Chapter 46 Digestion

Question 1

Metabolism

Answer 1

Refers to all the bodily activities and chemical reactions in an organism that maintain life.Refers to all the bodily activities and chemical reactions in an organism that maintain life.

Question 2

Metabolic Rate

Answer 2

Describes the rate at which an organism uses energy to power the reaction that maintain life.

Question 3

Postabsorptive State

Answer 3

Occurs when the GI tract is empty of nutrients and the body’s own stores must supply energy.

Question 4

Absorptive state

Answer 4

Occurs when ingested nutrients enter the blood from the gastrointestinal tract.

Question 5

Gluconeogenesis

Answer 5

(creation of new glucose) enzymes in the liver convert noncarbohydrates into glucose, which is then secreted into the blood. Mainly in mammals.

Question 6

Lipolysis

Answer 6

Enzymes within fat cells hydrolyze triglycerides into fatty acids and glycerol, both of which enter the bloodstream. The fatty acids diffuse into cells, where they are used as an alternate energy source to glucose.

Question 7

Glucose sparing

Answer 7

The brain and CNS require glucose, and the CNS reduces other organs need for glucose by increasing their dependence on fat. They do this by increasing their use of fat as an energy supply during this period.

Question 8

Convection

Answer 8

The transfer of heat by the movement of air or fluid next to the body.

Question 9

Glycogenolysis

Answer 9

Vertebrates increase their blood glucose concentrations … The glycogen that was formed during the absorptive period can be broken back down into molecules of glucose by hydrolysis. Primarily in the liver, glucose is released into the blood where it can travel to all cells.

Question 10

Glucagon

Answer 10

A protein hormone secreted by the pancreas that stimulates the processes of glycogenolysis, glyconeogenesis, and the processing of fatty acids to ketones of the liver.

Question 11

Kcal

Answer 11

Kilocalorie. Most biological activities, however, require much greater amounts of energy than a calorie and consequently, the more common unit of measurement is the kilocalorie.

Question 12

Basal metabolic rate

Answer 12

The most common measure to compare metabolic rates. It is called the metabolic cost of living, and is attributable to the heart, liver, kidneys, and brain. The metabolic rate of an animal under resting conditions, in a postabsoptive state, and at standard temperature.

Question 13

Direct calorimetry

Answer 13

A measure of metabolism, metabolic rate and heat production are directly related. Not practical with large animals.

Question 14

Indirect calorimetry

Answer 14

The more fuel being metabolized, the more oxygen consumed by the animal.

Question 15

Food induced thermogenesis

Answer 15

Mainly in mammals that eat meat. Eating and digesting increase the metabolic rate by 10-15%

Question 16

Mass-specific BMR

Answer 16

The amount of energy expended per gram of body mass.

Question 17

torpor

Answer 17

Many animals have evolved a strategy of lowering their internal body temperature to just a few degrees above that of the environment.

Question 18

Hibernation

Answer 18

A reduction of body temperature decreases the metabolic demands of all body cells, sometimes to <1 degree C. for months at a time.

Question 19

Leptin

Answer 19

Produced by adipose cells. As more fat is stored in adipose cells in the body, more is secreted into the blood. It actons on the hypothalamus to decrease appetite and increase metabolic rate.

Question 20

Satiety

Answer 20

Fullness, short-term control of feeding. Signals from the stomach sensory nerves and hormones suppress appetite.