- Introduction
- Rest time! Have fun
- Physics
- Chemistry
- BIOLOGY
- Reaching the age of Adolescence
- CROP PRODUCTION AND MANAGMENT
- Cells : The basic structural unit of life
- Nutrition in human beigns
- RESPIRATION IN HUMAN BEIGNS
- TRANSPORTATION IN HUMAN BEIGNS
- excretory system in human beigns
- NERVOUS SYSTEM
- PHOTOSYNTHESIS
- Respiration in plants
- REPRODUCTION IN PLANTS
- MOVEMENTS IN PLANTS
- Forest our lifeline
- WASTE WATER STORY
- WEATHER,CLIMATE AND ITS ADAPTATION .
- Reaching the age of Adolescence
- Model tests
- Animation time
NUTRITION IN HUMAN
INTRODUCTION TO SALIVARY GLAND IN DIGESTIVE SYSTEM Digestive glands associated with digestive system which produce secretions for enzymatic and hydrolytic breakdown of complex ingredients of food. Salivary glands are one of these digestive glands. There are three salivary glands in human beings.
Salivary Gland in Digestive System Human beings have three pairs of salivary glands- parotid, submandibular and sublingual.
i. Parotid glands: they are the largest of the salivary glands. Parotid glands lie in the cheeks on the sides of the face in front of and below the ears. The glands are compound tubular- acinar, irregular and yellowish in color. Their draining ducts are called stenson’s ducts. The two stenson’s ducts open in the vestibule on the inner side of the cheeks at the level of second upper molars.
ii. Submandibular glands: they are medium sized, irregular salivary glands which occur at the angles of the lower jaw. The two submandibular glands are compound acinar glands which pour their secretion through submaxillary ducts called wharton’s ducts. They open under the tongue near the lower central incisors.
iii.Sublingual glands: they are a pair of smallest salivary glands which occur in the lower jaw below the tongue. They are compound acinar. Each sublingual gland has several ducts called rivinian ducts. They open under the tongue. A major sublingual duct is bartholin’s duct.
A number of accessory salivary glands occur in the human buccopharyngeal cavity. They are lingual, labial, buccal and palatal. Minor or accessory salivary glands resemble the true salivary glands in structure but mainly produce mucus.
Saliva: the Secretion of Salivary Gland It is the secretion of alivary glands which is poured into buccopharyngeal cavity. Saliva consists of 99% water, some salts like Na+, K+, Cl- , serous fluids , epithelial debris, mucin, antimicrobial substances and enzyme ptyalin. secretion of saliva or salivation is controlled by sensation of smell, sight and thought of food as well as presence of food inside the oral cavity.
Ptyalin or salivary amylase: it is the only enzyme present in saliva. It is absent in most herbivorous animals. Ptyalin hydrolyses both glycogen and starch of cooked or baked food into limit dextrins, maltose and isomaltose.
Introduction to digestive system organs and functions: Digestive system functions include six basic processes:
Functions of digestive system
Mouth
Keeps food between teeth; Foods uniformly chewed during mastication.
Teeth
Solid foods reduced to smaller particles for swallowing.
Tongue
Food maneuvered for mastication.
Salivary Glands
Secrete saliva; lining of mouth and pharynx lubricated; Salivary amylase splits starch into smaller fragments.
Pharynx
Moves bolus of food from pharynx into esophagus; closes air passage ways.
Esophagus
Permits entry of bolus from pharynx into esophagus; pushes bolus down esophagus; permits entry of bolus into stomach; lubricates esophagus for smooth passage of bolus.
Stomach
Maceration of food; Mixes it with gastric juice; reduce food to chime; Kills many microbes in food; Activates Pepsin.
Pancreas
Contains enzymes that digest carbohydrates, proteins, triglycerides and nucleic acids.
Liver
Produces bile; Emulsification and absorption of lipids in small intestine.
Gall Bladder
Stores and concentrates bile and releases it into small intestine.
Small Intestine
Mixes chyme with digestive juices; Completes the digestion of carbohydrates, proteins, lipids and nucleic acids; Absorption of 90 % of nutrients and water.
Large Intestine
Drives the contents of colon into rectum; Absorption of some water, ions and vitamins; defecation.
They are glands found associated with the mouth and their secretion is called saliva. Saliva is a slightly alkaline secretion which contains 99% water. It consists of proteins like mucin which serves to lubricate the food and also helps in its passage along the alimentary canal. It also contains the enzymes salivary amylase (or ptyalin) and lysozyme. Amylase partially digests starch, a tasteless polysaccharide, into maltose, a sweet tasting disaccharide. (The complete digestion into glucose, a monosaccharide takes place later). Thus amylase is present in the saliva of animals that have starch-rich diet. For e.g., pigs as they feed on tubers and roots (Food rich in starch). Amylase is absent in the saliva of domestic herbivores such as cows and buffaloes and in carnivores like tiger, lion, etc. Lysozyme helps to kill the harmful bacteria.
There are several small salivary glands present in different areas of the mouth like the inner lining of the lips, cheeks, palate and pharynx and on the tongue. The main salivary glands are present outside the mouth. They are parotid, the largest (found beneath the earlobe), submandibular (below each side of the lower jaw) and submaxillary(below the tongue). All of them pour their secretions into the mouth through ducts. Human beings, on an average produce about 2 to 3 litres of saliva everyday.
Liver It is the largest gland and is found in the upper part of the abdomen on the right side just below the diaphragm. Its secretion is called bile juice. It is alkaline and rich in organic (steroid) salts called the bile salts. The alkaline nature serves to neutralize the acidic pH of the gastric juice and creates the right environment for the intestinal enzymes to function.
Diagram showing the association of Liver, Pancreas and the Duodenum
The bile salts help in the emulsification of fats. The bile salts reduce the surface tension of fat droplets breaking them into small globules which increases their surface area. The small globules form an emulsion of fats in the intestine. The bile juice is greenish yellow in colour due to the pigments called the bilirubin and biliverdin. These pigments are formed from the worn out and dead red blood cells. Thus, bile juice has an excretory function as it serves to remove the wastes from the blood stream. The bile juice passes out of the liver through hepatic ducts which then continue as a common bile duct. It opens into the duodenum of the small intestine. But if there is no food in the small intestine, it is passed along the cystic duct into the gall bladder. The latter is the storage organ for excess bile. About 1litre of bile is produced by the liver daily.
The liver is an important organ in the body, in addition to being a digestive gland, its importance can be understood by listing its functions which are as follows: 1) It produces bile which helps in digestion of fats and lipids.
2) It converts glucose to glycogen and helps to control the level of sugar in blood. 3) It carries out deamination of excess amino acids. The resultant ammonia is converted to harmless urea and transported to the kidneys. The carboxylic of the amino acids are converted to glucose.
4) It acts as a storehouse for fats, glucose, vitamins A,D,E & K, iron and copper. 5) It stores water and thus regulates the fluid balance in the blood.
6) It produces red blood cells in the embryos. In adults, it destroys old red blood cells. The new ones are synthesized in the bone marrow. 7) It produces the clotting factor fibrinogen.
8) It produces an anti-coagulant called heparin. 9) It metabolises the toxic chemicals and renders them harmless after which they are excreted.
10) It is a site of many metabolic reactions and this generates heat to maintain the body temperature.
Gall Blader
It is a small sac-like elongated organ near the liver. The excess bile juice is stored in the gall bladder. It is connected to the liver by a duct called the cystic duct. If there is no food in the intestine, the bile juice flows into the gall bladder and is stored there. It is pumped out by the muscular contraction of the gall bladder wall .
Structure of the digestive system The digestive system is an organ system. An organ system is a collection of organs which together carry out a life process.
The Digestive 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 rhythmic, wave-like muscle movements (called peristalsis) to force food from the throat into the stomach. This muscle movement gives us the ability to eat or drink even when we're upside-down. In the stomach - The stomach is a large, sack-like organ that churns the food and bathes it in a very strong acid (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 (the final part of the small intestine). In the small intestine, bile (produced in the liver and stored in the gall bladder), 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 (chemicals like sodium) are removed from the food. Many microbes (bacteria like Bacteroides, Lactobacillus acidophilus, Escherichia coli, and Klebsiella) in the large intestine help in the digestion process. The first part of the large intestine is called the cecum (the appendix is connected to 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. STRUCTURE OF HUMAN DIGESTIVE SYSTEM
MOUTH(INGESTION)
TO
OESOPHAGUS
TO
STOMACH
TO
SMALL INTESTINE
TO
LARGE INTESTINE
TO
RECTUM
TO
ANUS (EGISTION)
Salivary Gland in Digestive System Human beings have three pairs of salivary glands- parotid, submandibular and sublingual.
i. Parotid glands: they are the largest of the salivary glands. Parotid glands lie in the cheeks on the sides of the face in front of and below the ears. The glands are compound tubular- acinar, irregular and yellowish in color. Their draining ducts are called stenson’s ducts. The two stenson’s ducts open in the vestibule on the inner side of the cheeks at the level of second upper molars.
ii. Submandibular glands: they are medium sized, irregular salivary glands which occur at the angles of the lower jaw. The two submandibular glands are compound acinar glands which pour their secretion through submaxillary ducts called wharton’s ducts. They open under the tongue near the lower central incisors.
iii.Sublingual glands: they are a pair of smallest salivary glands which occur in the lower jaw below the tongue. They are compound acinar. Each sublingual gland has several ducts called rivinian ducts. They open under the tongue. A major sublingual duct is bartholin’s duct.
A number of accessory salivary glands occur in the human buccopharyngeal cavity. They are lingual, labial, buccal and palatal. Minor or accessory salivary glands resemble the true salivary glands in structure but mainly produce mucus.
Saliva: the Secretion of Salivary Gland It is the secretion of alivary glands which is poured into buccopharyngeal cavity. Saliva consists of 99% water, some salts like Na+, K+, Cl- , serous fluids , epithelial debris, mucin, antimicrobial substances and enzyme ptyalin. secretion of saliva or salivation is controlled by sensation of smell, sight and thought of food as well as presence of food inside the oral cavity.
Ptyalin or salivary amylase: it is the only enzyme present in saliva. It is absent in most herbivorous animals. Ptyalin hydrolyses both glycogen and starch of cooked or baked food into limit dextrins, maltose and isomaltose.
Introduction to digestive system organs and functions: Digestive system functions include six basic processes:
- Ingestion
- Secretion
- Mixing and Propulsion
- Mechanical and Chemical Digestion
- Absorption and
- Defecation
- Organs of the Gastrointestinal Tract include the mouth, most of the pharynx, esophagus, stomach, small intestine and large intestine.
- The Accessory digestive organs (that help the organs of GI tract in the process of digestion) include the teeth, tongue, salivary glands, liver, gall bladder and pancreas.
Functions of digestive system
Mouth
Keeps food between teeth; Foods uniformly chewed during mastication.
Teeth
Solid foods reduced to smaller particles for swallowing.
Tongue
Food maneuvered for mastication.
Salivary Glands
Secrete saliva; lining of mouth and pharynx lubricated; Salivary amylase splits starch into smaller fragments.
Pharynx
Moves bolus of food from pharynx into esophagus; closes air passage ways.
Esophagus
Permits entry of bolus from pharynx into esophagus; pushes bolus down esophagus; permits entry of bolus into stomach; lubricates esophagus for smooth passage of bolus.
Stomach
Maceration of food; Mixes it with gastric juice; reduce food to chime; Kills many microbes in food; Activates Pepsin.
Pancreas
Contains enzymes that digest carbohydrates, proteins, triglycerides and nucleic acids.
Liver
Produces bile; Emulsification and absorption of lipids in small intestine.
Gall Bladder
Stores and concentrates bile and releases it into small intestine.
Small Intestine
Mixes chyme with digestive juices; Completes the digestion of carbohydrates, proteins, lipids and nucleic acids; Absorption of 90 % of nutrients and water.
Large Intestine
Drives the contents of colon into rectum; Absorption of some water, ions and vitamins; defecation.
They are glands found associated with the mouth and their secretion is called saliva. Saliva is a slightly alkaline secretion which contains 99% water. It consists of proteins like mucin which serves to lubricate the food and also helps in its passage along the alimentary canal. It also contains the enzymes salivary amylase (or ptyalin) and lysozyme. Amylase partially digests starch, a tasteless polysaccharide, into maltose, a sweet tasting disaccharide. (The complete digestion into glucose, a monosaccharide takes place later). Thus amylase is present in the saliva of animals that have starch-rich diet. For e.g., pigs as they feed on tubers and roots (Food rich in starch). Amylase is absent in the saliva of domestic herbivores such as cows and buffaloes and in carnivores like tiger, lion, etc. Lysozyme helps to kill the harmful bacteria.
There are several small salivary glands present in different areas of the mouth like the inner lining of the lips, cheeks, palate and pharynx and on the tongue. The main salivary glands are present outside the mouth. They are parotid, the largest (found beneath the earlobe), submandibular (below each side of the lower jaw) and submaxillary(below the tongue). All of them pour their secretions into the mouth through ducts. Human beings, on an average produce about 2 to 3 litres of saliva everyday.
Liver It is the largest gland and is found in the upper part of the abdomen on the right side just below the diaphragm. Its secretion is called bile juice. It is alkaline and rich in organic (steroid) salts called the bile salts. The alkaline nature serves to neutralize the acidic pH of the gastric juice and creates the right environment for the intestinal enzymes to function.
Diagram showing the association of Liver, Pancreas and the Duodenum
The bile salts help in the emulsification of fats. The bile salts reduce the surface tension of fat droplets breaking them into small globules which increases their surface area. The small globules form an emulsion of fats in the intestine. The bile juice is greenish yellow in colour due to the pigments called the bilirubin and biliverdin. These pigments are formed from the worn out and dead red blood cells. Thus, bile juice has an excretory function as it serves to remove the wastes from the blood stream. The bile juice passes out of the liver through hepatic ducts which then continue as a common bile duct. It opens into the duodenum of the small intestine. But if there is no food in the small intestine, it is passed along the cystic duct into the gall bladder. The latter is the storage organ for excess bile. About 1litre of bile is produced by the liver daily.
The liver is an important organ in the body, in addition to being a digestive gland, its importance can be understood by listing its functions which are as follows: 1) It produces bile which helps in digestion of fats and lipids.
2) It converts glucose to glycogen and helps to control the level of sugar in blood. 3) It carries out deamination of excess amino acids. The resultant ammonia is converted to harmless urea and transported to the kidneys. The carboxylic of the amino acids are converted to glucose.
4) It acts as a storehouse for fats, glucose, vitamins A,D,E & K, iron and copper. 5) It stores water and thus regulates the fluid balance in the blood.
6) It produces red blood cells in the embryos. In adults, it destroys old red blood cells. The new ones are synthesized in the bone marrow. 7) It produces the clotting factor fibrinogen.
8) It produces an anti-coagulant called heparin. 9) It metabolises the toxic chemicals and renders them harmless after which they are excreted.
10) It is a site of many metabolic reactions and this generates heat to maintain the body temperature.
Gall Blader
It is a small sac-like elongated organ near the liver. The excess bile juice is stored in the gall bladder. It is connected to the liver by a duct called the cystic duct. If there is no food in the intestine, the bile juice flows into the gall bladder and is stored there. It is pumped out by the muscular contraction of the gall bladder wall .
Structure of the digestive system The digestive system is an organ system. An organ system is a collection of organs which together carry out a life process.
The Digestive 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 rhythmic, wave-like muscle movements (called peristalsis) to force food from the throat into the stomach. This muscle movement gives us the ability to eat or drink even when we're upside-down. In the stomach - The stomach is a large, sack-like organ that churns the food and bathes it in a very strong acid (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 (the final part of the small intestine). In the small intestine, bile (produced in the liver and stored in the gall bladder), 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 (chemicals like sodium) are removed from the food. Many microbes (bacteria like Bacteroides, Lactobacillus acidophilus, Escherichia coli, and Klebsiella) in the large intestine help in the digestion process. The first part of the large intestine is called the cecum (the appendix is connected to 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. STRUCTURE OF HUMAN DIGESTIVE SYSTEM
MOUTH(INGESTION)
TO
OESOPHAGUS
TO
STOMACH
TO
SMALL INTESTINE
TO
LARGE INTESTINE
TO
RECTUM
TO
ANUS (EGISTION)