Zone
where neurons collect and integrate information, either from the environment or from other cells
Integration Zone
where the decision to produce a neural signal is made
Conduction Zone
where information can be transmitted over great distance
Output Zone
where the neuron transfers information to other cells
Dendrite & Spine
-input zone
-where information is received
-dendrites from one neuron can receive information from many sources (environment and other neurons)
Soma - Cell Body
-Mitochondria: produce energy
-Cell Nucleus: contains genetic instructions
-Ribosomes: translate genetic instructions into proteins
Axon Hillock
-Axon Hillock: location where integration occurs
-Conduction Zone: information is electrically transmitted
Axon
-motor proteins aid in transporting materials carried by the transport vesicle
Axon Terminal
-output zone
Flow of information
presynaptic membrane –> synaptic cleft –> postsynaptic membrane
How many synapses can a neuron receive
-each neuron may receive and make thousands to tens of thousands of synapses
Types of Glial Cells
-astrocytes
-oligodendrocytes
-Schwann cells
-Microglial cells
Astrocytes
-Star-shaped cells that help form the blood
brain barrier by sitting between capillaries
(blood) and neurons
-Support the metabolic and biochemical
needs of neurons
-Directly regulate synaptic signaling
(tripartite synapse)
-React to brain injury (repair and scarring)
Oligodendrocytes
glial cells that form myelin sheath in the
central nervous system (brain and spinal cord)
Schwann Cells
glial cells that myelinate cells in the peripheral
nervous system
Microglial Cells
-inflammatory response
-Steps of a microglial cell
1. resting/surveillance microglia
2. Focal activation/directional process extension
3. Conversion to a phagocyte
4. Phagocytosis
