Digestion and Essential Nutrients Essay example

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Learning objectives for Chapter 41 – Digestion and Nutrition

Define and distinguish among carnivores, herbivores, omnivores.
Carnivores - animal that eats meat
Herbivores - animal that eats only plant material
Omnivores - anima that eats both plants and meat
Name the three nutritional needs that must be met by an animal’s diet.
The three nutrition needs that must be met are fuel (for chemical energy to turn into ATP), raw materials (carbon and nitrogen-containing macromolecules), and essential nutrients.

Define essential nutrients. Describe the four classes of essential nutrients.
Essential nutrients are chemicals an animal can not make itself and therefore must be included in the animal’s diet. There are four main classes of essential nutrients:

Essential amino acids - 8 of the 20 different amino acids can’t be be chemically synthesized so they must be included in our diet

Essential fatty acids - must be included in diet; linoleic acid in vegetable oil, fish oils, omega-3 Vitamins -organic molecules needed for various cellular processes; we need to obtain 13 vitamins in our diet either fat-soluble or water-soluble; vitamin D is essential for absorbing calcium into the bloodstream; deficiency leads to bone and muscle getting weak

Minerals - nonorganic molecules required in small amounts which play a variety of roles in body functioning

Explain the difference between vitamins and minerals, and know the function of minerals examples mentioned in class.
Vitamins are organic, minerals are inorganic

Distinguish between water-soluble and fat-soluble vitamins. Explain why megadoses of fat-soluble vitamins are more dangerous than equally large doses of water-soluble vitamins.
Water-soluble vitamins - B vitamins folic acid, biotin and vitamin C; hydrophilic + polar; excess intake leads to excretion in urine

Fat-soluble vitamins - vitamins A,D,E and K; hydrophobic and nonpolar; excess intake results in storing in body fat which is toxic

Distinguish among undernourishment, over nourishment, and malnourishment.
Undernourishment - diet supplies less chemical energy than the body requires; body uses up stored fat and carbs; then breaks down its own proteins and loses muscle mass and damages neurons

Over nourishment - taking in excess calories; linked to obesity, type 2 diabetes, and colon cancer

Malnourishment -not getting enough essential nutrients
Define and compare the four main stages of food processing, and where each occurs in humans.
Stage 1: Ingestion, defined as the consumption of food, occurs at the oral cavity as food enters the mouth.

Stage 2: Digestion starts in the oral cavity through chemical + mechanical digestion. In the stomach digestion continues both chemically and mechanically. In the duodenum of the small intestine most of the chemical digestion takes place as the chyme from the stomach mixes with digestive juices from the pancreas, liver + gallbladder, and cells lining the small intestine called brush boarder cells.

Stage 3: Absorption primarily occurs in the jejunum and illeum of the small intestine because there is a large surface area due to many folds. Monomers move from the lumen, across the epithelial cells into the bloodstream and lymph in lymph vessels.

Stage 4: Elimination of wastes called feces through the anus. The rectum holds the feces before elimination occurs

Describe the main components of the human alimentary canal, the associated digestive glands, and the order in which food passes through each organ.
Food first enters through the mouth where mechanical and chemical digestion occurs. The tongue then forms the food into a bolus which passes through the pharynx and down the esophagus via peristalsis. From there food enters the stomach where both mechanical and chemical digestion occurs creating chyme. Chyme then enters the duodenum of the small intestine where it mixes with digestive juices from the pancreas, liver + gall bladder and…