What is the nervous system?

• 23.1 Why do we need a nervous system?
• 23.2 Neurons are the building blocks of all nervous systems.
• 23.3 The vertebrate nervous system consists of the peripheral and central nervous systems.

How do neurons work?

• 23.4 Dendrites receive external stimuli.
• 23.5 The action potential propagates a signal down the axon.
• 23.6 At the synapse, neurons interact with other cells.
• 23.7 There are many types of neurotransmitters.

Our senses detect and transmit stimuli.

• 23.8 Sensory receptors are our windows to the world around us.
• 23.9 Taste: an action potential serves up a taste sensation to the brain.
• 23.10 Smell: receptors in the nose detect airborne chemicals.
• 23.11 Vision: seeing is the perception of light by the brain.
• 23.12 Hearing: sound waves are collected by the ears and stimulate auditory neurons.
• 23.13 Touch: the brain perceives pressure, temperature, and pain.
• 23.14 Other senses help animals negotiate the world.

The muscular and skeletal systems enable movement.

• 23.15 Muscles generate force through contraction.
• 23.16 Skeletal systems enable movement, among several other important functions.

The brain is organized into distinct structures dedicated to specific functions.

• 23.17 The brain is organized into several distinct regions.
• 23.18 Specific brain areas are involved in the processes of learning, language, and memory.
• 23.19 This is how we do it: Can intense cognitive training induce brain growth?

Drugs can hijack pleasure pathways.

• 23.20 Our nervous system can be tricked by chemicals.
• 23.21 A brain slows down when it needs sleep. Caffeine wakes it up.
• 23.22 Alcohol interferes with many different neurotransmitters.