The main role of sympathetic and parasympathetic nerves

The role of the para hand to take the line of acres of the sense nerve is ().

a.Causes the ciliary muscles to contract.

b.Relaxes bronchial smooth muscles.

c.Inhibits saliva secretion.

d.Promotes adrenaline secretion.

e.Promotes glycolysis and increases blood sugar concentration.

The correct answer is fierce: a

The autonomic nervous system functions to regulate the activity of the heart muscle, smooth muscles, and glands (digestive glands, sweat glands, and some endocrine glands). Except for a few organs, general tissues and organs are subject to the dual innervation of sympathetic and parasympathetic. In medieval arguing with organs with dual innervation, the concealment of sympathetic and parasympathetic nerves is often antagonistic.

The unity of antagonism is characteristic of the nervous system's regulation of visceral activity.

The sympathetic nervous system is generally broadly active, often involving the entire system in response. Its main function is to promote the body's ability to adapt to the rapid changes in the environment. In the case of strenuous muscle exercise, asphyxia, blood loss or freezing, the body has an accelerated heart rate, ** and abdominal splanchnic vasoconstriction, blood bank discharge of blood to increase circulating blood volume, red blood cell count increases, bronchiectasis, blood glucose concentration rises, adrenaline secretion increases and other phenomena.

Most of these phenomena are caused by hyperactivity of the sympathetic nervous system.

b) Functions of the parasympathetic nervous system.

The activity of the parasympathetic nervous system is not as extensive as that of the sympathetic nervous system, but rather limited. The activities of the whole system are mainly aimed at protecting the body, recuperating and restoring, promoting digestion, storing energy, and strengthening excretory and reproductive functions.

1. The difference between sympathetic and parasympathetic nerves:

1. The central part is different.

The lower center of the sympathetic nerve is located in the lateral angle of the first thoracic segment to the third lumbar segment of the spinal cord, and the lower center of the parasympathetic nerve is located in the brainstem and sacral part of the spinal cord.

2. The location of the peripheral ganglia is different.

The sympathetic preganglionic fibers emanating from the lateral horns leave the spinal nerve along with the anterior root and spinal nerve out of the intervertebral foramen and reach the sympathetic ganglia.

After a portion of neurons are exchanged within the ganglion, the postganglionic fibers leave the sympathetic trunk and return to the spinal nerve, where they are distributed with the spinal nerve to the blood vessels, sweat glands, and erector pili muscles of the continental limbs and body wall. After most of the preganglionic fibers exchange neurons within the sympathetic trunk, the postganglionic fibers no longer join the spinal nerves and form plexuses around the arteries, which are distributed with the arteries to the organs and glands of the head, neck, and thoracic and abdominal cavities.

The parasympathetic nerve from the center of the preganglionic fibers in the parasympathetic ganglion exchange neurons, postganglionic fibers are distributed to smooth muscle, myocardium and glands, the parasympathetic ganglia are generally near the organ or in the organ wall, the postganglionic fiber is short.

3. The effects of the two on the same organ are different.

When the sympathetic nerve is excited, the abdominal viscera and peripheral blood vessels constrict, and the heartbeat accelerates and strengthens; bronchial smooth muscle dilation; inhibition of gastrointestinal motility and gastric secretion; hypermetabolism; mydriasis, etc.

When parasympathetic is excited, the heartbeat slows and decreases; bronchial smooth muscle contraction; Gastrointestinal motility strengthens and promotes the secretion of digestive juices; miosis, etc. Generally, internal organs have sympathetic and parasympathetic dual branches, and the effects of these two nerves on the same organ are usually antagonistic, but the activities of the two types of nerves in the whole are opposite, unified and coordinated with each other.

2. The connection between sympathetic and parasympathetic nerves:

When the body is in a calm state, the excitation of the parasympathetic nerve is dominant, which is conducive to the digestion and absorption of nutrients and the replenishment of energy, and is conducive to the protection of the body. When exercising vigorously or in an adverse environment, the sympathetic nervous system activity is strengthened, mobilizing the potential of many organs of the body to improve the ability to adapt to rapid changes in the environment, and maintain the relative stability of the internal environment.