digestive system

Submucosa

A connective tissue layer that contains the larger vascular and lymphatic vessels that transport absorbed nutrients.

The colon is

A portion of the large intestine, which includes the cecum, colon, rectum and anus.

The esophagus connects to the stomach at the

Cardiac Orifice

The hormone that is most responsible for the amount of bile that enters the duodenum is:

Cholecystokinin (CCK) is released by intestinal cells in response to fat intake.

The bile duct is formed by the joining of the

Cystic duct and common hepatic duct

In which segment of the small intestine does bile enter?

Duodenum - The hepatopancreatic sphincter opens into the duodenum

The gallbladder is an organ that contributes most to the absorption of

Lipids

the two immune compounds found in saliva

Lysozyme and immunoglobulin A. Lysozyme is an enzyme that kills bacteria, and immunoglobulin A is an antibody that inhibits the growth of some bacteria.

how do the nutrients in food make it into the body?

Material moves from center of the lumen to the apical/tube-side, of the epithelial cells lining the digestive tract. Then it crosses the epithelial lining by moving through or between the epithelial cells until it enters interstitial fluid. From here it will move into blood capillaries for transport to the liver.

Pancreatic juice is delivered to the small intestine through the

Pancreatic duct

alimentary canal (aliment = "nourish")

also called the gastrointestinal (GI) tract or gut, is a continuous muscular tube that runs from the mouth to the anus. The GI tract is involved with the digestion of food -its breakdown into smaller fragments - and the absorption of digested food fragments (which may collectively be called nutrients) from the lumen through the alimentary canal wall and into the bloodstream.

submandibular gland

are in the floor of the mouth, secrete saliva into the mouth through the submandibular ducts near the lower central incisor. contains amylase, but in a liquid thickened with mucus.

lingual lipase

enzyme that is activated by stomach acid and digests fat after the food is swallowed

cecum

first part of large intestine, small sac, may have lost its function through evolution. The end of the cecum joins with the colon

stomach

food is mixed with gastric juice and pepsin which digests proteins

colon

large intestine, a long tube with several distinct areas. sigmoid colon joins the rectum in the pelvis

sublingual gland

lie below the tongue, use the lesser sublingual ducts to secrete saliva into the oral cavity. contain mostly mucous cells, and they secrete the thickest saliva with the least amount of salivary amylase.

throughout the gi tract walls are comprised of what same four fundamental tissue layers

mucosa, submucosa, muscularis, and serosa.

The main secretion of the large intestine is:

mucus to aid in the movement of chyme through the intestine.

serosa

outermost layer of the intestine that covers the parts of the GI tract that is exposed to the abdominal cavity. This serous membrane is made up of connective tissue

Lying outside the oral mucosa are the three pairs of extrinsic salivary glands:

parotid, submandibular, sublingual

liver

produces bile. It is also involved in blood detoxification by removing drugs and other chemicals.

pancreas

produces digestive enzymes and bicarbonate that are secreted into the small intestine. The bicarbonate is a base that neutralizes the acidic chyme entering the small intestine.

duodenum

receives the stomach contents, pancreatic juice and bile and participates in chemical digestion, Shortest and least mobile, receives substances from stomach, liver and pancreas

Most of the ingested water is absorbed in the

small intestine

muscularis

smooth muscle layer, which contracts to mix food with enzymes.

Gallbladder

stores and concentrates the bile produced by the liver and releases it in response to the hormone cholecystokinin

gallblader

stores and concentrates the bile produced by the liver.

The flow of bile into the intestine is controlled by

the hepatopancreatic sphincter relaxes when stimulated by CCK to release bile

The digestive system has three accessory organs:

the liver, gallbladder, and pancreas.

large intestine

the majority of absorption occurs in the small intestine, the large intestine does absorb some food residue, vitamins, water and electrolytes. From the large intestine, the remaining material moves to the anus where it exits the body.

how many pairs of salivary glands are there

three: parotid, submandibular, sublingual

Parietal cells secrete hydrochloric acid, to do what in the stomach?

to keep the pH of the stomach very low.

ileum

vitamin B12 and bile salts are absorbed as well as materials not absorbed by the jejunum

The most anterior teeth are the

incisors

What is the function of villi and microvilli along the GI tract

increase surface area for absorption

difference between the small and large intestine walls

large intestine is thicker, and has no circular folds, no villi, and essentially no enzyme-secreting cells. This is because most nutrients are already absorbed before chyme enters the large intestine.

rectum

A short tube at the end of the large intestine where waste material is compressed into a solid form before being eliminated. has three folds so you can fart without pooping

three sections of small intestine

1. Duodenum 2. Jejunum 3. Ileum

How many sphincters are located in the anal canal

2 - internal (involuntary), external (voluntary)

How many pairs of major salivary glands are there?

3 These include the parotid, sublingual and submandibular.

The small intestine absorbs

90% of the digestion and absorption of food occurs, the other 10% taking place in the stomach and large intestine

salivary amylase

Enzyme in saliva that breaks down starch

Which of the following is secreted in the stomach?

Acid, Pepsin, Mucus

The main digestive enzyme secreted in saliva is

Amylase is secreted in high concentration in the saliva and is involved in starch digestion.

Saliva can contain all of the following

Amylase, Antibodies, Mucus

Gallbladder removal because of gallstone formation is common. In those that have had their gallbladder removed, what happens

Bile is still formed and flows into the small intestine, just without any storage in the gallbladder. This generally doesn't necessitate any dietary or other changes, although a small percentage of these people experience diarrhea, likely because of the way that bile and chyme entry into the duodenum is regulated.

If someone can't make and secrete bile, the main waste product that would build up in the body would be:

Bilirubin. This breakdown product of hemoglobin would accumulate in the body, causing the person to be jaundiced (have a yellow tint).

The entirety of the structures that frame the mouth are sometimes called the

Buccal cavity

The enzyme amylase chemically digests

Carbohydrates

Where is the apendix located?

Hanging from the inferior end of the cecum is the appendix, which contains a high concentration of lymphocytes.

The structure(s) that form the roof of the mouth is/are the

Hard and Soft Palate

In comparison to the small intestine, the large intestine

Has less villi

The region of the small intestine with the highest density of lymph nodes around it is the

Ileum - Peyer's patches are found surrounding the ileum

In which section of the GI tract is most vitamin B12 absorbed?

Ileum - The distal part of the small intestine absorbs most vitamin B12

The gallbladder is located

Inferior to the liver

Which of the following is a digestive enzyme

Lipase, Pepsin, Amylase

Lipases

Lipases are enzymes that contribute to fat digestion by breaking down lipids

jejunum

Middle portion of the small intestine. responsible for the absorption of a majority of nutrients

The organs of the GI tract have a general design that includes four layers forming the wall of a tube. Starting with the layer that lines the lumen, which of the following would represent the correct ordering of the four layers to the outer surface?

Mucosa, submucosa, muscularis, serosa

The major secretion of the large intestine is:

Mucus. There is a high density of mucous glands in the large intestine.

Which of the following cell types secrete acid?

Parietal

Coordinated smooth muscle contractions that move substances through the GI tract is called

Peristalsis is an involuntary, well controlled migration contraction of smooth muscle

Which of the following is a function of the pancreas.

Produce enzymes for the digestion of proteins and lipids.

Mucosa

Produces mucus and absorbs nutrients.

The enzyme carboxypeptidase chemically digests

Proteins

The folds that allow the stomach to expand after a large meal are called:

Rugae are folds of the mucosa and submucosa.

Gallstones

Small crystals that form from bile in the gallbladder. In some people, the cholesterol salts in the bile precipitate into crystals in the gallbladder. These crystals might grow into larger stones.

What organ would be best adapted to absorption of nutrients?

Small intestine because it has large surface created by villi and microvilli. Note: Absorption only occurs after mechanical and chemical digestion have occurred.

"Heartburn" occurs when:

Stomach acid passes through the lower esophageal sphincter and damages the esophagus. If the lower esophageal sphincter does not stay closed (except when swallowing), stomach acid can reflux into the esophagus, creating a painful, burning sensation.

If a person was unable to produce digestive enzymes, in order to adequately absorb nutrients, they would need to?

Supplement with digestive enzymes because they are necessary in order to convert food to absorbable components

The gallbladder produces

The gallbladder doesn't produce anything

lumen

The internal space of the GI tube is called the lumen. The lumen is where food is mechanically and chemically digested.

Chemical digestion mainly occurs:

The lumen is where food is mechanically and chemically digested. Note: Digestion occurs prior to absorption.

Absorption involves moving substances from:

The lumen to the apical side of the cell.

Soon after a meal the gallbladder contracts and pushes bile into the cystic duct and then into the common bile duct. The bile then flows from the common bile duct into the:

The small intestine is where bile enters. In the Duodenum specifically.

parotid gland

They secrete saliva into the mouth through the parotid duct, which is located near the second upper molar tooth. Secrete a watery solution that contains salivary amylase.

The ability of the stomach to vigorously mix food is a result of

Three layers of smooth muscle

The hemorrhoidal veins do not contain valves. How does this increase their risk for becoming distended?

Valves aid in preventing the pooling of blood in the veins by making sure there is no "backflow". The lack of valves can contribute to pooling of blood and the associated distention.

pepsin

a protein-digesting enzyme produced by the stomach

Which portion of the large intestine is located directly inferior to the ileocecal valve?

cecum

The large intestine is subdivided into four main regions:

cecum, colon, rectum, and anus.

small intestine

completes digestion and absorbs the products of the breakdown of carbohydrates, protein, fat, and nucleic acid. Water, vitamins and electrolytes are also absorbed in the small intestine. It is the longest tube of the GI tract that is inferior to the stomach.

watch video on gallbladder

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