Biology Digestive System Quiz

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Questions and Answers

What is the primary function of the large intestine?

Production of digestive enzymes

Absorption of nutrients

Absorption of water and elimination of indigestible food (correct)

Digestion of carbohydrates

Which part of the large intestine is the first to receive material from the small intestine?

Transverse colon

Sigmoid colon

Cecum (correct)

Rectum

Which statement about the pancreas is true?

It is primarily responsible for the absorption of nutrients.

It secretes hormones into the bloodstream only.

It produces alkaline fluid that acts to neutralize acidic chyme. (correct)

It produces digestive enzymes that are released into the stomach.

What is the main purpose of bile produced by the liver?

To emulsify fats and aid in their digestion Signup and view all the answers

Which of the following is NOT a category of nutrients mentioned?

Fiber Signup and view all the answers

What is the outcome of mechanical digestion?

Production of smaller food particles without altering chemical structure. Signup and view all the answers

Which of the following statements about chemical digestion is true?

Enzymes are involved in transforming polymers into simpler monomers. Signup and view all the answers

Which process occurs first in the digestive system?

Ingestion. Signup and view all the answers

What role does absorption play in the digestive process?

It transports nutrients to various tissues via blood or lymph. Signup and view all the answers

What happens during the process of propulsion in the digestive system?

Food is moved from one part of the digestive system to another. Signup and view all the answers

What is the primary function of the stomach in the digestive process?

Storage and breakdown of food Signup and view all the answers

Which structure is responsible for conducting food from the pharynx to the stomach?

Esophagus Signup and view all the answers

What role do villi play in the small intestine?

Increase surface area for nutrient absorption Signup and view all the answers

Which type of teeth are fully formed by age two?

Deciduous teeth Signup and view all the answers

What type of muscle layers are involved in the movement of food through the pharynx?

Circular and longitudinal layers Signup and view all the answers

Study Notes

Biology 8 - Digestive System

The digestive system's function is to break down ingested food, absorb nutrients, transport them to tissues for metabolism, and produce cellular energy (ATP). It also facilitates constructive and degradative cellular activities.

Types of Digestion

Digestion is a catabolic process that breaks down complex molecules into simpler monomers like monosaccharides, glycerol and fatty acids, amino acids, and nucleotides for absorption.

Mechanical Digestion

Mechanical digestion does not chemically change food; it only breaks food into smaller pieces and mixes it with digestive juices. An example is chewing (mastication).

Chemical Digestion

Chemical digestion changes the food chemically. Polymers are broken down into monomers through hydrolysis reactions by enzymes within the digestive juices.

Six Processes of Digestion

Ingestion: Getting food into the mouth.
Propulsion: Moving food from one digestive region to another.
Mixing: Mixing food in the mouth by the tongue and churning in the stomach. Segmentation in the small intestine.
Mechanical Digestion: Includes chewing, churning, and segmentation.
Chemical Digestion: Enzymes break down food molecules into simpler components. Different enzymes target carbohydrates (sugars), proteins (amino acids), and fats (fatty acids and alcohols).
Absorption: The end products of digestion are absorbed into the blood or lymph; food must enter mucosal cells then blood or lymph capillaries.
Defecation: Elimination of indigestible substances as feces.

Divisions of Digestive System Organs

Alimentary Canal: Mouth, pharynx, esophagus, stomach, small intestine, large intestine, and anus.
Accessory Organs: Salivary glands, teeth, pancreas, liver, and gallbladder.

Mouth (Oral Cavity)

Mastication (chewing): Chewing of food.
Mixing with saliva: Mixing masticated food with saliva.
Initiation of swallowing: The tongue initiates swallowing.
Taste receptors. The mouth has taste receptors.

Salivary Glands/Saliva

Saliva is a mixture of mucus and serous fluids that forms a food bolus.
It contains salivary amylase to begin starch digestion.
Saliva dissolves chemicals for tasting.
Parotid, submandibular, and sublingual glands produce saliva.

Teeth

Teeth are used for mastication.
Humans have two sets of teeth: deciduous (baby/milk) and permanent.
20 deciduous teeth are fully formed by age two.

Pharynx

Serves as a passageway for air and food.
Food is propelled to the esophagus by two muscle layers (longitudinal and circular) through peristalsis.

Esophagus

Runs from the pharynx to the stomach, passing through the diaphragm.
Conducts food by peristalsis.
A passageway for food only.

Stomach

Located on the left side of the abdominal cavity.
Food enters at the cardioesophageal sphincter.
Regions include cardia, fundus, body, and pylorus.
The pylorus is the funnel-shaped terminal end.
Rugae are internal folds of the mucosa.
Food empties into the small intestine at the pyloric sphincter.
Stomach lining
Simple columnar epithelium forms the lining of the stomach
Mucous neck cells (goblet cells) produce mucus
Gastric glands secrete gastric juice
Chief cells produce protein-digesting enzymes (pepsinogens)
Parietal cells produce hydrochloric acid
Endocrine cells produce gastrin.
Gastric pits form the folded mucosa of the stomach. The specialized cells in the glands are in the gastric gland region.

Small Intestine

The major digestive organ.
Regions: duodenum, jejunum, and ileum.
Nutrient absorption into the blood.
Suspended from the posterior abdominal wall by the mesentery.
The duodenum curves around the head of the pancreas, receiving bile and pancreatic juices.
The jejunum attaches to the duodenum and the ileum extends from the jejunum to the large intestine.
Small intestine lining
Villi and plicae circulares (circular folds) increase surface area for absorption
Simple columnar epithelium with microvilli forms the surface.
Blood vessels absorb monosaccharides, amino acids, nucleic acids.
Lacteals (specialized lymphatic capillaries) absorb lipids.

Large Intestine (Colon)

Larger in diameter but shorter than the small intestine.
Forms the internal abdomen.
Parts include cecum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum, and anus.
Absorbs water;
Eliminates indigestible food as feces.
Goblet cells produce mucus to lubricate stool.
Site of Vitamin K production by symbiotic bacteria. Bacteria produce over 50% of fecal matter.

Appendix

Accumulation of lymphatic tissue.
Inflamed appendix is appendicitis.
Hangs from the cecum.

Accessory Organs

Pancreas: Produces a wide spectrum of digestive enzymes that break down all categories of food. Enzymes secreted into the duodenum; Alkaline fluid introduced to neutralize acidic chyme (in food). Endocrine products include insulin and glucagon.
Liver: Largest gland; composed of four lobes; stores bile; bile introduced to duodenum with presence of fatty food; bile produced by cells in the liver; connected to the gall bladder via the common hepatic duct.
Gallbladder: Stores bile from the liver. Bile is delivered to the duodenum through the cystic duct.

Nutrition

Categories of nutrients: Carbohydrates, lipids, proteins, vitamins, minerals, water.
Malnutrition: A lack of proper nutrients or an imbalance in the correct amounts of each nutrient. Even obese people can suffer malnutrition.
Carbohydrates: Primarily from plants; exceptions include lactose from milk and glycogen from meats.
Lipids: Include saturated fats (animal products), unsaturated fats (nuts, seeds, vegetable oils), and cholesterol (egg yolk, meats, milk).
Proteins: Complete proteins contain all essential amino acids (mostly from animals); incomplete proteins are lacking one or more essential amino acids (legumes, beans).
Vitamins: Used as cofactors with enzymes. Many are produced by plants.
Minerals: Play various roles; found in vegetables, legumes, milk, and some meats.

Diseases of Digestive System

Heartburn (Acid reflux): Stomach acid entering the esophagus causing burning sensation. Chronic severe cases can lead to damage, ulceration, scarring and possible esophagus cancer.
Ulcer: Weakened stomach or duodenum lining exposed to digestive enzymes and acid. Can create holes in mucosa; blood vessel involvement can cause severe bleeding. Now known that infection by Helicobacter pylori bacteria is linked to ulcers.
Crohn’s Disease: Inflammatory disease of the bowel; causes fever, pain, diarrhea, weight loss; affects any part of the bowel; most often affects the lower end of the small intestine junction with large intestine; leads to intestinal wall thickening and inflammation (ulcers/fissures); intestinal space narrowing.
Colon Cancer: Cancer starting in the inner layer of the colon and rectum; may spread through layers; knowing the layers and their extent can help diagnose stage of spread/severity. Over 95% are adenocarcinomas (cancer of cells lining inside of colon and rectum). Often referred to together as colorectal cancer. Polyps (adenomas) can be removed to prevent cancer.

Next Topic: Circulatory System

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Description

Test your knowledge on the human digestive system with this quiz covering key concepts and functions. Questions include the roles of various organs, types of digestion, and the nutrient categories involved. Perfect for biology students looking to reinforce their understanding.