· Receptors:
o Mechano- respond to touch, pressure, vibration, stretch, and itch
o Thermo- sensitive to changes in temp
o Photo- respond to light energy (retina)
o Chemo- respond to chemicals (smell, taste, changes in blood chemistry)
o Noci- sensitive to pain-causing stimuli
o Extero-
-respond to stimuli arising outside the body
-receptors in the skin for touch, pressure, pain, and temp
-most special sense organs
o Intero-
-respond to stimuli arising inside the body
-(visceroreceptors)
o Proprio-
-stretch receptors in muscles, tendons, ligaments, joints, and connective tissues
o Kinesthetic
· Nerve structure:
o Epineurium, perineurium, endoneurium: connective tissue coverings
-endoneurium: around an axon
-perineurium: around a group of axons (fascicle)
-epineurium: around groups of fascicles and blood vessels
· Spinal Nerves
o Ventral- motor //efferent; fibers innervate skeletal muscles
o Dorsal- sensory //afferent; impulses from peripheral receptors
-8 cervical (C1-C8), 12 thoracic (T1-T12), 5 lumbar (L1-L5), 5 sacral (S1-S5), 1 Coccygeal (C0)
· Reflexes:
o Intrinsic
-rapid, involuntary, predictable motor response to a stimulus
o Acquired
-result from practice or repetition
-ex) driving skills
· Components of a reflex arc:
o Receptor, sensory neuron, integration center, motor neuron, effector
1. Receptor: site of stimulus action
2. Sensory neuron: transmits afferent impulses to the CNS
3. Integration center: either monosynaptic or polysynaptic region within the CNS
4. Motor neuron: conducts efferent impulses from the integration center to an effector organ
5. Effector: muscle fiber or gland cell that responds to the efferent impulses by contracting or secreting