Chapter 41

What are the three main things animals need from food?

Chemical energy, organic building blocks, and essential nutrients.

What are essential amino acids?

Amino acids that humans cannot manufacture and must obtain from food; humans need 8, infants need 9 (including histidine).

Name two types of essential nutrients.

Essential amino acids and essential fatty acids.

What is the role of vitamins in the diet?

Vitamins are essential nutrients required for various bodily functions, classified into water-soluble (B vitamins, Vitamin C) and fat-soluble (Vitamins A, D, E, K).

What mineral is crucial for producing hemoglobin?

Iron.

What is malnutrition?

A condition that occurs when the diet lacks sufficient nutrients or energy.

What is folic acid and its significance?

Vitamin B9, crucial for preventing neural tube defects during fetal development, added to enriched grains in the U.S. since 1998.

What are the four stages of food processing?

Ingestion, digestion, absorption, and elimination.

Define ingestion in the context of food processing.

The act of taking food into the body.

What is mechanical digestion?

Physical breakdown of food into smaller pieces, such as chewing and grinding.

What is chemical digestion?

The breakdown of food into smaller molecules using digestive enzymes.

What type of digestive system do sponges have?

Intracellular digestion, where digestion occurs inside food vacuoles.

What is the function of the alimentary canal?

A complete digestive tract with a mouth and anus that allows one-way movement of food.

What organ produces bile and where is it stored?

The liver produces bile, and it is stored in the gallbladder.

What is the role of salivary amylase?

Begins the digestion of starch in the mouth.

What is chyme?

A mixture of partially digested food and gastric juices produced in the stomach.

How does the stomach protect itself from gastric acid?

The stomach lining is protected by mucus produced by mucus cells.

What secretes pepsinogen in the stomach?

Chief cells.

What is the primary site for nutrient absorption?

The small intestine.

What types of digestion occur in the small intestine?

Carbohydrate, protein, nucleic acid, and fat digestion.

How do fats get absorbed after digestion?

Fats are reassembled into triglycerides, packaged into chylomicrons, and enter lacteals before reaching the bloodstream.

What is the function of pancreatic lipase?

Breaks down triglycerides into fatty acids and monoglycerides.

What are villi and microvilli's role in the small intestine?

They increase surface area for nutrient absorption.

What is the function of the large intestine?

Absorbs water, compacts feces, and houses beneficial bacteria.

What is the role of gastrin in digestion?

Stimulates the secretion of gastric juice in the stomach.

Which hormone decreases appetite?

Leptin.

What does insulin do in blood glucose regulation?

Lowers blood glucose levels by increasing glucose uptake and promoting glycogen formation.

What is type 1 diabetes?

An autoimmune condition resulting in the destruction of beta cells in the pancreas, leading to little or no insulin production.

What role does ghrelin play in appetite regulation?

Increases hunger before meals and is released by the stomach.

How do mutualistic microbes contribute to digestion in herbivores?

They help digest cellulose and produce essential vitamins.

What major structural difference do herbivores have compared to carnivores in terms of their digestive tracts?

Herbivores generally have longer intestines and larger cecums or fermentation chambers.

What is the significance of pancreatic enzymes in digestion?

They aid in breaking down carbohydrates, proteins, and nucleic acids in the small intestine.

What is the importance of bile in fat digestion?

Bile emulsifies fats, making them easier for enzymes to digest.