21.3A Text A

What is the primary function of the nervous system?

• To produce hormones
• To collect, process, and respond to information
• To transport blood throughout the body
• To filter waste from the body

Which type of neuron carries impulses from sense organs to the central nervous system?

• Motor neurons
• Interneurons
• Sensory neurons
• Supporting neurons

What is the resting potential of a neuron?

• -50 millivolts
• -60 millivolts
• -70 millivolts
• -80 millivolts

Which of the following is NOT a common feature of neurons?

• Cell body
• Multiple dendrites
• Chloroplasts
• Axon

What creates the electrical charge in a neuron at rest?

• Electron flow through the axon
• Membrane proteins pumping ions
• Heat energy from cellular respiration
• Magnetic fields in the cell

What is a threshold stimulus?

• The maximum stimulus a neuron can handle
• The smallest stimulus that can produce an action potential
• The average stimulus needed for neuron function
• The stimulus that damages neurons

How does an action potential travel down an axon?

• Through direct electron flow
• By chemical diffusion only
• As a reversal of charge traveling like ripples
• Through gravity

Which structure increases the speed of nerve impulse transmission?

• Myelin sheath
• Cell membrane
• Dendrites
• Cell body

The central nervous system includes:

• All nerves in the body
• Only peripheral nerves
• The brain and spinal cord
• Just the sensory organs

What protects most of the central nervous system?

• Muscles and tendons
• Skin and fat tissue
• The skull and vertebral column
• Blood vessels