Chapter 12: Peripheral Nervous System Flashcards
Brain and Spinal Cord
CNS
Nerves and Ganglion
PNS
Collection of neuron cell bodies
Ganglion
PNS Categories
- Motor or Sensory
- General (widespread) or Specialized (local)
- Somatic or Visceral
Structure of the PNS
Sensory receptors, Nerves and ganglia, Motor ending
Exteroceptors
Sensitive to stimuli arising from outside body
Interoceptors
Or visceroreceptors, from internal viscera
Proprioceptors
Monitor degree of stretch in skeletal muscles, tendons, joints and ligaments
Mechanoreceptors
Respond to touch, pressure, vibrations
Baroreceptors
Respond to changes in blood pressure
Thermoreceptors
Respond to temperature change
Chemoreceptors
Respond to molecules tasted or smelled, and changes in the blood chemistry
Photoreceptors
Respond to light
Nociceptors
Respond to harmful stimuli (extreme heat and cold) that result in pain
Free Nerve Endings
- Monitor most type of sensory information (touch, pain, pressure, temperature, proprioception)
- Not surrounded by a capsule of connective tissue. Mostly nociceptors and thermoreceptors
Complete Receptor Cells
- Specialized epithelial cells or small neurons that transfer sensory information to sensory neurons (taste, vision, hearing, and equilibrium)
- Surrounded by a capsule of connective tissue (encapsulated). All mechanoreceptors
Proprioceptors
- Encapsulted nerve endings
- Skeletal muscles, joints, tendons, ligaments
- Degree of stretch, therfore information on body movement:
- to cerebrum
- cerebellum and
- spinal reflex arcs
- Include: - Muscle spindles
- Golgi tendon organs
- Joint kinesthetic receptors
Peripheral motor endings
- Innervation of skeletal muscle
- Innervation of visceral muscles and glands
Motor end plates
Motor axons innervate skeletal muscle fibers at neuromuscular junctions
Innervations of visceral muscles and glands
- Wider synaptic clefts
- Smooth muscle has NT receptor everywhere
- Action slow (NT diffuses)
Cranial Nerves
- 12 pairs of nerves attach to the brain, first to to forebrain, others to brain stem
- All except Vagus n. (which extends to abdomen) innervate head and neck
know the nerves on the brain
slide 17 and 18 of PNS