4.02 Nervous systems

Question 1

two components of the central nervous system (CNS)

Answer 1

brain and spinal cord

Question 2

bundle of neurons that carry messages between the brain and the body and are responsible for reflexes

Answer 2

spinal cord

Question 3

outer section of the spinal cord; carries messages to/from the brain; white because its axons are myelinated

Answer 3

white matter

Question 4

inner section of the spinal cord; responsible for fast, lifesaving reflexes; axons are not myelinated

Answer 4

gray matter

Question 5

neurons that carry messages from the senses to the spinal cord

Answer 5

afferent

Question 6

neurons that carry message from the spinal cord to muscles and glands

Answer 6

efferent

Question 7

neurons that connect afferent neurons to motor neurons and make up most of the spinal cord and brain

Answer 7

interneurons

Question 8

five steps in a reflex arc

Answer 8

1. stimulus activates pain receptors
2. sensory neurons excite interneurons in the gray matter of spinal cord
3. interneurons excite motor neurons in the spinal cord
4. motor neurons exit the spinal cord and excite a muscle
5. movement

Question 9

the brain’s ability to change structure and functions of its cells in response to experience and trauma

Answer 9

neuroplasticity

Question 10

three common examples of neuroplasticity

Answer 10

• recovery from trauma
• routine pruning
• new cells from stem cells

Question 11

ridding the brain of weak connections, usually during sleep

Answer 11

pruning

Question 12

caused by an interruption of the blood supply to brain tissue; can kill neurons, leading to loss of speech, memory or motor control

Answer 12

stroke

Question 13

made up of nerves and neurons that are not contained in the brain or spinal cord

Answer 13

peripheral nervous system (PNS)

Question 14

two divisions of the PNS

Answer 14

somatic and autonomic

Question 15

division of the PNS that consists of nerves that control voluntary muscles

Answer 15

somatic

Question 16

two pathways of the somatic nervous system

Answer 16

sensory and motor pathways

Question 17

division of the PNS that controls involuntary muscles in the heart, stomach and intestines

Answer 17

autonomic

Question 18

two divisions of the autonomic nervous system

Answer 18

sympathetic and parasympathetic

Question 19

division of the autonomic nervous system called the “fight or flight” system because it is active during times of stress

Answer 19

sympathetic

Question 20

division of the autonomic nervous system is sometimes called the “rest and digest” system because it helps return the body to normal functioning after a stressful situation ends

Answer 20

parasympathetic

Question 21

important actions of the sympathetic division of the autonomic nervous system

Answer 21

• dilates pupils
• increases heart rate
• decreases digestive functions
• inhibits bladder
• increases blood flow to skeletal muscles

Question 22

important actions of the parasympathetic division of the autonomic nervous system

Answer 22

• constricts pupils
• decreases heart rate
• increases digestive functions
• contracts bladder
• decreases blood flow to skeletal muscles