Autonomic Nervous System - Class XII

All living organism need to respond to change in their environment. They respond to stimuli after this detection takes place. 

The sympathetic nervous system is called the thoraco-lumbar outflow because its preganglionic neurons originate in the thoracic and lumbar segments of the spinal cord.

The nervous system is divided into two major divisions, central and peripheral nervous system. 

The sympathetic nervous system is responsible for the 'fight or flight' response, which is activated during stress.

In Humans, the autonomic nervous system is composed of the sympathetic nervous system (SNS) and parasympathetic nervous system (PNS). 

• Autonomous system the part of the nervous system responsible for the control of the bodily functions not consciously directed, such as breathing, the heartbeat, and digestive processes.
• Centre of the autonomic nervous system is located in Hypothalamus and Medulla oblongata.
  
• So, the correct answer is 'Both A and B'.

The sympathetic nervous system inhibits digestion, including gallbladder activity. Storing bile is a function associated with the parasympathetic system (rest and digest).

The autonomous nervous system controls the heartbeat rate via the cardioregulatory centre in the medulla oblongata. The emergency conditions activate the sympathetic motor nerve and make the adrenal medulla to release epinephrine and norepinephrine which in turn increase the heartbeat rate. On the other hand, vagus nerve conducts the parasympathetic motor impulses which in turn slow down the heartbeat rate by the effect of acetylcholine; a neurotransmitter released by the parasympathetic nervous system. Glycine and dopamine are neurotransmitters of the central nervous system while the heartbeat rate is controlled by an autonomous nervous system; a division of peripheral nervous system. Thus, the correct answer is option A.

• The sympathetic nervous system (SNS) is part of the autonomic nervous system (ANS), which also includes the parasympathetic nervous system (PNS).
• The sympathetic nervous system releases hormone called adrenaline most often termed as the fight or flight response.
•  Adrenaline, also known as epinephrine, is a hormone, neurotransmitter, and medication. Adrenaline is normally produced by both the adrenal glands and certain neurons. It plays an important role in the fight-or-flight response by increasing blood flow to muscles, the output of the heart, pupil dilation response, and blood sugar level. Hence, the Sympathetic nervous system is stimulated by the hormone Adrenaline. 

• The nervous system is divided into two types CNS and peripheral nervous system.
• The peripheral nervous system is in turn divided into the somatic nervous system and autonomic nervous system.
• The autonomic nervous system regulates the internal and involuntary movement.For example,respiration,cardiovascular,digestive etc.
• The autonomic(visceral) nervous system is again divided into the sympathetic and parasympathetic nervous system.
• The enteric nervous system receives inputs from the parasympathetic and sympathetic parts of the nervous system,
  
• Sympathetic decreases the rate of digestion whereas parasympathetic increases the rate of digestion via the enteric nervous system.
• A nerve leading to the small intestine causes the rate of digestion to increase, this nerve belongs to Peripheral, Peripheral and Enteric.
  

• The autonomic nervous system is a control system that acts largely unconsciously and regulates bodily functions such as the heart rate, digestion, respiratory rate, pupillary response, urination, and sexual arousal. Hence, Internal organs are regulated by the autonomic nervous system.

The parasympathetic nervous system is one of three divisions of the autonomic nervous system. Sometimes called as the rest and digest system, the parasympathetic system conserves energy as it slows the heart rate, increases intestinal and gland activity, and relaxes sphincter muscles in the gastrointestinal tract. 

A motor neuron is a nerve cell whose body is located in the spinal cord and the fiber projects outside the spinal cord. This directly or indirectly controls the effector organs such as the muscles and glands. The motor neurons are differentiated as alpha , beta and gamma motor neurons.  A single motor neuron may innervate many muscle fibers. The somatic nervous system also known as the voluntary nervous system consists of afferent and efferent nerves that innervate the skeletal muscles. 

• The autonomic nervous system is a control system that acts largely unconsciously and regulates bodily functions such as the heart rate, digestion, respiratory rate, pupillary response, urination, and sexual arousal. Hence, Heart rate, Digestion and Urination functions are influenced by the autonomic nervous system. 

The sense of smell and sight of food are governed by olfactory and optic responses which work together to initiate the neural response during the cephalic phase of digestion. Sight, smell and sense of food initiate the neural response in which central nervous system prepares the stomach to receive food. The responses include salivation and secretion of gastric juices. The ingestion of food stimulates the hormonal responses to food which includes endocrine system to ensure releases of various digestive hormones at appropriate time. Thus, tye correct answer is option B.

• The Peripheral Nervous System is divided into two systems: the autonomic nervous system, which regulates involuntary actions such as breathing and digestion, and the somatic nervous system, which governs voluntary action and body reflexes.
•  The autonomic nervous system is a control system that acts largely unconsciously and regulates bodily functions such as the heart rate, digestion, respiratory rate, pupillary response, urination, and sexual arousal. Hence, Autonomic nervous system controls Involuntary activities.

The stomach and intestines receive dual innervation from both the sympathetic and parasympathetic nervous systems to regulate motility and secretion.

The autonomic nervous system regulates the functions of internal organs (viscera) such as the heart, lungs, and digestive tract.

Multicellular organisms coordinate their activities using both the nervous system (fast, electrical) and the endocrine system (slower, chemical).

The parasympathetic nervous system, or PSNS, is a part of the nervous system. The nervous system sends signals to and from different parts of the body via nerves. The PSNS is responsible for all the activities that take place when the body is at rest. During a period of flight and fight, the pupils dilate to allow us to see more clearly and make faster decisions. During rest and digest, the PSNS causes the pupils to constrict.

John Newport Langley is widely recognized for his pioneering work in the late 19th century, where he coined the term autonomic nervous system and defined its sympathetic and parasympathetic divisions.

The autonomic nervous system (ANS) is responsible for regulating involuntary physiological processes, such as heart rate, digestion, and respiratory rate, which are associated with internal organs.

The sympathetic nervous system is anatomically referred to as the thoracico-lumbar outflow because its preganglionic neurons originate from the thoracic and lumbar segments of the spinal cord.

Sympathetic nerves emerge from the central nervous system specifically from the thoracic and lumbar regions of the spinal cord, which is why it is called the thoracico-lumbar system.

Pupillary diameter, which is primarily under the control of the autonomous nervous systems.

Motor neurons of the autonomic nervous system are found in autonomic ganglia. The activity of autonomic ganglionic neurons is modulated by preganglionic neurons located in the central nervous system.

The parasympathetic nervous system decreases respiration and heart rate and increases digestion. Stimulation of the parasympathetic nervous systems results in the construction of pupils. Decrease heart rate and blood pressure. And reverse goes for sympathetic.

The parasympathetic nervous system decreases respiration and heart rate and increases digestion. Stimulation of the parasympathetic nervous systems results in the construction of pupils. Decrease heart rate and blood pressure.

The parasympathetic nervous system differs from the sympathetic nervous system in origin because the parasympathetic nervous system develops both in the brain and spinal cord while the sympathetic nervous system only develops in the spinal cord. The parasympathetic nervous system originates from the sacral region of the spinal cord and cranial nerves of III, VII, IX, and X. So, the development region is called craniosacral.

Motor neurons of the autonomic nervous system are found in autonomic ganglia. The activity of autonomic ganglionic neurons is modulated by preganglionic neurons located in the central nervous system.

The parasympathetic nervous system decreases respiration and heart rate and increases digestion. Stimulation of the parasympathetic nervous systems results in the construction of pupils. Salivation, decrease heart rate and blood pressure.

• The autonomic nervous system is divided into two subdivisions. They are the sympathetic and parasympathetic nervous system.
• The sympathetic nervous system (SNS) controls the body's responses to a perceived threat and is responsible for the "fight or flight" response while The parasympathetic nervous system (PNS) controls homeostasis and the body at rest and is responsible for the body's "rest and digest" function.
  
• Hence Sympathetic and parasympathetic nervous systems are often antagonistic(opposing) in their functions.
• So, the given statement is false.

• The nervous system is divided into two major subdivisions. They are the Central nervous system(brain and spinal cord) and peripheral nervous system.
• The peripheral nervous system is in turn divided into two divisions. They are a somatic and autonomic nervous system.
• The main function of the PNS is to connect the CNS to the limbs and organs, essentially serving as a relay between the brain and spinal cord and the rest of the body.
  
• The autonomous nervous system is completely independent of the central nervous system is a false statement because, within the brain, the autonomic nervous system is regulated by the hypothalamus(part of CNS).
  

The sympathetic nervous system controls the fight response in the body. The parasympathetic nervous system controls the feed and breed activities of the body. The sympathetic nervous system (SNS) acts as an antagonist to the action of the parasympathetic nervous system(PNS) and the PNS acts as an antagonist to the action of SNS.

Myelin sheath is the insulating envelope of myelin, that surrounds the core of a nerve fiber or axon and that facilitates the transmission of nerve impulses, formed from the cell membrane of the Schwann cell in the peripheral nervous system and from oligodendroglia cells. Nonmyelinated nerve fiber lacks the fatty myelin insulating sheath. Such fibers form the gray matter of the nervous system, as distinguished from the white matter of myelinated fibers. 

The pupillary light reflex is a reflex that controls the diameter of the pupil, in response to the intensity of light that falls on the retina of the pupil and the eye. Parasympathetic nerve fibres from the third (oculomotor) cranial nerve innervate the muscle that causes constriction of the pupil, whereas sympathetic nerve fibres control dilation. 

The sympathetic branch of our autonomic nervous system originates in the spinal cord. It goes into action to prepare the body for physical or mental activity. Its general action is to mobilize the body in a fight response. It increases muscle blood flow and tension, dilates pupils, accelerates heart rate and respiration, and increases perspiration and arterial blood pressure. To conserve and concentrate energy, it slows down digestive activity.

Sympathetic and parasympathetic divisions function in opposition to each other. 

The autonomic nervous system (ANS), also known as the visceral nervous system and involuntary nervous system, is a division of the peripheral nervous system, that influences the function of internal organs. The autonomic nervous system is a control system, that acts largely unconsciously and regulates the heart rate, digestion, respiratory rate, pupillary response, urination, and sexual arousal.

If parasympathetic nerve of the rabbit is cut, the most immediate effect would be an increase in heart rate. Also, the regulation of heart rate, contractile state, and conduction of electrical impulses through the heart would be impaired. The reason for the observed effects is that the vagus nerve carries important information to the heart from a part of the central nervous system called the parasympathetic nervous system. The parasympathetic nervous system is often considered the "rest and digest" system. It decreases heart rate, decreases how strongly the heart contracts with each beat, and decreases the rate at which electrical impulses are conducted through the heart.

Parasympathetic autonomic nervous system (PNS) responses are highly specific, as supported by the direct innervation of target organs. The PNS is inhibitory, and promotes energy conservation. The primary defense strategies supported by the PNS involve energy conservation. PNS activation promotes passive coping strategies, such as withdrawal or disengagement, dissociation and the immobility response. Examples of passive coping styles include physical or emotional withdrawal.

The autonomic nervous system is the part of the nervous system, that supplies the internal organs, like blood vessels, stomach, intestine, liver, kidneys, bladder, genitals, lungs, pupils, heart, and sweat, salivary, and digestive glands. 

Urinary storage is a function of the sympathetic nervous system, whereas micturition is a function of the parasympathetic nervous system.

Parasympathetic innervation leads to pupillary constriction. A circular muscle called as the sphincter pupillae accomplishes this task. Sympathetic innervation leads to pupillary dilation. Dilation is controlled by the dilator pupillae, a group of muscles in the peripheral 2/3 of the iris.

Acetylcholine is the main vagal neurotransmitter. The vagus nerve controls the heart rate by electrical impulses to the SA node of the heart in which acetylcholine release slows down the pulse rate and decreases the blood pressure. Thus the correct answer is option A.

Sympathetic nervous system inhibits salivary gland secretion, accelerates the heart rate, decreases intestinal peristalsis and dilate the pupil of the eye. Whereas parasympathetic nervous system stimulates salivary gland secretion, slows heart rate, stimulates intestinal peristalsis and constricts pupil of the eye. The sympathetic and the parasympathetic nervous system are parts of the autonomic nervous system. These systems work in balance with each other and directly or indirectly affect almost every structure in the body. The sympathetic nervous system has an active "pushing" function, the parasympathetic has mainly a relaxing function.

Constriction of the pupil is the function of the parasympathetic system. The parasympathetic nervous system is one of the two divisions of the autonomic nervous system, the other is the sympathetic nervous system. The autonomic nervous system is responsible for regulating the body's unconscious actions. The parasympathetic system is responsible for stimulation of "rest and digest" or "feed and breed" activities that occur when the body is at rest, especially after eating, including sexual arousal, salivation, lacrimation (tears), urination, digestion and defecation. 

The central nervous system (CNS) includes brain and spinal cord. It integrates and stores the sensory information from external and internal sense organs and commands different organs to respond accordingly. 

The central nervous system includes brain and spinal cord. It integrates and stores the sensory information from external and internal sense organs and commands different organs to respond accordingly.

The autonomous nervous system controls the heart beat rate via cardioregulatory centre in the medulla oblongata. The emergency conditions activate the sympathetic motor nerve and make the adrenal medulla release epinephrine and norepinephrine which in turn increase the heart beat rate. Hence, the nerve which increases heart beat is part of autonomic and sympathetic nervous system. The central nervous system includes brain and spinal cord only. The peripheral nervous system includes all cranial and spinal nerves; the 12 pairs of cranial nerves, except Vagus nerve, are part of the peripheral nervous system and are mostly concentrated in head, neck and facial region of the body. Vagus nerve conducts the parasympathetic motor impulses which in turn slow down the heart beat rate by the effect of acetylcholine; a neurotransmitter released by the parasympathetic nervous system. 

The human sympathetic nervous system controls the functions (for example accelerated heartbeat, reduced digestion rate etc) that help prepare the organism for the physical strain which is required to escape from a dangerous situation.

The parasympathetic nervous system decreases respiration and heart rate and increases digestion. Stimulation of the parasympathetic nervous systems results in the construction of pupils. Salivation, decrease heart rate and blood pressure.

The parasympathetic nervous system decreases respiration and heart rate and increases digestion. Stimulation of the parasympathetic nervous systems results in the construction of pupils. Decrease heart rate and blood pressure.

Sympathetic ganglia are the ganglia of the sympathetic nervous system. It's function is to deliver information to the body about stress and when the body is in danger, and are responsible for the fight-or-flight response. There are usually 21-23 pairs of these ganglia are present that is, 3 in the cervical region, 11 in the thoracic region, 4 in the lumbar region and 4-5 in the sacral region.
So, the correct answer is option C.

The autonomic nervous system controls the coordinated and involuntary movements of the body. The peristalsis of the intestine is an involuntary visceral movement which is controlled by the autonomic nervous system. 

The parasympathetic division of autonomic nervous system. The nerve fibres of this system arise from the brain, the cranial nerves and the sacrum of the spinal cord, the sacral nerves