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Questions and Answers
What is the primary function of the Myenteric plexus in the enteric system?
What is the primary function of the Myenteric plexus in the enteric system?
Where is the Myenteric plexus located within the enteric system?
Where is the Myenteric plexus located within the enteric system?
Which statement about the Myenteric plexus is false?
Which statement about the Myenteric plexus is false?
What effect does stimulation of the Myenteric plexus have on gastrointestinal motility?
What effect does stimulation of the Myenteric plexus have on gastrointestinal motility?
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The Myenteric plexus primarily influences which aspect of the gastrointestinal system?
The Myenteric plexus primarily influences which aspect of the gastrointestinal system?
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Which author is known for their work in Human Physiology specifically in the twelfth edition published in 2017?
Which author is known for their work in Human Physiology specifically in the twelfth edition published in 2017?
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What edition of the work by K Sembulingam and Prema Sembulingam was published in 2016?
What edition of the work by K Sembulingam and Prema Sembulingam was published in 2016?
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Which publisher is associated with the fourth edition by K Sembulingam and Prema Sembulingam?
Which publisher is associated with the fourth edition by K Sembulingam and Prema Sembulingam?
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Among the authors listed, who contributed to the field of medical physiology in 2016?
Among the authors listed, who contributed to the field of medical physiology in 2016?
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What is the primary subject of the work published by Stuart Ira Fox?
What is the primary subject of the work published by Stuart Ira Fox?
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What is the primary function of the submucosal plexus?
What is the primary function of the submucosal plexus?
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How do the parasympathetic nerves affect the enteric nervous system?
How do the parasympathetic nerves affect the enteric nervous system?
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Which of the following statements accurately describes Meissner’s plexus?
Which of the following statements accurately describes Meissner’s plexus?
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In which part of the gastrointestinal tract is the submucosal plexus primarily located?
In which part of the gastrointestinal tract is the submucosal plexus primarily located?
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What overall effect does the parasympathetic nervous system have on the gastrointestinal tract?
What overall effect does the parasympathetic nervous system have on the gastrointestinal tract?
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What initiates the swallowing process in the oral cavity?
What initiates the swallowing process in the oral cavity?
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What characterizes the initial stage of swallowing?
What characterizes the initial stage of swallowing?
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Which of the following statements about the swallowing process is incorrect?
Which of the following statements about the swallowing process is incorrect?
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During the swallowing process, what happens to the food once it is ready for swallowing?
During the swallowing process, what happens to the food once it is ready for swallowing?
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What is the primary role of the sacral parasympathetics in the digestive system?
What is the primary role of the sacral parasympathetics in the digestive system?
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Which part of the body is primarily responsible for the voluntary stage of swallowing?
Which part of the body is primarily responsible for the voluntary stage of swallowing?
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What effect does the sympathetic nervous system have on the gastrointestinal tract?
What effect does the sympathetic nervous system have on the gastrointestinal tract?
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Which process comes directly after the ingestion of food?
Which process comes directly after the ingestion of food?
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In what manner does the parasympathetic nervous system generally affect the digestive process?
In what manner does the parasympathetic nervous system generally affect the digestive process?
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Which of the following best describes the relationship between sympathetic and parasympathetic systems in digestion?
Which of the following best describes the relationship between sympathetic and parasympathetic systems in digestion?
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What is the primary function of the tongue in the digestive process?
What is the primary function of the tongue in the digestive process?
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What action does the tongue perform when swallowing?
What action does the tongue perform when swallowing?
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Which of the following statements regarding the bolus is true?
Which of the following statements regarding the bolus is true?
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How does the tongue facilitate the swallowing process?
How does the tongue facilitate the swallowing process?
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What role does the tongue play in the initial phase of digestion?
What role does the tongue play in the initial phase of digestion?
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Study Notes
Gastrointestinal System Physiology
- The gastrointestinal system provides a continuous supply of water, electrolytes, vitamins, and nutrients to the body.
- This involves several processes:
- Movement of food through the alimentary tract
- Secretion of digestive juices and digestion of food
- Absorption of digestive products (water, electrolytes, vitamins)
- Circulation of blood to carry away absorbed substances
- Nervous and hormonal control of these functions
Major Organs of the Digestive System
- Mouth
- Pharynx
- Esophagus
- Stomach
- Small intestine
- Large intestine
- These form a tube called the digestive tract
Accessory Organs of the Digestive System
- Teeth
- Tongue
- Liver
- Pancreas
- Gall bladder
- Salivary glands
- These organs are not part of the alimentary canal but aid in digestion
Functions of the Digestive System
- Ingestion
- Secretion
- Mixing and propulsion
- Digestion (mechanical and chemical)
- Absorption
- Defecation
Enteric Nervous System
- The gastrointestinal tract has its own nervous system, the enteric nervous system, located in the wall of the gut.
- This system starts in the esophagus and extends to the anus.
- It consists primarily of two plexuses:
- Myenteric plexus (Auerbach's plexus): Situated between muscle layers, it controls rhythmic contractions and the rate/velocity of these contractions. It also plays a part in inhibiting the pyloric sphincter (controlling stomach emptying).
- Submucosal plexus (Meissner's plexus): Located in the submucosa, it controls functions in smaller gastrointestinal segments, local secretions, absorption, blood flow, and local contractions of the muscularis mucosa
Autonomic Control of the Gastrointestinal Tract
- Parasympathetic nerves: Increase the activity of the enteric nervous system. Cranial divisions innervate the esophagus, stomach, small intestine, pancreas, and the first half of the large intestine. Sacral divisions innervate the distal half of the large intestine through pelvic nerves.
- Sympathetic nerves: Usually inhibit activity in the gastrointestinal tract, causing effects opposite to those of the parasympathetic system.
Mouth (Digestion Part 1)
- Digestion begins in the mouth.
- Food enters the mouth (oral cavity).
- Chewing (mastication) involves teeth, tearing and grinding food.
- Anterior teeth (incisors): provide cutting action
- Posterior teeth (molars): for grinding
- Mixing food with saliva, which starts the breakdown of carbohydrates (starch) using the enzyme amylase
- Saliva contains the enzyme amylase for starch digestion
- Saliva also contains mucous for lubrication and protection
Swallowing (Deglutition)
- A complex process involving three stages:
- Voluntary stage: Tongue pushes food into the pharynx
- Pharyngeal stage: Involuntary, food travels down the pharynx into the esophagus
- Esophageal stage: Involuntary, food travels from the pharynx to the stomach
Stomach
- Three functions:
- Food storage until processed in the duodenum
- Mixing of food with gastric secretions to create chyme (a semi-fluid mixture)
- Emptying food into the intestine at a suitable rate for digestion and absorption
Tongue
- Mixes and rolls food into a bolus and pushes the bolus towards the pharynx and into the esophagus to be swallowed.
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Description
Test your knowledge on the physiology of the gastrointestinal system, including major and accessory organs as well as their functions. This quiz covers essential processes such as digestion, absorption, and circulation related to the digestive tract. Perfect for students studying human biology or medical science.
