Digestive System Flashcards
What is animal nutrition?
animal nutrition includes the processes by which food is ingested, digested, and absorbed into body cells and fluids
What is ingestion?
ingestion is the feeding method used to take food into the digestive cavity
What is digestion?
digestion is the splitting of carbohydrates, proteins, lipids, and nucleic acids in foods into chemical subunits small enough to be absorbed into an animal’s body fluids and cells
all organisms require sources of ____ and ____ for metabolism, homeostasis, growth, and reproduction
Matter and energy
all organisms require sources of matter and energy for ____, ____, ____, and ____
metabolism, homeostasis, growth, and reproduction
What is feeding?
for animals, meeting these nutritional requirements involves feeding, the uptake of food from the surroundings
What happens to food once it is ingested?
once food is ingested, digestive processes convert its molecules into absorbable subunits
What are herbivores?
Examples?
herbivores such as antelopes, horses, bison, giraffes, kangaroos, manatees, and grasshoppers obtain organic molecules primarily by eating plants
What are carnivores?
Examples?
carnivores such as cats, Tasmanian devils, penguins, sharks, and spiders, primarily eat other animals
What are omnivores?
Example?
such as crows, cockroaches, and humans, eat both plants and animals and, with appropriate digestive enzymes, may consume any source of organic matter
How is energy described?
energy requirements are described in terms of calories
How much is a calorie and a Calorie?
a calorie is the amount of energy required to raise the temperature of 1 g of pure water by 1°C
a kilocalorie [1 kcal = 4.2 kilojoules] equals 1,000 calories or one Calorie (capital C)
How many calories is fat, protein, and carbs?
carbohydrates contain about 4.2 kcal per gram, fats about 9.5 kcal per gram, and proteins about 4.1 kcal per gram
What is undernutrition?
animals whose intake of organic fuels is inadequate, or whose assimilation of such fuels is abnormal, suffer from undernutrition
What is malnutrition?
undernutrition is a form of malnutrition, a condition resulting from an improper diet
What is overnutrition?
overnutrition, the condition caused by excessive intake of specific nutrients, is another type of malnutrition
an animal suffering from undernutrition is starving for ____ ____ ____ ____ – taking in fewer calories than needed for daily activities
one or more nutrients
What happens in animals with chronic undernutrition?
animals with chronic undernutrition lose weight because they have to use energy-providing molecules of their own bodies as fuels
What do mammals used for food when undernourished?
What does this lead to?
mammals use stored fats and glycogen first, then proteins
use of proteins as fuel leads to muscle wastage and, in the long term, organ and brain damage, which leads to death
What do organic molecules serve as building blocks for?
organic molecules serve as building blocks for carbohydrates, lipids, proteins, and nucleic acids
What is it called when an animal cannot synthesize an organic molecule?
What is an example if an animal does not get these molecules?
animals synthesize many organic molecules – however, they cannot make certain essential amino acids and essential fatty acids, which must be obtained in the diet
EXAMPLE: In the absence of essential amino acids in the diet, an animal would have to break down its own proteins to provide amino acids for new protein synthesis
What are vitamins?
What is there general function?
vitamins are organic molecules required in small quantities that the animal cannot synthesize for itself
many are coenzymes, nonprotein
organic subunits that assist in enzymatic catalysis
What are essential minerals?
essential minerals are required inorganic elements such as calcium, iron, and magnesium
What are essential nutrients?
What do the vary between?
essential amino acids, fatty acids, vitamins, and minerals are known collectively as an animal’s essential nutrients
the list of essential nutrients differs from animal to animal