Chapter 34 – Digestive Systems & Nutrition
1. What do animals get from their food (3 things)?
Animals get proteins, fat and complex carbohydrates from their food. However, they require
amino acids, lipid molecules, nucleotides, and simple sugars.
2. What is an essential nutrient (define) and what are the 4 types of essential nutrients?
Nutrient the body cannot synthesize on its own, and must be provided by the diet, necessary for
the body to function properly is known as an essential nutrient.
The four types of essential nutrients are vitamins, essential fatty acids, essential amino acids
3. What are the major part of the mammalian digestive tract and briefly describe their key role(s).
The major parts of the mammalian digestive tract are the alimentary canal and the digestive
gland.
Alimentary canal: It is the compartment in which an animal temporarily stores its food.
Digestive cavity in which food is churned and mixed where food is transported, digested and
absorbed.
Digestive glands: They are of two types:
The salivary glands (sub maxillary, sublingual, and parotid), secrete saliva that contains
enzymes (amylase) that breaks down starch of food to maltose. Hence, saliva moistens the
masticated food and starts digestion of carbohydrate.
The gastric glands secrete HCL and gastric juice that help in food digestion. It contains
enzymes (pepsin) in the gastric juice that acts as proteins of the food and breaks them into
peptones and proteoses, which then gets passed to the small intestine.
4. Explain how the small intestine is specialized for digestion and absorption.
This is because it has a huge number of folds in order to increase the total surface area for
absorption. Furthermore, it has a number of fingers like projections called villi and micro villi,
which also helps in absorption. It also secretes several enzymes which help break down certain
complex food for absorption. It undergoes peristaltic contractions of its strong muscular walls
to pushes the chyme along its length.
5. Relate variation in dentition and length of the digestive system to the feeding strategies and diets
of herbivores, carnivores, and omnivores.
Herbivores: They do not require sharp teeth. They have scissor like incisors to cut up plant
matter, they contain big molars and premolars to ground down the plant material.
Carnivores: They have long pointy canine for biting and killing the prey, they consist of sharp
pre-molars to cut or tear flesh, they also have sharp molars to grind the food.
Omnivores: They consist of incisors for cutting the plant or vegetable materials, they also
consist of some sharp teeth as well.
