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Questions and Answers
What is the primary function of the epiglottis in the digestive system?
What is the primary function of the epiglottis in the digestive system?
Which enzyme is specifically mentioned as breaking down starch in the mouth?
Which enzyme is specifically mentioned as breaking down starch in the mouth?
What is the primary role of the small intestine's villi?
What is the primary role of the small intestine's villi?
Which part of the small intestine is most responsible for digestion?
Which part of the small intestine is most responsible for digestion?
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What is the primary substance produced by the liver for fat digestion?
What is the primary substance produced by the liver for fat digestion?
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Which component of gastric juice is responsible for breaking down food?
Which component of gastric juice is responsible for breaking down food?
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What are the three main parts of the small intestine in order?
What are the three main parts of the small intestine in order?
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Which organ secretes bicarbonate to neutralize acidic chyme?
Which organ secretes bicarbonate to neutralize acidic chyme?
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Study Notes
Stages of Digestion
- Digestion involves four stages: ingestion, digestion, absorption, and elimination.
- Ingestion is the intake of nutrients.
- Digestion is the breakdown of molecules.
- Absorption is the intake of digested molecules into the digestive tract.
- Elimination is the removal of waste food from the body.
Mouth
- Chemical digestion begins in the mouth.
- Salivary glands secrete saliva containing amylase.
- Amylase breaks down starch into simple sugars.
- Mechanical digestion occurs through teeth breaking down food.
- The tongue turns food into a soft bolus.
Teeth
- Different types of teeth exist, each with specific functions in mechanical digestion.
Esophagus
- A muscular tube that transports the bolus to the stomach using peristalsis.
- Peristalsis are wave-like muscular contractions.
- Mucus keeps the passage moist.
- The epiglottis prevents food from entering the lungs.
Stomach
- Food is stored temporarily for chemical and mechanical digestion.
- The muscular J-shaped stomach churns food into a thick liquid called chyme.
- Food triggers the secretion of gastric juice. Contains:
- Hydrochloric acid (HCl) to break down food.
- Mucus to protect the stomach lining from acid.
- Pepsin (an enzyme) to break down proteins (inactive until acid released)
- Salt and water
Small Intestine
- Covered with villi to increase surface area for nutrient absorption into the blood.
- Each villus is covered with microvilli.
- Nutrients are absorbed and carried via the bloodstream.
- Monosaccharides are converted to glucose, excess stored as glycogen.
- Amino acids are converted to waste or new proteins.
- Glycerol and fatty acids are reassembled into triglycerides for absorption.
- Three parts: duodenum, jejunum, and ileum
- Duodenum (0.5m): primary site for digestion due to pancreatic and gallbladder secretions.
- Jejunum (2.5m): large folds for digestion and absorption.
- Ileum (3m): fewest villi, pushing undigested material through .
Accessory Organs
- Pancreas: leaf-shaped; produces enzymes to break down food, bicarbonate to neutralize chyme, and insulin to control blood sugar.
- Liver: largest internal organ; produces bile to break down lipids (stored in gall bladder), stores glycogen, iron, and vitamins; disposes of waste products (alcohol, drugs).
- Gall bladder: stores bile from liver; releases it into the duodenum for fat digestion.
Large Intestine (Colon)
- Shorter but wider than the small intestine.
- Main function:
- Re-absorption of water into the blood.
- Housing anaerobic bacteria for continued food breakdown, vitamin production (folic acid, B, K).
- Converts waste into feces which are pushed to the rectum and anus.
Digestive Disorders
- Diarrhea: insufficient water absorption in the large intestine.
- Constipation: excessive water absorption in the large intestine.
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Description
Explore the four essential stages of digestion: ingestion, digestion, absorption, and elimination. This quiz delves into the roles of the mouth, teeth, esophagus, and stomach in the digestive process, highlighting the importance of both chemical and mechanical digestion.
