The Digestive System

Digestive System

•The digestive system is a group of organs working together to convert food into energy and basic nutrients to feed the entire body. Food passes through a long tube inside the body known as the alimentary canal or the gastrointestinal tract (GI tract).

Components

•Mouth•Pharynx•Esophagus•Stomach•Small Intestine•Large Intestine•Gall bladder•Liver•Pancreas

MOUTH

•Food begins its journey through the digestive system in the mouth, also known as the oral cavity.

PHARYNX

• The pharynx, or throat, is a funnel-shaped tube connected to the posterior end of the mouth. The pharynx is responsible for the passing of masses of chewed food from the mouth to the esophagus.

Esophagus• the tube that connects your mouth and

your stomach.

• It carries swallowed masses of chewed food along its length. At the inferior end of the esophagus is a muscular ring called the lower esophageal sphincter or cardiac sphincter. The function of this sphincter is to close of the end of the esophagus and trap food in the stomach.

Stomach•A stretchy bag that holds your food

after you eat. In an average person, the stomach is about the size of their two fists placed next to each other. 

•Helps to break food into smaller pieces so your body can use it for energy and nutrition

Stomach

Esophagus

Small Intestine•Tube that is 20 feet long.

•Continues to digest food

•Food stays in your small intestine for 4 to 8 hours

Large Intestine•Tube that is 5 feet long

•Gets waste from small intestine

•Waste stays for 10 to 12 hours

Gall Bladder•Storage tank for bile (a greenish-yellow

liquid) that helps your body break down and use fats

•Located under your liver

•Shaped like a pear

Gall Bladder

Liver•Factory for antibodies and bile

•Stores vitamins and sugars until your body needs them

Liver

Pancreas•Helps you digest food by breaking down sugars

6 Major Functions of Digestive System•Ingestion

- or the intake of food. The mouth is responsible for this function, as it is the orifice through which all food enters the body. The mouth and stomach are also responsible for the storage of food as it is waiting to be digested. This storage capacity allows the body to eat only a few times each day and to ingest more food than it can process at one time.

•Secretion In the course of a day, the digestive system secretes around 7 liters of fluids. These fluids include saliva, mucus, hydrochloric acid, enzymes, and bile. Saliva moistens dry food and contains salivary amylase, a digestive enzyme that begins the digestion of carbohydrates.

• Mixing and Movement • Digestion

Digestion is the process of turning large pieces of food into its component chemicals. Mechanical digestion is the physical breakdown of large pieces of food into smaller pieces. This mode of digestion begins with the chewing of food by the teeth and is continued through the muscular mixing of food by the stomach and intestines. Bile produced by the liver is also used to mechanically break fats into smaller globules. 

•AbsorptionOnce food has been reduced to its building blocks, it is ready for the body to absorb. Absorption begins in the stomach with simple molecules like water and alcohol being absorbed directly into the bloodstream. Most absorption takes place in the walls of the small intestine, which are densely folded to maximize the surface area in contact with digested food. 

•ExcretionThe final function of the digestive system is the excretion of waste in a process known as defecation. Defecation removes indigestible substances from the body so that they do not accumulate inside the gut. The timing of defecation is controlled voluntarily by the conscious part of the brain, but must be accomplished on a regular basis to prevent a backup of indigestible materials. 

Excretory System

•The excretory system is a passive biological system that removes excess, unnecessary materials from an organism so as to help maintain homeostasis within the organism and prevent damage to the body. It is responsible for the elimination of the waste products of metabolism as well as other liquid and gaseous wastes, as urine and as a component of sweat and exhalation. 

Excretory system parts and their functions

•Kidneys - removes the nitrogenous wastes from the

blood such as urea and salts and excess water are also removed from the blood and excrete them in the form of urine. 

•Liver- detoxifies and breaks down chemicals,

poisons and other toxins that enter the body.

•Bile - After bile is produced in the liver, it is

stored in the gall bladder. It is then secreted within the small intestine where it helps to break down ethanol, fats and other acidic wastes including ammonia, into harmless substances.

•Large intestine - collects waste from throughout the body.

It extracts any remaining usable water and then removes solid waste. At about 10 feet long, it transports the wastes through the tubes to be excreted.

• Skin - Skin excretes sweat through sweat glands

throughout the body. This helps to remove additional wastes, such as excess urine. Furthermore, the sweat, helped by salt, evaporates and helps to keep the body cool when it is warm.

• Eccrine - Like sweat glands, eccrine glands allow

excess water to leave the body.The majority of eccerine glands are located mainly on the forehead, the bottoms of the feet, and the palms, although the glands are everywhere throughout the body. They help the body to maintain temperature control.