10.2 Chapter Questions - Digestive System

Question 1

filter feeders, fluid feeders, substrate feeders, or bulk feeders?
An animal that feeds on plant sap has a long, beak-like mouthpart that can pierce plant tissues.

Answer 1

fluid feeders.

Question 2

filter feeders, fluid feeders, substrate feeders, or bulk feeders?
An animal eats its way through the upper surface of a leaf.

Answer 2

substrate feeders.

Question 3

filter feeders, fluid feeders, substrate feeders, or bulk feeders?
An animal captures its prey with its teeth and tears off pieces of meat.

Answer 3

bulk feeders.

Question 4

filter feeders, fluid feeders, substrate feeders, or bulk feeders?
An aquatic animal has gills in which mucus traps food.

Answer 4

filter feeders.

Question 5

describe the path of food as it moves through the digestive system

Answer 5

1. Mouth: Food enters and undergoes mechanical digestion.
2. Esophagus: Food is pushed down to the stomach through peristalsis.
3. Stomach: Food is further broken down into chyme.
4. Small Intestine: Most digestion and nutrient absorption occur.
5. Large Intestine (Colon): Water and electrolytes are absorbed, and fermentation occurs.
6. Rectum: Waste material is stored temporarily.
7. Anus: Waste is eliminated through defecation.

Question 6

Differentiate between mechanical and chemical digestion

Answer 6

Mechanical Digestion:
- Definition: Mechanical digestion refers to the physical breakdown of food into smaller particles without altering its chemical composition.
- Function: It increases the surface area of the food, making it easier for enzymes to act upon and facilitating chemical digestion.

Chemical Digestion
- Definition: Chemical digestion involves the breakdown of complex food molecules into simpler components through chemical reactions.
- Function: It enables the body to break down macromolecules (such as carbohydrates, proteins, and lipids) into their building blocks (such as glucose, amino acids, and fatty acids) for absorption and utilization.

Question 7

Why is it necessary for food to be digested?

Answer 7

• To break down complex food molecules into simpler forms that can be absorbed by the body.
• To release nutrients that can be used for energy production, growth, and repair.
• To facilitate the absorption of essential nutrients into the bloodstream.
• To remove waste materials and toxins from the body through the elimination of undigested matter.
• To support the proper functioning of cells, tissues, and organs by providing necessary nutrients.

Question 8

Describe where the digestion of carbohydrates begins in the body, the major glands involved, and the digestive secretions produced.

Answer 8

• Carbohydrate digestion begins in the mouth.
• The major glands involved are the salivary glands
• The digestive secretions produced include saliva in the mouth

Question 9

Explain why you can still swallow a mouthful of food, even if you are standing on your head.

Answer 9

• Swallowing is a reflex action controlled by muscles in the throat.
• The muscles involved in swallowing are capable of moving food in the correct direction regardless of body position.
• The swallowing process is coordinated by the brainstem, which ensures proper muscle contraction and coordination.
• Gravity does not significantly affect the ability to swallow as the muscles involved are strong enough to overcome its influence.
• Therefore, you can still swallow a mouthful of food even if you are standing on your head.

Question 10

A doctor orders a pH test of the esophagus for a patient who is complaining about having heartburn and a burning sensation in the chest. What do you expect the doctor to find and why?

Answer 10

• The doctor is likely to find an elevated pH in the esophagus.
• The elevated pH indicates the presence of acid reflux, where stomach acid flows back into the esophagus.
• Acid reflux can cause heartburn and a burning sensation in the chest due to the irritation of the esophageal lining by the acidic content.

Question 11

Explain two functions of pancreatic fluid.

Answer 11

• Pancreatic fluid helps neutralize the acidic chyme from the stomach, creating an optimal pH environment for the enzymes in the small intestine.
• It contains digestive enzymes, such as pancreatic amylase, pancreatic lipase, and pancreatic proteases, which aid in the breakdown of carbohydrates, fats, and proteins, respectively.

Question 12

What happens to fats before they are digested and absorbed by the intestinal cells? Explain why this occurs.

Answer 12

• Fats undergo emulsification before they are digested and absorbed by intestinal cells.
• Emulsification is the process of breaking down large fat droplets into smaller droplets.
• This process occurs due to the action of bile salts produced by the liver and stored in the gallbladder.
• Emulsification increases the surface area of fats, allowing enzymes called lipases to act more efficiently.
• The increased surface area enhances the digestion and absorption of fats in the small intestine.
• Emulsification aids in the solubilization of fats in the watery environment of the digestive system.

Question 13

What is the role of the gallbladder in digestion?

Answer 13

• Storage: The gallbladder stores and concentrates bile, a digestive fluid produced by the liver.
• Release: When food containing fat enters the small intestine, the gallbladder releases bile into the digestive tract.
• Emulsification: Bile helps in the emulsification of fats, breaking them into smaller droplets, which increases their surface area for efficient digestion.
• Fat Digestion: Bile aids in the digestion and absorption of dietary fats by enhancing their breakdown by lipase enzymes.
• Nutrient Absorption: Bile also facilitates the absorption of fat-soluble vitamins (A, D, E, and K) and certain fatty acids.
• Not Essential: While the gallbladder plays a role in digestion, it is not essential for survival, and its removal (in cases of gallbladder disease) does not prevent normal digestion.

Question 14

How are the small and large intestines different in structure and function?

Answer 14

• Small Intestine: Longer, with folds and villi, where digestion and absorption of nutrients primarily occur.
• Large Intestine: Shorter, with a smooth inner surface, responsible for water absorption, feces storage, and bacterial fermentation.

Question 15

A baby is born with a mutation that results in an unusually smooth small intestine that has far fewer villi than a normal small intestine. Describe one possible consequence of this mutation.

Answer 15

• Reduced surface area for nutrient absorption
• Impaired absorption of nutrients from the small intestine
• Potential malnutrition or nutrient deficiencies
• Digestive problems and poor weight gain
• Possible gastrointestinal symptoms like diarrhea or nutrient intolerance

Question 16

A family member has recently had their gallbladder removed (cholecystectomy). Now they must take medication to prevent diarrhea. Why would removal of the gallbladder cause diarrhea?

Answer 16

• The gallbladder is responsible for storing and releasing bile, a digestive fluid produced by the liver.
• Bile helps in the digestion and absorption of dietary fats.
• After gallbladder removal, bile flows continuously from the liver into the small intestine, rather than being stored and released in response to meals.
• The continuous flow of bile can overwhelm the ability of the small intestine to absorb it effectively.
• Excess bile in the small intestine can lead to diarrhea, as it can stimulate the intestines and cause increased fluid secretion.
• Medication may be prescribed to help bind excess bile and reduce its impact on the intestines, thus preventing diarrhea.

Question 17

The small intestine is divided into three different regions. Describe the structure and function of each of these regions

Answer 17

• Duodenum: Receives partially digested food, neutralizes stomach acid, and continues digestion.
• Jejunum: Plays a major role in nutrient absorption.
• Ileum: Completes nutrient absorption, absorbs vitamin B12 and bile salts, and passes waste into the large intestine.

Question 18

Why are most digestive enzymes not found in the stomach?

Answer 18

• Most digestive enzymes are not found in the stomach due to the acidic environment.
• The stomach has a low pH (highly acidic) to aid in the digestion of proteins.
• The high acidity of the stomach can denature or inactivate many enzymes.
• Stomach acid can also be harmful to certain types of enzymes.
• Digestive enzymes are primarily found in the small intestine, where pH is less acidic and more suitable for their optimal activity.

Question 19

Some animals do not have teeth like humans do (ie. birds). In what ways would a digestive system that did not use mechanical digestion differ from one that does?

Answer 19

a digestive system without mechanical digestion, as seen in birds, relies more on chemical digestion, may have a longer digestive tract, and may possess specialized adaptations for processing food.

Question 20

Which structural features of the small intestine increase surface area?

Answer 20

• Circular folds (plicae circulares): Deep folds of the intestinal lining.
  
  • Villi: Finger-like projections on the surface of the intestinal lining.
  • Microvilli: Tiny, hair-like extensions on the surface of individual cells within the villi.

Question 21

Some people have a band surgically inserted near the top of the stomach to help them control their weight. What impact would this have on their digestion?

Answer 21

• The band restricts the size of the stomach and limits the amount of food that can be consumed.
• Impact on digestion:
  
  • Smaller stomach capacity leads to reduced food intake.
  • Food is temporarily held in the upper part of the stomach above the band, creating a feeling of fullness.
  • Digestion and absorption of nutrients occur as usual in the lower part of the stomach and the rest of the digestive system.
  • The band does not directly affect the chemical breakdown of food or nutrient absorption.

Question 22

why is the structural features of the small intestine increasing surface area important?

Answer 22

• Maximizes the absorption of nutrients from digested food.
  
  • Enhances the efficiency of nutrient absorption by providing a larger area for contact and exchange between digested food and the intestinal lining.
  • Increases the effectiveness of enzymes and transport processes involved in nutrient absorption.
  • Enables the body to obtain a greater amount of nutrients from the digested food.