Download Brain Cell or Neuron

Brain Cell or Neuron
Cell Body: contains the nucleus, mitochondria and other organelles
Dendrites: receive information from another cell and send the
message to the cell body.
Axon: sends messages away from the cell body.
Terminals: place where two cells meet to allow messages to pass
from one cell to another.
How message is passed from
cell to cell.
Central Nervous System
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contains the brain and spinal cord
Brain
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responsible for all functions in the body
o heart beating to writing your name
so powerful that it controls many things in our body without us even being aware
of it.
we would not be able to survive if we had to consciously think about everything
the brain does.
Spinal Cord
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like a superhighway for the sending and receiving of messages to and from the
brain.
thousands of roads branch off this highway to every muscle, organ and receptor in
our body.
Peripheral Nervous System
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contains only nerves and connects the brain and spinal cord (CNS) to the rest of
the body.
axons and dendrites are surrounded by a white myelin sheath.
brain nerves in the PNS take impulses to and from the brain (CNS).
spinal nerves take impulses to and away from the spinal cord.
We are not aware of most sensory input carried in the PNS.
There are two major subdivisions of the PNS: the somatic and the autonomic
Somatic Nervous System
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includes all nerves controlling the muscular system and external sensory
receptors (i.e. skin, nose, eyes etc.)
the reflex arc is an automatic, involuntary reaction to a stimulus.
o When the doctor taps your knee with the rubber hammer, she/he is testing
your reflex (or knee-jerk). The reaction to the hammer is involuntary, with
the CNS being told but not consciously controlling the leg kick.
o Examples of reflex arcs include balance, the blinking reflex, and the
stretch reflex.
Motor neurons of the somatic system are distinct from those of the autonomic system.
Stop signals, cannot be sent through the motor neurons of the somatic system.
Autonomic Nervous System
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part of PNS consisting of motor neurons that control internal organs.
controls muscles in the heart, the smooth muscle in internal organs such as the
intestine, bladder, and uterus.
two subsystems.
o Sympathetic Nervous System involved in the fight or flight response.
o Parasympathetic Nervous System involved in relaxation. Each of these
subsystems operates in the reverse of the other (antagonism). For example:
when you are scared the sympathetic system causes your heart to beat
faster; the parasympathetic system reverses this effect.
From a top view, notice how the brain is divided into two halves, called hemispheres.
Each hemisphere communicates with the other through the corpus callosum, a bundle of
nerve fibers. (Another smaller fiber bundle that connects the two hemispheres is called
the anterior commissure).
Central Nervous Systems
Perifial Nervous System
Autonomic Nervous system