Chapter 7 Animal nutrition

Herbivore

Eats plant

Carnivore

Eats meat

Omnivore

Eats plant and meat

Nutrition

Process by which animal takes in and makes use of food.

Essential nutrients

1. Essential amino acids - 9 amino acids that we can’t synthesize

2. Essential fatty acids - Get from seeds, grains, and vegetables

3. Vitamins - 13 organic molecules

4. Minerals - Inorganic nutrients required in small amounts 

Malnutrition

- Ingesting too much/little of an essential nutrient over an extended period of timeDeficiencies can cause deformities, disease, and death

Undernourisment

Diet does not provide enough chemical energy
Use stored fat and carbs

Break down own proteins

Loss of muscle

Brain protein deficiency

Overnourishment

Consumption of more chemical energy than needed
Fat accumulation

Type 2 diabetes risk

Colon cancer risk

Cardiovascular disease: Can lead to stroke or heart attack

Food processing

1. Ingestion - eating or feeding

2. Digestion - breaking down food into smaller molecules

3. Absorption - uptake of broken-down molecules

4. Elimination - removal of waste

Filter feeder

filter or trap food particles from the surrounding medium

Substrate feeder

live on or in their food source

Fluid feeders

suck nutrient-rich fluid from a living host

Bulk feeders

eat relatively large pieces of food

Mechanical digestion

Physically breaking food into smaller pieces. It occurs in your mouth and the function is to increase the surface area.

Chemical digestion

Splits food into small molecules that can pass through membranes
Enzymatic hydrolysis splits bonds in molecules with the addition of water

Intracellular Digestion 

Digestion of food inside cells within membrane-protected compartments

Extracellular digestion 

Breakdown of food particles outside of cells in compartments “outside” of animal’s body

Incomplete digestive tract 

one opening: Gastrovascular cavity and Simplest body plan

Complete digestive tract

two openings- mouth and anus

Salivary glands

Produce and secrete saliva to begin carbohydrate digestion in the mouth.

Pancreas

Secretes bicarbonate (neutralizes stomach acid) and digestive enzymes

Liver

Make bile that is stored in the gallbladder and

detoxifies organic molecules then heart circulates nutrients

and absorbed by Lacteals in Vili

Gallbladder

Stores and concentrate bile produced by the liver.

Oral cavity

Mechanical digestion of food

Salivary glands

deliver saliva through ducts

Teeth

chew food and increase surface area, more exposure to salivary amylase (carbs)

Tongue

shapes food into a bolus and swallowsP

Pharanx

1. (throat) opens to both the esophagus and tracheaCartilage flap covers trachea when swallowing

Esophagus

Tube that transports food to the stomach via peristalsis

peristalsis 

Rythimic contraction

Stomach

Stores food and secretes gastric juice

Following food

1. Gastric juice - HCl and pepsin (protease- dissolves proteins) pH of 2, kills bacteria

2. ◦Stomach mixes food and gastric juice to form chyme

3. ◦Muscles contract and churn food

4. ◦Sphincters at top and bottom regulate movement through digestive system.

Small intestine

Major organ of digestion and absorption and Meeting site of accessory organ secretions

What are some accesory organs

pancreas, liver, gallbladder

What does bile do

digests and absorbs fats and destroys old RBCs

Duodenum

The first part of the small intestine where chyme mixes with digestive secretions from the pancreas, liver, gallbladder, and intestinal wall.

Vili

Finger-like projections lining the small intestine that greatly increase surface area for nutrient absorption.

Microvili

Microscopic projections on epithelial cells that form the brush border, increasing surface area even more.

Epithelial Cells

Cells lining the intestine that absorb nutrients through active or passive transport.

Active transport

Movement of substances across a membrane using energy (ATP), usually against the concentration gradient.

Passive Transport

Movement of substances across a membrane without energy, from high to low concentration.

Hepatic portal vein

Carries nutrient-rich blood from the digestive tract to the liver before it reaches the heart.

Disaccahrides

Carbohydrates made of two sugars (sucrose, lactose, maltose).

Monosaccharides

Single sugars absorbed by the body (glucose, fructose, galactose).

Large intestine

1. Absorbs water & nutrients; forms, stores, & eliminates fecesT junction from small intestine to colon and cecum

How does food follow

1. Cecum aids in fermentation of ingested material- has appendix

2. Appendix is reservoir for symbiotic microorganisms

3. ◦Colon absorbs water; remnants are feces that move to rectum

4. ◦Two sphincters control bowel movements

Inscisor

For cutting

Canines

for piercing/tearing

Premolar and molar

For grinding

What vertebrae has less specialized dentition

Snake fangs

What type of stomach does carnivors have

They have a large, expandable stomach and short digestive system

What type of stomach does herbivoers or omnivores have

longer digestive systems

Regulation of Digestion

Process where each step in the digestive system is activated as needed.

Enteric Nervous System

Network of neurons in the digestive tract that locally regulates digestion.

Endocrine System

Hormonal system that regulates digestion via hormones like gastrin, CCK, and secretin.

Gastrin

Hormone that stimulates the secretion of gastric juice in the stomach.

CCK (Cholecystokinin)

Hormone that stimulates the gallbladder to release bile and the pancreas to release digestive enzymes; also inhibits gastric juice secretion.

Secretin

Hormone that stimulates the pancreas to release bicarbonate (HCO₃⁻) and digestive enzymes; also inhibits gastric juice secretion.

Stimulation (↑)

Process where hormones or signals increase digestive activity (e.g., gastrin → gastric juice).

Inhibition (↓)

Process where hormones or signals decrease digestive Activity (e.g., CCK/secretin → gastric juice).

Metabolic Rate

Animal’s energy use per unit time; determined by monitoring its rate of heat loss, O₂ consumption, or amount of CO₂ produced.

Resting Metabolic Rates

Minimum energy needed for cell functions at rest.

Basal Metabolic Rate (BMR)

Resting metabolic rate in endotherms.

Standard Metabolic Rate (SMR)

Resting metabolic rate in ectotherms.