A & P 1 Exam #4 Ch.14

-it helps in the stability of our internal environment....- it is the system of motor neurons that innervate smooth muscle, cardiac muscle and glands......-it makes adjustments to ensure optimal support for body activities....-it shunts blood to areas that need it, adjusts heart rate, bld pressure, digestive processes....-operate via subconscious control

The involuntary nervous system (reflects subconscious control) or general visceral motor system (indicates the location of most of its effectors)

-they both have motor fibers....-but they differ in their: effector;, efferent pathways and ganglia; and the target organ responses to neurotransmitters

-somatic nervous system innervates/stimulates skeletal muscles.......-ANS innervates cardiac muscle, smooth muscle and glands

Somatic NS: the motor neuron cell bodies are located in the CNS and one axon extends in the spinal or cranial nerve to the skeletal muscle; it is a thick, myelinated group A fiber that conducts nerve impulses rapidly

ANS: uses a 2 neuron chain to reach effectors: preganglionic neuron (1st neuron), cell body resides in the brain or spinal cord, its thin, lightly myelinated axon synapses with 2nd motor neuron......postganglionic neuron: also called ganglionic neuron, is 2nd neuron, its cell body is in an autonomic ganglion outside the CNS, its axon extends to the effector organ

Somatic NS: -all somatic motor neurons release acetylcholine.... - the effect is always excitatory ..... ANS: -release 2 transmitters....-preganglionic fibers release acetylcholine......-postganglionic fibers release norepinephrine or ACh at effectors.....-effect is either stimulatory or inhibitory, depending on type of receptors

-higher brain centers regulate and coordinate both systems...-most spinal and many cranial nerves contain both somatic and autonomic fibers ......-adaptations usually involve both skeletal muscles and visceral organs

Parasympathetic division and sympathetic division

Promotes maintenance functions, conserves energy

Mobilizes body during activity

The parasympathetic and sympathetic divisions serve the same visceral organs but cause opposite effects; while one stimulates muscles to contract or secrete, the other inhibits the action, this causes a counterbalance to maintain homeostasis

-sometimes called the rest and digest system....- keeps body energy use as low as possible, even while carrying out maintenance activities.......-bld pressure, heart rate and respiratory rate are low...-gastrointestinal tract activity is high...-pupils constricted, lenses accommodated for close vision

-sometimes called fight or flight system...-mobilizes body during activity...- exercise, excitement, emergency, embarrassment activates this system......-increase heart rate, dry mouth, cold sweaty skin, dilated pupils.....-during vigorous activity it shunts bld to skeletal muscles and heart, dilates bronchioles for increase air flow and causes liver to release glucose to increase energy

It temporarily reduces nonessential activities like the gastrointestinal tract