Lecture 6 - Metabolism Flashcards
What are the foods and their percentages used by the body?
Carbohydrates (50% of American dietary calories)
Proteins (11-14%)
Lipids
Cholosterol
What is the only food that can move through the intestinal mucosa in its native state?
Cholesterol
What are the four main functions of the Digestive System?
- Motility
- Secretion
- Digestion
- Absorption
What is Motility?
Movement through the Digestive Tract
What is Secretion?
Release of enzymes, hormones and other substances that help the body digest food.
What is Digestion?
Breaking down the food into smaller components so it is able to cross the plasma membrane
What is Absorption?
Transfering the nutrient to the blood or lymph system
What is a Herbivore?
An animal that only eats plants (Deer)
What is a Carnivore?
An animal that only eats meat (Lion)
What is an Omnivore?
An animal that eats both plants and meat
What are the two types of herbivores?
- Ruminants
- Simple Stomach Herbivores
What is different about Ruminants compared to Simple Stomach Herbivores?
Ruminants are able to absorb FA and microbiota as they have a large intestine while SS herbivores cat use fermentation as they do not have a large intestine
What Is a Ruminants stomach like?
As ruminants, cows have a four-chamber stomach designed to break down parts of plants that humans, with our single-chamber stomachs, can’t. Each chamber in the ruminant stomach has a distinct function: The rumen is a 55-gallon chamber where a cow’s gut bacteria begin the process of digestion.
What are the two types of Digestion in animals?
1.) Enzymatic Digestion
2.) Microbial Digestion: Fermentation
What is the Digestion in Carnivores mostly?
Enzymatic
What is the Digestion in Herbivores and Omnivores?
Enzymatic and Microbial
What is the consequence of enzymatic and mcirobiotal digestion in SS herbivores and ruminants?
Reversed
What are polysaccharides?
Starch: complex carbohydrate
What are Disaccharides?
Maltose, Sucrose, Lactose
What are Monosacchardies?
Glucose, Galactose, Fructose
What are most carbs ingested as?
Starches
What is the most commonly digested sugar?
Sucrose (table sugar) and lactose (milk)
What does amylase do?
Takes starch (polysaccharide) and convert it into disaccharide
What are some brush border enzymes?
Dextrinase, Glucoamylasse, Lactase, Maltase, Sucrase
What do the BB enzymes do?
They convert the disaccharide into a monosaccharide
What does a-dextrinase do?
Targets small polymers of glucose into multiple molecules of glucose
What happens when we chew food?
It mixes our food with our salivary secretions that contains ptylalin (a-amylase)
What does ptyalin do?
Hydrolyze starch into maltose and other glucose polymers (30-40%) in the mouth and stomach
What happens to the salivary amylase?
Because people do not chew their food for very long periods of time. the salivary amylase turns inactive by the stomach pH and the rest of the complex carb gets digested by the pancreatic amylase
What do pancreatic secretions contain?
Large amounts of amylase
What is pancreatic amylase?
Is more potent then salivary amylase
Where do carbohydrates get hydrolyzed?
In the small Intestine (duodenum)
What happens within 30 minutes of carbohydrate digestion?
All carbohydrates will be hydrolyzed into maltose (and other glucose polymers) in the duodenum and jejunum
What is an overview of the Digestion of Carbohydrates?
Salivary amylase starts in the mouth, gets inactivated in stomach, pancreatic amylase begins to start in the stomach, Brush border enzymes in the small intestine turn the starch into monosaccharides
What happens to disaccharides?
Sucrose, lactose and maltose get broken down by brush border enzymes: lactase, sucrase and maltase
What happens to the monosaccharides that are formed?
Internalized by the absorptive cell and and diffuse out into the intestinal villi (go into small small intestine, diffuse into microvilli)
What is the solubility of a monosaccharides?
Water-soluble, therefore absorb right into the blood stream
What is the typical breakdown product?
80% glucose
10% fructose
10% galactose
What happens to the blood leaving the villi of the small intestine?
It drains into blood vessels leading to the hepatic portal system (liver)
What is the blood leaving the villi like?
Rich in nutrients
Where can this blood go?
Tthe general circulation system
What happens to blood viscosity?
It can be increased which can have an effect on blood pressure
What is the first pass effect?
As the blood passes through the vessels of the liver, much of the nutrient loaf is removed
What are the stages of the Hepatic Portal System?
1.) SI absorbs the products of digestion
2.) Nutrient molecules travel to hepatic portal vein to liver
3.) Liver monitors blood content
3.) Blood enters general circulation by hepatic vein
What is Glucose?
An essential nutrient for energy production