Question 1

In your digestive tract,movement of food from the stomach into the esophagus is normally prevented by

Accepted Answer

A sphincter, specifically the lower esophageal sphincter (LES), prevents the backflow of food from the stomach into the esophagus.

Question 2

Which structure of the vertebrate gut is most responsible for peristalsis?

Accepted Answer

Circular and longitudinal muscle layers are responsible for peristalsis, which is the coordinated contraction and relaxation of muscles that propels food along the digestion system. The mucosal layer, submucosal layer, peritoneum, and lumen are important structures in the gut but not directly involved in peristalsis.

Question 3

Use the following to answer questions :
Facilities that recycle consumer electronics such as computers and cell phones often have entrance halls leading to disassembly rooms where the products are broken down into their parts,such as transistors,useful wires,and so on.The parts are then put on conveyor belts taking them to other areas where they can be re-used.
-In this scenario,the disassembly room is analogous to the _______ in a digestive system.

Accepted Answer

The disassembly room breaks down the consumer electronics into their individual parts, which is similar to how the stomach and small intestine break down food into nutrients that can be used by the body. The other options do not closely relate to the process described in the scenario.

Question 4

Which layer in the vertebrate gut can constrict the gut lumen?

Accepted Answer

The circular muscle layer in the vertebrate gut can constrict the gut lumen. This layer is responsible for peristalsis, which is the rhythmic contraction and relaxation of the gut muscles that propels food forward. When this layer contracts, it constricts the lumen of the gut, aiding in the mechanical breakdown of food and pushing it down the digestive tract.

Question 5

Use the following to answer questions :
Facilities that recycle consumer electronics such as computers and cell phones often have entrance halls leading to disassembly rooms where the products are broken down into their parts,such as transistors,useful wires,and so on.The parts are then put on conveyor belts taking them to other areas where they can be re-used.
-In this scenario,the conveyor belts and distribution of useful items to other areas are most analogous to the blood and lymph vessels in the _______ of a digestive system.

Accepted Answer

The conveyor belts and distribution of useful items to other areas is similar to how the blood and lymph vessels in the intestines of a digestive system absorb nutrients and distribute them to other parts of the body. The esophagus only moves food to the stomach, the gizzard grinds food in birds, the crop stores food temporarily, and the anus is the exit point of waste.

Question 6

Which statement about digestion in the midgut (small intestine)of vertebrates is false?

Accepted Answer

The small intestine does not rely on aerobic conditions with high O2 levels for digestion; digestion is primarily a chemical process involving enzymes and does not require high oxygen levels.

Question 7

An earthworm doesn't need teeth because it has a(n)

Accepted Answer

The gizzard is a muscular structure in the digestive system of many invertebrates, including earthworms, that grinds up food particles. This allows the earthworm to break down food without the need for teeth.

Question 8

Pepsinogen is converted into pepsin by

Accepted Answer

Pepsinogen is converted into pepsin by low pH. When food enters the stomach, gastric acid is secreted, which lowers the pH level to around 2, and this acidic environment activates pepsinogen to become pepsin.

Question 9

The sweetness that you taste if you keep chewing a piece of bread is due to the action of the enzyme

Accepted Answer

The enzyme responsible for breaking down starch in bread into glucose is amylase. Amylase is found in saliva and pancreatic juice and breaks down carbohydrates and starches into smaller sugar molecules such as glucose. As we chew bread, the level of amylase increases, and it breaks down the bread into glucose, which gives it a sweet taste. Neither maltase, sucrase, nor lactase can break down starch into glucose, so they cannot be responsible for the sweet taste of bread. Pepsin is an enzyme that breaks down proteins, so it also cannot be responsible for the sweetness of bread.

Question 10

The major enzyme produced by your stomach is

Accepted Answer

Pepsin is the major enzyme produced by the stomach. It breaks down proteins into smaller peptides. Amylase is produced in the mouth and pancreas and breaks down carbohydrates. HCl is produced in the stomach and helps to denature proteins and activate pepsin. Mucus is produced in the stomach to protect the lining from the acidic gastric juice. Trypsin is produced in the pancreas and helps to further break down proteins in the small intestine.

Question 11

Which of the following is not caused by the HCl secreted in the stomach?

Accepted Answer

The secretion of HCl in the stomach does not directly release bile, which is produced by the liver and stored in the gallbladder before being released into the small intestine to aid in the digestion of fats.

Question 12

For most vertebrates,absorption of nutrients occurs in the

Accepted Answer

For most vertebrates, absorption of nutrients occurs in the midgut, which consists of the small intestine and sometimes the large intestine. This is where most of the chemical digestion and absorption of nutrients occurs. The esophagus and crop are involved in the initial stages of digestion and storage of food. The gastrovascular cavity is present in some invertebrates, but not in vertebrates. The coelomic body cavity is a fluid-filled space that surrounds the internal organs, but it is not directly involved in the absorption of nutrients.

Question 13

Most absorption of nutrients in the vertebrate digestive tract takes place in the

Accepted Answer

The small intestine is where most absorption of nutrients takes place in the vertebrate digestive tract. This is because the small intestine has a large surface area due to its long length, finger-like projections called villi, and microvilli on the surface of the cells lining the intestine. These structures increase the surface area available for nutrient absorption. The stomach primarily functions in the mechanical and chemical breakdown of food, while the large intestine primarily reabsorbs water and electrolytes from the remaining material. The liver and pancreas both play important roles in digestion, but they do not directly absorb nutrients.

Question 14

Which layer of the vertebrate gut shows adaptations for increasing absorptive surface area?

Accepted Answer

The mucosa layer of the gut is made up of folds, villi, and microvilli, which increase the surface area available for nutrient absorption. This is an adaptation to maximize the efficiency of the digestive system.

Question 15

In your small intestine,nutrients are absorbed by the intestinal epithelium and then passed to blood and lymph vessels lying in the _______ layer(s)of the intestine.These vessels then carry the nutrients away from the gut.

Accepted Answer

Nutrients are absorbed by the intestinal epithelium and then passed to blood and lymph vessels lying in the villi, mucosa, and submucosa layers of the intestine. These vessels then carry the nutrients away from the gut. The microvilli on the epithelial cells increase the surface area for absorption, but they do not contain blood or lymph vessels. The circular and longitudinal muscles are involved in peristalsis, which moves food through the intestines, but they do not play a direct role in nutrient absorption.

Question 16

Which of the following is not a function of the pancreas?

Accepted Answer

The production of lipid-emulsifying bile is not a function of the pancreas, but rather the liver. The pancreas is responsible for producing digestive enzymes that break down carbohydrates, lipids, and proteins, as well as producing bicarbonate to neutralize acidic material from the stomach.

Question 17

The vertebrate gut could be considered analogous to a(n)

Accepted Answer

The answer of The vertebrate gut could be considered analogous...

Question 18

Which structure is not directly encountered by a bite of food as it passes through your digestive system?

Accepted Answer

The answer of Which structure is not directly encountered by...

Question 19

Which statement about movement of food in the vertebrate gut is false?

Accepted Answer

The primary function of peristalsis is to move food through the digestive tract, not to mix food in the stomach.

Question 20

The inactive form of stomach enzymes is activated by

Accepted Answer

The inactive form of stomach enzymes, such as pepsinogen, is activated by low pH. The acidic environment of the stomach (pH around 2) is crucial for converting these zymogens into their active forms, enabling the digestion of proteins.

Quiz 30: Nutrition and Digestion