Midterm 1 Content

what is the central nervous system made up of?

brain and spinal cord

• contained w/n skull and vertebral column

• connected to body through PNS

peripheral nervous system (anatomy)

• outside CNS but connected by nerves

  • nerves- bundles of many axons(nerve fibers) that are all throughout the body(trunk, limbs, head, neck, internal organs)

    • cranial nerves- head and neck

    • spinal nerves- thorax, abdomen, upper/lower limbs, pelvis

    • autonomic nerves

ganglia

definition- cell bodies of sensory neurons OUTSIDE CNS

• dorsal root ganglia- ganglia part of dorsal root of spinal nerve

  • made up of cell bodies of sensory neurons associated w/spinal nerves

• autonomic ganglion- where cell body of second neuron in a two-neuron chain of autonomic nerves is located

somatic nervous system

subdivision of PNS

• somatic motor- provides motor info FROM CNS to skeletal muscles for voluntary control of movement and posture

• somatic sensory- provides conscious sensation TO CNS from skin, mucosal surfaces and organs

autonomic nervous system

visceral(internal), involuntary

• reflex control of smooth muscle in cardiac muscle, and secretory glands found in viscera(internal organs)

• sensory innervation of viscera

• parasympathetic and sympathetic divisions

functional overview of nervous system

spinal cord overview

• begins as continuation of brainstem at foramen magnum(gateway b/n brain and spinal cord) and ends around L1-L2 disc

• located in upper 2/3 of vertebral canal(long tunnel formed by all vertebrae stacked on top of each other)

• each spinal segment gives rise to one left and one right spinal nerve

nerves

• cranial nerves- 12 pairs

• spinal nerves- 31 pairs

  • 8 cervical(neck)

  • 12 thoracic(thorax)

  • 5 lumbar (lower limb+ pelvis)

  • 5 sacral (sacrum)

  • 1 coccygeal(coccyx)

  • spinal nerves exit vertebral column through intervertebral foramina(small openings b/n 2 vertebrae where spinal nerves exit spine)

• C1 nerve exits b/n skull and atlas

• C2-C7: exit superiorly above their corresponding vertebrae

• C8: exits below C7 vertebrae

• all other nerves exits inferior to their corresponding vertebrae

spinal nerves diagram