Digestion and Excretion

What are the 3 roles of nutrients in the body?

• Provide energy

• Build and repair tissues

• Regulate body processes

What is the definition of "essential nutrients" and list the four types of essential nutrients?

Essential nutrients are nutrients that the body cannot synthesize and must be obtained from the diet.
The four types are:

1. Vitamins

2. Minerals

3. Essential fatty acids

4. Essential amino acids

What are the functions of the key vitamins (B2, B12, C, A, D)?

• B2 (Riboflavin): Helps with energy production and skin health

• B12 (Cobalamin): Important for nerve function and red blood cell production

• C (Ascorbic Acid): Antioxidant, promotes immune function, and aids in collagen synthesis

• A (Retinol): Supports vision, immune function, and skin health

• D (Calciferol): Aids in calcium absorption and bone health

What are the functions of the key minerals (Ca, P, K, Cl, Na, Fe)?

• Ca (Calcium): Important for bone and teeth health, muscle function

• P (Phosphorus): Essential for energy production and bone formation

• K (Potassium): Regulates fluid balance, nerve signals, and muscle function

• Cl (Chlorine): Helps with digestion and fluid balance

• Na (Sodium): Maintains fluid balance, nerve function

• Fe (Iron): Necessary for oxygen transport in blood (hemoglobin)

Label the components of the mammalian digestive system on a diagram, and match those components to their function.

• Mouth: Mechanical breakdown of food, enzymatic digestion of starch

• Esophagus: Transports food to the stomach

• Stomach: Protein digestion, food storage

• Small intestine: Nutrient absorption

• Large intestine: Water absorption, formation of feces

• Liver: Produces bile for fat digestion

• Pancreas: Secretes digestive enzymes and insulin

• Rectum and Anus: Elimination of waste

What are the different types of digestive systems in animals?

• Complete digestive system: Has two openings (mouth and anus), such as in humans.

• Incomplete digestive system: Has one opening, such as in cnidarians.

• Carnivorous: Digestive system adapted to break down animal-based foods.

• Herbivorous: Digestive system adapted to break down plant-based foods.

• Omnivorous: Digestive system adapted to process both plant and animal foods.

Where does mechanical and chemical digestion of carbohydrates, proteins, and fats occur in the mammalian digestive system?

• Carbohydrates:

  • Mechanical digestion: Mouth

  • Chemical digestion: Mouth (salivary amylase) and small intestine (pancreatic amylase)

• Proteins:

  • Mechanical digestion: Stomach

  • Chemical digestion: Stomach (pepsin) and small intestine (trypsin, chymotrypsin)

• Fats:

  • Mechanical digestion: Stomach and small intestine (bile emulsification)

  • Chemical digestion: Small intestine (lipase)

Match digestive enzymes to their function, organ of production, and secretion site.

• Amylase:

  • Function: Breaks down starch

  • Organ: Salivary glands and pancreas

  • Secretion site: Mouth and small intestine

• Pepsin:

  • Function: Breaks down proteins

  • Organ: Stomach

  • Secretion site: Stomach

• Lipase:

  • Function: Breaks down fats

  • Organ: Pancreas

  • Secretion site: Small intestine

• Trypsin:

  • Function: Breaks down proteins

  • Organ: Pancreas

  • Secretion site: Small intestine

How does diet affect digestive enzyme production across and within species?

Different diets influence enzyme production. For example, herbivores produce more enzymes like cellulase to break down plant fibers, while carnivores produce more proteases for protein digestion. Species adapted to high-fat or high-protein diets may have more lipase or protease production

How is glucose level in the blood regulated hormonally, and what diseases can result from imbalances?

• Insulin: Reduces blood glucose by promoting uptake into cells.

• Glucagon: Increases blood glucose by promoting glucose release from the liver.
  Imbalances can lead to diseases such as diabetes mellitus, where blood glucose levels are either too high (insulin deficiency) or too low (impaired glucagon function).

Describe the hormonal regulation of digestion and appetite.

• Gastrin: Stimulates gastric acid secretion and motility in the stomach.

• Cholecystokinin (CCK): Stimulates bile release and enzyme secretion, promotes satiety.

• Ghrelin: Stimulates appetite.

• Leptin: Suppresses appetite and promotes energy expenditure.

What is the gut microbiome and how is it related to diet?

The gut microbiome is the community of microorganisms living in the digestive tract. It plays a crucial role in digestion, immunity, and overall health. Diet influences the diversity and composition of the microbiome, with fiber-rich diets supporting beneficial bacteria, while high-fat and high-sugar diets may lead to an imbalance of harmful bacteria.