Automatic Nervous System - Essay Example

This is called orthostatic hypotension. Blood pools in the lower extremities and lesser blood reaches the brain (Marieb, 2006). Consequently, increased environmental temperature causes vasodilatation in the skin that further shunts more blood away from the brain. The manifestations of the decreased blood supply in the brain that include dizziness and fainting pose risk of injury to this vulnerable population. Thus, safety considerations should be taken by making sure that the environmental temperature is not too warm, and instructing the elderly to waggle the feet first before arising and avoiding sudden changes in position as much as possible.

On the other hand, when the sympathetic vasoconstriction is exaggerated, the blood pressure remains high that results into hypertension. Normally, the autonomic nervous system maintains the balance of sympathetic and parasympathetic activity (Marieb, 2006). When the balancing mechanism is impaired for a long time due to electrolyte imbalance, underlying acute and chronic condition, and overall cardiovascular pathology, the walls of arteries and veins become thickened to withstand the increased pressure.

Thus, baroreceptors are reset to maintain higher blood pressure causing hypertension (McCance & Huether, 2004). This can be controlled while taking anti- hypertensive maintenance medications. Explicitly, the age- related changes in the autonomic nervous system ultimately affects other body systems. 2. A patient suffers nerve damage to the sciatic nerve, requiring surgery to suture the nerve together. After surgery, the patient reports that sensation from the lateral and medial sides of the knee seem to be reversed.

How could this happen? Surgery of the sciatic nerve is almost a “blind” procedure because there is no actual guide that one end of a nerve fiber connects to its exact other end. Nerve fibers do not necessarily follow a straight single path (McCance & Huether, 2004). Their naturally complex branches are difficult to follow to regain the original connections. Thus, there is a high tendency that new synapses are built along the process and that the brain cannot adhere to the new pattern. Thus, sensations from either side of the knee, as in this case, can be reversed.

However, there are certain nerves which are difficult to repair when damaged. For instance, when the ventral root of the gray matter of the spinal cord is injured, the innervated muscles cannot move, a condition called flaccid paralysis. Motor impulses cannot reach their target muscle groups to cause movement. As the muscles become unused for a long period of time, they decrease in mass and eventually atrophy (Marieb, 2006). References Marieb, E.N. (2006). Essentials of human anatomy and physiology (8th ed).

Singapore: Pearson Education, Inc. McCance, K.L. & Huether, S.E. (2004). Understanding pathophysiology (3rd ed). St. Louis: