Autonomous nervous system

A special feature of the iris is its autonomic innervation. Sympathetic activation widens the aperture of the iris whereas impulses from the parasympa thetic nervous system decrease the aperture size. Therefore adrenergic agonists and anticholinergic compounds both increase the aperture of the iris, i.e., cause mydriasis, and antiadrenergic and cholinergic agonists decrease it, i.e., cause miosis. The iris can thus be considered an excellent mirror reflecting the balance of the autonomic nervous system in the body. " ... 

Autonomic nervous system. The portion of the nervous system outside of the brain and spinal cord that is responsible for monitoring and controlling the digestive system, cardiovascular system, and other organs that are not under direct conscious control. 

Parasympathetic nervous system. That portion of the autonomic nervous system that utilizes acetylcholine as the neurotransmitter at the neuro-effector junctions. 

The baroreceptor reflex is a central reflex mechanism, which reduces heart rate following an increase in blood pressure. Each change in blood pressure is sensed by baroreceptors in the carotid arteries, which activate the autonomic nervous system to alter heart rate and thereby readjust blood pressure. 

Local anaesthetics are drugs that reversibly interrupt impulse propagation in peripheral nerves thus leading to autonomic nervous system blockade, analgesia, anaesthesia and motor blockade in a desired area of the organism. 

The locus cemleus is important for the regulation of attentional states and autonomic nervous system activity. It has also been implicated in the autonomic and stress-like effects of opiate withdrawal. A noradrenergic pathway originating from the locus cemleus which descends into the spinal cord is part of the descending inhibitory control system, which has an inhibitory effect on nociceptive transmission in the dorsal horn. 

It is well established that the autonomic nervous system shows marked plasticity. The expression of cotransmitters and receptors shows dramatic changes during development and ageing, in nerves that remain... 

Autoimmune Disease Autonomic Nervous System Autophagy... 

The PNS is further divided into the somatic nervous system and the autonomic nervous system. The somatic branch of the PNS is concerned witii sensation and voluntary movement. The sensory part of the somatic nervous system sends messages to the brain concerning die internal and external environment, such as sensations of heat, pain, cold, and pressure The voluntary part of die somatic nervous system is concerned witii die voluntary movement of skeletal muscles, such as walking, chewing food, or writing a letter. 

The autonomic branch of die PNS is concerned witii functions essential to the survival of the organism. Functional activity of the autonomic nervous system... 

TABLE 22-1 Action of the Autonomic Nervous System on Body Organs and Structures... 

The PNS is a part of the autonomic nervous system (see Chap. 22). It helps conserve body energy and is partly responsible for activities such as slowing the heart rate, digesting food, and eliminating body wastes. 

Smooth muscle cell activity is in general under neural control. Thus, the many transmitters of the autonomic nervous system are paired with receptors on the smooth muscle cell membrane. One of the current questions about smooth muscle function is What intracellular processes are the different transmitters modulating in the smooth muscle cells, in addition to their effects on the contractile state ... 

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