Chapter 41 - Animal Nutrition

What 3 things must an animal’s diet supply?

1. Chemical energy for cellular processes
2. Organic building blocks for macromolecules
3. Essential nutrients

What are required materials that animals cannot assemble from simple organic molecules?

Essential nutrients

What are the 4 classes of essential nutrients?

1. Essential amino acids
2. Essential fatty acids
3. Vitamins
4. Minerals

How many amino acids do all organism require?

20

Where do animals get the half that aren’t considered essential amino acids?

Synthesize them from molecules in their diet

What are complete proteins?

Foods that provide all essential amino acids

What are unsaturated fatty acids?

Fatty acids with at least one double bond

Where can essential fatty acids be sourced

Seeds, grains, and vegetables

What are fatty acids that must be obtained from the diet and include certain unsaturated fatty acids?

Essential fatty acids

What are organic molecules required in the diet in very small amounts?

Vitamins

How many vitamins are essential for humans?

13

What are the 2 categories of vitamins?

1. fat-soluble
2. water-soluble

What are simple inorganic nutrients, usually required in small amounts?

Minerals

What is an animal that dines mainly on plants or algae?

Herbivores

What is an animal that mostly eats other animals?

Carnivores

What is an animal that regularly consumes animals as well as plants or algae?

Omnivores

What is an animal considered when it broadens its diet when necessary?

Opportunistic feeders

What is the failure to obtain adequate nutrition?

Malnutrition

What can deficiencies in essential nutrients result in? (3)

Deformities, disease, and death

When do most children struggle with protein deficiency?

Shifting from breast milk to foods with little protein

What is the result of a diet not providing enough chemical energy?

Undernourishment

What is the result of undernourishment? (5)

1. using up stored fat and carbs
2. breaking down one’s own proteins
3. losing muscle mass
4. suffering protein deficiency of the brain
5. death or irreversible damage

Epidemiology has been used to learn more about human nutrition. Neural tube defects were caused by what deficiency of pregnant mothers?

Folic acid

What is the act of eating or feeding?

Ingestion

What are the 4 steps to food processing?

Ingestion → Digestion → Absorption → Elimination

What are the 4 different feeding mechanisms?

1. Filter feeders
2. Substrate feeders
3. Fluid feeders
4. Bulk feeders

What is the feeding mechanism that involves sifting small food particles from the surrounding medium (usually water)?

Filter feeders

What is the feeding mechanism that involves animals that live in or on its food source?

Substrate feeders

What is an example of a substrate feeder and its food source?

Caterpillars and leaves

What feeding mechanism involves sucking nutrient-rich fluid from a living host?

Fluid feeders

What feeding mechanism involves eating relatively large pieces of food?

Bulk feeders

What are 2 good examples of bulk feeders?

1. Snakes
2. Humans

What is the process of breaking food down into molecules small enough to absorb?

Digestion

What are the 2 forms of digestion?

1. Mechanical digestion
2. Chemical digestion

What is the form of digestion that involves chewing/grinding food to increase surface are?

Mechanical digestion

What is the form of digestion that splits food into small molecules that pass through membranes?

Chemical digestion

What are the small molecules broken down via Chemical digestion used to build later on?

Large molecules

What process in chemical digestion is used to split bonds in molecules via the addition of water?

Enzymatic hydrolysis

What is the rxn for the enzymatic hydrolysis of a disaccharide?

Sucrose + h2O → glucose + fructose, using sucrase as the enzyme

What is the uptake of small molecules by body cells?

Absorption

What is the passage of undigested material out of the digestive system?

Elimination

How do most animals process food?

Specialized compartments

What is the purpose of specialized digestive compartments?

To reduce the risk of an animal digesting its own cells and tissues

What is the process where food particles are engulfed by phagocytosis and liquids by pinocytosis?

Intracellular digestion

What contains food and fuses with lysosomes containing hydrolytic enzymes?

Food vacuoles

What animal completely digests its food utilizing intracellular digestion?

Sponges

What is the breakdown of food particles outside of cells?

Extracellular digestion

How does hydrolysis occur in most animal species?

Extracellular digestion

What occurs in compartments that are continuous with the outside of the animal’s body?

Extracellular digestion

What functions in both digestion and distribution of nutrients for animals with simple body plans?

Gastrovascular cavity

What digestive tube has two openings, found in more complex animals?

Alimentary canal

What do organs that are specialized for sequential stages of food processing form?

Mammalian digestive system

What are the 4 mammalian accessory glands?

1. Salivary glands
2. Pancreas
3. Liver
4. Gallbladder

Where does food processing begin?

Oral cavity

What delivers saliva to lubricate food?

Salivary glands

What does Saliva contain?

mucus, water, salts, glycoproteins, cells

What enzyme found within the mouth breaks down starch?

Amylase

What is the function of the tongue’s movements?

To shape food into a bolus and help with swallowing?

What is the junction that opens to both the esophagus and trachea?

Pharynx

What is the pharynx also known as?

Throat

What connects the mouth to the stomach?

Esophagus

What connects the mouth to the lung?

Trachea

What blocks the entry to the trachea when eating?

Epiglottis

What triggers the epiglottis to block the trachea entrance?

Swallowing

What is the upper part of the respiratory tract?

Larynx

What guides the bolus?

Larynx

What occurs when the swallowing reflex fails and food or liquids reach the windpipe?

Coughing

What are the alternating waves of smooth contraction and relaxation that help push food along the esophagus?

Peristalsis

What are the valves that regulate the movement of material between compartments?

Sphincters

What stores food and processes it into a liquid suspension?

Stomach

What is secreted by the stomach and mixes with the food within it via a churning action?

Gastric juice

What is the mixture of ingested food and gastric juice called?

Chyme

What is the pH of gastric juice?

2

What is the function of gastric juice?

Kill bacteria and denature proteins

What 2 components make up gastric juice?

1. Hydrochloric acid (HCl)
2. Pepsin

What enzyme cleaves proteins into smaller polypeptides by breaking down peptide bonds? (general name)

Protease

What is the protease found within gastric juice?

Pepsin

What secretes hydrogen and chloride ions separately into the lumen of the stomach?

Parietal cells

What secretes inactive pepsinogen into the stomach?

Chief cells

What activates pepsinogen into pepsin?

Mixing with hydrochloric acid in the stomach

What protect the stomach lining from gastric juice?

Mucus

What adds a new epithelial layer every 3 days?

Cell division

What prevents chyme from entering the esophagus and regulates its entry into the small intestine?

Sphincters

What results from the sphincter at the top of the stomach allowing the movement of chyme back to the lower end of the esophagus?

Heartburn

What is the longest compartment of the alimentary canal?

Small intestine

Where does most enzymatic hydrolysis of macromolecules from food occur within the digestive tract?

Small intestine

What does it mean if most enzymatic hydrolysis of macromolecules from food occurs in the small intestine?

Most water absorption occurs

**familiarize yourself with this chart**

What is the first portion of the small intestine?

Duodenum

Where does chyme from the stomach mix with digestive juices from the pancreas, liver, gallbladder, and small intestine itself?

Duodenum

What produces the proteases trypsin and chymotrypsin?

Pancreas

Where are the proteases of the pancreas activated?

Lumen of the duodenum

What is the acidity of the pancreas?

Alkaline

Why is the pancreas’s solution alkaline?

To neutralize the acidic chyme

What facilitates digestion of fats?

Bile salts

What are bile salts a major component of?

Bile

Where is bile made in?

Liver

Where is bile stored and concentrated in?

Gallbladder

What is the other function of bile?

Destroy nonfunctional red blood cells

What is the main role of the duodenum?

Digestion