Chapter 2

When carbohydrates are at low levels in the body proteins are broken down to simpler molecules that are used to make glucose. What is this process called?

Gluconeogenisis: proteins are broken down into amino acids, transported to the liver, and converted to the carbohydrate glucose which can then be used for energy by the body's tissues.

What happens to fats once they are put into the mouth?

Mastication breaks up fat into smaller pieces, and lingual lipase in the saliva initiates the enzymatic digestive process.

What is steady state exercise and what is it's significance?

Of the three energy systems, muscle cells rely mostly on the Aerobic system because of its unending ability to make ATP. If the energy requirements of the activity are low enough for the aerobic energy systems to meet the energy demands, exercise can be continued for long duration resulting in steady state exercise.

What is the primary function of the stomach?

Once in the stomach, the food is subjected to stomach acids and other enzymes that further the digestive process. The stomach has a muscular wall that churns the food, mixing it with stomach acid and enzymes. This digestive process continues for roughly an hour before food begins to exit the stomach. Some absorption of nutrients occurs in the stomach.

What happens to nutrients after they are ingested?

Process of digestion

What happens to proteins once they are put into the mouth?

Proteins do not undergo enzymatic digestion in the mouth.

How are simple sugars absorbed into the intestinal wall?

1. Passive Diffusion 2. Facilitated Diffusion 3. Active Transport 4. Endocytosis

How are minerals digested, absorbed, transported, and assimilated in the body?

Minerals do not need to be broken down into smaller units via digestion to be absorbed into the body. Water soluble vitamins dissolve in the watery mix of food in the GI tract + are absorbed with water. Fat soluble vitamins dissolve in the fatty portion of the GI contents and absorbed through passive diffusion.

How are proteins digested, absorbed, transported, and assimilated in the body?

Proteins do not undergo enzymatic digestion in the mouth. The majority of protein digestion occurs in the stomach and upper portion of the small intestine. HCL (hydrochloric acid), secreted by the stomach lining, denatures protein. Enzyme pepsin in the stomach is responsible for 10-20% of protein digestion. Short peptides and amino acids can be absorbed by intestinal cells. Amino Acid absorption takes place through facilitated diffusion and active transport.

How do the energy systems work together to supply ATP during sport performance?

Simultaneously

What are the characteristics of the anaerobic and aerobic energy systems?

The anaerobic and aerobic energy systems must generate ATP via more complex cellular processing

What happens to carbohydrates once they are put into the mouth?

The digestion of carbs begins in the mouth with mastication and from enzyme amylase secreted from salivary glands. Food is swallowed and enters esophagus.

How are carbohydrates digested, absorbed, transported, and assimilated in the body?

The digestion of carbs begins in the mouth with mastication and from enzyme amylase secreted from salivary glands. Once in the stomach it is exposed to HCL. Majority of digestion and absorption happens in the small intestine by pancreatic amylase.

What do ATP, ADP, and AMP stand for?

ATP: Adenosine Triphosphate ADP: Adenosine Diphosphate AMP: Adenosine Monophosphate

Of the three energy systems which is the most complex, involving the most processes and steps?

Aerobic System

What do BMR and RMR stand for? What are their differences?

Basal Metabolic Rate: The absolute minimal amount of energy required to keep humans alive. Resting Metabolic Rate: Requires a slightly higher energy amount.

What are the functions of the various parts of the digestive system?

Digestive System: Mouth, Salivary glands, Esophagus, Stomach, Liver, Gallbladder, Pancreas, Small intestine, Large intestine, Rectum, Anus Mouth & Esophagus (Salivary Glands): Ingestion and Digestion Stomach & Small Intestine: Digestion and Absorption [Liver, Gallbladder, Bile Duct, Pancreas, and Small Intestine: These organs produce and secret substances that aid in digestion] Large Intestine: Absorption and elimination Rectum: Elimination

What is energy?

Energy is what enables cells, muscles, and other tissues of the body to perform work.

What is energy metabolism, and why is it important?

Energy metabolism: cellular machinery and metabolic pathways responsible for deriving energy from the macronutrients once they reach the cell. Knowledge of energy metabolism enables the SNP to to objectively asses the potential effectiveness of a diet/supplement, to educate their athlete about the energy needs of the sport, and to create an individualized diet plan.

How does carbohydrate intake affect protein metabolism?

When diets are low in carbohydrates or when an athlete is involved in training that depletes the carbohydrate stores, the body must get its carbohydrates from somewhere else (gluconeogenisis). If carbohydrate intake is adequate to meet energy demands and carbohydrate stores are replenished after training, proteins do not need to be converted to carbohydrates, and muscle protein is spared.

What are the six basic forms of energy?

Chemical, nuclear, electrical, mechanical, thermal, radiant.

What are the three sections of the small intestine and in which section does the majority of digestion occur?

1. Duodenum 2. Jejunum 3. Ileum As the partially digested food exits the stomach, it enters the duodenum. The duodenum is where the food from the stomach is barraged with more digestive enzymes from the gallbladder and the pancreas. Most of the digestion of foodstuffs in completed in the duodenum.

Define and differentiate the four absorptive processes.

1. Passive diffusion: Water and water soluble substances and small lipids move with a concentration gradient. 2. Facilitated Diffusion: Transmembrane protein carrier changes shape to facilitate entry and exit of some nutrients 3. Active Transport: Minerals, some sugars, and most amino acids move against a concentration gradient with an input of energy 4. Endocytosis: The cell membrane surrounds small molecules and engulfs them

How are fats digested, absorbed, transported, and assimilated in the body?

The digestive system subjects fats to substance known as emulsifiers which breaks down lipids into small globules that stay suspended in the watery contents of the GI Tract and increase the exposed SA of fats to the action of digestive enzymes. Once absorbed, water soluble glycerol and short and medium chain fatty acids pass through intestinal cells and diffuse into capillaries, thus directly entering the bloodstream.

What is the human body's source of chemical energy?

The direct source for energy for all biological processes comes from a high energy molecule Adenosine Triphosphate.

Where in the digestive system and by what means do nutrients first begin to digest?

The mouth, or oral cavity is the entry point for ingested nutrients. The main digestive process that occurs in the mouth is mastication (chewing). The mechanical process of mastication breaks food into pieces, increasing SA of food and facilitating enzymatic action. The parotid, submandibular, and sublingual glands secrete saliva into the oral cavity, saliva moistens the food and and contains enzymes that initiate the enzymatic breakdown of carbohydrates and fats.

What are the three energy systems? What are their differences?

The three systems that function within the metabolic factories of muscle cells to prevent ATP depletion are Phosphagen system: low; one step process; very fast ATP production; very limited capacity to make ATP Anaerobic system: Moderate; 12 step process; fast ATP production, limited capacity to make ATP Aerobic system: Very high; many processes and steps; very slow distant third; unlimited capacity to make ATP