Podcast
Questions and Answers
What is the main purpose of segmentation in the digestive tract?
What is the main purpose of segmentation in the digestive tract?
- Propel food along the tract
- Absorb nutrients
- Metabolize drugs
- Facilitate mixing of food (correct)
Which factor affects drug absorption through buccal delivery?
Which factor affects drug absorption through buccal delivery?
- Temperature of the mouth
- Drug's hydrophobicity (correct)
- pH level of saliva
- Drug's molecular weight
What is a major barrier to absorption in buccal delivery?
What is a major barrier to absorption in buccal delivery?
- Low blood supply in oral mucosa
- Enzymatic degradation in buccal tissue (correct)
- Rapid absorption into the bloodstream
- High surface area of the oral cavity
What oral/dental problem can dry mouth lead to?
What oral/dental problem can dry mouth lead to?
Which challenge must be considered for buccal drug delivery?
Which challenge must be considered for buccal drug delivery?
What is a key requirement for drugs to achieve greater bioavailability through buccal administration?
What is a key requirement for drugs to achieve greater bioavailability through buccal administration?
What factors could limit drug efficacy in buccal delivery?
What factors could limit drug efficacy in buccal delivery?
What is a common treatment for oral thrush?
What is a common treatment for oral thrush?
What role do tight junctions between mucosal epithelial cells serve in gastric protection?
What role do tight junctions between mucosal epithelial cells serve in gastric protection?
During which phase of gastric secretion is there an increase due to the sight, smell, taste, thought of food, or a decrease in blood glucose?
During which phase of gastric secretion is there an increase due to the sight, smell, taste, thought of food, or a decrease in blood glucose?
What effect do prostaglandins have on the gastric mucosa?
What effect do prostaglandins have on the gastric mucosa?
What triggers the intestinal phase of gastric secretion?
What triggers the intestinal phase of gastric secretion?
Which local hormones are involved in inhibiting gastric secretion during the intestinal phase?
Which local hormones are involved in inhibiting gastric secretion during the intestinal phase?
What role does saliva play in the digestive process?
What role does saliva play in the digestive process?
Which pair of salivary glands produces watery saliva rich in alpha-amylase?
Which pair of salivary glands produces watery saliva rich in alpha-amylase?
What type of fluid do acinar cells produce in the salivary glands?
What type of fluid do acinar cells produce in the salivary glands?
Which factor does NOT influence the final composition of saliva?
Which factor does NOT influence the final composition of saliva?
What type of saliva does the sympathetic nervous system stimulate?
What type of saliva does the sympathetic nervous system stimulate?
During the pharyngeal stage of swallowing, what action is performed by the soft palate?
During the pharyngeal stage of swallowing, what action is performed by the soft palate?
What characterizes the muscularis layer of the esophagus?
What characterizes the muscularis layer of the esophagus?
Salivation can be stimulated by which of the following factors?
Salivation can be stimulated by which of the following factors?
What is the primary function of alpha-amylase in saliva?
What is the primary function of alpha-amylase in saliva?
What is the average daily secretion of saliva in milliliters?
What is the average daily secretion of saliva in milliliters?
What role do zymogenic (chief) cells play in gastric juice production?
What role do zymogenic (chief) cells play in gastric juice production?
Which of the following substances can contribute to tooth decay when misused?
Which of the following substances can contribute to tooth decay when misused?
What is the primary function of the parietal cells in the gastric glands?
What is the primary function of the parietal cells in the gastric glands?
What is the role of gastrin in the stomach?
What is the role of gastrin in the stomach?
What is the main reason the stomach does not digest itself?
What is the main reason the stomach does not digest itself?
Which type of cell is responsible for secreting mucous in the gastric glands?
Which type of cell is responsible for secreting mucous in the gastric glands?
Which medication type potentially leads to oral health issues like dry mouth?
Which medication type potentially leads to oral health issues like dry mouth?
What is the primary function of gastric lipase?
What is the primary function of gastric lipase?
Which of the following is a recommended practice for dental hygiene?
Which of the following is a recommended practice for dental hygiene?
In which part of the stomach are parietal cells most concentrated?
In which part of the stomach are parietal cells most concentrated?
Flashcards
What salivary glands produce saliva?
What salivary glands produce saliva?
Saliva is produced by three pairs of salivary glands: parotid, submandibular, and sublingual.
What are the main functions of saliva?
What are the main functions of saliva?
Saliva contains substances for lubrication, carbohydrate breakdown, and other enzymatic activity.
What system regulates saliva production?
What system regulates saliva production?
Saliva secretion is regulated by the autonomic nervous system (ANS).
How does the parasympathetic nervous system affect saliva?
How does the parasympathetic nervous system affect saliva?
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What effect does sympathetic stimulation have on saliva?
What effect does sympathetic stimulation have on saliva?
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What controls swallowing?
What controls swallowing?
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What happens during the voluntary stage of swallowing?
What happens during the voluntary stage of swallowing?
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Describe the pharyngeal stage of swallowing.
Describe the pharyngeal stage of swallowing.
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What is the advantage of taking drugs orally?
What is the advantage of taking drugs orally?
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What is one limitation of oral drug absorption?
What is one limitation of oral drug absorption?
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What are other challenges to oral drug absorption?
What are other challenges to oral drug absorption?
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How can enzymes affect oral drug absorption?
How can enzymes affect oral drug absorption?
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What are the consequences of dry mouth?
What are the consequences of dry mouth?
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How are oral ulcers usually treated?
How are oral ulcers usually treated?
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What can cause oral thrush?
What can cause oral thrush?
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What medications can lead to tooth decay?
What medications can lead to tooth decay?
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What are the main functions of the stomach?
What are the main functions of the stomach?
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Where does most mechanical digestion in the stomach occur?
Where does most mechanical digestion in the stomach occur?
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What happens to food in the stomach and where does it go next?
What happens to food in the stomach and where does it go next?
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What is the structure of the stomach's inner lining?
What is the structure of the stomach's inner lining?
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What types of cells are found in gastric glands?
What types of cells are found in gastric glands?
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What do zymogenic cells secrete?
What do zymogenic cells secrete?
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What do parietal cells secrete?
What do parietal cells secrete?
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What do goblet cells secrete?
What do goblet cells secrete?
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What do G cells secrete and what is its function?
What do G cells secrete and what is its function?
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What do enterochromaffin-like cells secrete?
What do enterochromaffin-like cells secrete?
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What do D cells secrete and what is its function?
What do D cells secrete and what is its function?
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How is HCl production in the stomach facilitated?
How is HCl production in the stomach facilitated?
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What is the role of HCl in protein digestion?
What is the role of HCl in protein digestion?
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How is the stomach lining protected from gastric juice?
How is the stomach lining protected from gastric juice?
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How does mucus contribute to stomach protection?
How does mucus contribute to stomach protection?
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How do prostaglandins contribute to stomach protection?
How do prostaglandins contribute to stomach protection?
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What stimulates the cephalic phase of gastric secretion?
What stimulates the cephalic phase of gastric secretion?
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What stimulates the gastric phase of gastric secretion?
What stimulates the gastric phase of gastric secretion?
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What stimulates the intestinal phase of gastric secretion?
What stimulates the intestinal phase of gastric secretion?
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Study Notes
###Â Mouth - Saliva Production and Function
- Saliva is produced by three pairs of salivary glands: parotid, submandibular, and sublingual.
- Approximately 1500ml of saliva is secreted each day.
- Saliva contains mucus for lubrication, alpha amylase for carbohydrate breakdown, and other enzymes.
- Saliva formation begins as an isotonic fluid produced by acinar cells that secrete electrolytes and water.
- The final composition of saliva depends on flow rate and neuronal input.
- Saliva secretion is regulated by the autonomic nervous system (ANS).
- Parasympathetic stimulation produces watery saliva, rich in amylase and mucous.
- Sympathetic stimulation produces thicker mucous and reduces blood flow to the glands.
###Â Swallowing
- Swallowing is a coordinated reflex controlled by the deglutition center in the medulla and pons of the brain.
- The voluntary stage involves pushing the bolus of food backwards to the oropharynx.
- During the pharyngeal stage, the soft palate and uvula move up to seal off the nasopharynx, the larynx raises and the glottis is sealed, and the epiglottis covers the glottis.
Oral Absorption of Drugs
- Drugs delivered buccally or sublingually need to cross the oral mucosa to enter the bloodstream directly.
- This bypasses the digestive system and avoids first-pass metabolism, leading to greater bioavailability and faster action.
- Limited surface area of the oral mucosa (~200cm2) is a barrier to absorption.
- Drug solubility in saliva and its passage through the lipophilic cell membrane and hydrophilic interior of cells are other barriers.
- Enzymatic barrier in buccal tissue can rapidly degrade peptides and proteins, limiting their transport across the epithelium.
Dental Problems
- Dry mouth (xerostomia) can lead to oral ulcers, dental caries, and complications with digestion and drug absorption.
- Oral ulcers often resolve without treatment but may require intervention in some cases.
- Oral thrush, a yeast infection, can be caused by antibiotic overuse, a weakened immune system, underlying illness, smoking, or dentures.
- Tooth decay can be caused by some medications including antacids, pain medications like opioids, antihistamines, and asthma inhalers.
###Â Dental Hygiene Advice
- Drink plenty of water.
- Brush your teeth twice a day and get regular dental check-ups.
- Use a moisturizing mouth spray.
- Reduce or give up smoking.
- Reduce intake of caffeinated and dehydrating drinks like coffee, tea, and alcohol.
- Use a hydrating mouth rinse.
###Â Stomach - Physiology and Function
- The stomach temporarily stores food, performs mechnical digestion, chemically digests proteins, regulates the passage of chyme into the small intestine, and secretes intrinsic factor necessary for vitamin B12 absorption.
- Muscularis layer enables churning of food, particularly in the antrum where the muscle wall is thicker.
- Food is mixed with gastric juice to produce chyme, which passes through the pyloric sphincter into the duodenum.
Gastric Glands
- The stomach mucosa is composed of epithelium containing pits/glands.
- Gastric glands contain three key cell types: zymogenic (chief/peptic) cells, parietal (oxyntic) cells, and goblet (neck) cells.
- Zymogenic cells secrete pepsinogen.
- Parietal cells secrete HCl and intrinsic factor.
- Goblet cells secrete mucous.
Additional Gastric Gland Cells
- G cells secrete gastrin.
- Enterochromaffin-like cells secrete histamine.
- D cells secrete somatostatin.
Gastric Acid Production
- HCl secretion is facilitated by a proton pump in parietal cells.
- HCl converts pepsinogen to pepsin, which actively breaks down proteins in the acidic environment of the stomach.
Stomach Protection
- A mucosal barrier prevents leakage of gastric juice onto underlying tissue.
- Mucus secreted by epithelial/goblet cells provides a localized neutralisation and physical barrier to acid.
- Prostaglandins increase mucosal thickness and stimulate bicarbonate secretion.
Gastric Secretion Phases
- Cephalic Phase: Stimulated by sight, smell, taste, thought of food, or decreased blood glucose. This leads to increased parasympathetic stimulation of HCl and pepsin secretion.
- Gastric Phase: Stimulated by stomach distension and presence of food. This triggers further HCl, pepsin, and gastrin secretion.
- Intestinal Phase: This phase inhibits gastric secretion and begins when chyme containing fat or enough HCl to lower the pH below 2 enters the duodenum.
- Neuronal impulses from the gut wall decrease parasympathetic stimulation.
- Local reflexes in the gut wall lead to decreased secretion.
- Hormones like secretin, gastric inhibitory peptide, and cholecystokinin inhibit gastric gland secretion.
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Description
This quiz explores the anatomy and physiology of saliva production and the swallowing process. It covers salivary glands, components of saliva, and the stages involved in swallowing. Test your understanding of how these bodily functions are regulated and coordinated.
