Transcript Digestive System

What is the Digestive System?
• A series of hollow organs joined in a long,
twisting tube from the mouth to the anus—
and other organs that help the body break
down and absorb food.
Why is digestion important?
• When you eat foods such as bread, meat, and
vegetables they are not in a form that the body
can use as nourishment. Food and drink must be
changed into smaller molecules of nutrients
before they can be absorbed into the blood and
carried to cells throughout the body. Digestion is
the process by which food and drink are broken
down into their smallest parts so the body can
use them to build and nourish cells and to
provide energy.
How is food digested?
• Digestion involves mixing food with digestive
juices, moving it through the digestive tract,
and breaking down large portions of food into
smaller portions. Digestion begins in the
mouth, when you chew and swallow, and is
completed in the small intestine.
Digestive system process
•
•
•
•
•
•
The start of the process - the mouth: The digestive process begins in the mouth. Food is
partly broken down by the process of chewing and by the chemical action of salivary
enzymes (these enzymes are produced by the salivary glands and break down starches into
smaller molecules).
On the way to the stomach: the esophagus - After being chewed and swallowed, the food
enters the esophagus. The esophagus is a long tube that runs from the mouth to the
stomach. It uses rhythm like, wave muscle movements to force food from the throat into the
stomach. This muscle movement gives us the ability to eat or drink even when we're upsidedown.
In the stomach - The stomach is a large, sack-like organ that churns the food and bathes it in
a very strong gastric acid Food in the stomach that is partly digested and mixed with stomach
acids is called chyme.
In the small intestine - After being in the stomach, food enters the duodenum, the first part
of the small intestine. It then enters the jejunum and then the ileum. In the small intestine,
bile ,pancreatic enzymes, and other digestive enzymes produced by the inner wall of the
small intestine help in the breakdown of food.
In the large intestine - After passing through the small intestine, food passes into the large
intestine. In the large intestine, some of the water and electrolytes are removed from the
food. Many microbes in the large intestine help in the digestion process. The first part of the
large intestine is called the cecum. Food then travels upward in the ascending colon. The food
travels across the abdomen in the transverse colon, goes back down the other side of the
body in the descending colon, and then through the sigmoid colon.
The end of the process - Solid waste is then stored in the rectum until it is excreted via the
anus.
Different food groups how there broken down and
what there used for
• Carbohydrates- These are the starches and sugars in your diet. They are
broken up into smaller molecules by digestive juices in the mouth and in
the small intestines with the help of digestive enzymes produced by the
pancreas. The glucose that results from this digestion is used for energy
throughout the body.
• Proteins- Meat, eggs, and beans are protein foods. They are made up of
giant molecules that are broken apart in the stomach and the small
intestine, with help from the pancreas. The smaller protein molecules
become the building blocks for your body's cells.
• Fats- Fats are a rich source of energy for your body. Bile from your liver is
needed to digest fat. Bile is stored in your gallbladder and added to
digestive juices in the small intestine where fat is dissolved. Bile acids are
like detergents that dissolve grease in a frying pan.
• Fiber- This is the mostly indigestible food that keeps moving through the
digestive system and makes up the bulk of the final waste products of
digestion.
How does diet affect the digestive
system?
• Anorexia: Anorexia can cause digestive
disruptions, including stomach cramps,
indigestion, ulcers, heartburn, constipation, and
diarrhea.
• Bulimia: Bulimia forces the bowel to NOT work.
So the nutrients of food are not absorbed, just
the calories. You can have serious problems and
in some cases may have to have surgery.
The main parts of the digestive system and what they do
•
•
•
•
•
•
•
•
•
Liver-Thirty per cent of the blood pumped through the heart in one minute passes through the body's chemical factory, which is called the
liver. The liver cleanses the blood and processes nutritional molecules, which are distributed to the tissues. The liver also receives bright
red blood from the lungs, filled with vital oxygen to be delivered to the heart.
Epiglottis-The epiglottis is the flap of cartilage lying behind the tongue and in front of the entrance to the larynx (voice box). At rest, the
epiglottis is upright and allows air to pass through the larynx and into the rest of the respiratory system. During swallowing, it folds back to
cover the entrance to the larynx, preventing food and drink from entering the windpipe.
Trachea-The trachea begins immediately below the larynx (voicebox) and runs down the center of the front part of the neck ends behind
the upper part of the sternum. Here it divides to form two branches which enter the lung cavities. The trachea (windpipe) forms the trunk
of an upside-down tree and is flexible, like a vacuum tube, so that the head and neck may twist and bend during the process of breathing.
Salivary Glands-The mouth also contains the salivary glands which are accessory digestive glands that produce a fluid secretion called
saliva. Saliva functions as a solvent in cleansing the teeth and dissolving food particles so that they may be tasted. Saliva also contains
starch-digesting enzymes and mucus, which lubricates the pharynx to facilitate swallowing.
Rectum-The rectum is a short, muscular tube that forms the lowest portion of the large intestine and connects it to the anus. Feces collects
here until pressure on the rectal walls cause nerve impulses to pass to the brain, which then sends messages to the voluntary muscles in
the anus to relax, permitting expulsion.
Small Intestine-If the small intestine were not looped back and forth upon itself, it could not fit into the abdominal space it occupies. It is
held in place by tissues which are attached to the abdominal wall and measures eighteen to twenty-three feet in the average adult, which
makes it about four times longer than the person is tall.
Stomach-A hollow, sac-like organ connected to the esophagus and the duodenum (the first part of the small intestine), the stomach
consists of layers of muscle and nerves that continue the breakdown of food which begins in the mouth. It is also a storage compartment,
which enables us to eat only two or three meals a day. If this weren't possible, we would have to eat about every twenty minutes. The
average adult stomach stretches to hold from two to three pints and produces approximately the same amount of gastric juices every
twenty-four hours.
large intestine-Extends from the ileocecal junction to the anus and is about 1.5m long. On the surface, you can identify bands of
longitudinal muscle fibers called taeniae coli, each about 5mm wide. There are three bands and they start at the base of the appendix and
extend from the cecum to the rectum. Along the sides of the taeniae, you will find tags of peritoneum filled with fat, called epiploic
appendages (or appendices epiploicae). The sacculations, calledhaustra, are characteristic features of the large intestine, and distinguish it
from the rest of the intestinal tract.
Esophagus-Is a muscular tube connecting the throat (pharynx) with the stomach. The esophagus is about 8 inches long, and is lined by
moist pink tissue called mucosa. The esophagus runs behind the windpipe (trachea) and heart, and in front of the spine. Just before
entering the stomach, the esophagus passes through the diaphragm.
How do you care for your digestive
system
• step1: eat right, consume protein, carbohydrates in right amount and
make sure you get plenty of fiber. Eat on right time schedule.
• step2: drink plenty of water and avoid sugary drinks or those that contain
caffeine. Limit alcohol drinks to 2 times a day.
• step3: exercise. Moving around helps things move along
• step4: be alert problems that don't go away. Symptoms such as heartburn,
constipation and stomach upset can be caused by things as minor as bad
chili dog or as serious as cancer. If you've been suffering for more than a
couple of weeks, see your doctor.
• step5: get scheduled tests. your doctor will tell you when you need to
have regular colonoscopies' to find and remove precancerous polyps. If
your doctor recommend you other tests, get those as well.
• step6: quit smoking. Among the many reasons to quit smoking, it
contributes digestive problems such as heartburn, ulcers, and gallstones.