Digestive System Overview

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Questions and Answers

Which part of the digestive system is responsible for mechanical digestion of food?

  • Mouth (correct)
  • Stomach
  • Pharynx
  • Small intestine

The epiglottis prevents food from entering the respiratory tract.

True (A)

What is the substance that helps digest carbohydrates in the mouth?

Saliva

The food bolus is turned into ________ after digestion in the stomach.

<p>chyme</p> Signup and view all the answers

Match each part of the digestive system with its function:

<p>Mouth = Mechanical digestion and saliva production Stomach = Chemical digestion of proteins Small intestine = Nutrient absorption Pharynx = Transports food to the esophagus</p> Signup and view all the answers

What is the primary function of the small intestine?

<p>Absorb nutrients (C)</p> Signup and view all the answers

The esophagus uses a series of muscles to transport food to the stomach.

<p>True (A)</p> Signup and view all the answers

Name the first part of the small intestine.

<p>Duodenum</p> Signup and view all the answers

What is the primary function of bile that is secreted by the liver?

<p>Help digest lipids (fats) (A)</p> Signup and view all the answers

The pancreas has both digestive and endocrine functions.

<p>True (A)</p> Signup and view all the answers

What is formed in the mouth when food is mixed with saliva?

<p>Bolus</p> Signup and view all the answers

The last section of the small intestine is called the _____ .

<p>ileum</p> Signup and view all the answers

Match the parts of the digestive system to their primary function:

<p>Salivary Glands = Secrete digestive enzymes in saliva Liver = Secrete bile for fat digestion Pancreas = Produce pancreatic juices to neutralize stomach acid Large Intestine = Absorb water and transform undigested products into feces</p> Signup and view all the answers

Which part of the small intestine is characterized by having villi?

<p>Jejunum (B)</p> Signup and view all the answers

Chyme is the solid material that exits the large intestine.

<p>False (B)</p> Signup and view all the answers

What type of digestion is mastication?

<p>Mechanical digestion</p> Signup and view all the answers

The unicellular bacteria in the large intestine that aid in digestion are referred to as _____ .

<p>gut flora</p> Signup and view all the answers

Match the accessory glands to their main secretion:

<p>Salivary Glands = Amylase Liver = Bile Pancreas = Pancreatic juices Gallbladder = Store bile</p> Signup and view all the answers

Which of the following structures increases the surface area for nutrient absorption in the small intestine?

<p>Microvilli (B)</p> Signup and view all the answers

Water and minerals are primarily absorbed in the small intestine.

<p>False (B)</p> Signup and view all the answers

What is the role of the intestinal juices in the small intestine?

<p>They help in the chemical digestion of chyme.</p> Signup and view all the answers

The first part of the small intestine is known as the _____.

<p>duodenum</p> Signup and view all the answers

Flashcards

Digestive Tract

The long tube that runs through the body, responsible for breaking down food and absorbing nutrients. It includes the mouth, pharynx, esophagus, stomach, small intestine, large intestine, and anus.

Mechanical Digestion

The physical breakdown of food into smaller pieces. Examples include chewing with teeth and the churning actions of the stomach.

Chemical Digestion

The breakdown of food molecules into smaller components using enzymes. This happens in the mouth, stomach, and small intestine.

Mouth

The first part of the digestive tract where food enters, is chewed, and mixed with saliva.

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Salivary Glands

Glands in the mouth that produce saliva which helps break down carbohydrates and lubricates food.

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Stomach

A muscular organ that churns food and mixes it with gastric juices for protein digestion.

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Small Intestine

A long tube where most digestion and absorption of nutrients occurs. It has villi to increase surface area for absorption.

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Duodenum

The first part of the small intestine, where food from the stomach enters.

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What is the role of the small intestine in digestion?

The small intestine receives digestive juices from the liver and pancreas. It also produces its own juices to break down food into nutrients. This process transforms the chyme into chyle, a milky fluid containing nutrients.

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What is chyme?

Chyme is a semi-liquid mixture of food that leaves the stomach and enters the small intestine. This is what results after stomach acids and enzymes break down swallowed food.

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What is chyle?

Chyle is a milky fluid that is formed in the small intestine. It contains digested nutrients and water, ready for absorption into the bloodstream.

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What are villi?

Villi are small finger-like projections found on the inner lining of the small intestine. They increase the surface area for nutrient absorption.

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What does the jejunum do?

The jejunum is the middle part of the small intestine. It's characterized by villi and is responsible for absorbing most of the nutrients from digested food.

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What is the role of the ileum in digestion?

The ileum is the last part of the small intestine. Here, most of the remaining water and nutrients are absorbed.

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What are the parts of the large intestine?

The large intestine has three parts: the cecum, the colon, and the rectum. It's wider than the small intestine and primarily responsible for absorbing water and forming feces.

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What are accessory glands?

Accessory glands are located outside the digestive tract, but they release digestive juices into it. Examples include the salivary glands, liver, and pancreas.

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What is the role of the liver in digestion?

The liver produces bile, which helps in the digestion of fats. It also stores glucose, iron, and vitamins.

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What is the role of the pancreas in digestion?

The pancreas produces pancreatic juices that help neutralize stomach acid and digest proteins, carbohydrates, and fats.

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What is mechanical digestion?

Mechanical digestion is the physical breakdown of food into smaller pieces. It involves chewing, grinding, and mixing with saliva.

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What is chemical digestion?

Chemical digestion is the breakdown of food using enzymes and other substances in digestive juices. It occurs in the mouth, stomach, and small intestine.

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How does the small intestine maximize absorption?

The small intestine has a large surface area for absorption due to its length, folds, villi, and microvilli.

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What happens to undigested food in the large intestine?

Undigested food is transformed into feces by gut bacteria in the large intestine. The feces are then eliminated from the body through the anus.

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What is fiber's role in digestion?

Fiber is not digested by our bodies, but it's important for a healthy digestive system. It adds bulk to stool, helps with regularity, and promotes good bacteria growth.

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Study Notes

Digestive System Overview

  • The digestive system comprises the digestive tract (a long tube) and accessory digestive glands.
  • The digestive tract includes the mouth, pharynx, esophagus, stomach, small intestine, large intestine, and anus.

Mouth

  • Chewing (mastication) and grinding of food occur.
  • The tongue (with taste buds) provides taste.
  • Salivary glands produce saliva, initiating carbohydrate breakdown (chemical digestion).
  • Food is formed into a bolus.

Pharynx

  • Shared by digestive and respiratory systems.
  • The epiglottis acts as a lid, preventing food blockage of the respiratory tract.

Esophagus

  • Peristaltic movements push food to the stomach.

Stomach

  • Connected to the esophagus by the cardia.
  • Strong stomach muscles (mechanical digestion) and glands secrete gastric juices (containing pepsin).
  • Gastric juices break down proteins.
  • Stomach converts bolus into chyme.

Small Intestine

  • Very long tube with glands secreting intestinal juices.
  • Intestinal villi contain capillaries for nutrient absorption.
  • Three main parts: duodenum, jejunum, and ileum.
  • Duodenum receives digestive juices from the liver (bile for lipids) and pancreas (pancreatic juices to reduce acidity).
  • The small intestine makes intestinal juices.
  • Chyme is transformed into chyle (a milky fluid).
  • Jejunum, characterized by villi, increases absorption surface area.
  • Ileum, further down the small intestine, absorbs most remaining water and nutrients.

Large Intestine

  • Wider than small intestine; consists of caecum, colon, and rectum.
  • Absorbs water and minerals.
  • Gut flora converts undigested products into feces.
  • Feces are expelled through the anus (egestion/defecation).

Accessory Glands

  • Located outside the digestive tract.
  • Secrete digestive juices containing enzymes.
  • Include salivary glands, liver, and pancreas.

Salivary Glands

  • Three pairs secrete saliva into the mouth.
  • Saliva contains amylase for carbohydrate digestion.

Liver

  • Largest gland, performing crucial functions beyond digestion.
  • Produces bile stored in the gallbladder.
  • Bile aids in lipid (fat) digestion (acts as a detergent).
  • Stores glucose, iron, and vitamins; eliminates toxins like alcohol.

Pancreas

  • Arrowhead-shaped gland beneath the stomach.
  • Digestive function: secretes pancreatic juices into the intestine to counteract the acidity.
  • Endocrine function: releases substances into the bloodstream.

Mechanical Digestion

  • Reduces food particle size for easier processing.
  • Stages: mastication (chewing), insalivation (mixing with saliva to form bolus), deglutition (swallowing).

Chemical Digestion

  • Food is transformed into nutrients.
  • Mouth - saliva acts on carbohydrates
  • Stomach - gastric juices act on proteins
  • Small Intestine - intestinal juices, bile, and pancreatic juices complete digestion, converting chyme into chyle.

Absorption in the Small Intestine

  • Large surface area for rapid absorption (approximately 200 square meters).
  • Intestinal folds, villi, and microvilli greatly increase the surface area.
  • Nutrients enter the bloodstream through capillaries.

Absorption in the Large Intestine

  • Absorbs most remaining water and minerals.
  • No villi; gut lora processes undigested material into feces.

Food Components and Digestion

  • Fibrous components are indigestible and not absorbed.

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