Biology 1012:  Chapter 43: Animal Nutrition - Part 1

 

Why do animals need food?

 

1.      Energy

2.      Building Blocks

 

1. Energy:  How much energy is in food?

 

            Carbohydrates: 

 

            Protein:

 

            Fats: 

 

How Much Energy Do We Need?

 

 

 

Under nourishment

 

Over nourishment

 

 

2. Food Provides Building Blocks

 

Biosynthesis

 

Mostly done in liver

 

Building blocks

amino acids

simple sugars

fatty acids

 

Some Nutrients are Essential – They can’t be synthesized

 

Essential Nutrients:

 

a. Amino Acids for Humans

 

8 are essential for adults

 

 

b. Essential fatty acids

 

linoleic – phospholipids

 

 

c Vitamins

 

Fat-soluble Vitamins - can accumulate

 

A – eye pigments, antioxidant

D – Ca and P uptake

E – antioxidant

K – blood clotting

 

 

Water soluble vitamins – quickly excreted so overdose less likely

 

Vitamin function often determined by deficiency studies

 

·        Vitamin A deficiency 

 

·        Vitamin D deficiency

 

·        Vitamin C Deficiency

 

d. Minerals

 

Inorganic

·        Calcium, Magnesium – bones

 

 

·        Iron – hemoglobin

 

 

·        Sulfur – Amino Acids

 

 

·        Phosphorus – Bones, Nucleotides, ATP

 

3. Obtaining Food

 

·        Suspension (filter) feeders

 

 

·        Fluid

 

 

·        Deposit

 

 

·        Mass (bulk)

 

4. Digestive Systems

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

·        Alimentary Canals

·        Tube with mouth and Anus

·        Extracellular

 

 

Human Digestion

 

1. Experiments in Digestion

 

Wm Beaumont and Alexis St. Martin

 

2.      Digestion Mechanisms

 

 

·        Peristalsis

 

·        Sphincters

 

·        Accessory Glands

 

 

3. Human Digestive Tract

 

A Trip through the Digestive System

 

·        Oral Cavity

§         Physical and chemical breakdown

·        chewing

§         saliva

·        mucin - lubricant

·        Amylase

·        buffers

·        antimicrobial agents

§         Tongue

·        Lipase

§         Bolus

 

 

·        The Stomach

 

Pepsin: a Protease Enzyme - Theodor Schwann 1837

 

 

Where does it come from?

 

·        Schwann: “Must be stored in inactive form”

 

·        Chief cells: pepsinogen

 

·        Activated by HCl

 

Where does HCl come from?

 

·        Parietal Cells: HCl

 

·        Mechanism

 

o       Antiporter system moves Cl- ions from blood to parietal cell.

o       Proton pumps push H+ to stomach

o       Cl- difuses through chloride channels to stomach

o       Why doesn’t acid damage the stomach?

o       Goblet cells secrete mucus

 

What causes Ulcers?

 

·        HCl?

 

·        Helicobacter pylori  (Warren and Marshall 1983)