Nervous System
Brain
Spinal Cord
Nerves
Neurons
Neurons
Parts of a Neuron
•
•
•
•
Soma – cell body
Dendrite – receive messages
Axon – send messages out
Myelin – help speed up messages,
made up of Schwann cells
Types of Neurons
• Sensory – incoming signals
• Motor - movement
• Interneurons – in brain and spinal
cord only (processors/relay
terminals)
Neural Connections
• Synapse – space between axon of
neuron A and dendrite of neuron
B
• Neurotransmitter – chemicals
that diffuse across synapse to
change polarity of neuron B’s
dendrite membrane
Central Nervous System
• Brain
• Spinal Cord
Control center, coordinates body
functions
Peripheral Nervous System
Carry messages to and from CNS
Motor and sensory neurons found
here.
No interneurons here!
Brain
Thalamus
Cerebellum
Brain Stem:
Pons,
Midbrain,
Medulla
Oblongata
Cerebrum
Corpus
Callosum
Hypothalamus
Pituitary
Gland
Autonomic Nervous System
• Involuntary
• Two divisions
– Sympathetic – fight-or-flight
responses
– Parasympathetic – body at rest
Somatic Nervous System
• Cranial and spinal nerves
• Reflexes – automatic responses
to stimuli
Senses
• Chemoreceptors – chemicals
• Photoreceptors – light
• Mechanoreceptors – pressure,
vibration
Chemoreceptors
• Taste – taste buds
– Sweet
– Salty
– Bitter
– Sour
• Olfaction - smell
Photoreceptors
• Vision
• Retina
– Cones – color
– Rods – black & white
Mechanoreceptors
• Hearing – vibration in cochlea
• Balance – semicircular canals in
ears
• Touch – pressure, pain, heat, cold