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Home , Human digestive system, Pancreas

Digestive System and Nutrition - Chapter 26

All animals are heterotrophs and need organic molecules as food. We need food to get nutrients and energy. Body Mass Index (BMI) is a measure to understand desirable body weight for a person of certain height. It is considered overweight if its value is above 25. Formula used to calculate BMI is: Body Mass Index = body weight in Kg / height in m2 Cnidarians and flat worms have incomplete digestive system with one opening . Actually this cavity acts as a gastrovascular cavity and serves as both digestive and vascular system. Complete digestive tract Round worms evolved complete digestive system with both mouth and . It has a tube within tube design. Most animals including have a digestive tract and associated . Digestive System Humans have digestive tract with: mouth  mouth cavity   anus. The associated glands are salivary glands, , and . Liver and Pancreas Liver: is the largest in body. It stores its waste in Gall Bladder. Bile is released into duodenum and helps in of . Liver secretion, bile, does not have any in it. Liver absorbs excess from blood and release it back when needed. Pancreas: is the 2nd largest gland in . It secretes into duodenum. The juice changes the acidic food from stomach into slightly basic food. It is very rich in digestive enzymes and help in digestion of , fats, and nucleic . 4-stages of food-processing Ingestion is the of food by an animal. Digestion is mechanical ( and churning) and chemical (hydrolase enzymes) breakdown of food. The polymers like starch, proteins, and nucleic acids are broken down to monomers like glucose, amino acids and nucleotides. Bigger molecules like fats are broken into fatty acids and glycerol. Absorption is entry of food from alimentary canal into blood. Elimination is removal of undigested food from anus in the form . Digestion Digestion in oral cavity: Salivary glands add to lubricate and bind the food in mouth cavity. Saliva has and starts digestion of Starch. -- salivary amylase Starch------ () Pharynx: Both food pipe = esophagus and wind pipe = open in Pharynx. Air from the enters trachea. A ball of food from oral cavity is swallowed into esophagus. During of food covers the , the opening of trachea. Uvula a free hanging part of blocks the internal opening of nasal cavity. Digestion in Stomach: secrete HCl (hydrochloric ) and enzyme and change food into an acidic semi-fluid. kills in food and activates the enzyme pepsin. Pepsin starts the Digestion in stomach. Mellitus Pancreas also secretes 2 and that control the amount of glucose in blood. Insulin lowers blood glucose and glucagon raises it. Diabetes Mellitus: T1DM is caused due to deficiency of insulin (5%). It can be can be cured with insulin injections. T2DM is caused due to malfunction of receptors for insulin (95%) and cannot be cured with insulin injections. Recap 1 Digestive System

1. Alimentary canal has only mouth in ------and ------2. ------glands open into mouth cavity 3. ------is a common passage for air and food 4. During swallowing of food --- covers glottis and --- covers nasal cavity 5. Stomach leads to 1st part of small intestine named ------6. ----- is the largest gland and ------is the 2nd largest gland in body 7. 4 kinds of teeth in are -----, ----, and ------8. Most digestion takes place in ------9. Feces formation takes place in ------10. Water soluble vitamins include ------and ------11. soluble vitamins are vitamin ------, ------, ------, and ------12. We need to eat small quantity of -----, -----, and ----- fats. 13. ------% calories in diet should come from fats. 14. Fruits and vegetables provide ---, -- that reduce the chance of