Chapter 3 Nutrition

Why is acid important for protein digestion?

Acid is important in denaturing protein.

What is the function of bile in fat digestion and absorption?

Bile emulsifies fat into small droplets and increases area for enzymes to digest lipids.

Where do water-soluble nutrients go after leaving intestinal cells? Which organ deals with their processing after absorption from the intestine?

Blood vessels. Liver

What are the 3 mechanisms of absorption of nutrients?

Diffusion, Active transport, Osmosis

Name the organ systems in the body which contribute to digestion and absorption of nutrients.

Digestive system

Where do fat-soluble nutrients go after being absorbed? Why do they not go where the water-soluble nutrients go?What re the main functions of the TCA cycle? What are the input and output for the TCA cycle?

Fat-solube nutrients enter through the lymph vessels. The TCA cycle input is ACETYL Coa and the out put is Citric Acid, NADPH, ATP, FADH

Why can't we digest fiber?

Fiber contains certain complex carbohydrates that human enzymes can't digest

Describe the process of protein digestion in our gastrointestinal tract. Which enzymes are responsible for digestion and where are they produced/perform their function?

HCl and pepsin begin digestion of protein in the stomach. The small intestine breaks down polypeptides into amino acids. Amino acids pass from mucosa cell into blodd and travel to the liver.

Where do most of the bacteria in our gastrointestinal tract predominate? Why do they proliferate in this segment of the GI tract more than others?

In the large intestine. Slow movement of waste material causes bacterial growth because waste tends to be there for 24 to 72 hrs.

What is the function of mucus in our gut?

It acts to lubricate, moisten, and protect cels from the harsh environment.

What is the function of bicarbonate in our gastrointestinal tract?

It is to neutralize the acidity of chyme

What 3 key structural features are important for digestion and absorption by the small intestine? What do they do to the surface area of the small intestine?

Large circular folds, entire inner surface covered with villi. Mucosal cell on surface covered by microvill to increase surface are.

Which layer of tissue in the gut wall is responsible for absorbing digestive end products?

Mucosa

Which cells produce hydrochloric acid in the stomach? Which cells produce pepsinogen?

Parietal cells produce HCl. Gastric chief cells produce pepsinogen.

What is the difference between peristalsis and segmentation?

Peristalsis pushes food down canal. Segmentation mixes and churn food.

What is the function of the gallbladder?

Produces bile

Describe the process of carbohydrate digestion in our gastrointestinal tract. Which enzymes are responsible for digestion and where are they produced/perform their function?

Salivary amylase in mouth starts the breakdown of starch. In the stomach it is inactivated and carbs do not get digested. In small intestine pancrietic amylase finishes break down of starch. Small Intestine, enzymes attach to microvilli complete the digestion into monosaccharides. Large intestine, fiber and other indigestible carbs are partially broken down by bacteria and then excreted. Carbs first transported to liver through portal vein.

How do the hormones secretin, gastrin, and CCK affect digestion?

Secretin increases bile output from liver. CCK stimulates contraction of gallbladder to expel bile. Gastrin inhibits gastric secretion and motility.

Describe the process of fat digestion in our gastrointestinal tract. Which enzymes are responsible for digestion and where are they produced/perform their function?

Small amount of digestion occurs in the stomach due to gastic lipase. Liver produces bile which is stored in the gallbladder and released into small intestine to aid in digestion of fat. Pancrease produces lipase which is release to break down triglycerides into monoglycerides and fatty acids. Products of fat digestion and bile acids form micelles to allow lipids to move across mucosal cells.

What is the cephalic phase of digestion?

The cephalic phase of digestion is before food enters the g.i tract. It involves sight, smell, and taste of appetite.

What is transit time?

The time between the ingestion of food and the elimination of the solid waste from that food