ch19 digestive system

What are the two kinds of digestion?

Mechanical Chemical

Which layer of the digestive tube contains lots of elastic fibers, blood vessels, and lymphatic vessels?

Submucosa

The hepatic portal system has two distinct capillary beds separated by a portal vein. The functions of these two capillary beds are what?

The first picks up nutrients and the second delivers these nutrients to liver cells.

What structure flaps over the glottis when we swallow food?

Epiglottis

Which vitamin requires intrinsic factor in order to be absorbed?

Vitamin B12

What are the three main characteristics of the large intestine?

1) It absorbs much of the water and salts; 2) It contains the ascending, transverse, and descending colon.; 3) It contains abundant bacteria.

What are the three main characteristics of the small intestine?

It is the site of nutrient absorption It breaks down fats, proteins, and carbohydrates Breakdown products of fats enter its lacteals.

Where does food first encounter proteinsplitting enzymes?

Stomach

What is the function of the gallbladder?

Storage (not secretion!) of bile

hen the acidic contents of the stomach enter the normally alkaline duodenum, what hormone is released that causes the pancreas to secrete bicarbonate?

Secretin

What is the semi-fluid paste called that is aresult of the food in the stomach being repeatedly squeezed and mixed with gastric juice?

Chyme

What are four characteristics of the duodenum?

1) It receives chyme from the stomach.; 2) It is within the body cavity with the ileum or jejunum (not retroperitoneal).; 3) It is shorter than either the ileum or jejunum.; 4) It is the site of action of liver and pancreas secretions.

What are the five the primary functions of the stomach?

1. Store Food, so it can be slowly released into asmall intestine.; 2. Churns food into a paste (chime) by mechanical means; 3. Kill bacteria.; 4. Starts digestion of proteins.; 5. Some absorption of water, alcohol

Does it dehydrate food materials before passing them to the small intestine?

No

Does it store food for later use in the form of fat?

No

What is the terminal portion of the small intestine called?

Ileum

Which layer of the digestive tract is responsible for the peristaltic waves that propel materials from one portion to another?

muscularis externa

Of the basic digestive processes, the one in which nutrients enter capillaries is called what?

Absorption

What is the only role of the levator ani muscle in defecation?

It lifts the anal canal superiorly around the feces.

hat is the correct sequence of layers in the wall of the alimentary canal, from internal to external?

mucosa, submucosa, muscularis, serosa

What is the digestive organ primarily responsible for the reabsorption of water?

Large intestine

Why are bacteria are abundant in the large intestines, but not in the small intestines or the stomach?

Secretions of parietal cells kill bacteria in the stomach, and the Ileocecal valve prevents the bacteria in the large intestines from migrating up into the small intestines.

What is the only function of the greater omentum?

Stores fat

The epithelium that lines the stomach and intestines is simple columnar. What are the basic functions of this epithelium?

secretion and absorption

Digestion of what food type would be affected the most if the bile—secreting liver were severely damaged?

Lipids

What are some functions of the liver?

1) detoxification of poisons; 2) makes blood proteins; 3) Regulates glucose levels; 4) Processes fats and amino acids; 5) Makes cholesterol; 6) Picks up and processes nutrients from the portal blood; 7) Storage of some vitamins; 8) Makes and secretes bile to emulsify fats

Does the liver produce digestive enzymes?

Just lipase to digest fats. It does not make protein digesting enzymes…they are made by the stomach and pancreas only.

Lipids are primarily broken down by substances that are made where?

Liver and pancreas

What organ makes most of the digestive enzymes?

Pancreas

What cells secrete hydrochloric acid and digestive enzymes which kill bacteria in the stomach?

PARIETAL CELLS

What stomach cells secrete an enzyme to digest protein?

CHIEF CELLS

Which cells secrete digestive enzymes in the pancreas? | Which region of the pancreas secretes insulin?

Acinar cells Islets of Langerhans

Functions of the digesting system.

1. INGESTION Taking food in by mouth; 2.DIGESTION to break food down into simple molecules (Mechanical: churning of food in the stomach, manipulation of food with tongue, tearing and grinding with teeth. (Chemical: breakdown of food with hydrochloric acid); 3.ABSORPTION nutrients enter capillaries; 4. DEFECATION to eliminate solid waste products

Regional terms of digestive system.

Uper GI= stomach and areas superior, lower GI = areas inferior to the stomach

Roof of the mouth is also known as ?

Palate. Hard Palate = bone. Soft Palate = soft tissue.

The flap of skin under the tongue at the midline.

Lingual Frenulum

Fibers in the tongue go in all direction and have no fascicles, allowing what?

Good Range of Motion

What is the primary function of salivary glands?

To prevent bacterial growth and moisten food

How many deciduous teeth (baby teeth) are there?

20

How many incisors are there?

8: for cutting like scissors

How many canines are there?

4: for tearing

What are pre-molar bicuspids?

(Bicuspids = 2 roots) 8: for chewing, some tearing.

How many molars are there?

12

Gums are also known as what?

Gingiva

What is the major cause of tooth loss?

Periodontitis, which is when the gums pull away from the tooth and the bacteria extends down to the periodontal ligament and erode it.

What is the hardest substance in your body?

The enamel of teeth

What is a rhythmic contraction to push something along by smooth muscle contraction?

Peristalsis

A back-and-forth squeezing of the muscle to grind up food. Food moves forward then backward a little, then forward again. Function is to churn up the food inside.

Segmentation

The esophagus goes through the thoracic cavity and empties to the stomach through this. It is a thickening of the muscularis externa

Cardiac Sphincter.

What are the regions of the stomach?

1. Cardiac region. 2. fundus 3. body 4. pyloric region. 5. pyloric sphincter.

What are the folds that allow the stomach to expand?

Rugae

The parietal cells in the stomach secrete asubstance called?

Intrinsic factor.

What vitamin requires intrinsic factor in order to be absorbed?

Vitamin B12

Third layer of the muscularis externum found only in the stomach, that helps churns food in a third plane.

Oblique Layer

This describes when acid from the stomach leaks into the esophagus, and causes erosion of the lining. This is known as heartburn.

Acid reflux

How is Helicobacter pylori infections spread?

Sharing saliva with someone who has stomach ulcers, especially sharing a toothbrush.

How can people vomit?

Because the cardiac sphincter is not a true sphincter, it doesn’t close well, which allows us to throw up.

Part of the stomach, protrudes through esophageal hiatus, that causes pain and difficulty swallowing.

HIATAL HERNIA

This is where most digesting and absorption of food takes place.

Small Intestine.

Folds in the small intestine.

Plicae Circularis

What is a Brush Border?

Plicae, which have villi, which have microvilli

Regions of the small intestine.

Duodenum, jejunum, ileum

Where is the site of action of liver and pancreas secretions?

DUODENUM

What organ is an endocrine gland, and adigestive gland, and makes most of the digestive enzymes?

Pancreas

What makes bicarbonate to increase the pH (decrease the acidity) of the chyme coming from the stomach.

Pancreas

What hormone tells the pancreas to secrete bicarbonate?

Secretin

What happens when bile salts crystallize?

Gall Stones Form.

What are treatments for gall stones?

Gall bladder is usually taken out.

This is the part of the small intestine where most digestion and much absorption occurs

JEJUNUM

All the rest of the absorption in the small intestine takes place here.

Ileum

This is where the new epithelial cells come from, and they are pushed upwards into the villi to replace the digested cells.

Crypt of Lieberkuhn

Its function is to absorb breakdown products of fat

Lacteals

Its an autoimmune disease of the GI tract, and commonly affects the small intestine. It is usually caused by genetics, and commonly occurs to males in their 20’s

Crohns Disease.

Genetic autoimmune disorder of the small intestine, causing chronic diarrhea when the person is allergic to gluten.

Celiac disease (sprue)

What is steatorrhea?

having pale, loose and greasy stools

How do you get intestinal gas?

When there are certain carbohydrates that are not digested, and are instead eaten by bacteria in the intestine. The bacteria produce the gas

a disease which attacks the large intestine, preventing water absorption, and can be fatal in 24-48 hours.

Cholera

Regions of the Large Intestine

Cecum, Ascending colon, Transverse colon, descending colon, sigmoid colon, rectum, anus

This is a lymph node below the cecum and is a lymph node, and contains E Coli

Appendix

This muscle lifts the sigmoid colon superiorly, to allow fecal matter to release. When it is relaxed, only gas can pass.

Levator Ani muscle

These muscles control defecation at the rectum/anus.

Internal and External anal sphincter.

How long does it take food to be processed through the entire digestive tract?

24 hrs

What are the four functions of intestinal bacteria (coliforms)?

1) Makes vitamins (B5, K, and biotin); 2) Keeps out harmful bacteria; 3) Eats fiber (plant cell walls), which we cannot digest; 4) Allows material to move through the large intestine easier

is a group of inflammatory condition of the colon and small intestine.

Inflammatory Bowel Disease (IBD)

An intermittent disease, the main symptom is constant diarrhea mixed with blood, of gradual onset. Colectomy (partial or total removal of the large bowel through surgery) is occasionally necessary, and is considered to be a cure.

Ulcerative Colitis

Symptoms of this are chronic abdominal pain, bloating, and alteration of bowel habits in the absence of any detectable organic cause. May manifest as diarrhea or constipation or may alternate between the two

IRRITABLE BOWEL SYNDROME (IBS)

What is an accurate test for colon cancer?

Colonoscopy

Varicose veins in the rectum.

Hemorrhoids

This is the largest internal organ of the body, located on the right side, below the diaphragm, and extends below the costal margin (can palpate). It has many functions and is the most complex organ except the brain, and as over 500 known functions.

The Liver

What are the two main sources of blood for the liver?

The hepatic artery, and the Hepatic portal system.

What is the functional unit of the liver?

Liver Lobule

Function of Hepatocytes

Detox of poisons, picking up and processing of nutrients from the portal blood, and storage of some vitamins.

What are Kupffer Cells?

They are macrophages in the liver.

How does the liver remove old RBC’s?

As blood flows through the sinusoids, they phagocytize old erythrocytes. The released Hgb is given to the hepatocytes, which convert it to bilirubin, one of the main components of BILE.

What is Hepatitis?

Infection of the liver.

Why is it that liver transplant patients and donors end up successful?

Because the liver is able to regenerate

Congenital condition in which the major visceral organs in the thorax and abdomen are reversed or mirrored from their normal positions.

Situs Inversus