The Autonomic Anatomy & Physiology II - Ch. 14

Parasympathetic preganglionic fibers are long and extend from the central nervous system to the ganglia, while postganglionic fibers are short and connect the ganglia to the target organs. This arrangement allows for a more localized and specific control of bodily functions by the parasympathetic nervous system.

During sympathetic activation, the body's "fight or flight" response is triggered, leading to various physiological changes. These changes include an elevated heart rate, elevated blood pressure, sweating, and elevated blood glucose levels. These responses are necessary to prepare the body for potential danger or stress, allowing it to respond quickly and effectively. Therefore, all of the given options are correct as they are all associated with sympathetic activation.

The sympathetic and parasympathetic fibers that innervate the heart pass through the cardiac plexus. The cardiac plexus is a network of nerves located at the base of the heart, where the sympathetic and parasympathetic fibers come together. These fibers play a crucial role in regulating heart rate and cardiac function.

Beta-blockers are a class of drugs that work by blocking the effects of adrenaline on the heart. This helps to reduce excessive heart rate and can be useful in conditions such as tachycardia or high blood pressure. However, beta-blockers are not typically used to treat constipation, diarrhea, excessive salivation, or prostate disorders.

The correct answer is parasympathetic. The parasympathetic division of the autonomic nervous system is often referred to as the "rest and digest" division because it is responsible for promoting relaxation, conserving energy, and facilitating digestion. It counteracts the effects of the sympathetic division, which is responsible for the body's fight or flight response.

Ganglionic neurons innervate various structures, including smooth muscle, cardiac muscle, adipose tissue, and glands. These neurons are responsible for transmitting signals from the central nervous system to these target tissues, allowing for coordinated and regulated function. Therefore, the correct answer is "all of the above" as ganglionic neurons innervate all the mentioned structures.

Sympathetic preganglionic fibers are short and postganglionic fibers are long. This is because sympathetic preganglionic fibers originate from the intermediolateral cell column of the spinal cord and synapse with postganglionic neurons in the sympathetic ganglia, which are located close to the spinal cord. From there, the postganglionic fibers travel a longer distance to reach their target organs or tissues.

The celiac ganglia innervate all of the above organs, including the liver, spleen, stomach, and pancreas. The celiac ganglia are clusters of nerve cell bodies located near the celiac artery in the abdomen. They are part of the autonomic nervous system and play a role in regulating the functions of these organs, such as digestion and blood flow.

The parasympathetic outflow is responsible for rest and digest activities in the body. The vagus nerves, also known as the tenth cranial nerves, play a significant role in carrying parasympathetic fibers to various organs in the body, including the heart, lungs, and digestive system. These nerves are responsible for regulating heart rate, promoting digestion, and controlling various involuntary functions. Therefore, it is correct to say that almost 75 percent of all parasympathetic outflow travels along the vagus nerves.

The craniosacral division is another name for the parasympathetic division of the autonomic nervous system (ANS). The parasympathetic division is responsible for the "rest and digest" response, which promotes relaxation, digestion, and other activities that conserve and restore energy. This division is activated during times of rest and relaxation, and it helps to counterbalance the effects of the sympathetic division, which is responsible for the "fight or flight" response. Therefore, the correct answer is the parasympathetic division of the ANS.

If Mary accidentally ate poison mushrooms containing muscarine, she would likely experience symptoms such as diarrhea, salivation, a very low heart rate, and sweating. Muscarine is known to stimulate the parasympathetic nervous system, which can lead to increased secretions in the digestive system (diarrhea and salivation), a decrease in heart rate, and excessive sweating. Therefore, all of the mentioned symptoms would be expected in this case.

Clusters of ganglionic sympathetic neurons that innervate organs in the abdominopelvic region are called collateral ganglia. These ganglia are located outside the sympathetic chain and are associated with specific organs or regions within the abdominopelvic area. They receive preganglionic fibers from the sympathetic chain and provide postganglionic fibers to the target organs. The collateral ganglia play a crucial role in regulating the sympathetic innervation of these organs, coordinating various physiological functions and responses.

The sympathetic collateral ganglia include the celiac, superior mesenteric, and inferior mesenteric ganglia. These ganglia are part of the sympathetic nervous system and are located outside of the spinal cord. They play a role in regulating various functions in the abdominal region, such as digestion and blood flow. Therefore, the correct answer is "all of the above" as all three ganglia mentioned are included in the sympathetic collateral ganglia.

The adrenal medullae are part of the adrenal glands and are responsible for secreting hormones. In this case, the correct answer is "both epinephrine and norepinephrine." Epinephrine and norepinephrine are both catecholamines that are released by the adrenal medullae. They play a role in the body's response to stress, increasing heart rate, blood pressure, and glucose levels.

Dual innervation refers to the phenomenon where an organ receives nerve fibers from both the sympathetic and parasympathetic divisions of the autonomic nervous system. These two divisions have opposing effects on the organ, with the sympathetic division generally stimulating activity and the parasympathetic division generally inhibiting activity. This dual innervation allows for precise control and regulation of organ function.

The statement "It controls the diameter of the pupil" is true for both the parasympathetic and sympathetic nervous systems. The parasympathetic system controls the constriction of the pupil, while the sympathetic system controls the dilation of the pupil. Both systems work together to regulate the size of the pupil in response to different stimuli and lighting conditions.

Autonomic motor neurons are responsible for conducting impulses to smooth and cardiac muscles and glands. These neurons are part of the autonomic nervous system, which controls involuntary bodily functions. Unlike somatic motor neurons that control skeletal muscles, autonomic motor neurons regulate activities such as digestion, heart rate, and glandular secretion. Therefore, the correct answer is that autonomic motor neurons conduct impulses to smooth and cardiac muscles and glands.

A visceral motor neuron whose cell body is within the CNS is called a preganglionic neuron. This type of neuron is responsible for transmitting signals from the central nervous system to the autonomic ganglia, which then relay the signals to the target organs or tissues. Preganglionic neurons are part of the autonomic nervous system and play a crucial role in regulating involuntary bodily functions such as heart rate, digestion, and breathing.

Injury to the cervical sympathetic ganglia can affect the function of the heart, pupils, salivary glands, and lungs. The cervical sympathetic ganglia are part of the autonomic nervous system and are responsible for regulating various bodily functions. Damage to these ganglia can disrupt the normal functioning of these organs and lead to symptoms such as abnormal heart rate, pupil dilation or constriction issues, dry mouth, and difficulty breathing. Therefore, all of the above options can be affected by injury to the cervical sympathetic ganglia.

The control of the diameter of the respiratory passages depends on both parasympathetic and sympathetic levels of stimulation. The parasympathetic system causes bronchoconstriction, which narrows the airways, while the sympathetic system causes bronchodilation, which widens the airways. Therefore, both systems work together to regulate the diameter of the respiratory passages and control airflow.

The parasympathetic nervous system is responsible for rest and digest functions in the body. During digestion, the parasympathetic nervous system is particularly active as it helps in stimulating the release of digestive enzymes, increasing blood flow to the digestive organs, and promoting the relaxation of the gastrointestinal muscles. This allows for optimal digestion and absorption of nutrients from the food we consume. Therefore, the correct answer is digestion.

Parasympathetic stimulation refers to the activation of the parasympathetic nervous system, which is responsible for promoting rest and relaxation in the body. One of the effects of parasympathetic stimulation is an increase in gastric motility, which means that it enhances the movement and contractions of the muscles in the gastrointestinal tract, leading to improved digestion and absorption of nutrients. This can help to speed up the process of food passing through the stomach and intestines, ultimately aiding in the breakdown and absorption of nutrients from the food we consume.

All of the options listed are examples of visceral reflexes. A visceral reflex is an automatic response that occurs in the body without conscious control, in response to stimuli affecting the internal organs. The defecation reflex is the reflex that triggers bowel movements. The cardioacceleratory reflex increases the heart rate in response to certain stimuli. The pupillary reflex controls the size of the pupils in response to changes in light. Ejaculation in response to tactile stimuli is also a visceral reflex. Therefore, all of the options listed are examples of visceral reflexes.

The statement "there is always a synapse in a peripheral ganglion between the CNS and the effector organ" is true for both the parasympathetic and sympathetic nervous systems. In both systems, the preganglionic neurons originating from the CNS synapse with postganglionic neurons in peripheral ganglia before reaching the effector organs. This synapse allows for the transmission of signals from the CNS to the effector organs, enabling the control of various physiological processes.

The celiac ganglion is a cluster of nerve cells located near the base of the diaphragm. It plays a crucial role in the autonomic nervous system by innervating various organs in the abdominal region. The stomach, liver, and pancreas are all innervated by the celiac ganglion, making "all of the above" the correct answer. This means that the celiac ganglion sends nerve fibers to these organs, allowing for the regulation of their functions and communication between them and the central nervous system.

Preganglionic axon terminals release acetylcholine in both the parasympathetic and sympathetic nervous systems. In the parasympathetic nervous system, acetylcholine is released at the ganglionic synapse, where it acts on postganglionic neurons. In the sympathetic nervous system, acetylcholine is released at the ganglionic synapse for most preganglionic neurons, but not for those that innervate the adrenal medulla. In both systems, acetylcholine acts as a neurotransmitter to transmit signals from the preganglionic neurons to the postganglionic neurons.

The correct answer is lateral gray horns of segments T1 to L2 of the spinal cord. Preganglionic neurons of the sympathetic nervous system are located in the lateral gray horns of the spinal cord. These neurons originate from segments T1 to L2, which corresponds to the thoracic and upper lumbar regions of the spinal cord. This is where the cell bodies of these neurons are found before they project to the sympathetic ganglia.

Specialized ganglionic sympathetic neurons that release hormones into the bloodstream are found within the adrenal glands. The adrenal glands are located on top of the kidneys and consist of two parts: the outer adrenal cortex and the inner adrenal medulla. The adrenal medulla is responsible for producing and releasing hormones such as adrenaline and noradrenaline directly into the bloodstream, which helps to regulate the body's response to stress and maintain homeostasis. Therefore, the adrenal glands are the correct answer in this case.

The sympathetic division of the ANS is known as the thoracolumbar division. This division is responsible for the body's "fight or flight" response, mobilizing energy and preparing the body for action. It is called thoracolumbar because the preganglionic neurons originate from the thoracic and lumbar regions of the spinal cord.

This statement is true only for the parasympathetic nervous system. In the parasympathetic nervous system, the ganglia are located near or within the end organ, allowing for a shorter distance for the transmission of signals. In contrast, in the sympathetic nervous system, the ganglia are located closer to the spinal cord, resulting in a longer distance for signal transmission. Therefore, this statement does not apply to the sympathetic nervous system.

Stimulation of beta-adrenergic receptors can lead to an increase in metabolic activity because these receptors are involved in regulating metabolism. It can also cause relaxation of airway smooth muscle, which helps in the treatment of conditions like asthma. Additionally, the stimulation of beta-adrenergic receptors can lead to the breakdown of triglycerides within adipocytes, promoting fat metabolism. Therefore, all of the given options are correct.

Adrenergic receptors are proteins in the plasma membrane that are involved in the response to epinephrine and norepinephrine. When these receptors are activated, the levels of cAMP (cyclic adenosine monophosphate) are affected, leading to various physiological responses. Both epinephrine and norepinephrine can activate both alpha and beta types of adrenergic receptors, although norepinephrine mainly activates the alpha type. Therefore, all of the above statements are true.

When a neuron with nicotinic receptors is exposed to acetylcholine, it will lead to the activation of chemically gated ion channels. This activation will cause the entry of sodium ions into the neuron, which will result in the excitation of the neuron. Therefore, all of the above options are correct.

The person's physical responses, such as increased heart rate, dilated pupils, and hairs standing up, are all characteristic signs of sympathetic activation. Sympathetic activation is the body's automatic response to a perceived threat or danger. It involves the release of epinephrine (also known as adrenaline) into the blood, which increases heart rate and prepares the body for a fight or flight response. The autonomic centers in the hypothalamus play a crucial role in coordinating and regulating these physiological responses. Therefore, all of the given options - sympathetic activation, increased levels of epinephrine in the blood, and increased activity of autonomic centers in the hypothalamus - are correct explanations for the person's physical signs.

The correct answer is "chain". Clusters of ganglionic sympathetic neurons that are located along both sides of the spinal cord are referred to as sympathetic chain ganglia. These ganglia form a chain-like structure and are responsible for transmitting sympathetic signals throughout the body.

The parasympathetic division of the autonomic nervous system is responsible for rest and digest functions. Preganglionic neurons are the type of neurons that exit the brain stem in the parasympathetic division. These neurons carry signals from the brain stem to ganglionic neurons located in peripheral ganglia. From there, the ganglionic neurons transmit the signals to target organs, allowing for the regulation of various bodily functions such as digestion, heart rate, and glandular secretion.

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The correct answer is abdominopelvic. Collateral ganglia are part of the autonomic nervous system and are located outside of the central nervous system. They contain neurons that innervate tissues and organs in the abdominopelvic cavity, which includes the organs in the abdomen and pelvis.

The statement "it initiates contraction of urinary bladder smooth muscle" is true only for the parasympathetic nervous system. This is because the parasympathetic nervous system is responsible for promoting rest and digestion, and it stimulates the contraction of smooth muscles in the urinary bladder to initiate the process of urination. The sympathetic nervous system, on the other hand, is responsible for the fight or flight response and does not directly control the contraction of urinary bladder smooth muscle.

Preganglionic fibers are nerve fibers that originate in the central nervous system (CNS) and travel to ganglia, which are clusters of nerve cell bodies outside the CNS. These preganglionic fibers then synapse on postganglionic fibers, which are nerve fibers that extend from the ganglia to their target organs or tissues. Therefore, the correct answer is ganglionic neurons, as these are the neurons that receive the synaptic connections from preganglionic fibers.

Stimulation of the beta receptors on heart muscle cells leads to the activation of cAMP, which in turn increases heart rate and enhances the force of contraction. Therefore, all of the given options are correct.

The statement that preganglionic fibers are relatively short and postganglionic fibers are relatively long is false. In the parasympathetic division of the autonomic nervous system, the opposite is true. Preganglionic fibers are long, extending from the brainstem and sacral region of the spinal cord to ganglia near or within the target organs. On the other hand, postganglionic fibers are short and directly innervate the target organs.

Injury to the neurons of a collateral ganglion would affect the function of the digestive tract. Collateral ganglia are part of the autonomic nervous system, which controls involuntary functions such as digestion. These ganglia contain neurons that innervate various organs, including the digestive tract. If these neurons are injured, it can disrupt the normal functioning of the digestive tract, leading to issues with digestion and absorption of nutrients.

Ganglionic neurons typically synapse with preganglionic neurons in the autonomic ganglia. These ganglionic neurons then have axons that innervate visceral effectors. This means that the synapse between the preganglionic and ganglionic neurons occurs in the autonomic ganglia, and the ganglionic neurons are responsible for transmitting signals to the visceral effectors, such as smooth muscle or glands.

When sympathetic stimulation is increased, the autonomic tone of peripheral blood vessels also increases. The sympathetic nervous system is responsible for the fight-or-flight response, which includes increasing heart rate, constricting blood vessels, and redirecting blood flow to vital organs. This increased sympathetic stimulation causes the blood vessels to constrict, leading to an increase in autonomic tone.

A sweat gland is an example of an organ of the cholinergic type because it releases acetylcholine instead of norepinephrine.

The preganglionic fibers of parasympathetic neurons are responsible for transmitting signals from the central nervous system to the ganglia, which then relay the signals to the target organs. Cranial nerves III (oculomotor), VII (facial), IX (glossopharyngeal), and X (vagus) all contain preganglionic fibers of parasympathetic neurons. However, cranial nerve XII (hypoglossal) does not contain these fibers. Instead, it is responsible for controlling the muscles of the tongue.

The drug mentioned in the question decreases heart rate by blocking a receptor on cardiac pacemaker cells. The receptor that is responsible for increasing heart rate is the beta-1 adrenergic receptor. Therefore, the drug is likely to bind to beta-1 adrenergic receptors in order to decrease heart rate.

A decrease in the autonomic tone of the smooth muscle in a blood vessel would result in both an increase in vessel diameter and an increase in blood flow through the vessel. Autonomic tone refers to the level of activity in the autonomic nervous system, which controls involuntary bodily functions such as blood vessel constriction and dilation. When the autonomic tone decreases, the smooth muscle in the blood vessel relaxes, causing the vessel to dilate and increase in diameter. This dilation allows for more blood to flow through the vessel, resulting in an increase in blood flow.

Autonomic tone is important for ANS function because it allows ANS neurons to have the ability to both increase and decrease their activity levels. This provides a range of control options, allowing the ANS to respond appropriately to different situations and maintain homeostasis in the body. It ensures that the ANS can regulate various bodily functions, such as heart rate, blood pressure, digestion, and respiration, based on the needs of the body at any given time.