HN&F 171 Exam 2

Digestive System

the organs and glands associated with the ingestion and digestion of food

Step 1 of digestion system

Chewing breaks up food and mixes it with saliva into nutrients in preparation of absorption

Step 2 of Digestive System

Absorption- the uptake of nutrients by cells of the small intestine for transport into either the blood or lymph

Bolus

A term used to describe food after it has been chewed and mixed with saliva

Gastric Juice

A digestive fluid secreted by the stomach digests protein

What is the enzyme that starts the breakdown of starch in the mouth?

Salivary amylase

What connects the mouth to the stomach?

esophagus

Enzymes involved in the digestion of food

Lipase- made in the pancreas breaks down fats

Amylase-made in the mouth and pancreas breaks down complex carbohydrates

Protease- made in the pancreas breaks down proteins

What are the accessory organs of the digestive system?

Gallbladder, Pancreas, and Liver

Where does most digestion and absorption occur?

Small intestine

Microvilli and villi are found in the

Small intestine

What is produces in the pancreas to regulate blood glucose

Insulin and glucagon

What is the main function of the large intestine?

store undigested food material, absorb water, short-chain fatty acids, and electrolytes

What are the three segments of the small intestine?

Duodenum, jejunum, and illeum

What vitamins does the gastrointestinal microbe produce?

B6, B12, and K

Segmentation

Contraction of circular muscles in small intestine and stomach

Carbohydrates

Broken down into glucose to provide energy

Preferred energy source for nerve cells

Source of Carbohydrates

All plant foods- whole grains, vegetables, legumes, fruits, and milk

Monosaccharides

Single sugar molecules (simple sugars)

3- Glucose, fructose, and galactose

Glucose

Essential energy source, part of every disaccharide, most abundant CHO

Characteristics of Fructose

Sweetest of sugars, same formula as glucose but structured differently

-Monosaccharide

Disaccharides

pair of two monosaccharides

-Maltose, sucrose, and lactose

Characteristics of Sucrose

glucose and Fructose together, naturally in fruits and honey. Sweetest of disaccharides. Found in brown, white, and powdered sugars.

Composition of Sucrose

Glucose + Fructose

Maltose

found in seeds and alcoholic beverages

Maltose composition

glucose + glucose

Characteristics of Lactose

Principal carbohydrate of milk that contributes half of the energy (kcals) provided by fat-free milk.

-Disaccharide

Composition of Lactose

Glucose + Galactose

Polysaccharides

Carbohydrates that are made up of more than two monosaccharides

Starch

A storage polysaccharide in plants consisting entirely of glucose.

-Digestible polysaccharide

Fiber

Structural part of plants. INDIGESTIBLE

What are the two types of dietary fibers?

Soluble and insoluble

Soluble fiber

Can dissolve in a given solvent

Insoluble fiber

cannot dissolve in a given solvent

Pancreatic amylase

An enzyme secreted by the pancreas into the small intestine that digests any remaining starch into maltose

Where is the storage form of glucose stored?

In the liver as glycogen

Function of Insulin

Moves glycose from blood into cells lower blood glucose levels

Source of Insulin

Pancreas

When blood glucose rises above normal

Insulin can signal the cells to take in glucose for energy

Hormone which helps to regulate extremely low blood sugar/glucose

glucagon

Characteristics of Hypoglycemia (low blood sugar)

weakness, rapid heartbeat, sweating, anxiety, hunger, and trembling

Characteristics of Hypoglycemia (low blood sugar)

weakness, rapid heartbeat, sweating, anxiety, hunger, and trembling

Benefits of lower glycemic index

Less fluctuations in blood glucose

-Risk reduction for heart disease and colon cancer

Foods with lower glycemic index

beans, fresh vegetables, whole wheat

Foods with higher glycemic index

dry cereal, white bread, candy

Type 1 diabetes

Form of diabetes that usually develops during childhood or adolescence and is characterized by a severe deficiency of insulin, leading to high blood glucose levels.

Type 2 Diabetes

Form of Diabetes that develops especially in adults and most often obese individuals and that is chacterized by high blood glucose resulting from impaired insulin utilization coupled with the body’s inability to compensate with increased insulin production.

Most common form of diabetes

Type 2 diabetes

Lower-card diet facts

Metabolism similar to fasting, uses glycogen stored first, uring monitoring, and ketosis

DRI Carbohydrates

45%-65% of daily calories

RDA of carbohydrates

130 grams per day

DRI Fiber

14 grams per 1000 kcals

25g/day for women

28g/day for men

How many g of fiber do vegetables contain?

2 to 3 g per serving

How many g of fiber in fruits

2

How many g of fiber do legumes contain

abt 6-8 g

Alcohol is linked to increase risk for:

• Breast cancer

• Hypertension

• hemorrhagic stroke

  • NOTE: Alc provides energy not nutrients

How much energy per day do lipids provide?

9kcal/g

Lipids

insoluble in water. Energy-rich organic compounds, such as fats, oils, and waxes, that are made of carbon, hydrogen, and oxygen.

• 3- triglycerides, phospholipids, and sterols

Dietary lipids are found in what form?

Triglycerides

Triglycerides are made up of

3 fatty acids + glycerol

Most lipids you can consume are…

triglycerides

Liquid v. solid room temp fat

Degree of unsaturated influences firmness

• Unsaturated = lipid

• Saturated = solid

Monounsaturated fats

one double bond- lacks hydrogen atom on carbon

polyunsaturated fats

one double bond- lacks hydrogen atom on carbon

Hydrogenation

more than one double bond- lacking associated hydrogen atoms on carbons

Main site for fat hydrolysis

Small intestine

Phospholipids

Soluble in fat and water, emulsifies in food industry, having a polar, hydrophilic head and non polar, hydrophobic tail

High-density lipoproteins (HDL’s)

Made in liver, to remove cholesterol from the cells and carry back to the liver for recycling, composed mostly of proteins

Low-density lipoproteins (LDL’s)

Circulated throughout the body. It takes triglycerides, cholesterol, and phospholipid to use for energy. Makes hormones/ compounds, or build new membranes.

How much energy does fat provide while at rest

60%

Daily energy intake from fat AMDR

20 to 35%

What differentiates amino acids from each other?

the 4th attachment site distinguishes each amino acid from the others

Bonding of two amino acids?

Peptide bonds connect the two

Proteins contains

carbon, hydrogen, oxygen, nitrogen

Protein denaturation

Breakdown of proteins that permanently alters their biological activity; it can be caused by excessive heat

building blocks of proteins

amino acids (20 types)

4 types of lipoproteins

The four main classes of lipoproteins are chylomicrons, very low-density lipoproteins (VLDL), low-density lipoproteins (LDL), and high-density lipoproteins (HDL)

Highest Quality protein

Animal protein

Enzymes

Proteins that speed up chemical reactions act as catalyst

How many nonessential amino acids are there?

11- Can be made by the body

Essential amino acids

Histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine

How many essential amino acids are there?

9: must be obtained from diet

Protein synthesis

Refers to the fact that everyone is different due to differences in proteins. Differences are determined by amino acid sequences of proteins which are determined.

Protein Structure: Primary

sequence of amino acids

Protein Structure: Secondary

Polypeptide chain that forms twists and folds/hydrogen bonds between amine and carboxyl groups

Protein structure: Tertiary

Complex shapes

quaternary structure

the fourth level of protein structure; the shape resulting from the association of two or more polypeptide subunits

Negative Nitrigen Balance

Body degrades more proteins than synthesizes (starvation)

Positive Nitrogen Balance

body synthesizes more proteins than degrades (GROWTH)

Protein turnover

in each cells