ASI 318 - exam 2

What is the placebo effect?

The psychological effect of being on a treatment, even if it is an inactive one

False cause

Assuming that a correlation between 2 things means that one caused the other is a logical fallacy referred to as:

An epidemiological study

You read a study that compared the long-term health characteristics of people who consumed eggs daily vs. those who almost never consumed eggs, over a 20-year period. This is an example of:

Salivary amylase is expected to be active:

In the mouth

Where are disaccharidases released in the GI tract?

Into the jejunum, from intestinal epithelial

Digestion of \__________ often begins in the mouth.

Starch

These experimental details might make the results of a study questionable, or limit the application of the findings

-Very few animals on each treatment
-A "control" or comparison group that is fed an unreasonable diet
-Doses or inclusion rate of treatments that are not relevant to the question at hand
-Evaluation of a nutrient in an animal that does not mimic the animal of interest very well

Increasing digesta passage rate generally results in:

-Lower nutrient digestibility
-Greater fecal loss of nutrients
- Decreased retention time

Where are disaccharidases released in the GI tract?

Into the jejunum, from intestinal epithelial

A dog food that has \_____________ would be the best strategy to reduce fecal quantity.

high digestibility

It is realistic to measure ileal digestibilty in your dog.

It is unrealistic to measure ileal digestibility in animals outside of a laboratory or research setting because it requires surgical insertion of an ileal cannula.

The protein in dog food is digested to which of the following monomers?

Amino acids

A dog food with a high quantity of \___________ nutrients is most likely to have the best digestibility and therefore least quantity of fecal production due to its ability to be absorbed by diffusion.

Small, fat-soluble

What is the term for the absorption of nutrients from the intestine into the bloodstream?

Digestibility

What is the term for the quantity of nutrients in the bloodstream that pass to the cell?

Bioavailability

When selecting a dog food to minimize fecal output, you should pay more attention to total protein than digestible protein.

False

true digestability

Differences between intake and digesta collected at the end of the small intestine. Takes into account nutrients from digestive enzymes and sloughed intestinal cells. Tested by feeding a nutrient free diet.
-Greatest precision
-requires cannula

illeal digestibility

Differences between intake and digesta collected at the end of the small intestine
-Requires cannula
-more precise than total digestibility

Total digestibility

\=intake-excretion
Does not take into account losses and gains from fermentation, sloughed cells, and enzymes

Epidemiology

Branch of medical science concerned with the incidence, distribution, and control of diseases that affect large numbers of people.

Controlled Studies

Those in which comparisons are made between experimental and control populations that are identical (as far as possible) in every factor except the one variable being studied.

Digestibility

Nutrient intake-Nutrient excretion
Amount of nutrient digested / Amount of nutrient consumed

Physical Breakdown

Mastication

chemical hydrolysis

Acid (least important)

enzymatic hydrolysis

nutrient specific enzymes

Hydrolysis

water is added across a bond as it is broken

Acid Hydrolysis

Occurs in stomach where there is low pH. Some peptide and ester cleavage. Influencing enzyme activity and denaturing proteins (enzymes require a certain pH and temp to be active)

Enzymes needed for digestion that are made by the animal are developed in the

Salivary glands, stomach, pancreas, small intestine

Enzymes needed for digestion that are made by microbes in the

crop, rumen, large intestine
Microbes have 10x the genes

Polysaccharides breaks down to

monosaccharides

Triglycerides breakdown into

Fatty Acids and glycerol

peptides break down into

amino acids

How are carbs digested in non-ruminants? End Products?

1. Salivary amylase
2. Amylase in Small intestine
3. Intestinal Maltase and Isomaltase
End products\= simple sugars, mainly glucose

How are carbs digested in ruminants? End Products?

1. Bacterial cellulase and hemicellulase
2. Starch is degraded in the rumen. As well as by microbes
3. Leftover is digested in Small intestine
End products\= Some simple sugars, mostly VFA's and acetate

What are the end products of carb digestion in ruminants consuming a high fiber diet?

More Acetate

What are the end products of carb digestion in ruminants consuming a high starch diet?

More propinate

How are triglycerides digested in non-ruminants? End Products?

1. Pancreatic Lipase
2. Gastric Lipase
3. Bile salts and phospholipids
End products\= Glycerol and Fatty acids, monoglycerides\= micelles

What happens to micelles with the absorption process?

Conversion to Chlylomicrons, which are then transported to the lymphatic system

Chylomicrons

fat droplets covered in protein that diffuse into capillaries in small intestine

Where do chylomicrons go after exocytosis from the enterocyte?

Lacteals

Ruminal Metabolism alters fats

Most triglycerides exposed to rumen microbes are rapidly hydrolyzed to glycerol and free fatty acids

How are fats digested in ruminants? End Products?

1. Triglycerides
2. Rumen microbes
-glycerol to VFA's
-or free fatty acids that are saturated by microbes becomes absorbed in SI and passed to lymphatic system and deposited as saturated fatty acids

What determines the mechanism of transport?

size, chemical properties, location in gut

What type of molecule is most likely to enter by diffusion?

small fat soluble nutrient (ex. VFA)

Diffusion

molecules move from high to low concentration

passive transport

Requires NO energy, Movement of molecules from high to low concentration, Moves with the concentration gradient

active transport

Energy-requiring process that moves material across a cell membrane against a concentration difference

What is the main type of nutrient that requires active transport?

Minerals

facillitated diffusion

Movement of specific molecules across cell membranes through protein channels

ATPase driven transport

ATP powers a pump that directly moves nutrients across a membrane, up the concentration gradient

What is the most important way to move nutrients that contain energy?

ATPase driven transport, 40% of your energy needs

What does digestion primarily rely on?

Particle Size Reduction

How many carbons are in acetate?

2

How many carbons are in lactate and proprionate?

3

How many carbons are in Butyrate?

4

What kind of diet would cause the bile to be more acidic?

High Grain Diet

End VFA product of a high fiber diet

acetate

End VFA product of a high grain diet

propionate
more rapidly fermented, starch digesting bacteria outcompete fiber digesters in an acidic environment

When is methane production most sucessful

When fed a low digestibility diet

What does methane production represent?

waste of nutrient energy

How do you decrease methane production?

feeding a higher quality diet (grain)

How do Ionophores alter ruminal metabolism?

they disrupt the passage of ions across the cell membrane selectively inhibiting growth of certain microorganisms whichs shifts VFA production toward proprionate

End products of cellulose (fiber digestion

microbial metabolism\=acetate for energy
host animal metabolism\= fatty acids

End products of starch digestion

microbial metabolism\=more propionate
host animal metabolism\= glucose

Gluconeogenesis

formation of glucose from fats and proteins

Would gluconeogenesis help a pig who is fed corn?

No he already is consuming glucose

The cori cycle

the cycle of lactate to glucose between the muscle and liver

Where does gluconeogenesis occur?

liver and kidney

WHich VFA is ideal for an animal that has low glycogen storage?

propionate because it can be made into glucose through gluconeogenesis

Insulin

hormone produced by the pancreas that regulates uptake and storage of glucose

Glucagon

regulates cell breakdown of glycogen and release of glucose

What happens in carb digestion?

1. Glucose is absorbed by active transport
2. Enters portal vein and transported to liver

What is glucose used for?

fuel or stored as glycogen

When glucose levels are increased aafter a meal where does it move to?

the Liver

After a meal what does the pancreas release?

Insulin which activates glycogen synthase and deactivated glycogen phylorase

What happens when insulin drops?

Glucagon or epinephrine increase, glycogen can be broken up to release glucose into blood

Which of the following is a hormone released by adrenal glands which can alter metabolism?

Epinephrine

Hormones can influence metabolism by altering:

-translation
-cellular location of proteins
-transcription
-protein activity

What hormone stimulates the production of IGF-1 and promotes growth of muscle tissue rather than adipose tissue?

Growth Hormone

You're late for class and are sprinting to make it on time for the first question. Pretty soon you are out of breath and your muscle hurt. What process (involving glucose) is occuring in your muscles?

Anaerobic glycolysis

Which of the following transport mechanisms requires energy?

Active Transport

Ruminal bacteria are able to digest:

Hemicellulose
Lactose
Starch
Celulose

How do triglycerides move through the bloodstream?

The are carried within lipoproteins

Which of the following nutrients is most likely to move through a cell membrane by passive diffusion (NOT facilitated diffusion)?

VFA's

Conversion of glucose to lactate by tissues, followed by conversion of lactate to glucose in the liver, is known as:

The cori cycle

Homeostasis can be defined as:

The maintenance of an internal body state

the most important nutrient that is absorbed from the gut to ultimately supply the brain with glucose for a cat

glucogenic amino acids

the most important nutrient that is absorbed from the gut to ultimately supply the brain with glucose for a pig

glucose

the most important nutrient that is absorbed from the gut to ultimately supply the brain with glucose for a cow

proprionate

An animal cannot get fat unless it has fat in its diet.

false

When excess glucose is available in an animal, it is stored in the liver in the form of:

Glycogen

anecdotal evidence

Personal stories about specific incidents and experiences.

false cause

a fallacy in which a speaker mistakenly assumes that because one event follows another, the first event is the cause of the second

Appeal to Authority

A fallacy in which a speaker or writer seeks to persuade not by giving evidence but by appealing to the respect people have for a famous person or institution.

the texas sharpshooter

Cherry-picking data clusters to suit an argument, or finding a pattern to fit a presumption.

appeal to nature

Making the argument that because something is 'natural' it is therefore valid, justified, inevitable, good, or ideal.

What are the most common substrates for glucose and triglyceride synthesis in ruminants? Do they absorb glucose?

Primary Energy substrate \= Acetate
Primary Fat substrate \= Acetate
Primary gluconeogenic \= Propionate
Glucose Absorption \=Low

What are the most common substrates for glucose and triglyceride synthesis in non-ruminants? DO they absorb glucose?

Primary Energy substrate \= Glucose
Primary Fat substrate \= Glucose
Primary gluconeogenic \= Lactate (min)
Glucose Absorption \= High

What are the most common substrates for glucose and triglyceride synthesis in carnivores? Do the absorb glucose?

Primary Energy substrate \= FA or AA
Primary Fat substrate \= Dietary FA
Primary gluconeogenic \=Gluconeogenic FA
Glucose Absorption \= Low

What is the central dogma of biology? How does it relate to homeostasis?

DNA-RNA-Protein-Function