1. What are some of the primary functions of the sympathetic nervous system?
The Sympathetic nervous system engages the 'fight or flight' response, such as increased heart rate, pupillary dilation, and reduced digestion before a stressful event occurs.
2. How does the parasympathetic nervous system affect heart rate?
The parasympathetic nervous system represents the part of the nervous system that reduces the heart rate, which enables an animal during rest to relax and conserve its energy.
3. How does the sympathetic nervous system differ from the parasympathetic nervous system?
Whereas the sympathetic nervous system activates the stress responses of the body, the parasympathetic nervous system is involved in relaxation and recovery.
4. How do the Sympathetic and Parasympathetic Systems interact to maintain Homeostasis?
The sympathetic system acts antagonistically to the parasympathetic in the control of most visceral functions. The former is stimulatory of activity whilst the latter induces relaxation; thus, counterbalancing to maintain homeostasis within the body.
5. What are common disorders related to the autonomic nervous system?
The common disorders are generally associated with an imbalance between the sympathetic and parasympathetic activities, including hypertension, heart disease, and digestive disorders.
6. What is the main difference between the sympathetic and parasympathetic nervous systems?
The main difference lies in their functions: the sympathetic nervous system prepares the body for "fight or flight" responses, while the parasympathetic nervous system promotes "rest and digest" activities. The sympathetic system activates during stress or excitement, while the parasympathetic system dominates during relaxed states.
7. How do the effects of the sympathetic and parasympathetic systems on heart rate differ?
The sympathetic nervous system increases heart rate, while the parasympathetic nervous system decreases it. This is achieved through different neurotransmitters: norepinephrine for sympathetic stimulation and acetylcholine for parasympathetic stimulation.
8. How do the sympathetic and parasympathetic systems affect pupil size?
The sympathetic nervous system causes pupil dilation (mydriasis), allowing more light into the eye. The parasympathetic nervous system causes pupil constriction (miosis), reducing light entry.
9. What is the effect of these two systems on bronchial tubes in the lungs?
The sympathetic nervous system causes bronchodilation (widening of the airways), while the parasympathetic nervous system causes bronchoconstriction (narrowing of the airways).
10. Which neurotransmitters are primarily associated with the sympathetic and parasympathetic systems?
The sympathetic nervous system primarily uses norepinephrine (also called noradrenaline) as its neurotransmitter. The parasympathetic nervous system mainly uses acetylcholine.
11. What is the "dual innervation" concept in relation to these two systems?
Dual innervation refers to the fact that many organs receive input from both sympathetic and parasympathetic systems. This allows for fine-tuning of organ function through the balance between these opposing influences.
12. What is the concept of "tone" in relation to these two systems?
"Tone" refers to the baseline level of activity in each system. Both sympathetic and parasympathetic systems maintain a certain level of activity at all times, with their balance determining the overall state of the body.
13. What is the effect of the sympathetic nervous system on blood vessels?
The sympathetic nervous system generally causes vasoconstriction (narrowing) of blood vessels, except in skeletal muscles and the heart, where it causes vasodilation to increase blood flow during "fight or flight" responses.
14. What is the "vagus nerve," and which system does it belong to?
The vagus nerve is the tenth cranial nerve and a major component of the parasympathetic nervous system. It innervates many organs in the chest and abdomen, playing a crucial role in "rest and digest" functions.
15. How do these systems influence blood pressure?
The sympathetic system generally increases blood pressure by increasing heart rate, contractility, and vasoconstriction. The parasympathetic system tends to decrease blood pressure by slowing heart rate and promoting vasodilation.
16. How does the parasympathetic nervous system earn the nickname "rest and digest"?
The parasympathetic nervous system promotes relaxation, digestion, and energy conservation. It slows heart rate, increases digestive activity, and generally prepares the body for rest and recovery, hence the nickname "rest and digest."
17. How does the parasympathetic nervous system affect saliva production?
The parasympathetic nervous system stimulates increased saliva production, preparing the mouth and digestive system for food intake and initiating the digestive process.
18. How do the origins of sympathetic and parasympathetic neurons differ in the central nervous system?
Sympathetic neurons originate in the thoracic and lumbar regions of the spinal cord (T1-L2). Parasympathetic neurons originate in the brainstem (cranial nerves III, VII, IX, and X) and the sacral region of the spinal cord (S2-S4).
19. How do these two systems affect blood glucose levels?
The sympathetic nervous system tends to increase blood glucose levels by stimulating the liver to release glucose and inhibiting insulin secretion. The parasympathetic system generally promotes insulin release and glucose uptake, lowering blood glucose levels.
20. How do these systems influence digestion?
The parasympathetic nervous system stimulates digestion by increasing gut motility and secretion of digestive enzymes. The sympathetic nervous system inhibits digestion by reducing blood flow to the digestive organs and decreasing gut motility.
21. What is the "sympathetic chain," and what role does it play?
The sympathetic chain is a series of interconnected ganglia running parallel to the spinal cord. It serves as a relay station for sympathetic signals, allowing for widespread and rapid activation of the sympathetic nervous system throughout the body.
22. What is the "fight or flight" response, and which system is responsible for it?
The "fight or flight" response is the body's reaction to perceived danger or stress, characterized by increased heart rate, blood pressure, and alertness. The sympathetic nervous system is responsible for initiating and maintaining this response.
23. What is the effect of the sympathetic nervous system on sweat glands?
The sympathetic nervous system stimulates sweat gland activity, increasing perspiration. This helps in thermoregulation, especially during stress or physical exertion.
24. How do the sympathetic and parasympathetic systems affect the bladder?
The sympathetic system relaxes the bladder and contracts the internal sphincter, promoting urine retention. The parasympathetic system contracts the bladder and relaxes the internal sphincter, facilitating urination.
25. What is the role of these systems in sexual arousal and function?
The parasympathetic system is primarily responsible for sexual arousal, causing vasodilation in genital tissues. The sympathetic system is involved in orgasm and ejaculation in males.
26. How do these systems influence tear production?
The parasympathetic nervous system stimulates tear production, while the sympathetic system has minimal effect on tear glands.
27. How does the parasympathetic nervous system affect the gastrointestinal tract?
The parasympathetic system increases peristalsis (wave-like muscle contractions), relaxes sphincters, and stimulates secretion of digestive enzymes, all of which promote digestion and absorption of nutrients.
28. How do these systems affect the liver?
The sympathetic system stimulates glucose release and inhibits glucose storage in the liver. The parasympathetic system promotes glucose storage and inhibits glucose release.
29. What is the effect of these systems on the pupils during the accommodation reflex?
During accommodation (focusing on near objects), the parasympathetic system causes pupil constriction and lens thickening. The sympathetic system has minimal involvement in this reflex.
30. What is the concept of "antagonistic control" in relation to these systems?
Antagonistic control refers to the opposing effects of the sympathetic and parasympathetic systems on many organs. This allows for fine-tuning of organ function through the balance between these two systems.
31. How do these systems affect the adrenal glands?
The sympathetic nervous system stimulates the adrenal medulla to release epinephrine and norepinephrine, amplifying the "fight or flight" response. The parasympathetic system has minimal direct effect on the adrenal glands.
32. What is the role of these systems in thermoregulation?
The sympathetic system plays a major role in thermoregulation by controlling sweat glands and blood vessel dilation/constriction. The parasympathetic system has minimal direct involvement in temperature regulation.
33. How do these systems affect the pancreas?
The parasympathetic system stimulates the release of insulin and digestive enzymes from the pancreas. The sympathetic system inhibits insulin release and stimulates glucagon secretion, raising blood glucose levels.
34. What is the effect of these systems on skeletal muscles?
The sympathetic nervous system has minimal direct effect on skeletal muscles but increases blood flow to them during "fight or flight" responses. The parasympathetic system has no direct effect on skeletal muscles.
35. How do these systems influence salivary gland function?
The parasympathetic system stimulates watery saliva production in large quantities. The sympathetic system produces small amounts of thick, protein-rich saliva.
36. What is the role of these systems in the sleep-wake cycle?
The parasympathetic system dominates during sleep, promoting rest and recovery. The sympathetic system becomes more active during wakefulness, especially upon awakening.
37. How do these systems affect the kidneys?
The sympathetic system decreases urine production by reducing blood flow to the kidneys and stimulating sodium reabsorption. The parasympathetic system has minimal direct effect on kidney function.
38. What is the concept of "autonomic balance"?
Autonomic balance refers to the relative activity levels of the sympathetic and parasympathetic systems. Optimal health requires a proper balance between these two systems, with the ability to adapt to changing circumstances.
39. How do these systems influence the immune system?
The sympathetic system generally suppresses immune function to conserve energy during stress. The parasympathetic system, particularly through the vagus nerve, can have anti-inflammatory effects and promote immune balance.
40. What is the effect of these systems on the skin?
The sympathetic system causes piloerection (goosebumps) and increased sweating. The parasympathetic system has minimal direct effect on the skin.
41. How do these systems affect the release of hormones from the pituitary gland?
The autonomic nervous system, particularly the sympathetic system, can influence the hypothalamus, which in turn affects pituitary hormone release. However, hormonal control is primarily regulated by other mechanisms.
42. What is the role of these systems in the stress response?
The sympathetic system initiates and maintains the stress response, preparing the body for action. The parasympathetic system helps to terminate the stress response and restore the body to a resting state.
43. How do these systems influence pain perception?
The sympathetic system can enhance pain perception in some circumstances, while the parasympathetic system, particularly through vagal stimulation, can have pain-reducing effects.
44. What is the concept of "autonomic reflexes"?
Autonomic reflexes are rapid, involuntary responses mediated by the autonomic nervous system. Examples include the baroreceptor reflex (blood pressure regulation) and the pupillary light reflex.
45. How do these systems affect the esophagus during swallowing?
The parasympathetic system promotes peristalsis in the esophagus and relaxation of the lower esophageal sphincter, facilitating swallowing. The sympathetic system has minimal direct effect on esophageal function.
46. What is the effect of these systems on the spleen?
The sympathetic nervous system causes contraction of the spleen, releasing stored red blood cells into circulation. The parasympathetic system has minimal direct effect on the spleen.
47. How do these systems influence cognitive function?
The sympathetic system can enhance alertness and cognitive performance in short-term stress situations. The parasympathetic system promotes a calm state conducive to focused attention and memory consolidation.
48. What is the role of these systems in the regulation of body temperature?
The sympathetic system plays a major role in increasing body temperature through mechanisms like vasoconstriction and shivering. The parasympathetic system is less involved but can contribute to temperature decrease through vasodilation.
49. How do these systems affect the gallbladder?
The parasympathetic system stimulates the gallbladder to contract and release bile. The sympathetic system relaxes the gallbladder and reduces bile release.
50. What is the concept of "autonomic dysfunction"?
Autonomic dysfunction refers to conditions where the autonomic nervous system doesn't work properly, leading to issues with involuntary functions like heart rate, blood pressure, and digestion.
51. How do these systems influence respiratory rate?
The sympathetic system generally increases respiratory rate and depth. The parasympathetic system tends to decrease respiratory rate, although its effect on breathing is less pronounced than that of the sympathetic system.
52. What is the effect of these systems on the urinary sphincter?
The sympathetic system contracts the internal urinary sphincter, promoting urine retention. The parasympathetic system relaxes the internal sphincter, facilitating urination.
53. How do these systems affect the ciliary muscle in the eye?
The parasympathetic system stimulates the ciliary muscle to contract, causing the lens to become more convex for near vision. The sympathetic system has minimal direct effect on the ciliary muscle.
54. What is the role of these systems in the regulation of blood flow to different organs?
The sympathetic system generally reduces blood flow to digestive organs and increases flow to skeletal muscles and the heart. The parasympathetic system tends to increase blood flow to digestive organs.
55. How do these systems influence the secretion of gastric acid in the stomach?
The parasympathetic system stimulates the secretion of gastric acid, promoting digestion. The sympathetic system generally inhibits gastric acid secretion, particularly during stress responses.
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