Nutrition: Unit 1: Chapter 3:

List at least 2 functions of saliva

1. It functions as a lubricant 2. It help protect and sanitize the mouth.

List and briefly explain the 4 mechanisms by which nutrients are absorbed across intestinal lining cells.

1. Passive diffusion: is the process by which nutrients are absorbe due to a concentration gradient. 2. Facilitated diffusion: is the process where nutrients have to be helped across the membrane by specific carrier proteins. 3. Active transport: is the process of the absorption of nutrients from a low to a high concentration that requires both a carrier molecule and energy in the form of ATP to shuttle nutrients across the cell membrane. 4. Endocytosis: happens when a cell forms a vesicle to surround and engulf a nutrient. Often referred to as "cell drinking".

Describe the three conditions that must ve present in order for an enzyme to work.

1. The compatible enzyme and nutrient must both be present. 2. The pH of the surrounding environment falls in the correct range. 3. The temperature of the environment is optimal.

Ulcerative colitis

A chronic inflammation of the colon or large intestine that results in ulcer forming in the lining of the colon.

Sphincter

A circular ring of muscle that opens and closes in response to nerve input.

Bolus

A soft mass of chewed food

Breifly describe the role of bacteria in the colon.

Bacteria in the colon can produce some vitamins. It can also ferment undigested or unabsorbed carbs and ferments them into simpler compounds like methane gas, carbon dioxide, and hydrogen.

What is the function of bicarbonate? Into which organ is its secretion critical to protect the digestive tract?

Bicarbonate ions alter the pH of food at various points in the GI tract. It is critical in the duodenum where it helps protect the cells lining the duodenum, because they are not resistant to damage by HCI.

What is the function of bile? Where is it produced and stored?

Bile helps digest dietary fats. It is stored in the gallbladder.

Distinguish between the precesses of digeston and absorption.

Digestion is the process of breaking down food, while absorption is the process of moving nutrients from the GI tract to the circulatory system.

Briefly describe two common digestive disorders and two more serious intestinal disorders.

Gallbladder disease and heartburn are two common digestive disorders and Esophageal cancer and ulcers are more serious intestinal disorders.

The stomach secretes hydrocholoric acid (HCL). How does it assist with chemical digestion?

Hydrochloric acid is essential in the digestion process because it can change the acidity of digestive fluids to a pH close to 1.5. it assist with chemical digestion by denaturing the proteins.

Distinguish between chemical and mechanical digestion

Mechanical digestion is the process of tearing, shredding, and mixing, while chemical digestion is the process of the salivary amylase breaking down the food.

In which part of the digestive tract are most of the nutrients absorbed? In which part of the digestive trat is most of the water absorbed?

Most nutrients are absorbed in the small intestines. The most water is absorded in the large intestines.

List the organs of the digestive tract and tell their major functions

Mouth: mechanical and chemical digestion. Pharynx and esophagus: swallowing and moving the food to the stomach. Stomach: mechanical, chemical, and absorption. Small intestines: Mechanical, propulsion, chemical, and absorption. Large intestines: Chemical digestion, absorption, and propulsion. Rectum: Elimination

Peristalsis and segmentation are both types of muscle contractions. How does their function differ?

Peristalsis is the squeezing of food that moves the food forward. It is a form of mechanical digestion that influences movement and doesnt add chemical secretions. Segmentation is the shifting of food, which washes the insides of the intestines. This allows for it to break the food into smaller and smaller pieces and combines it with digestive juices.

List the accessory organs to the digestive tract and tell their major functions

Salivary glands: Produce saliva, and mix saliva, water and mucus and enzymes to help break down food. Liver: Produces bile to help digest fats. Gallbladder: stores bile where it is then released into the small intestines through the bile duct. Pancreas: Produces enzymes and bicarbonate ions which release into the small intestines through the pancreatic duct.

List the segments of the large intestine. How does it differ from the small intestine?

The large intestines have three segments, the cecum, colon, and rectum. The large intestines are differetn from the small intestines in that it is much shorter and doesnt have villi, or microvilli, and it does not produce digestive enzymes. It is also not in a tight coil.

What types of nutrients are distributed throughout the body via the lymphatic system?

The lymphatic system transports fat- soluble nutrients, like fat soluble vitamins, long- chain fatty acids, and some proteins throughout the body.

How does the mouth contribute to mechanical digestion? How does the mouth contribute to chemical digestion?

The mouth contributes to mechanical digestion with the teeth shredding and tearing the food. Then the saliva helps break down food which is chemical digestion.

How to intrisic and extrinsic nerves work together to regulate digestive processes?

The nerves work together with the GI tract which in turn affect the motility and the release or inhibition of digestive juices.

What are the functions of the pharynx, epiglottis, and esphagus?

The pharynx is the gateway to the esophagus where it transports food and fluids to the stomach. The epiglottis if working properly closes the wind pipe so that when the food is going down the esophagus it doesnt go into the lungs.

Enterohepatic cirulation

The process of recycling bile from the large intestine back to the liver to be reused during fat digestion.

Chyme

The semi- liquid, partially digested food mass that leaves the stomach and enters the small intestines.

List the segments of the small intestines. considering its length, why is it called the "small" intestines?

The small intestines consists of three segments; the duodenum, jejunum, and the ileum. It is called the "small" intestine not because of its length but because of its diameter.

How does the small intestines contribute to mechanical digestion? to chemical digestion? to nutrient absorption?

The small intestines contribute to the mechanical digestion because muscular contractions allow the organ to squeeze while secretions from the pancreas, gallbladder and intestinal lining chemically break it down. while all that is going on the villi or fingerlike projections allow for maximum surface are to allow for maximum absorption.

How does the stomach contribute to mechanical digestion? To chemical digestion?

The stomach continues the mechanical digestion started in the mouth by continuing to mix the foods. The acids and enzymes in the stomach continue the chemical digestion started in the mouth by the saliva.

In general, how do hormones regulate digestion?

They help to signal and send a message to the rest of the digestive tract when you are eating to prepare for digestion.

Emulsify

To break large fat globules into smaller droplets

What type of nutrients are distributed throughout the body via the blood stream?

Water- soluble nutrients like carbs, amino acids, and water soluble vitamins are transported and distributed via the blood stream.