Nutrition chapter 3 digestive system

what are the 5 segments of the large intestine?

1. cecum/appendix 2. ascending colon 3.transverse colon 4. descending colon 5. sigmoid colon.

absorption

The process by which substances are taken up from the GI tract and enter the bloodstream or the lymph.

umami

a brothy, meaty, savory flavor in some foods. Monosodium glutamate enhances this failure when added to foods. Amino acid

gallbladder

an organ attached to the underside of the liver. site of bile storage, concentration, and eventual secretion into the small intestine

phagocytosis

in a further means of active absorption, absorptive cells literally engulf compounds.

ileum

last segment of the small intestine; approximately 5 feet in length.

Liver

produce bile to aid fat digestion and absorption

enzymes

produced in the mouth, stomach, small intestine, and pancreas. They promote digestion of carbohydrates, fats, and proteins into forms small enough for absorption. Examples amylases, lipase, proteases

active absorption

requires energy in addition to the need for a carrier protein, some nutrients also require energy input to move from the lumen of the small intestine into the absorptive cells. this mechanism makes it possible for cells to take up

amylase

starch-digesting enzyme produced by salivary glands, stomach, and pancreas.

What are the digestive functions of the stomach

store, mix, dissolve, and continue the digestion of food. Dissolve food particles with secretions, kill microorganisms with acid. Release protein-digesting (pepsin) and fat-digesting (lipase) enzymes.

epiglottis

the flap that folds down over the trachea during swallowing.

duodenum

1st segment of the small intestine that receives chyme from the stomach and digestive juices from the pancreas and gallbladder. This is the site of most chemical digestion of nutrients; approximately 10 inches in length.

bile

A liver secretion stored in the gallbladder and released through the common bile duct into the first segment of the small intestine.. It is essential for the digestion and absorption of fat.

rectum

A short tube at the end of the large intestine where waste material is compressed into a solid form before being eliminated

pyloric sphincter

A valve between the stomach and the small intestine that regulates the flow of chyme into the small intestine.

Lipase

An enzyme secreted in the digestive tract that catalyzes the breakdown of fats into individual fatty acids that can be absorbed into the bloodstream

pancreas

An organs in the abdominal cavity with two roles. The first is an exocrine role: to produce digestive enzymes and bicarbonate, which are delivered to the small intestine via the pancreatic duct. The second is an endocrine role: to secrete insulin and glucagon into the bloodstream to help regulate blood glucose levels.

digestion

Process by which large ingested molecules are mechanically and chemically broken down to produce basic nutrients that can be absorbed across the wall of the GI tract.

lower esophageal sphincter

Spincter muscle closing off stomach content from the esophagus. (if does not work right=heart burn=GERD

prebiotic

Substances that stimulate bacterial growth in the large intestine.

digestive system

System consisting of the gastrointestinal tract and accesorry structures (liver, gallbladder, and pancreas). This system performs the mechanical and chemical processes of digestion, absorption of nutrients, and elimination of wastes.

Mechanical digestion

Takes place as soon as you start chewing your food and continues as muscular contractions simultaneously mix and move food through the length of the GI tract.

peristaltic

The general term for the wave of muscle contraction which moves food down the esophagus is

lumen

The hollow opening inside a tube, such as the GI tract.

stomach

a large sac that can hold up to 4 cups of food for several hours until all of the food is able to enter the small intestine. Where food is mixed with gastric juice, which contains water, hydrochloric acid, and enzymes.

chyme

a mixture of stomach secretions partially digested food. It slowly leaves the stomach a teaspoon at a time and enters the small intestine.

intrinsic factor

a protein like compound produced by the stomach that enhances vitamin B-12 abosorption

mucus

a thick fluid secreted by many cells throughout the body. It contains a compound that has both carbohydrate and protein parts. It acts as a lubricant and means of protection for cells.

vili

are constantly moving, which helps them trap food to enhance the absorption. Each villus (singular) are made up of many absorptive cells (enterocytes), and mucosal surface of each of these is folded even further into microvilli. The combined folds. villi, and microvilli in the small intestine increase its surface area 600 times beyond that of a simple tube.

Chemical digestion

breakdown of foods by acid and enzymes secreted into the GI tract.

What are the digestive functions of the mouth and salivary glands

chew food, perceive taste, moisten food with saliva, lubricated food with mucus, release small amount of starch-digesting (amylase) and fat digestion (lipase) enzymes.

saliva

contains enzymes that make a minor contribution to starch and fat digestion.

small intestine

digest and absorb most substances using enzymes made by the pancreas and small intestinal cells (lactase, sucrase, maltase, peptidases). Small intestine is not covered with mucus to protect itself, because if it were then it would be very limited in being able to digest and absorb. Therefore the pancreas and intestinal cells secrete bicarbonate to neutralize the acid. the neutral PH also optimizes the activity of the digestive enzymes that work in this area.

large intestine

doesn't have villi or digestive enzymes. Little absorption takes place here in comparison to the small intestine. nutrients absorbed here include water, some vitamins, and some fatty acids, and the minerals sodium and potassium. mucus is produced here and secreted. This mucus functions to hold the feces together. has a population of over 500 bacteria.

lipase

fat digesting enzyme produced by the salivary glands, stomach, and pancreas.

motility

generally the ability to move spontaneously. It also refers to the movement of food through the GI tract.

What are the digestive functions of the esophagus

lubricate with mucus, move food to the stomach by peristalic waves (swallowing)

gastrointestinal tract

main sites in the body used for digestion and absorption of nutrients. It consists of the mouth, esophagus, stomach, small intestine, large intestine, rectum, and anus.

jejunum

middle segment of the small intestine, approximately 4 feet in length.

bicarbonate

produced in the pancreas, small intestine. Neutralizes stomach acid when it reaches the small intestine.

acid

produced in the stomach. It promotes digestion of protein, destroys pathogens, solubilizes some minerals, activates some enzymes

probiotics

product that contains specific types of bacteria. Use is intended to colonize the large intestine with the specific bacteria in the product. An example is yogurt.

pharynx

the organ of the digestive tract and respiratory tract located at the back of the oral and nasal cavities, commonly known as the throat.