BIOL 1001 Lecture 23: Nervous System
1 May 2018
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BIOL 1001 – Lecture 23 – The Nervous System
The Nervous System – Integration and Control
• Identify the principle parts of the nervous system
• Describe the cells that make up the nervous system
• Describe the initiation and propagation of an action potential
• Describe a chemical synapse
• Neurotransmitters and SSRIs
• CNS and peripheral nervous system
• Nervous system disorders
Neurons
• Is the basic unit of communication in nearly all nervous systems
• Monitor information in and around the body and issue commands for responsive
actions
• Neurons are excitable cells – undergo a change in charge (voltage) across the plasma
membrane
Three Classes of Neurons
• Sensory neurons – converting external stimuli
o Connect to CNS
o Example: olfactory neurons that connect to olfactory bulb
• Interneurons (relay neurons) – connects afferent neurons (signals to CNS from
receptors) and efferent neurons (send nerve impulses away from CNS to organs, etc.) is
neural pathways
• Motor neurons – project their axons outside the CNS and directly or indirectly control
muscles
o ALS is a motor neuron disease that may involve the enzyme
Two Types of Neurons
• Afferent neurons – carry nerve impulses from receptors or sense organs toward the CNS
o Fro Lati eaig arryig ito
o Olfactory neurons are afferent neurons
• Efferent neurons – or motor – carry nerve impulses away from the CNS to muscles or
glands
o A motor neuron is an efferent neuron
Neuroglia (Glial Cells)
• Make up more than half the volume of the vertebrate nervous system
• Make up 50% of brain tissue
• A variety of cells that metabolically assist, structurally support, and protect the neurons
• Astrocytes, oligodendrocytes and microglia are examples of glial cells
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