Chapter 25

______ relay messages from the brain spinal cord to muscles. a. Neuroglia b. Motor neurons c. Interneurons d. Sensory neurons

An action potential occurs when ______. a. membrane potential increases to threshold level b. gated sodium channels close c. neurotransmitter is reabsorbed d. gated potassium channels open

Neurotransmitter is released by _____ at a chemical synapse. a. axon endings b. dendrites c. the cell body d. Schwann cells

A myelin sheath _____. a. prevents toxins from entering cerebrospinal fluid b. encloses all axons c. speeds transmission of signals along an axon d. gives gray matter its color

When you are startled, output from the _____ system increases. a. sympathetic b. parasympathetic

Skeletal muscles are controlled by the _____ system. a. sympathetic b. parasympathetic c. somatic

Match each animal with a description of its nervous system: Sea anemone grasshopper human a. paired ventral nerve cords b. nerve net c. brain, spinal cord, peripheral nerves

Signals that cause voluntary movement of your right arm originate in your ______ . a. right cerebral cortex b. left cerebral cortex c. cerebellum d. hippocampus

The spinal cord ______. a. contains neuron cell bodies, but no myelinated axons b. evolved from the notochord of early chordates c. extends through the vertebral column d. secretes cerebrospinal fluid

_______ both involve chemoreceptors. a. Hearing and smell b. Taste and touch c. Touch and smell d. Smell and taste

________ is a reduced response to an ongoing stimulus. a. Propagation b. Perception c. Sensory adaptation d. Synaptic integration

Porpoises use _____ to navigate and to locate prey. a. echolocation b. statocysts c. infrasound d. thermoreceptors

In a vertebrate eye, photoreceptors are in the _____. a. conjunctiva b. cornea c. lens d. retina

The compound eye of a fly has many _____. a. pheromone receptors b. chemoreceptors c. hair cells d. lenses

Match each structure with its function. rod cell cochlea cerebellum brain stem cerebral cortex taste bud limbic system neurotransmitter blood-brain barrier vomeronasal organ a. detects pheromones b. connects to spinal cord c. sorts out pressure waves d. protects brain and spinal cord from toxins e. governs emotions f. contains chemoreceptors g. secreted at synapse h. governs higher thought i. coordinates voluntary moves j. detects light