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Outline the features of the principal components of the digestive system.
• Mouth: Mechanical and chemical digestion.
• Esophagus: Peristalsis action.
• Stomach: Rugae, lumen, mucous coating.
• Small Intestine: Villi and microvilli for absorption.
• Large Intestine: Water balance, vitamin absorption.
• Pancreas: Production of enzymes.
• Liver: Production of bile.
• Gall Bladder: Storage of bile.
State the typical pH values found throughout the digestive system.
• Mouth: 5.5 to 7.5
• Stomach: 1.0 to less than 4.0
• Small Intestine: 6.0 to 8.0
Describe the function of enzymes in the context of macronutrient digestion.
• Enzymes act as catalysts.
• They are proteins.
• Active under optimum temperature and pH.
• Each reaction requires a specific enzyme.
List the enzymes responsible for the digestion of carbohydrates, fats, and proteins from the mouth to the small intestine.
• Carbohydrates: Salivary amylase, pancreatic amylase.
• Fats: Pancreatic lipase.
• Proteins: Pepsin, trypsin.
• Bile: Involved in fat digestion.
Describe the absorption of glucose, amino acids, and fatty acids from the intestinal lumen to the capillary network.
Back:
• Nutrients cross the brush-border membrane.
• Pass through the cytosol of the absorptive cell.
• Cross the basolateral membrane before entering the capillary network (glucose and amino acids) or the lymphatic system (fats).
State the reasons why humans cannot live without water for a prolonged period.
Back:
• Basic substance for metabolic processes.
• Regulates body temperature.
• Enables transport of essential substances.
• Allows exchange of nutrients and metabolic end products.
State where extracellular fluid can be located throughout the body.
Back:
• Blood plasma and lymph.
• Saliva.
• Fluid in the eyes.
• Fluid secreted by glands and the digestive tract.
• Fluid surrounding the nerves and spinal cord.
• Fluid secreted from the skin and kidneys.
Compare water distribution in trained and untrained individuals.
Trained individuals have a greater capacity to store water in their muscles due to higher muscle mass and lower fat mass compared to untrained individuals.
Explain that homeostasis involves monitoring levels of variables and correcting changes in levels by negative feedback mechanisms.
Negative feedback mechanisms help maintain stable internal conditions by counteracting changes from the normal range.
Explain the roles of the loop of Henlé, medulla, collecting duct, and ADH in maintaining the water balance of the blood.
• Loop of Henlé: Concentrates urine by reabsorbing water and salts.
• Medulla: Osmotic gradient helps water reabsorption.
• Collecting Duct: ADH increases permeability to water, leading to reabsorption.
Describe how the hydration status of athletes can be monitored.
By monitoring urine color, urine osmolarity, and variation in body mass loss.
Explain why endurance athletes require a greater water intake.
To prevent dehydration, maintain performance, and avoid heat-related illnesses.
Compare water distribution in trained and untrained individuals.
Trained individuals have a greater capacity to store water in their muscles due to higher muscle mass and lower fat mass compared to untrained individuals.
Discuss the regulation of electrolyte balance during acute and chronic exercise.
Electrolyte balance is regulated through dietary intake, hydration, and hormonal control (e.g., aldosterone).
Define the term basal metabolic rate (BMR).
BMR is the rate of energy expenditure per unit time at rest.
State the components of daily energy expenditure.
Limit to: basal metabolic rate (BMR), thermic effect of physical activity, thermic effect of feeding.
Explain the relationship between energy expenditure and intake.
The relationship between energy expenditure and intake is that energy expenditure must balance energy intake to maintain body weight; if intake exceeds expenditure, weight gain occurs, and if expenditure exceeds intake, weight loss occurs.
Discuss the association between body composition and athletic performance.
Consider body composition from two components: fat and fat-free mass. A distinction between fat-free mass and lean body mass should be made. The discussion should include reference to typical levels of body fat and consider the accuracy of body fat measurements.
Discuss dietary practices employed by athletes to manipulate body composition.
Aim 8: Include dietary practices used to decrease body fat, for example, a recommended dietary approach and more controversial methods such as diet pills, fad diets, and crash diets. Also include the significance of a high-protein diet for athletes aiming to increase muscle mass.
State the approximate glycogen content of specific skeletal muscle fibre types.
Limit fibre types to: slow twitch (type I)—low-glycogen content, fast twitch (type IIa)—medium-glycogen content, fast twitch (type IIb)—high-glycogen content. Note: Type IIa and type IIb are high in glycogen content depending on training status.
Define the term glycemic index (GI).
Glycemic index (GI) is the ranking system for carbohydrates based on the immediate effect of the food on blood glucose concentrations when compared with a reference food such as pure glucose.
List food with low and high glycemic indexes.
High (for example, glucose) =100, Medium (for example, brown rice) = 50, Low (for example, green vegetables) = less than 15
Explain the relevance of GI with regard to carbohydrate consumption by athletes pre- and post-competition.
The use of high GI foods post-exercise may assist the body in restoring its glycogen stores more rapidly, aiding refuelling prior to future training/competition bouts. There is some evidence that lower GI foods may be beneficial prior to exercise and that our general diet, in terms of good health, should be based on carbohydrate foods with a low to medium GI.
Discuss the interaction of carbohydrate loading and training programme modification prior to competition.
Include nutritional strategies as well as training strategies, such as tapering prior to an event.
State the reasons for adding sodium and carbohydrate to water for the endurance athlete.
The reasons for adding sodium and carbohydrate to water for the endurance athlete are to replenish electrolytes lost through sweat, maintain hydration, and provide a quick source of energy to sustain performance during prolonged exercise.
iscuss the use of nutritional ergogenic aids in sports.
Limit to: sports drinks, bars and gels, caffeine, creatine, bicarbonate. Aim 8: Include ethical, health and performance enhancement considerations.
State the daily recommended intake of protein for adult male and female non-athletes.
The World Health Organization (WHO) recommends a minimum of 0.8 g kg-1 body weight.
List sources of protein for vegetarian and non-vegetarian athletes.
Vegetarian sources of protein include lentils, chickpeas, quinoa, tofu, tempeh, edamame, nuts, seeds, Greek yogurt, cottage cheese, and peas. Non-vegetarian sources of protein include chicken breast, turkey, beef, pork, fish, eggs, milk, whey protein, shrimp, and lean cuts of lamb.
Discuss the significance of strength and endurance training on the recommended protein intake for male and female athletes.
Strength and endurance training significantly increase the recommended protein intake for both male and female athletes, as these activities require more protein to repair and build muscle tissue, support recovery, and enhance overall performance. Athletes engaged in such training typically need more protein than non-athletes to meet their body’s heightened demands.
Outline the possible harmful effects of excessive protein intake.
Excessive protein intake can lead to harmful effects such as kidney strain or damage, increased risk of heart disease due to high intake of saturated fats, dehydration, digestive issues like constipation, and potential nutrient imbalances as other essential nutrients may be neglected.
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