the nervous system your friend. the nervous system regulates our internal functions involved in how...
TRANSCRIPT
The Nervous System
Your Friend
The Nervous System
• Regulates our internal functions• Involved in how we react to the external
environment• Two main parts
– Central Nervous System– Peripheral Nervous System
Neurons
• Nerve cells that run through our entire body and communicate with each other
• Receive messages from parts of the body (muscles, glands, etc)
• 100 Billion in our bodies, mostly in the brain
• Neurons are composed of:– Cell body (soma): directs actions of the cell– Dendrites: extensions that receive
information– Axon: extends from cell body, carries
electrical potential, sends a chemical message to adjacent neurons via terminal buttons
Neurons are for Communicating
Messages are sent from the axon
terminals of one neuron to the dendrites of
another
Synapse
• In order for the message to send from neuron to neuron they must cross the synapse
• The message only goes in one direction
Dendrites > Cell Body > Axon > Axon Terminals > Dendrites…..
Synapse
Neurotransmitters
• Neurons send messages across the synapse through the release of neurotransmitters
• Chemicals stored in sacs in the axon terminals
• Several types, each with a specific structure and can only fit into a specific receptor site
Types of Neurotransmitters• Serotonin – affects mood, sleep, sensory
perception, and other functions, may play a role in psychological disorders like depression
• Acetylcholine – involved in memory, muscle action, sleep, emotions, those w/ Alzheimer’s have lower levels
• Dopamine – affects movement, attention, memory, learning, plays role in addiction
• Norepinephrine – affects learning, memory, emotions, eating, alertness, etc.
• Epinephrine – emotions, memory storage…
Central Nervous System• Made up of:
– Brain (we will talk about this later)– Spinal Cord
• Extends from the brain down the back• Column of nerves, as thick as your thumb• Spinal Reflexes
– When your knee kicks at the doctors office– Blinking when you get something in our eye
QuickTime™ and a decompressor
are needed to see this picture.
Peripheral Nervous System
• Responsible for transmitting messages between the CNS and the rest of the body
• Two Main Systems in the PNS:– Somatic Nervous System– Autonomic Nervous System
Somatic Nervous System
• Transmits messages to the CNS• Activated by touch, pain, changes in
temperature or changes in body positions
• Sends messages to muscles and glands
Autonomic Nervous System
• Regulates the body’s vital functions– Heartbeat, breathing, digestion, etc.
• Two divisions:– Parasympathetic – Sympathetic
Autonomic Nervous SystemParasympathetic
• Restores bodies energy after an action has occurred
• Slows down heartbeat, digestion, breathing
Sympathetic• Fight or flight
response• Activated when the
body is put in a stressful situation