THE DIGESTIVE SYSTEM

THE DIGESTIVE SYSTEM

INTRODUCTION

Digestion is the chemical breakdown of large food molecules into smaller molecules that can be used by cells. The breakdown occurs when certain specified enzymes are mixed with the food.

Background information about the system

THE DIGESTIVE SYSTEM CONSISTS OF:a.) DIGESTIVE TRACTMOUTHAlso known as the oral cavity, the mouth is the hollow cavity that allows food and air to enter the body.

AIRFOODlies behind and below the mouth. When food and fluids leave the mouth, they pass through the throat. Swallowing of food and fluids begins voluntarily and continues automaticallyTHROAT

is a thin-walled, muscular channel lined with mucous membranes that connects the throat with the stomach.ESOPHAGUS

The stomach is a muscular sac that lies between the esophagusand the small intestinein the upper abdomen. It is responsible for breaking down food that is easier to digest for the rest of the intestines.STOMACH

the part of the intestine that runs between the stomach and the large intestine witch consists of the duodenum, jejunum, and ileum. It is in the small intestine, wherenutrientsoffoodsget absorbed. It also helps to remove the carbon dioxide in the blood flowing to it and in change, it supplies them with oxygen from the food.Small intestines

The large intestine is the final section of the gastrointestinal tract which consists of the cecum, colon, and rectum that performs the important task of absorbing water and vitamins while converting digested food into feces or bower (waste).LARGE intestines

the final section of the large intestine that ends at the anus. As being the last part of the digestive tract, the rectum acts as a temporary storage facility for feces / waste material.rectum

Theanusis the opening in the human body that is between thebuttocks. It is at the end of thegastrointestinal system(including the organs that digest food), wherefecesorwaste materials from the rectum comes out of the body.anus

anusB.) organspancreasThepancreasis anorganthat makeshormonesandenzymesto helpdigestion. The pancreas helps break downcarbohydrates,fats, andproteins. The pancreas is behind thestomachand is on the left side of the human body.

The liver is a large, meaty organ that sits on the right side of the belly. Weighing about 3 pounds. Itsfunctionwithin the digestivesystem is to process the nutrients absorbed from the small intestine. Bile from theliversecreted into the small intestine also plays an importantroleindigestingfat.liver

It is the small sac-shaped organ beneath the liver. The gallbladder holds bile produced in the liver until it is needed for digesting fatty foods in the duodenum of the small intestine. Bile is a bitter greenish-brown alkaline fluid that aids digestion and is secreted by the liver and stored in the gallbladder.gallbladder

Functions of the system

The first step to obtaining nutrition is ingestion, a process where food is taken in through the mouth and broken down by teeth and saliva.

INGESTION

Mastication or chewing is the process by which food is crushed and ground by teeth. It is the first step of digestion, and it increases the surface area of foods to allow more efficient break down by enzymes. During the mastication process, the food is positioned by the cheek and tongue between the teeth for grinding.mastication

Propulsionis the movement of food along thedigestive tract. The major means ofpropulsionis peristalsis.Peristalsisis a series of wave-like muscle contractions that moves food to different processing stations in thedigestive tract. The process of peristalsisbegins in the esophagus when food is swallowed.Propulsion

Is the preparatory stage of digestion where certain enzymes and acids to help in the process of digestion. The secretions are the following:1. Mucus - secreted along entire digestive tract, lubricates food and lining, coats lining and protects from mechanical digestion from acid and from digestive enzymes2. Water - liquefaction makes food easier to digest and absorb3. Bile emulsifies/blends fats4. Enzymes - chemical digestionSECRETION

Digestionis the breakdown of large insoluble food molecules into small water-soluble food molecules so that they can be absorbed into the watery blood plasma.digestion

During the process ofabsorption, nutrients that come from the food (including carbohydrates, proteins, fats, vitamins, and minerals) pass through channels in theintestinalwall and into the bloodstream. The blood works to distribute these nutrients to the rest of the body.absorption

Defecationis the final act ofdigestion, by which organisms eliminate solid, semisolid, and/or liquid waste material from thedigestive tractvia the anus. Humans expel feces with a frequency varying from a few times daily to a few times weekly.Defecation/Excretion/Elimination