Choose one organ of the body that has dual innervation, and explain the action of the sympathetic and parasympathetic nervous systems on that organ.

Cite the main nerve plexuses of the body and mention their territory of innervation. Mention the three layers of the eye and their functions.

Mention the three divisions of the ear and their functions.

Mention the general structures and functions of the taste and smell senses.

How can autonomic nervous system imbalances create problems or failures in our bodies?

Answer:

1)Dual innervation to the eye: the sympathetic and parasympathetic innervation is necessary in order for the muscular effects of the eye, sympathetic nerve ending causes the papillary dilator muscle to respond this is in turn creates dilation and the parasympathetic nerve endings also cause a response by the papillary constrictor muscles which inturn create the pupils constriction.

2)A nerve plexus is a plexus of intersecting nerves, a nerve plexus is composed of a afferent and efferent fibers that arise from the merging of the anterior rami of spinal nerves and blood vessels they are several plexuses in the body they are A) spinal plexuses: a) cerival plexus: serves the head , neck and shoulders, b)Brachial plexus: to the chest, shoulders, arms and hands, c) lumbar polexus: to the back, abdomen, groin, thighs, knes and claves and feet, d) sacral plexus: to the pelvis, buttocks, gent=itals, thighs, calves and feet, e) coccygeal plexus: to the region over the coccyx.Three layers of the eye and their function: sclera it is the tough outer layer white clear infront to form cornea, choroid: it is the vascular layer providers eye with nutrients and oxygen, cilliary body and muscles, retina it is the inner layer contains photoreceptors.

3)The 3 major divisions of the ear and is its function: externa (outer ) ear: hearing only, 2) middle ear(tympanic cavity) hearing only, 3) internal ear: hearing and equilibrium.

4) general structures and functions of the taste and smell senses: taste: the chemoreceptors for tasst are located in specialized microscopic organs called taste buds they are located on the tongue and some in the soft palate , pharyx and esophagus , The olfactory receptors are located in the superior portion of the nasal cavity including the superior nasal conchae and nasal septum and the olfactory receptors called olfacctory epithelial cells of the olfacctory epithelium and they for the senses of smell.

5)The autonomous nervous system dysfunction: it leads to the problems including the regulation of heart rate , blood pressure, body temperature , perspiration and bowel and bladder functions, and other symptoms include fatigue, lightheadedness, feeling faint or passing out , weakness and cognitive impariment etc