Digestive System Overview and Functions
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Questions and Answers

What is the primary function of the villi and microvilli in the small intestine?

  • To absorb excess water from digested food
  • To facilitate the elimination of waste products
  • To promote the secretion of digestive enzymes
  • To increase the surface area for greater absorption (correct)

What is the role of peristalsis in the digestive system?

  • To break down food mechanically
  • To move undigested food to the large intestine (correct)
  • To assist in the absorption of nutrients
  • To provide lubrication for the intestinal tract

Which of the following describes a function of the large intestine?

  • Synthesis of digestive enzymes
  • Absorption of water and formation of solid waste (correct)
  • Chemical breakdown of carbohydrates
  • Mechanical digestion of food

Which statement about the rectum is true?

<p>It stores solid waste until excretion (B)</p> Signup and view all the answers

What is the significance of microbial activity in the large intestine?

<p>It helps synthesize vitamins such as K and folic acid (A)</p> Signup and view all the answers

What is the primary function of the accessory organs associated with the alimentary canal?

<p>To help in the chemical breakdown of food (B)</p> Signup and view all the answers

What does mastication refer to in the digestive process?

<p>The act of chewing food (C)</p> Signup and view all the answers

Which of the following processes occurs during chemical digestion?

<p>Conversion of carbohydrates into simple sugars (B)</p> Signup and view all the answers

Which term describes the elimination of undigested materials from the body?

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

What is the end product of lipids during chemical digestion?

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

Which activity is NOT part of the functions of the large intestine?

<p>Chemical breakdown of food (B)</p> Signup and view all the answers

Which best describes digestion?

<p>The mechanical and chemical breakdown of food (B)</p> Signup and view all the answers

What is egestion?

<p>Removal of digestive waste (D)</p> Signup and view all the answers

Which of the following is not considered a metabolic waste?

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

Which organ is responsible for excreting carbon dioxide during exhalation?

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

Which of the following processes involves the breakdown of amino acids to form urea?

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

What is the primary function of the kidneys?

<p>To filter blood and remove waste (C)</p> Signup and view all the answers

In what form are metabolic wastes primarily excreted from the body?

<p>Liquid waste as urine (B)</p> Signup and view all the answers

Which part of the excretory system stores urine before it is excreted?

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

What substances do the sweat glands allow to diffuse from the blood?

<p>Water, salt, and urea (A)</p> Signup and view all the answers

What is the primary role of saliva in digestion?

<p>To begin the digestion of starch (D)</p> Signup and view all the answers

Which of the following structures is NOT part of the digestive tract?

<p>Gall bladder (C)</p> Signup and view all the answers

What is the function of the tongue during digestion?

<p>To mix and roll food into a bolus (A)</p> Signup and view all the answers

Which phase of digestion involves the movement of food through the digestive system?

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

What role do teeth play in digestion?

<p>Mechanical breakdown of food (D)</p> Signup and view all the answers

What is the primary function of the rectum in the digestive system?

<p>Storage of feces (D)</p> Signup and view all the answers

Which accessory organ secretes enzymes that aid in the digestion of fats, proteins, and carbohydrates?

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

What coordinated activity is involved in swallowing?

<p>Tongue, soft palate, pharynx, and esophagus (D)</p> Signup and view all the answers

What is the primary function of the liver related to blood glucose levels?

<p>Converts glycogen back into glucose in the presence of glucagon (C)</p> Signup and view all the answers

Which of the following statements accurately describes bile?

<p>Bile emulsifies fats for easier digestion in the intestine (A)</p> Signup and view all the answers

What enzyme is NOT produced by the pancreas?

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

Which substance is primarily stored in the gall bladder?

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

What is the primary role of pancreatic juice?

<p>To break down carbohydrates, fats, and proteins (B)</p> Signup and view all the answers

How does the liver contribute to hormone regulation?

<p>It inactivates hormones such as insulin and glucagon (D)</p> Signup and view all the answers

Which of the following is considered an accessory organ of digestion?

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

What process is primarily facilitated by the emulsifying action of bile?

<p>Digestion of fats (A)</p> Signup and view all the answers

What role does the soft palate play during swallowing?

<p>It raises to block the nasal part of the pharynx. (A)</p> Signup and view all the answers

How long does food typically take to pass through the esophagus to the stomach?

<p>4 to 8 seconds (B)</p> Signup and view all the answers

What is the main function of hydrochloric acid in gastric juice?

<p>To kills bacteria and break down food (D)</p> Signup and view all the answers

Which part of the small intestine is primarily responsible for receiving digestive juices from the pancreas and liver?

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

What is the function of villi in the small intestine?

<p>To absorb digested nutrients (A)</p> Signup and view all the answers

What is the process called that moves food through the digestive tract?

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

What activates pepsinogen into its active form, pepsin?

<p>Hydrochloric acid (C)</p> Signup and view all the answers

What prevents injury to the stomach wall during digestion?

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

Which phase of swallowing is controlled voluntarily?

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

What is the main purpose of the cardiac sphincter in the digestive system?

<p>To allow food into the stomach (C)</p> Signup and view all the answers

Flashcards

Digestion

The process of breaking down food into smaller molecules that the body can absorb.

Ingestion

The first stage of the digestive process where food enters the mouth and is chewed and mixed with saliva.

Movement (Peristalsis)

The movement of food through the digestive tract, aided by muscle contractions called peristalsis.

Absorption

The absorption of nutrients into the bloodstream from the digestive tract.

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Further Digestion

The process of breaking down food into smaller molecules that the body can absorb.

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What is the digestive tract?

A long, muscular tube that begins at the mouth and ends at the anus, responsible for the digestion and absorption of food.

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What is the esophagus?

A muscular tube that connects the mouth to the stomach and carries food down.

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What is the duodenum?

The first part of the small intestine, where most of the digestion occurs.

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Mechanical Digestion

The physical breakdown of food through chewing, tearing, grinding, mashing, and mixing.

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Chemical Digestion

The chemical breakdown of food using digestive enzymes, specialized proteins that break down large molecules into smaller ones.

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Elimination

The expulsion of indigestible substances from the body as faeces.

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Deglutition

The act of swallowing food.

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Peristalsis

Rhythmical muscular contractions that propel food and waste products along the alimentary canal.

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Swallowing: Voluntary Phase

The voluntary phase of swallowing where the tongue pushes food toward the pharynx, the tongue blocks the mouth, the soft palate closes off the nose, and the larynx rises to allow the epiglottis to close the trachea.

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Swallowing: Involuntary Phase

The involuntary phase of swallowing where the pharynx muscles propel the bolus into the esophagus. The soft palate rises to seal off the nasal passage, ensuring food goes down the esophagus and not up the nose.

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Mastication

The process of chewing food using your teeth and jaw muscles, breaking it down into smaller pieces.

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Bolus

A soft, round mass of food formed in the mouth during chewing and swallowing.

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Esophagus

A muscular tube that connects the mouth to the stomach. It uses rhythmic muscle contractions (peristalsis) to move food down.

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Stomach

A large, muscular sac that receives food from the esophagus. It mixes food with gastric juices, breaks it down into smaller pieces, and prepares it for further digestion in the small intestine.

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Gastric Juice

A mixture of hydrochloric acid, enzymes, and other fluids produced by the stomach lining. It aids digestion by breaking down food and killing bacteria.

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Duodenum

The first part of the small intestine. It receives chyme from the stomach and mixes it with digestive juices from the pancreas and liver.

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Small Intestine

The long, coiled middle portion of the small intestine where most of the digestion and absorption of nutrients occurs.

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Microvilli

Tiny projections that extend from the surface of the villi in the small intestine, greatly increasing surface area for absorption of digested food.

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Small Intestine Function

The process in the small intestine where food is mixed, lubricated, liquefied, digested, and absorbed into the bloodstream.

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Rectum

The largest part of the large intestine, where solid waste is stored before excretion.

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Appendix

The small, finger-like projection attached to the large intestine, with a role in immune function, but no clear digestive purpose.

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What is the liver's role in digestion?

The largest gland in the body, responsible for producing and storing bile, converting glucose to glycogen, storing vitamins A, D, E, and K, and detoxifying harmful substances like alcohol.

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What is bile, and what is its function?

A watery, greenish substance produced by the liver that helps digest fats by emulsifying them.

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What is the gallbladder's function?

A small pouch-like organ that stores bile produced by the liver and releases it into the duodenum during digestion.

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What does the pancreas do?

An elongated organ situated behind the stomach, responsible for producing digestive enzymes (amylase, lipase, and peptidases) and hormones (insulin and glucagon) that regulate blood sugar levels.

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What is pancreatic juice?

A mixture of water, mineral salts, and enzymes secreted by the pancreas to break down carbohydrates, fats, and proteins in the small intestine.

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What is mechanical digestion?

A process that physically breaks down food into smaller particles using the teeth, tongue, and stomach muscles.

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What is chemical digestion?

A process that uses digestive enzymes to break down food molecules into smaller units that can be absorbed by the body.

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What is defecation?

A process by which waste products from the digestive system are eliminated from the body through the anus.

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Excretion

The removal of metabolic waste products from the body.

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Skin Excretion

The skin is involved in excretion by releasing sweat, which contains water, salt, and urea.

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Lung Excretion

Lungs are involved in excretion by releasing carbon dioxide and water vapor during exhalation.

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Liver Excretion

The liver removes excess amino acids and converts them into urea, a waste product excreted in urine.

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Kidneys Excretion

The kidneys are the main excretory organs, filtering blood and producing urine, which contains water, salts, and urea.

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Ureter

The ureter is a tube that carries urine from the kidneys to the urinary bladder.

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Urinary Bladder

The urinary bladder is a sac that stores urine before it is excreted.

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Study Notes

Digestive System Overview

  • The digestive system is a long muscular tube, starting at the mouth and ending at the anus
  • It has multiple sections, including the mouth, esophagus, small intestine, large intestine, rectum, and anal canal
  • The system involves both mechanical (physical) and chemical breakdown of food

Digestive System Learning Outcomes

  • Identify structures of the alimentary canal
  • Identify accessory organs associated with the alimentary canal
  • State the activities of the alimentary canal
  • Explain mastication and deglutition
  • Explain chemical digestion within the alimentary canal
  • Describe functions of the large intestine
  • Describe functions of accessory organs associated with the alimentary canal

Glossary of Terms

  • Ingestion: Taking food into the alimentary canal
  • Digestion: Mechanical (chewing, tearing, grinding, mixing) and chemical breakdown of food by enzymes
  • Absorption: Digested food substances entering the blood and lymph
  • Elimination: Undigested substances exiting the body as feces
  • Mastication: The act of chewing
  • Deglutition: The act of swallowing
  • Peristalsis: Rhythmical muscular contractions that move food through the intestines

Digestion

  • Breaks down complex biological molecules into component parts: lipids to fatty acids, proteins to amino acids, carbohydrates to simple sugars
  • Filters out harmful substances
  • Removes solid wastes

Mechanical Digestion

  • Changes the physical form of food
  • Involves chewing, tearing, grinding, and mixing

Chemical Digestion

  • Changes the chemical composition of food
  • Uses digestive enzymes as specialized proteins, breaking large food molecules into smaller ones for absorption

Phases of Digestion

  • Ingestion
  • Movement
  • Digestion
  • Absorption
  • Further digestion

Mouth

  • Food enters the mouth/oral cavity; tasting occurs
  • Mechanical breakdown of food through chewing
  • Secretion of salivary glands (salivary amylase) to begin starch digestion

Mouth - Tongue

  • Mixes and rolls food into a bolus
  • Pushes bolus toward the pharynx and into the esophagus during swallowing

Mouth - Teeth

  • Cut, tear, crush, and grind food

Swallowing Mechanics

  • Coordinated activity of tongue, soft palate, pharynx, and esophagus
  • Food to pharynx (voluntary)
  • Tongue blocks mouth
  • Soft palate closes off nose
  • Larynx and epiglottis to prevent food from entering the windpipe
  • Phases: Buccal, Pharyngeal, Esophageal

Mastication & Deglutition

  • Saliva moistens food
  • Bolus formation
  • Voluntary tongue/cheek muscles move bolus to pharynx
  • Pharynx muscles push bolus to esophagus
  • Bolus in pharynx initiates peristalsis
  • Other routes closed to bolus
  • Soft palate occludes nasal part of pharynx

Esophagus

  • Straight muscular tube connecting the mouth to the stomach
  • Food passage takes 4-8 seconds.
  • Peristaltic waves propel food downward

Stomach

  • J-shaped muscular sac
  • Inner folds (rugae) increase surface area
  • Churns and grinds bolus into smaller pieces
  • Mixes with gastric juices (HCl and enzymes)
  • HCl helps break down food and kill bacteria
  • Creates chyme

Gastric Juice Components

  • Water
  • Hydrochloric acid
  • Pepsinogen (activated to pepsin)
  • Intrinsic factor (for Vit B12 absorption)
  • Mucus

Small Intestine

  • Long, coiled tube beneath the stomach
  • Has three parts: duodenum, jejunum, ileum
  • Duodenum receives digestive juices from pancreas and liver
  • Chyme is mixed with secretions, becoming thin and watery
  • Digestion and nutrient absorption occur

Small Intestine - Absorption

  • Mucosa (inner wall) secretes enzymes
  • Digested nutrients absorbed through intestinal walls
  • Absorbed materials cross mucosa into bloodstream for storage or further chemical change
  • Folded inner walls covered with villi (finger-like projections) and microvilli (tiny projections on villi)
  • Increases surface area for greater absorption
  • Peristalsis moves undigested food to large intestine

Small Intestine - Movement

  • Mixing: Segmental contractions
  • Secretion: Lubrication, liquefaction, digestion
  • Digestion: Mechanical and chemical
  • Absorption: Movement into circulation or lymph
  • Elimination: Waste products removed from body

Large Intestine (Colon)

  • Larger diameter, but shorter than small intestine (5 ft.)
  • Water is absorbed from undigested food, making waste harder (solid)
  • Waste stays for 10-12 hours.
  • Waste is pushed into the rectum
  • Solid waste excreted as feces through anus
  • Appendix hangs on the right side

Large Intestine - Functions

  • Absorption of water, mineral salts, and some drugs
  • Microbial activity (synthesis of Vit K and folic acid)
  • Defecation (elimination of feces)

Accessory Organs - Liver

  • Produces or stores enzymes for digestion
  • Largest gland
  • Stores Vitamins A,D,E,K
  • Produce bile (watery, greenish substance)
  • Stores glycogen / sugar
  • Secretes bile -> gallbladder -> hepatic duct -> cystic duct
  • Converts glucose to glycogen with insulin , changes glycogen back to glucose with glucagon
  • Desaturates fats

Accessory Organs - Gall Bladder

  • Stores bile between meals
  • Secretes bile to duodenum during mealtimes
  • Bile contains bile salts, pigments, cholesterol & phospholipids
  • Bile is an emulsifier (not enzyme, dissolves fat to watery contents)

Accessory Organs - Pancreas

  • Produces juice with enzymes (amylase, lipase) to break down carbs, fats, and proteins
  • Secretes juice into duodenum via pancreatic duct
  • ~12-15cm long
  • Head in duodenum curve
  • Tail near left kidney
  • Body behind stomach
  • Pancreatic duct joins common bile duct -> ampulla
  • Islets of Langerhans (endocrine function)

Pancreatic Juice

  • Water
  • Mineral salts
  • Enzymes (pancreatic amylase, lipase, and peptidases)

Excretory System

  • Gets rid of wastes the body doesn't need
  • Digestive waste (egestion): feces
  • Metabolic waste: water, carbon dioxide, salts, urea

Excretory Organs - Skin

  • Allows water, salt, and urea to diffuse from blood into sweat glands
  • Releases sweat through pores

Excretory Organs - Lungs

  • Excretes carbon dioxide and water vapor during exhalation

Excretory Organs - Liver

  • Removes excess amino acids
  • Breaks down amino acids into urea (excrete in urine)

Excretory Organs - Kidneys

  • Major excretory organs
  • Purify blood by filtering out water, salts, digested food particles, and urea.
  • Urine passes through urinary tract (ureter -> bladder -> urethra)

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APL6 Digestive System PDF

Description

This quiz covers the components of the digestive system, including the structures of the alimentary canal and the functions of accessory organs. Learn key terms related to digestion, absorption, and the mechanical and chemical processes involved in breaking down food.

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