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
Cerebrum
Thalamus
Cerebellum Corpus
Callosum
Hypothalamus
Brain Stem:
Pons,
Midbrain,
Pituitary
Medulla Gland
Oblongata
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