TOPIC :---LIFE PROCESSES CLASS :--- 10 th SUB TOPIC :--- NUTRITION IN HUMAN BEINGS
GENERAL OBJECTIVES :--- To develop scientific attitude among students To develop the habit of working in groups To corelate knowledge with the environment To inculcate spirit of inquiring To finish the work in required time
SPECIFIC OBJECTIVES :--- To impart knowledge about nutrition to the students To impart knowledge about the functions of alimentry canal Importance of digestive system
PREVIOUS KNOWLEDGE TESTING (MOTIVATION ) Q1. Why we take food ? Q2. Is nutrition is necessary for both plants/animals. Q3. How plants take food ? Q4. How animals get food ? Q5. In which form we take food ?
TIME MANAGEMENT S NO. ACTIVITIES TIME INTERVALS 1. Motivation & P.K Testing 3 min. 2. Presentation by teacher 8 min. 3. Group formation & their activities 11 min. 4. Assignments & feedback 10 min. 5. Home Assignments 3 min.
Presentation by teacher NUTRITION IN HUMAN BEINGS Human beings are heterotrophic,carnivorous organisms. They obtain their food from plants, animals and animal products by holistic mode of nutrition. They take this food in complex form which requires to break down into simpler substances. This is done by digestive system present in our body. The human digestive system consists of alimentary canal and associated glands.
ALIMENTARY CANAL The alimentary canal is long tube with muscular walls and glandular epithelium which extends from mouth to anus. The alimentary canal consists of several organs. 1. MOUTH 2. BUCCAL CAVITY 3. PHARYNX 4. OESOPHAGUS 5. STOMACH 6. SMALL INTESTINE 7. LARGE INTESTINE
Presentation By the Teacher 8min. Digestive system :- Alimentary canal Digestive Glands Mouth Buccal cavity Oesophagus Salivary gland Gastric Stomach gland Small intestine Liver Intestinal Large intestine gland Rectum Pancreas anus
MOUTH It is the uppermost opening of the digestive system which is guarded by two soft movable lips and opens into buccal cavity.
BUCCAL CAVITY It is a large space bounded by upper immovable and lower movable jaw which bears four types of teeth and a soft muscular tongue. The buccal cavity has three pairs of salivary glands (parotid, sublingual and sub maxillary) which secrets saliva through their ducts. The saliva contains water,mucus and salivary amylase(ptyalin ). The enzymes salivary amylase breaks down the starch and glycogen into maltose. \
Pharynx T he pharynx is about 12cm long funnel shaped vertical canal which serves as a passage way for food from buccal cavity to the esophagus.
Esophagus The esophagus is a long tubular structure which serves to carry the food from pharynx to stomach by peristaltic movement.
Stomach The stomach is wide J-shaped muscular sac present ton the left side of the abdomen consisting of three partsv.iz. cardiac,fundus and pyloric parts. The stomach serves four main functions 1. Storage of food 2. Mechanical churning of food 3. Partial digestion 4. Regulation of the flow of food into the small intestine The walls of the stomach possesses three types of gastric glands which secrete gastric juice containing HCl, pepsin protein digesting enzyme & mucus. gastric juice also contain some lipase which partially break down lipids
Small intestine It is largest part of alimentary canal measuring 6m further divided into three parts –duodenum,jejunum and ileum. Duodenum is a U shaped structure that starts after the pyloric end of the stomach and ends into jejunum. The duodenum receives the secretion of common duct formed by the union of bile duct and pancreatic duct. The bile duct carries bile. The bile is secreted by liver and stored in the gallbladder until needed in the duodenum.
SMALL INTESTINE CONTD. The jejunum is the upper part and ileum is the lower part of small intestine which follows the duodenum. Completion of digestion and absorption of the digested food occurs in the small intestine. The intestinal juice is called succus entericus which is a mixture of several enzymes. All these enzymes act upon different types of food. The action of these enzymes causes conversion of PROTEINS into AMINO ACIDS, CARBOHYDRATES into GLUCOSE, FATS into FATTY ACIDS and GLYCEROLS etc.
VILLI :--- The wall of small intestine is raised into numerous projections called VILLI.The villi are leaf shaped in duodenum, tongue like in jejunum and finger like in ileum. The villi greatly increases the absorptive surface area of the inner lining of intestine.
LARGE INTESTINE :--- The small intestine is followed by large intestine which consists of three parts --- caecum, colon and rectum. The large intestine is shorter but wider than small intestine. It is arranged around the mass of small intestine in the form of a ( ? ).It lacks vile but secretes mucous.
CAECUM The caecum is a short sac like structure present between the ileum and colon. It bears a short worm like projection called appendix.
Colon The greater part of large intestine is colon which gives sacculated appearance due to a series of constrictions. The colon is followed by about 15-20 cm. long vertical column called rectum.
rectum Rectum has longitudinal folds and large blood vessels. The undigested food is collected as faeces in the rectum. The rectum leads through 2-5 cm. long anal canal to the exterior at the anus. The rectal wall mainly absorb water from the undigested food. It also secretes mucus for lubrication. The faecal matter is egested out through anal opening.
GROUP FORMATION Group 1draw and label the diagram of human alimentary canal. Group 2. Give the functions of bile juice. Group 3. Name types of enzymes involved in the digestion of food. Group 4.Draw the flow chart of digestive system. Group 5. Match the following : --- Liver secretion of HCL & mucus Small Intestine Absorption of water Gall bladder Completion of digestion Gastric gland Bile stored
ASSIGNMENT / FEEDBACK 1. -------IN THE STOMACH KILLS GERMS. 2. THE SALIVA CONTAINS AN ENZYMES CALLED -------. 3. THE RHYTHMIC MOVEMENT BY WHICH THE FOOD IS TAKEN TO THE STOMACH THROUGH FOOD PIPE. 4. -------IS SECREATED BY THE LIVER. 5. DEFINE ENZYME. 6.WHICH IS THE LONGEST PART OF THE ALIMENTARY CANAL. 7. DEFINE ALIMENTARY CANAL. 8. GIVE EXAMPLES OF SAPROPHYTES. 9. THE INNER LINING OF SMALL INTESTINE HAS NUMEROUS FINGER LIKE PROJECTIONS CALLED --------
1.Home assignments Q1. What is the role of saliva in the digestion of food? Q2. What is the difference between autotrophic and heterotrophic nutrition? Q3. What is the role of acid in our stomach? Q4. How is small intestine design to absorb digested food? Q5. What is the function of digestive enzymes'?