Chapter 41 Digestion & Nutrition

Digestion-Stomach

Protein digestion begins here---- -Stomach stores 2L mixing and chemical digestion -Chemical: Hydrochloric acid breaks down protein and kills bacteria secreted into the lumen. Pepsin breaks down protein. The pH in the stomach is low 1-2. -Proteins--->smaller polypeptides

Which of the following increases the surface area to volume ratio of the epithelial cells of the small intestine? a.) Folding b.) Villi c.) Microvilli d.) All of the above

d.)

*How does the stomach protect itself?

mucous barrier

Digestion-accessory organs

pancreas- Makes many digestive enzymes and delivers to small intestine. liver-Makes bile, fat digestion needs help of bile salts. gallbladder-Stores and delivers to small intestine salivary glands

What are some stomach diseases?

-Gastric Ulcers: Inhibit proton H+ secretion from parietal cells (Nexium) -Indigestion: Neutralize pH of Stomach Lumen (Bicarbonate TUMS)

Predict how perturbations in levels of blood sugar, insulin, or glucagon, such as in diabetes, will affect the homeostatic control of blood glucose levels.

-if your blood sugar is too high the pancreas releases beta cells (make Insulin) and the insulin makes its way to the liver and body cells. When the insulin reaches the body cells its receptors tell the cells to take in more glucose.

Absorption in the small intestine is increased by

-the many villi present on the inner surface of the small intestine. -the brush border formed by microvilli on the cells of the villi. -the presence of numerous transporter molecules on the epithelial cells.

The Four Steps of Food Processing

1. Ingestion- Eat (Salivary glands) 2. Digestion-Break down into smaller molecules that can cross cell membranes (Gallbladder, Stomach, and Pancreas) 3. Absorption-Take up into cells (Small intestine, Large intestine) 4. Elimination-Shit (Large intestine, Anus)

Which is the correct sequence of bodily responses to decreased temperature? 1. Thermostat in hypothalamus activates heating mechanisms. 2. Body temperature decreases. 3. Body temperature increases. 4. Muscles cause shivering, and blood vessels in skin constrict.

2,1,4,3

In type 1 diabetes _________ the control center is/are not able to produce insulin.

Beta cells

What are bile salts?

Bile salts break up fat globules, increasing exposure of triglycerides to hydrolysis. -the enzyme lipase breaks triglycerides down to fatty acids and monoglycerides.

In type 2 diabetes ___________ and __________, the effectors are not able to respond to insulin, and thus can not reduce blood glucose level.

Body cells the Liver

Which is NOT true about processing of macromolecules? -Fat digestion by human enzymes is completed in the small intestine. -Carbohydrate digestion begins in the stomach. -Carbohydrate digestion by human enzymes is completed in the small intestine. -Protein digestion begins in the stomach.

Carbohydrate digestion begins in the stomach.

Digestion-Mouth

Carbohydrates digestion begins here---- -As you chew, salivary amylase begins breaking down starch molecules into sugars (maltose disaccharide and smaller polysaccharides) .

Digestion-Small intestine

Carbohydrates, Proteins & Fats digestion here---- Enzymes digest most macromolecules (including proteins, starch, glycogen, lipids, and nucleic acids; not cellulose) in food into monomers. Most digestion and absorption done here. These enzymes are secreted by pancreas into SI: - lipase (for lipids Fats) - amylase (for starch)

Describe the digestion and absorption of the three major macronutrients in humans (carbohydrates, proteins, and fats), including the enzymes and other molecules, like bile, involved and the organs that secrete them.

Carbohydrates: Broken down into sugars Proteins: Broken down into amino acids Fats: Broken down into glycerol and fatty acids Macronutrients- we need large amounts of Micronutrients- we need small amounts of (vitamins and minerals)

The bile salts function in fat digestion by _____. -chemically degrading fat molecules to glycerol and fatty acids -dissolving individual fat molecules in water -triggering the secretion of pancreatic lipase -dispersing big droplets of fats to small droplets

Dispersing big droplets of fats to small droplets

Luteinizing hormone (LH) is secreted by the anterior pituitary of the brain to stimulate testosterone production in the testes. When testosterone levels are high, it results LH secretion to decrease. Which type of feedback is this ? -Positive feedback -No feedback control -Negative feedback

Negative feedback

Chemical digestion and absorption of nutrients both occur primarily in the _____________. -small intestine -stomach -large intestine -pancreas

Small intestine

Glucagon, a pancreatic hormone, functions to _____. -increase fat storage in fat cells -stimulate the liver to release glucose -reduce glucose levels in the blood -inhibit activity in the small intestine

Stimulate the liver to release glucose

*Describe the structure of the small intestine that increases the surface area for efficient absorption

There are large foldings in the small intestine that increases the surface area without changing the volume. Increased area means high S/V which increases the rate of diffusion.

HCL in the Stomach a.) is secreted all the time b.) breaks down fats c.) activates pepsinogen into pepsin d.) irritates epithelial cells of a healthy stomach

c.)

Where are the enzymes that digest foods in the small intestine made? a.) Small intestine b.) Pancreas c.) Small Intestine and pancreas d.) Small intestine, pancreas, and liver

c.)