Chapter 14: "the Digestive System And Body Metabolism" #2

Front 1

Most foods are used by the body as metabolic fuels. They are oxidized and transformed into...

Back 1

ATP, the chemical energy form needed by body cells to drive their many activities.

Front 2

The energy value of foods is measured in units called...

Back 2

calories

Front 3

A nutrient is a...

Back 3

substance in food that is used by the body to promote normal growth, maintenance, and repair.

Front 4

The nutrients divide neatly into six categories. The major nutrients are...

Back 4

carbohydrates, lipids, and proteins.

Water is also considered to be a major nutrient.

Front 5

Minor nutrients are...

Back 5

vitamins and minerals and are required in minute amounts.

Front 6

A diet consisting of foods selected from each of the five food groups:

Back 6

grains, fruits, vegetables, meats and meat alternatives, and milk products normally guarantees adequate amounts of all the needed nutrients.

Front 7

Except for milk, sugar, and small amounts of glycogen in meats, all ingested _____________________ are derived from plants. Sugars come mainly from fruits, sugar cane, and milk.

Back 7

carbohydrates (sugars and starches)

Front 8

Most dietary __________ are _________________ (neutral fats).

Back 8

lipids

triglycerides

Front 9

Saturated fats are found in...

Back 9

animal products such as meat and dairy foods and in a few plant products, such as coconut.

Front 10

Unsaturated fats are present in...

Back 10

seeds, nuts, and most vegetable oils. Major sources of cholesterol are egg yolk, meats, and milk products.

Front 11

Animal products contain the highest-quality...

Back 11

proteins.

Front 12

Eggs, milk, fish, and most meat proteins are...

Back 12

complete proteins that meet all of the body's amino acid requirements for tissue maintenance and growth.

Legumes (beans and peas), nuts, and cereals are also protein-rich, but their proteins are nutritionally incomplete because they are low in one or more of the essential amino acids.

Front 13

The essential amino acids are...

Back 13

the eight amino acids that the body cannot make.

These amino acids must be obtained through diet. When ingested together, cereal grains and legumes provide all needed amino acids.

Front 14

Vitamins

Back 14

are organic nutrients of various forms that the body requires in small amounts.

Although vitamins are found in all major food groups, no one food contains all the required vitamins.

A balanced diet is the best way to ensure a full vitamin complement.

Front 15

The body also requires adequate supplies of seven minerals including...

Back 15

calcium, phosphorus, potassium, sulfur, sodium, chloride, magnesium, and trace amounts of about a dozen others.

The most mineral rich foods are vegetables, legumes, milk, and some meats.

Front 16

Metabolism

Back 16

is a broad term referring to all chemical reactions that are necessary to maintain life.

Front 17

catabolism

Back 17

in which substances are broken down to simpler substances

Front 18

anabolism

Back 18

in which larger molecules or structures are built from smaller ones.

Front 19

Glucose

Back 19

also known as blood sugar, is the major breakdown product of carbohydrate digestion.

Front 20

___________ is the major fuel for making ATP, and homeostasis of _______________ is critically important.

Back 20

Glucose, blood glucose levels .

Front 21

If the blood glucose levels are excessively high...

Back 21

hyperglycemia

some of the excess is stored in body cells (particularly the liver and muscle cells) as glycogen.

If blood glucose levels are still too high, excesses are converted to fat.

Front 22

When blood glucose levels are too low

Back 22

hypoglycemia

the liver breaks down stored glycogen and releases glucose to the blood for cellular use.

Front 23

Fats are used to make...

Back 23

cell membranes and myelin sheaths, and insulate the body with a fatty cushion.

They are also used as the body's main energy fuel for making ATP when carbohydrates in the diet are inadequate.

Front 24

The ________ controls most lipid or fat metabolism that goes on in the body.

Back 24

liver

Front 25

Excess fats are stored in fat depots such as the...

Back 25

hips, abdomen, breasts, and subcutaneous tissues.

Front 26

Proteins make up the bulk of ______________ and are carefully conserved by body cells.

Back 26

cellular structures

Front 27

Ingested proteins are broken down to ________________.

Back 27

amino acids

Front 28

Cells cannot build their proteins unless all the needed _______________ are present.

Back 28

amino acids (about 20)

Front 29

The ____________ is the body's major metabolic organ.

Back 29

liver

Nutrients take a detour through the liver to ensure that the liver's needs are met first.

Front 30

As blood circulates slowly through the liver, liver cells remove ______________________ from the blood.

Back 30

amino acids, fatty acids, and glucose

Front 31

The liver's ______________ remove and destroy bacteria that have managed to get through the walls of the digestive tract and into the blood.

Back 31

phagocytic cells

Front 32

After a carbohydrate-rich meal, thousands of glucose molecules are removed from the blood and combined to form the large polysaccharide molecules called__________.

Back 32

glycogen, which are then stored in the liver.

Front 33

Nutrients that are not needed by the liver cells, as well as the products of liver metabolism, are released into the blood and drain from the liver in the...

Back 33

hepatic vein to enter the systemic circulation, where they become available to other body cells.

Front 34

The liver cells then release glucose little by little into the blood to...

Back 34

maintain homeostasis of the blood glucose levels.

Front 35

Cholesterol

Back 35

serves as the structural basis of steroid hormones and vitamin D, and is a major building block of plasma membranes.

Front 36

Only about _____ of blood cholesterol comes from the diet, the other ____ is made by the liver.

Back 36

15%
85%

Front 37

Fatty acids, fats, and cholesterol are insoluble in water, so they cannot circulate freely in the bloodstream. They are transported bound to the small lipid-protein complexes called...

Back 37

lipoproteins

Front 38

Low-density lipoproteins, or LDLs

Back 38

transport and move cholesterol and other lipids to body cells, where they are used in various ways.

If large amounts of LDLs are circulating, the chance that fatty substances will be deposited in arterial walls is high.

Front 39

The lipoproteins that transport cholesterol from the tissue cells (or arteries) to the liver for disposal in bile are...

Back 39

high-density lipoproteins, or HDLs.

Front 40

Energy intake

Back 40

is the energy liberated during food oxidation.

Front 41

Energy output

Back 41

includes the energy immediately lost as heat or used to do work, plus energy that is stored in the form of fat of glycogen.

When energy intake and energy output are balanced, body weight remains stable. When they are not, weight is lost or gained.

Front 42

When nutrients are broken down to produce ATP, they yield varying amounts of energy. The energy value of foods is measured in a unit called the ___________.

Back 42

kilocalorie

Front 43

In general, carbohydrates and proteins yield ______, and fats yield ______ when they are broken down for energy production.

Back 43

4 kcal/gram
9 kcal/gram

The amount of energy used by the body is also measured in kilocalories.

Front 44

basal metabolic rate (BMR)

Back 44

is the amount of heat produced by the body per unit of time when it is at rest.

It reflects the energy supply a person's body needs to perform essential life activities such as breathing, maintaining the heartbeat, and kidney function.

Front 45

When active, the body must...

Back 45

oxidize more glucose to provide energy for the additional activities

Front 46

Total metabolic rate (TMR)

Back 46

refers to the total amount of kilocalories the body must consume to fuel all ongoing activities.

Muscular work is the major body activity that increases the TMR.

When the total number of kilocalories consumed is equal to the TMR, homeostasis is maintained, and weight remains constant.

Front 47

Most energy that is released as foods are...

Back 47

oxidized escapes as heat.

Less than 40% of available food energy is actually captured to form ATP.

Front 48

Body temperature reflects the balance between _______________and____________.

Back 48

heat production
heat loss

Front 49

They body's thermostat is...

Back 49

in the hypothalamus of the brain.

Through autonomic nervous system pathways, the hypothalamus continuously regulates body temperature.

Front 50

If the temperature of the circulating blood falls, body heat must be conserved and more heat generated to restore normal body temperature. Short-term means of accomplishing this are...

Back 50

vasoconstriction of blood vessels of the skin and shivering.

Front 51

Most heat loss occurs through the skin via...

Back 51

radiation or evaporation.