1. Peripheral Nervous System
carries information to and from CNS
components
sensory receptors
motor endings
nerves
ganglia
Fig 14.2

2. classification systems
Sensory receptors
classification systems
based on location
exteroceptors
interoceptors
proprioceptors
based on relevant stimulus
Mechanoreceptors detect physical deformation
Photoreceptors detect light
Chemoreceptors detect chemicals (nose and tongue)
Thermoreceptors detect temp
Nociceptors detect pain
based on structure
free nerve endings
encapsulated nerve endings
Interoceptors detect things inside the body (ex. Bladder full, stomach empty, BP, etc.)
Proprioceptor are in the joint. Detect stretch and tension in muscles/tendons
Free nerve endings are specialized nerve processes
Encapsulated nerve endings encapsuled in connective tissue/schwann cells to help modify nerve endings (ex. Not overly stimulated)

3. Sensory receptors types of receptors free nerve endings
abundant
stretch, pain, Temp
Meissner’s corpuscles
Located in dermal papillae
light touch
Pacinian corpuscles
close to hypodermis
deep pressure, vibration
Ruffini’s corpuscles
dermis
prolonged pressure
Meissner’s corpuscles are very common in skin without hair ex. hands, lips, etc.

4. Sensory receptors types of receptors muscle spindles
wrap around intrafusal fibers
of skeletal muscle
detect rate and amount of
stretch on muscle
Golgi tendon organs
muscle/tendon junction
detect tension
joint kinesthetic receptors
sensory endings in joint capsules
similar to integument & Golgi receptors
Fig 14.4

5. Peripheral motor endings
synapse at neuromuscular junctions
1 axon terminal per fiber; > or = 1 fiber per neuron
motor unit = neuron + muscle fibers
Fig 10.10

6. Peripheral motor endings
smooth muscle & glands
innervation less direct than at NMJ
swellings in visceral motor neuron terminals in contact with or close to target
response is slower than in skeletal muscle
** no direct innervation of cardiac muscle
Can have more than 1 vericosities per smooth muscle cell

7. Cranial – details in lab
Nerves
Cranial – details in lab
can be sensory, motor,
or both (mixed)
innervate (targets) head & neck, abdomen (vagus nerve)
Spinal nerves
31 pairs
attach to cord by dorsal
and ventral roots (Fig 14.2)
ventral rami form plexuses
Sensory = eye (light receptor)
Motor = ocular motor nerve
Trigimineal detects pain
Vagus nerve innverates heart, lungs, gut, etc.
Rami = branching of spinal nerves
Plexuses = crossing of nerve fiber (allows for “cross talk”)
Fig 14.6

8. rapid, involuntary motor responses pathway requires at least 2 neurons
Reflex pathways
rapid, involuntary motor responses
somatic or visceral
pathway requires at least 2 neurons
receptor  sensory neuron  (CNS) 
motor neuron  effector/target
Visceral reflexes = swallowing, gagging, etc.
Monosynpatic reflex = no inter-neuron
Polysnaptic reflex = yes inter-neuron -> cross talk
sensory
neuron
Monosynaptic reflex
Polysynaptic reflex
inter-
neuron
motor
neuron