Medical Terminology Simplified

Boldfaceindicates a word root or combining form. Blueindicates a suffix. Pinkindicates a prefix.

422 CHAPTER 9• Endocrine and Nervous Systems

9–88 The medulla contains three vital centers that regulate internal activities of

the body. The cardiac center slows the heart rate when the heart is beating too rap-

idly; the respiratory center controls muscles of respiration in response to chemicals

or other stimuli; and the vasomotor centeraffects (constricts or dilates) the muscles

in the walls of blood vessels, thus influencing blood pressure.

The vital center that influences blood pressure by dilating or constricting blood

vessel walls is the____________________center.

The ____________________center slows heart rate when it is beating too rapidly.

The ____________________center controls respiratory muscles in response to

chemicals or other stimuli.

Competency Verification:Check your labeling of Figure 9–8 in Appendix B: Answer Key, page 592.

Spinal Cord

The spinal cord is a long, narrow cable of nervous tissue within the spinal canal and is part of the CNS. It descends
from the brainstem to the lumbar part of the back and contains about 100 million neurons. Thirty-one pairs of spinal
nerves originate from the spinal cord. (See Fig. 9–9.) Each pair of nerves serves a specific region on the right or left
side of the body. Spinal nerves are mixed nerves that provide a two-way communication between the spinal cord and
parts of the upper and lower limbs, neck, and trunk.

9–89 Spin/al nerves are named according to locations of their respective verte-

brae. As shown in Figure 9–9, there are 8 pairs of cervic/al nerves, identified as

C1–C8; 12 pairs of thorac/ic nerves, identified as T1–T12; 5 pairs of lumb/ar

nerves, identified as L1–L5; 5 pairs of sacr/al nerves, identified as S1–S5; and 1 pair

of coccyg/eal nerves, identified as Co1.

In Figure 9–9, label the (1) cervical nerves,(2) thoracic nerves,(3) lumbar nerves,

(4) sacral nerves,and (5) coccygeal nerve.

9–90 Build medical words that mean pertaining to nerves

of the neck:____________________ / __________ ____________________

in back of the chest:__________ / __________ ____________________

of the sacrum:__________ / __________ ____________________

9–91 The spin/al cord, like the brain, is protected and nourished by the meninges,

which consist of three layers: dura mater,the outermost membrane; arachnoid mem-

brane,the second layer, which surrounds the brain and spin/al cord; and pia mater,the

third layer, which is closest to the brain and spinal cord. Additional protection is pro-

vided by cerebr/o/spin/al fluid circulating in the subarachnoid space. (See Fig. 9–9.)

Identify terms in this frame that mean pertaining to

the spine:__________ / __________

the cerebrum and the spine:

____________________ / _____ / __________

vasomotor

VĀ-sō-mō-tor

cardiac

KĂR-dē-ăk

respiratory

RĔS-pĭ-ră-tor-ē

cervic/al nerves

SĔR-vĭ-kăl

thorac/ic nerves

thō-RĂS-ĭk

sacr/al nerves

SĀ-krăl

spin/al

SPĪ-năl

cerebr/o/spin/al

sĕr-ē-brō-SPĪ-năl