Ch. 15.1 Comparison of the Somatic and Autonomic Nervous System Flashcards
What does the autonomic nervous system innervate?
Cardiac
Smooth muscle
Glands
How many lower motor neurons extend from the CNS for the somatic motor nervous system?
One: they always releases ACh.
How many lower motor neurons extend from the CNS fo the autonomic motor nervous system?
Two:
First neuron- is preganglionic neuron which is in the brainstem and spinal cord thus is a cranial or spinal nerve. Myelinated axons small in diameter. Always result in the release of ACh to excite the second neuron.
Second neuron- ganglionic neuron- cell body exhaust within the ganglion itself and a postganglionic. Axon extends outside it. Unmyelinated and axon diameter is smaller than preganglionic diameter. Release ACh or norepinephrine.
These together can cause excitation or inhibition.
What is the advantage of the ANS two-neuron motor pathway?
Allows for increasing communication and control.
Neuronal convergence
Axons from lots of preganglionic neurons converge and influence one postganglionc neuron.
Neuronal divergence
Axons from one preganglionic cell influence multiple ganglionic neurons.
What regions regular the ANS?
Hypothalamus, brain stem, and spinal cord.
These regions may be influenced by the cerebrum, thalamus, and limbic system.
How does the Hypothalamus function in the ANS?
It is the command center.- Controls emotion and physiologic processes.
What is the role of the brainstem?
Regulating of visceral reflexes.- Blood pressure, vessel diameter, digestive activities, heart rate, pupil size, and sense shape for close up focusing.
