Life Sciences Grade 11 Chapter 5: Animal Nutrition

Introduction

• Animals require nutrients for daily use, which are absorbed by their digestive system.
• Nutrients provide energy, repair tissues, and regulate bodily processes.

Key Terminology

• Herbivore: Eats plants or parts of plants.
• Carnivore: Eats other animals or their remains.
• Omnivore: Eats plants and animals.

Types of Teeth

• Incisors: Chisel-shaped; used for biting or cutting food.
• Canines: Pointed; used for catching, holding, tearing, or killing prey.
• Premolars: Flat and uneven; used for grinding and crushing food.
• Molars: Flat and uneven; used for grinding and crushing food.
• Carnassial Teeth: Specialized molars and premolars with jagged, triangular edges used for cutting meat in carnivores.
• Differences in dentition among herbivores, omnivores, and carnivores.

Human Nutrition

Key Terminology

• Bolus: Mixture of food and saliva formed in the mouth.
• Bile: Aids lipid digestion in the small intestine.
• Exocrine Gland: Uses ducts to transport secretions out of the body.
• Endocrine Gland: Secretes hormones directly into the bloodstream.
• Peristalsis: Moves food through the digestive tract via muscle contractions.
• Chyme: Semi-liquid mass of digested food in the stomach.
• Villus: Increases surface area for absorption in the small intestine.

Digestive System

• Breaks down molecules for absorption to sustain life.
• Consists of the alimentary canal and accessory organs (e.g., liver, pancreas).

Functions of Digestive System Parts

• Mouth Cavity: Teeth grind food; tongue mixes; palate forms mouth roof; salivary glands release enzymes.
• Pharynx & Oesophagus: Food moves to pharynx, then oesophagus via peristalsis.
• Stomach: Muscular sac mixes food with gastric juices.
• Liver & Gall Bladder: Produces bile for fat emulsification; bile neutralizes stomach acids.
• Pancreas: Secretes digestive enzymes; controls blood glucose levels.
• Small Intestine: Site of most digestion and absorption.
• Colon: Absorbs water and mineral salts; egests undigested food.

Activities

• Activity 1: Study dentition using skulls.
• Activity 2: Dissection of a sheep’s digestive system.
• Activity 3: Study the human digestive system.

Digestion

Mechanical Digestion

• Occurs during mastication, stomach churning, and peristalsis.

Chemical Digestion

• Involves breaking down food using enzymes.
• Enzymes function optimally at specific temperatures and pH levels.

Enzyme Summary

• Carbohydrases: Break down carbohydrates.
• Proteases: Break down proteins.
• Lipases: Break down fats into glycerol and fatty acids.

Absorption and Transport

• Active Absorption: Requires energy to move nutrients against concentration gradient.
• Passive Absorption: Diffusion without energy use.
• Glucose and amino acids are absorbed in the small intestine, transported to the liver, then to the heart.

Assimilation

• Incorporation of nutrients into the body's cells.
• The liver plays a role in nutrient metabolism and detoxification.

Egestion

• Removal of undigested material via the colon and anus.

Homeostatic Control of Blood Sugar Levels

• Insulin: Lowers blood glucose by converting it to glycogen.
• Glucagon: Raises blood glucose by converting glycogen back to glucose.

Diabetes Mellitus

• Occurs when insulin does not function properly, leading to high blood glucose levels.

Balanced Diet

• A balanced diet consists of necessary nutrients in correct proportions.
• Nutrient requirements vary based on age, gender, and activity level.

Different Diets

• Vegan: Avoids all animal products.
• Vegetarian: Eats dairy and eggs, avoids meat.
• Halaal: Follows Islamic dietary laws.
• Kosher: Follows Jewish dietary laws.

Malnutrition

• Caused by imbalanced diet, leads to disorders such as kwashiorkor, marasmus, anorexia, and obesity.

Food Allergies

• Triggered by consuming specific foods, leading to immune response.

End of Topic Exercises

• Various activities to solidify understanding of animal nutrition.