Somatic nervous system
SNS, Provides conscious and subconcious control over the SKELETAL muscles of the body.
Autonomic nervous system
ANS, controls VISCERAL function, largely outside of our awareness.
In the SNS, what do motor neurons do?
They exert direct control over skeletal muscles. The lower motor neurons may be controlled by reflexes in the spinal cord or brain, or by upper motor neurons whose cell bodies lie within nuclei of the brain or at the primary motor cortex.
In the ANS, what do the motor neurons do?
Motor neurons of the CNS synapse on visceral motor neurons in autonomic ganglia, and these ganglionic neurons control visceral effectors.
Where are the integrative centers for autonomic activity located?
In the hypothalamus.
What are preganglionic neurons?
Visceral motor neurons whose cell bodies lie in the brain stem and spinal cord.
Ganglionic neurons are...
Visceral motor neurons in peripheral ganglia. The axons of preganglionic neurons leave the CNS and synapse here.
The ganglionic neurons, which contain hundreds to thousands of ganglionic neurons are called this.
Identify the major divisions of the autonomic nervous system.
The major divisions of the autonomic nervous system are the sympathetic division, the parasympathetic division, and the enteric division.
What division of the NS is responsible for the physiological changes you experience when startled by a loud noise?
The sympathetic division of the ANS is responsible for the physiological changes that occur when you are startled by a loud noise.
Compare the anatomy of the sympathetic division with the parasympathetic division.
In the smypathetic division, axons emerge from lumbar and thoracic segments of the spinal cord and innervate ganglia relatively close to the spinal cord, whereas in the parasympathetic division, axons emerge from the brain stem and sacral segments of the spinal cord and innervate ganglia very close to (or within) target organs.
What is sympathetic division?
(also called thorcolumbar division) where axons emerge from the thoracic and superior lumbar segments of the spinal cord and innervate ganglia relatively close to the spinal cord. FIGHT OR FLIGHT.
what is parasympathetic division?
(also called craniosacral division) where axons emerge from the brain stem and the sacral segments of the spinal cord and they innervate ganglia very clost to (or within) target organs. REST AND DIGEST
What are the sympathetic division and the parasympathetic division part of?
Most often, the sympathetic and parasympathetic work together or have opposing effects?
Most often they have opposing effects, however, not always. The two may work independently.
Both primary divisions of the ANS influence the third autonomic division. What is it called?
The enteric nervous system.
What is the enteric nervous system?
An extensive network of neurons and nerve networks located in the walls of the digestive tract.
What happens because the ganglionic neurons are relatively close to the vertebral column?
The axons of the preganglionic neurons (preganglionic fibers) are short, and the axons of the ganglionic neurons (postganglionic fibers) are long.
The parasympathetic division is concerned with?
With the regulation of visceral function and energy conservation. "Rest and digest" system.
The effects of sympathetic simulation result primarily from the interactions of what?
Norepinephrine (NE) and epinephrine (E) with adrenergic receptors in the plasma membrane
What are some effects of sympathetic activation?
*increased alertness via stimulation of the reticular activating system causing the individual to feel "on edge." *A feeling of energy and euphoria *Increased activity in the cardiovascular and respiratory centers of the pons and medulla oblongata (which elevates blood pressure, heart rate, breathing rate, and depth of respiration. *A general elevation in muscle tone through stimulation of the medial and lateral pathways so the person looks tense and may begin to shiver. *The mobilization of energy reserves through the accelerated breakdown of glycogen in muscle and liver cells and the release of lipids by adipose tissues.
What are some effects of the parasympathetic activation?
*Constriction of the pupils and focusing of the lenses of the eyes on nearby objects. *Secretion by digestive glands. *Secretion of hormones that promote the absorption and utilization of nutrients by peripheral cells. *Changes in blood flow and glandular activity associated with sexual arousal. *Increase smooth muscle activity along the digestive tract. *Stimulation and coordination of defecation. *Contraction of the urinary bladder during urination. *Constriction of the respiratory passageways. *reduction in heart rate and in the force of contraction.
What is the parasympathetic system also called and why?
The anabolic system, because its stimulation leads to a general increase in the nutrient content of the blood.
The output of the ANS has an impact on.....
virtually every body system.
Many vital organs receive what, receiving instructions from both the sympathetic and parasympathetic divisions.
Dual innervation. The effects may be opposing or complementary.
What play key roles in the control of visceral function by the autonomic nervous system.
Baroreceptors and chemoreceptors.
What are baroreceptors?
They are stretch receptors that monitor changes in pressure. The receptor consists of free nerve endings that branch within the elastic tissues in the walls of hollow organs, blood vessels, and tubes in the respiratory, digestive, or urinary tract.
What are chemoreceptors?
Specialized neurons that can detect small changes in the concentrations of specific chemicals or compounds.
Where are chemoreceptors located?
-within the medulla oblongata and elsewhere in the brain. -in the carotid bodies, near the origin of the internal carotid arteries on each side of the neck. -in the aortic bodies between the major branches of the aortic arch.
define baroreceptor and chemoreceptor.
chemoreceptors are receptors that detect changes in the concentrations of specific chemicals or compounds.
which type of receptor is sensitive to changes in blood pH?
Chemoreceptors are sensitive to changes in blood pH.
Where are the baroreceptors located within the body?
Baroreceptors are located along the digestive tract (stomach, intestines, and colon), within the walls of the urinary bladder, in the carotid and aortic sinuses and in the lungs.