Digestive System Overview

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Questions and Answers

What substance is primarily absorbed in the ileum?

  • Cellulose
  • Fatty acids and glycerol (correct)
  • Mineral salts
  • Glucose and amino acids (correct)

The ileum is responsible for the initial digestion of food.

False (B)

What is the role of the pyloric sphincter?

It regulates the release of chyme into the duodenum.

The primary function of the colon is to reabsorb ______ into the bloodstream.

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

What structure transports absorbed nutrients from the villi to the liver?

<p>Hepatic portal vein (C)</p> Signup and view all the answers

Match the following components of the digestive system with their respective functions:

<p>Ileum = Absorption of nutrients Stomach = Churning and digestion of food Colon = Reabsorption of water Lacteals = Transport of fatty acids</p> Signup and view all the answers

Villi increase the surface area of the ileum for absorption.

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

Which enzyme is responsible for chemically digesting proteins in the stomach?

<p>Pepsin (D)</p> Signup and view all the answers

The small intestine is primarily responsible for the absorption of nutrients.

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

What are the thick liquid formed in the stomach during digestion called?

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

What is the role of hydrochloric acid (HCl) in the stomach?

<p>To create acidic conditions for pepsin and to kill bacteria.</p> Signup and view all the answers

The teeth used primarily for biting and cutting food are called __________.

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

Match the following types of human teeth with their primary functions:

<p>Incisors = Cutting food Canines = Tearing food Premolars = Crushing food Molars = Grinding food</p> Signup and view all the answers

What is the pH level in the stomach, favored for pepsin activity?

<p>Acidic (around pH 2) (C)</p> Signup and view all the answers

The pancreas secretes bile to aid digestion in the stomach.

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

Name one enzyme found in pancreatic juice and its function.

<p>Lipase; it digests fats.</p> Signup and view all the answers

What is the primary function of bile produced by the liver?

<p>Lipid emulsification (D)</p> Signup and view all the answers

The rectum is responsible for storing feces until it is expelled from the body.

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

What process converts excess glucose into glycogen in the liver?

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

The liver plays a significant role in removing ________ from the blood and converting them to less harmful substances.

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

Match the digestive organ to its function:

<p>Salivary glands = Begin starch digestion Pancreas = Produce digestive enzymes Liver = Produce bile Ileum = Absorb nutrients</p> Signup and view all the answers

Which enzyme in the pancreas is responsible for breaking down lipids?

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

Detoxification in the liver only involves removing alcohol from the blood.

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

What is the final end product of protein digestion in the ileum?

<p>amino acids</p> Signup and view all the answers

Which process of digestion breaks down food into smaller pieces without altering its chemical structure?

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

Chemical digestion involves breaking down food into smaller, soluble molecules that can be absorbed by the body.

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

What enzyme in saliva begins the chemical digestion of starch?

<p>salivary amylase</p> Signup and view all the answers

The tube that leads from the mouth to the anus is known as the __________.

<p>alimentary canal</p> Signup and view all the answers

Match the digestive structures with their primary functions:

<p>Teeth = Chewing food Esophagus = Transporting food to the stomach Liver = Producing bile Pancreas = Releasing digestive enzymes</p> Signup and view all the answers

Which of the following organs does NOT participate in physical digestion?

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

Peristalsis occurs in the mouth.

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

What is the main function of saliva in the digestive process?

<p>To moisten food and help stick food particles together</p> Signup and view all the answers

Flashcards

Circular muscles

Muscles that contract in rings around a tube to move contents.

Longitudinal muscles

Muscles that run along the length of a tube to facilitate movement.

Gastric juice

Digestive fluid with enzymes and hydrochloric acid produced in the stomach.

Pepsin

An enzyme in gastric juice that digests proteins into polypeptides.

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Role of bile

Bile neutralizes stomach acid and emulsifies fats in the small intestine.

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Pancreatic juice

A fluid from the pancreas containing enzymes for starch, protein, and fat digestion.

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Enzymatic digestion

The breakdown of food molecules into smaller components by enzymes.

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pH importance in digestion

Enzymes require specific pH levels for optimal activity in digestion.

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ILEUM

The last part of the small intestine, crucial for absorption.

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VILLI

Tiny finger-like projections in the ileum that increase surface area for absorption.

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Diffusion

Movement of molecules from high to low concentration, essential in nutrient absorption.

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Hepatic portal vein

Vein that transports blood from the intestines to the liver.

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Assimilation

The process of converting food nutrients into living tissue.

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COLON

The part of the large intestine responsible for water reabsorption and feces formation.

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Peristalsis

Waves of muscle contractions that move food through the digestive tract.

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Chyme

The thick liquid food mixture that leaves the stomach for the duodenum.

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Digestion

The breakdown of food into absorbable molecules by physical and chemical processes.

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Physical Digestion

The breakdown of food into smaller particles without changing their molecular structure.

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Chemical Digestion

The breakdown of complex molecules into smaller, absorbable molecules through enzyme activity.

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Alimentary Canal

The tube from mouth to anus through which food passes, including digestive organs.

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Amylase

An enzyme in saliva that begins the chemical digestion of starch into maltose.

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Salivary Glands

Glands in the mouth that produce saliva to moisten food and initiate digestion.

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Bolus

A small, rounded mass of chewed food ready to be swallowed.

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Rectum

The final section of the large intestine where feces is stored until expelled.

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Defecation

The process of expelling feces from the body.

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Bile

A digestive juice produced by the liver that helps emulsify fats.

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Deamination

The process of breaking down excess amino acids to remove nitrogen, producing urea.

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Detoxification

The process of removing toxins from the blood and converting them into safer substances.

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Glycogen

A stored form of glucose found in the liver, converted when blood sugar is low.

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Study Notes

Digestive System Overview

  • Digestion is the physical and chemical breakdown of food into absorbable substances.
  • Physical digestion breaks down large food particles into smaller ones, increasing surface area for enzymes.
  • Chemical digestion breaks down complex molecules into smaller, soluble molecules.
  • The digestive system includes the alimentary canal and associated organs (e.g., teeth, liver, gallbladder, pancreas).
  • The alimentary canal is the tube from mouth to anus, where food travels during digestion. Peristalsis is the involuntary rhythmic movement in the alimentary canal.

Digestive System Structures

  • Teeth: used for biting and chewing, increasing surface area and starting physical digestion.
  • Esophagus: tube connecting mouth to stomach; peristalsis moves food.
  • Liver: produces bile for fat emulsification. Stores nutrients like iron and vitamins. Maintains blood sugar levels.
  • Gall bladder: stores bile produced by the liver.
  • Duodenum: first part of small intestine; mixing of food with digestive juices.
  • Small intestine: contains enzymes to break down nutrients. Absorbs digested food into bloodstream
  • Large intestine: absorbs water and salts. Forms feces.
  • Pancreas: produces enzymes to break down carbohydrates, proteins and fats.
  • Stomach: churns food, mixes with gastric juice (enzymes and HCl).
  • Appendix: small pouch at beginning of large intestine.

Digestion in the Mouth

  • Ingestion: intake of food.
  • Saliva: produced by salivary glands; contains water, mucus, and amylase (enzyme that starts starch digestion).
  • Tongue: moves food around in mouth during chewing. Forms bolus (swallowed food mass).

Digestion in the Stomach

  • Gastric juice: produced in stomach; contains enzymes (pepsin) and HCl, which breaks down proteins and kills bacteria.
  • Chyme: semi-liquid mixture of partially digested food and gastric juice.

Digestion in the Small Intestine

  • Duodenum: bile (from liver/gallbladder) neutralizes chyme and emulsifies fats. Pancreatic juices contain enzymes.
  • Ileum: contains enzymes for final breakdown of nutrients. Absorbs digested nutrients into bloodstream.

Digestion in the Large Intestine

  • Colon: absorbs water and salts from undigested material.
  • Rectum: stores feces.
  • Defecation: removal of feces from body.

Enzymes

  • Enzymes are biological catalysts speeding up digestion. Each enzyme is specific to a substrate (nutrient).
  • Amylase breaks down starch.
  • Pepsin breaks down proteins.
  • Lipase breaks down lipids (fats).
  • Maltase breaks down maltose.
  • Peptidase breaks down polypeptides.
  • Sucrase breaks down sucrose.
  • Lactase breaks down lactose.

Role of the Liver

  • Processes nutrients absorbed from small intestine.
  • Stores glucose as glycogen; releases glucose as needed.
  • Removes toxins from blood.
  • Produces bile.

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