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 protein-

splitting enzymes

Stomach

What is the function of the gallbladder?

Storage (not secretion!) of bile

When 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 a

result of the food in the stomach being

repeatedly squeezed and mixed with gastric

juice?

Chyme

.What are four characteristics of the

duodenum?

) 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.

3. What are the five the primary functions of

the stomach?

1. Store Food, so it can be slowly released into a

small 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

14. 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?

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.

what 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

CHIEF CELLS

What stomach cells secrete an enzyme to

digest protein?

CHIEF CELLS

Which cells secrete digestive enzymes in the

pancreas?

Acinar cells

Which region of the pancreas secretes

insulin?

Islets of Langerhans

Functions of the digesting system

. 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

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; cut 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

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?

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 a

substance 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 a

digestive 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?

24hrs

What are the four functions of intestinal

bacteria (coliforms)?

) 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

s 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