Nervous System Brain Spinal Cord Nerves Neurons

Communication between cells through nerve signals.

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 Nerve cells contain receptor molecules for neurotransmitters

Synapses Neurotransmitter being released into synapse and attaching to receptors on dendrite Based on Harvard Medical School Family Health Guide

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

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