Digestive System (Test Review)

soft and hard palate

- Located at the roof of the mouth -Soft palate presses down on food to swallow - Hard palate holds the roots of the teeth

What mechanical and chemical digestion occurs in the oral cavity?

- Mechanical digestion begins in the mouth as the food is chewed. - Chemical digestion involves breaking down the food into simpler nutrients that can be used by the cells. Chemical digestion begins in the mouth when food mixes with saliva. Saliva contains an enzyme (amylase) that begins the breakdown of carbohydrates.

What cells in the stomach function to form enzymes and acids?

- chief cells produce enzymes - parietal cells produce acids

pancreas

- produces digestive enzymes into the small intestine and bicarbonate; secretes insulin & glucagon into the bloodstream - 6 inches (12-15 cm) long - location: sits across the back of the abdomen, behind the stomach; connected to the duodenum through a small tube called the pancreatic duct and the gallbladder

What enzymes are produced by the pancreas and what are their functions?

- trypsin, protease, peptidase, chymotrypsin (protein) - pancreatic amylase (carbohydrates/starch) - lipase (fats)

3 sections of large intestine

1. Cecum - it increases in diameter to let food travel from the small intestine into the large intestine; absorbs fluids and salts that remain after completion of intestinal digestion and absorption and mixes its contents with a lubricating substance, mucus (for absorption). 2. Colon - made up three parts: the ascending colon, the transverse colon that absorbs fluids and salts, and the descending colon which contains waste and is where bacteria helps digests the remaining food that is left. 3. Rectum - stores feces; lets the person know that there is stool to be evacuated.

3 sections of small intestine

1. Duodenum - most chemical digestion using enzymes takes place here 2. Jejunum - its lining absorbs nutrients (carbohydrates & proteins) 3. Ileum - absorbs vitamin B12, bile salts, and any products of digestion that weren't absorbed by the jejunum.

pH of small intestine

7-8 (neutral or slightly alkaline)

bile

A substance produced by the liver that breaks up fat particles.

How is insulin related to the digestive system?

After food is digested in the small intestine the glucose is released into the bloodstream, when this is detected insulin is released to allow the glucose into cells and out of the bloodstream.

Why doesn't gastric juice digest the inside of the stomach?

B/c it's lined with epithelial cells, which produce mucus. This forms a barrier between the lining of the stomach and the contents.

Sphincters

Circular muscles that encircle and, by contracting, constrict a duct, tube, or opening.

Salivary glands

Glands of the mouth that produce saliva, a digestive secretion (produces salivary amylase to break down carbohydrates) - parotid, submandibular, sublingual

Does any digestion of food occur in the esophagus?

Inside the esophagus, there is no digestion (b/c it only pushes food down to the stomach), only in the mouth, stomach, and intestines.

What is the function of the large intestine in relation to digestion?

It absorbs the water and salts from the remaining indigestible food matter and transmit the useless waste material from the body as a solid that will leave the body.

How does food move through the intestines?

Peristaltic movement is what forces the food to move through the intestines. Pathway: duodenum -> jejunum -> ileum -> cecum -> colon -> rectum

Mechanical digestion

Physical breakdown of large pieces of food into smaller pieces (chewing)

Chemical digestion

Process by which enzymes break down food into small molecules that the body can use

peristaltic movement

The constriction and relaxation of esophageal muscles in the esophagus. - It also occurs in stomach and small intestines. - peristaltic movement continually forces food through the digestive system.

Relationship between liver and gallbladder

The gallbladder holds bile produced in the liver until it is needed for digesting fatty foods in the duodenum of the small intestine.

large intestine

The last section of the digestive system, where water is absorbed from food and the remaining material is eliminated from the body

What mechanical and chemical digestion occur in the stomach?

The muscles in the stomach walls churn the bolus (mechanical), allowing it to mix with digestive enzymes and gastric acids (chemical). This process converts the bolus into a liquid called chyme.

Primary functions of stomach

The primary functions of the stomach are to break down food after feeding and releases nutrients (nutrients are actually absorbed in small intestine), store food, "sanitize" food with HCL, gastric juices are released to continue chemical digestion, breaking down protein (with pepsin) and turning the food into chyme.

What role does the stomach play in decontaminating the incoming food matter?

The stomach releases hydrochloric acid that kill bacteria in food and balance pH.

Where do bile and pancreatic enzymes enter the small intestine?

They enter the duodenum through the sphincter of Oddi

Bolus

a small rounded mass of a substance, especially of chewed food at the moment of swallowing.

Where does bile enter the digestive tract?

bile travels through the common bile duct to reach the duodenum

Sphincters of the stomach

cardiac sphincter and pyloric sphincter

oral cavity (mouth)

cavity that receives food for digestion

Tongue

facilitates the movement of food during mastication and assisting swallowing. Other important functions include speech and taste.

What does the oral cavity contain?

lips, teeth, tongue, hard & soft palate, salivary glands, gums,

enzymes (produced by pancreas or liver) in small intestine

pancreatic amylase (carbohydrates), maltase (maltose; produced by small intestine), trypsin (proteins), peptidase (proteins into amino acids), nuclease (DNA, RNA), nucleosidase (nucleoside), lipase (fat into glycerol and fatty acids)

Pharynx (throat)

performs the swallowing action that passes food from the mouth into the esophagus

Liver

produces bile (breaks down fat in small intestine) and stores glycogen - Size increases with age, from an average span of 5 cm at the age of five years, to 15 cm in adulthood. - located mainly in the upper right portion of your abdomen, beneath the diaphragm and above your stomach.

Chyme

the pulpy acidic fluid that passes from the stomach to the small intestine, consisting of gastric juices and partly digested food (the stomach creates chyme by mixing food/bolus and secretions of the stomach)

How does the large intestine help maintain a water balance in the body?

By absorbing water (solidies feces)

What mechanisms are in place to make sure food does not "go down the wrong tube" and into the windpipe?

Epiglottis (flap of skin) separates the esophagus from the trachea (windpipe).

Teeth function

mastication (chewing) to break down food into pieces that can be swallowed and digested easily.

How is pH maintained in the small intestine?

Sodium bicarbonate