NERVOUS SYSTEM PERIPHERAL N.S. errything else CENTRAL N.S. brain & spinal cord SENSORY DIVISION afferent nerves MOTOR DIVISION efferent nerves SOMATIC N.S. voluntary* AUTONOMIC N.S. Involuntary* SYMPATHETIC “Fight-or-flight” PARASYMPATHETIC “Rest-n-digest”
control of skeletal muscles with conscious effort the end neurons connected to the muscles release the neurotransmitter Acetylcholine, causing myofibrils to contract T HREE T YPES OF M USCLES - Skeletal - Smooth - Cardiac
MUSCLE MYOFIBRIL / MUSCLE FIBER / MUSCLE CELL AXON TERMINAL
SYNAPTIC CLEFT
Acetylcholine (Ach)
Involuntarily reaction to a stimulus sensory neuron sends signal to spinal cord; spinal cord sends message to muscle bypasses the brain Evolutionarily evolved for time-sensitive reactions
controls smooth muscles without conscious effort Regulates functions of our internal organs Heavily related to the Endocrine System blood pressure, heart rate, breathing rates, body temperature, digestion/metabolism, water balance, the production of body fluids (saliva, sweat, and tears), urination, defecation, sexual response, etc.
a cluster of neurons with a common purpose somatic ganglia – bundles of nerves connected to skeletal muscles sympathetic ganglia vs parasympathetic ganglia
the sympathetic and parasympathetic systems innervate the same organs but have opposite effects
Norepinephrine increased heart rate dilated blood vessels dilated airways dilated pupils activates sweat glands slows “less important” processes such as digestion