PSYCH 10 Lecture 3: PSYCH10 LEC3
1/22/18 The Nervous System
- Neurons: basic units of the nervous system that operate via electro-chemical signals
- Nervous system
o Central – brain and spinal cord
o Peripheral
▪ Somatic – controls voluntary movements of skeletal muscles
▪ Autonomic – controls self-regulated action of internal organs and glands
• Sympathetic – arousing
• Parasympathetic – calming
- Types of neurons and their function
o Sensory neurons: body to brain
▪ Carry info from sensory receptors to the CNS
o Motor neurons: brain to body
▪ Carry info from CNS to muscles and glands
▪ Direct muscles to contract or relax (produce movement)
o Interneurons
▪ Communicate within CNS; intervene between sensory inputs and motor outputs
▪ Reflexes – neurons are converting sensation to action
- Parts of a neuron
o Dendrite – detect incoming signals from other neurons
o Cell body/soma – collects/sums input; contains nucleus and cellular material
o Axon – transmits signal to axon terminals and ultimately to other neurons
o Myelin sheath – covers the axon of some neurons and helps speed up neural impulses
o Terminal buttons – small nodules at the end of the axon that release chemical signals from the
neuron into the synapses
o Synapse – the spae etee the ao of a sedig euro ad the dedrite of a reeiig
neuron
▪ This is where/how neurons communicate
Josh us a quarterback on a football team. He throws the ball into the air and the wide receiver catches I and
scores a touchdown. In a neuron, which physical part plays a role similar ot that od the wide receiver in
football?
- Myelin
- Axon
- Synapse
- Dendrite
- Neuronal communication
o Neuron receives signals from other neurons
o The threshold is reahed he eitator fire! sigals outeigh the ihiitor do’t fire!
signals by a certain amount
o Once reached, action potential starts moving down the axon
o all or oe
- Restig erae potetial: a euro’s at rest eletrial harge
o Polarized – cell is more negative inside than outside
▪ More sodium ions OUTSIDE and more potassium ions INSIDE
o -70 mV
o Sodium-potassium pump
- Action potential is caused by changes in the electrical and chemical gradients across the cell membrane
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