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What is the first part of the small intestine?
What is the first part of the small intestine?
What substance is responsible for emulsifying fats in the small intestine?
What substance is responsible for emulsifying fats in the small intestine?
Where does bile enter the small intestine?
Where does bile enter the small intestine?
What is the role of bicarbonate in pancreatic juice?
What is the role of bicarbonate in pancreatic juice?
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What type of cells in the pancreas secrete pancreatic juice?
What type of cells in the pancreas secrete pancreatic juice?
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What is the main pigment found in bile that provides its greeny-yellow color?
What is the main pigment found in bile that provides its greeny-yellow color?
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Which enzyme is responsible for fat digestion in the small intestine?
Which enzyme is responsible for fat digestion in the small intestine?
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What is the primary function of the gall bladder related to bile?
What is the primary function of the gall bladder related to bile?
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What is the primary function of the digestive system?
What is the primary function of the digestive system?
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Which of the following organs is NOT involved in digestion?
Which of the following organs is NOT involved in digestion?
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What term describes the entire tube from the mouth to the anus?
What term describes the entire tube from the mouth to the anus?
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Which layer of the alimentary canal secretes mucus and digestive enzymes?
Which layer of the alimentary canal secretes mucus and digestive enzymes?
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What is the role of the muscularis externa in the digestive system?
What is the role of the muscularis externa in the digestive system?
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How does the submucosa contribute to digestion?
How does the submucosa contribute to digestion?
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What primarily remains in the chyme after absorption in the small intestine?
What primarily remains in the chyme after absorption in the small intestine?
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What is the function of the ileocecal valve?
What is the function of the ileocecal valve?
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Which type of digestion involves breaking down food mechanically?
Which type of digestion involves breaking down food mechanically?
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What protective feature does the mucosa provide in the digestive system?
What protective feature does the mucosa provide in the digestive system?
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What is the primary function of the large intestine?
What is the primary function of the large intestine?
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Where is waste matter stored before elimination?
Where is waste matter stored before elimination?
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What must happen for waste to be eliminated via the anus?
What must happen for waste to be eliminated via the anus?
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What happens to food after it has been swallowed?
What happens to food after it has been swallowed?
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What role does hydrochloric acid play in the stomach?
What role does hydrochloric acid play in the stomach?
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What is chyme?
What is chyme?
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Which enzyme is responsible for the thickening of milk in infants?
Which enzyme is responsible for the thickening of milk in infants?
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How does the gastric mucosa protect itself from hydrochloric acid?
How does the gastric mucosa protect itself from hydrochloric acid?
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What is the connection between gastric ulcers and alcohol consumption?
What is the connection between gastric ulcers and alcohol consumption?
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What is the primary action taken place in the stomach during digestion?
What is the primary action taken place in the stomach during digestion?
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What is the approximate length of the small intestine?
What is the approximate length of the small intestine?
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What enzyme continues the digestion of carbohydrates in the small intestine?
What enzyme continues the digestion of carbohydrates in the small intestine?
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What is the primary function of lipase in the digestive process?
What is the primary function of lipase in the digestive process?
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What structure in the small intestine increases the surface area for absorption?
What structure in the small intestine increases the surface area for absorption?
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What do lacteals transport in the small intestine?
What do lacteals transport in the small intestine?
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What is a primary function of the liver?
What is a primary function of the liver?
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What do hepatocytes help convert in the liver?
What do hepatocytes help convert in the liver?
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Which nutrient passes into the capillaries from the villi?
Which nutrient passes into the capillaries from the villi?
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What role does the liver play in regulating body temperature?
What role does the liver play in regulating body temperature?
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What happens to breathing during the pharyngeal-oesophageal phase?
What happens to breathing during the pharyngeal-oesophageal phase?
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How long can the process of food moving through the oesophagus take?
How long can the process of food moving through the oesophagus take?
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Which type of food typically remains in the stomach for the longest duration?
Which type of food typically remains in the stomach for the longest duration?
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What process occurs in the small intestine in addition to peristalsis?
What process occurs in the small intestine in addition to peristalsis?
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What role do pacemaker cells play in the digestive process?
What role do pacemaker cells play in the digestive process?
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How does parasympathetic nerve activity affect digestion?
How does parasympathetic nerve activity affect digestion?
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What happens immediately after the ileocecal valve opens?
What happens immediately after the ileocecal valve opens?
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Which type of food is likely to slow gastric emptying due to the need for emulsification?
Which type of food is likely to slow gastric emptying due to the need for emulsification?
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Study Notes
Digestive System I
- Food does not travel through the body like an egg goes through a snake.
- When injured, bits of food are not found in the blood.
- The digestive system breaks food down into nutrients, allowing them to be used by the body.
- Nutrients in a burger include fibre, protein, carbohydrates (bread), and fats (from lettuce, cheese).
Digestion
- Digestion breaks down food to be dissolved and part of the body.
- Chemicals are added to food to dissolve it.
- Mechanical digestion involves mashing food to increase surface area. This happens in the mouth while chewing, and in the stomach from churning.
- Chemical digestion involves breaking down chemicals until they are small and soluble enough to be carried in the blood. Enzymes aid this process.
Digestive System Organs
- The digestive system's main organs include the mouth, oesophagus, stomach, small intestine, large intestine, rectum and anus. This tube structure is called the alimentary or gastrointestinal (GI) tract.
- The stomach has a pouch-like structure, acting as a temporary storage organ.
Digestive System Wall Layers
- Mucosa: Moist epithelium with mucus, enzymes and hormone secretion to absorb nutrients and protect from disease. Loose areolar connective tissue and lymph nodes are beneath.
- Submucosa: Richly vascularized areolar tissue with elastic fibres, providing structural support.
- Muscularis externa: Two smooth muscle layers - inner is circular, outer is longitudinal - responsible for movement of food (involves wave-like contractions).
- Serosa: Outermost layer; areolar tissue covered with a single layer of squamous cells. Fibrous tissue may replace this in some areas (e.g. oesophagus) to hold the organs in place and is called adventitia.
Ingestion
- Taking a bite out of food.
- Nutrients from the bite are called ingestion.
Mouth
- Teeth – cut, tear, and grind food (physical digestion).
- Tongue – mixes food with saliva to form a bolus.
- Saliva contains amylase, which starts breaking down carbohydrates like starch.
- Soft palate and uvula prevent food from entering the nose.
- Hard palate provides a surface for tongue to push food against during chewing.
Oesophagus
- A muscular tube that moves food to the stomach.
- Peristalsis—involuntary muscle contractions—move food down the oesophagus.
Stomach
- Stomach acts as a temporary storage area.
- Mechanical churning mixes food with gastric juice (containing pepsin and rennin).
- Parietal cells make hydrochloric acid (HCl).
- Chief cells make pepsinogen, which HCl converts to pepsin (protein-digesting enzyme).
- Rennin thickens milk in babies.
- Food is then called chyme.
- Mechanical digestion from churning occurs here.
Duodenum (small intestine)
- Chyme enters the duodenum from the stomach.
- Bile enters from the liver and gall bladder: Emulsifies fats.
- Pancreatic juice (from pancreas) contains enzymes (e.g., amylase, lipase): continue digesting.
- Chyme has been further processed into semi-solid or paste like material, called chyme.
Small Intestine
- Most absorption occurs here; has microvilli to maximize surface area.
- Nutrients are absorbed into capillaries (to bloodstream) and lacteals (to lymphatic system).
- Fats, steroids, and fat-soluble vitamins are absorbed through the lymph system.
- The small intestine is made of three parts: duodenum, jejunum, and ileum.
- The ileocecal valve prevents back flow and prevents going back into the system.
Large Intestine (Colon)
- Absorbs water from undigested food.
- Undigested food, fibre, and dead cells remain.
- Compacts waste into faeces.
- Faeces are stored in the rectum.
- Eliminated via the anus through the anal sphincter.
Additional Digestive Organ Information
- Epiploic appendages of the colon.
- Plicae circulares of the small intestine.
- Blood supply to the stomach, liver, small & large intestines.
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Description
Explore the fundamentals of the digestive system, including its main functions, processes of digestion, and key organs involved. This quiz delves into both mechanical and chemical digestion, providing insights into how food is broken down into essential nutrients for the body.
