Digestive System Structure & Function
What did the endoscopy reveal about M’Kenna’s small intestine compared to a healthy person’s?
Her small intestine appeared smoother with fewer ridges (damaged villi).
What enzyme in saliva helps break down complex carbohydrates?
Amylase.
Why was fiber not detected in the bloodstream during the digestion investigations?
Fiber is not broken into small absorbable molecules and passes into waste.
What chemical reaction occurs in cells to provide energy for the body?
Cellular respiration.
What condition was determined to be the most likely cause of M’Kenna’s symptoms?
Celiac disease.
What are the finger-like projections in the small intestine called, and what is their function?
They are called villi. They increase surface area and allow nutrients to be absorbed into the bloodstream.
What happens to complex carbohydrates in the mouth of a healthy digestive system?
They begin to be broken down into glucose by a chemical reaction.
In the dialysis tube investigation, glucose moved outside the tubing but starch did not. What does this demonstrate about semi-permeable membranes?
Small molecules can move through semi-permeable membranes, but large molecules cannot.
Which molecules are reactants in cellular respiration?
Glucose and oxygen.
How does damage to villi explain M’Kenna’s weight loss?
Damaged villi reduce surface area, so fewer nutrients are absorbed, leading to weight loss and other symptoms.
True or false: the esophagus breaks down nutrients.
False
Data showed glucose increased while complex carbohydrates decreased in the mouth. What explains this pattern?
A chemical reaction is breaking complex carbohydrates into glucose.
What conclusion can you draw about molecule size and membrane permeability?
Only small molecules are able to pass through membranes; large molecules must be broken down first.
When fat is burned in a closed system, what products form?
Carbon dioxide and water.
Describe one difference between food processing in a healthy digestive system and M’Kenna’s digestive system.
In a healthy system, nutrients are fully absorbed through villi. In M’Kenna’s system, damaged villi reduce absorption.
What happens to glucose molecules in the small intestine of a healthy person?
They are absorbed through the intestinal wall into the bloodstream.
Why must large food molecules be broken into smaller molecules before absorption?
Large molecules cannot pass through the intestinal wall. Only small molecules can move through semi-permeable membranes into the bloodstream.
How does the dialysis investigation model what happens in the small intestine?
The tubing acts like the intestinal wall. Small molecules like glucose pass through into the “bloodstream,” while larger molecules like starch remain inside.
How are the digestive, circulatory, and respiratory systems interconnected?
The digestive system breaks down food into nutrients, the respiratory system provides oxygen, and the circulatory system transports nutrients and oxygen to cells and removes waste.
Why do molecules that are not absorbed in the small intestine end up in the large intestine?
If they are not small enough to pass through the intestinal wall, they continue through the digestive tract into the large intestine as waste.
If the small intestine appears smoother with fewer ridges, how would this most likely affect nutrient absorption? Explain why.
Nutrient absorption would decrease because fewer villi means less surface area for nutrients to pass into the bloodstream.
Explain why starch decreases in the small intestine of a healthy person but is not absorbed directly into the bloodstream.
Starch is broken down into smaller molecules like glucose. Only glucose is small enough to be absorbed, so starch itself is not absorbed directly.
How does evidence from investigations support the idea that M’Kenna has decreased nutrient absorption?
Investigations show only small molecules can be absorbed. Since M’Kenna’s villi are damaged and surface area is reduced, fewer nutrients can pass into the bloodstream.
Which molecule is NOT a reactant in cellular respiration, and why?
Carbon dioxide is not a reactant because it is a product of cellular respiration.
Use evidence to explain why M’Kenna most likely has celiac disease.
M’Kenna most likely has celiac disease. Her small intestine appeared smoother with fewer ridges, and she had symptoms like diarrhea and weight loss. Celiac disease damages villi in the small intestine, reducing nutrient absorption, which explains her symptoms.