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It More Than Just a Gut Feeling

It More Than Just a Gut Feeling. The Digestive System. TAKS. Objective 2 – The student will demonstrate an understanding of living systems and the environment. TEKS Science Concepts.

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It More Than Just a Gut Feeling

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  1. It More Than Just a Gut Feeling The Digestive System

  2. TAKS • Objective 2 – The student will demonstrate an understanding of living systems and the environment.

  3. TEKS Science Concepts • 3 The student uses critical thinking and scientific problem solving to make informed decisions. The student is expected to: • (B) evaluate promotional claims that relate to biological issues such as product labeling and advertisements; • 9 The student knows metabolic processes and energy transfers that occur in living organisms. The student is expected to: • (A) compare structures and functions of different types of biomolecules such as carbohydrates, lipids, proteins, and nucleic acids; • (C) investigate and identify the effects of enzymes on food molecules; and • 10 The student knows that, at all level of nature, living systems are found within other living systems, each with its own boundary and limits. The student is expected to: • (A) interpret the functions of systems in organisms including circulatory, digestive, nervous, endocrine, reproductive, integumentary, skeletal, respiratory, muscular, excretory, and immune; • (B) compare the interrelationships of organ systems to each other and to the body as a whole; • 11 The student knows that organisms maintain homeostasis. The student is expected to: • (C) analyze the importance of nutrition, environmental conditions, and physical exercise on health

  4. Engage • Watch this digestive system clip with gold medalist Bonnie Blair from PBS video Universe Within.

  5. Explore • Digestion Simulation • As a result of participating in this simulation, you will learn the structures and the functions of the digestive system. • Overall Digestive System Function • Breaks up food physically and chemically. • Stores food for a short period of time. • Absorbs the digested foods and passes them into the circulatory system. • Stores and eliminates undigested food from the body.

  6. Explain • What are the two main types of digestion? • Physical/Mechanical: The physical breakdown of food by non-enzyme means. • Chemical: The use of enzymes to breakdown food.

  7. List in Order the Pathways of Food Through the Digestive System. • The Mouth • Pharynx • Esophagus • Stomach • Small Intestine • Large Intestine • Rectum • Anus

  8. Oral Cavity

  9. Oral Cavity (Mouth) • What type of digestion occurs in the mouth? • Both physical and chemical digestion takes place • Tongue – taste manipulates food prepares food for swallowing by forming into a ball (bolus) • Saliva is secreted • Moistens • Protects mouth from abrasion • Buffer against acids • Kills some bacteria • What enzyme is secreted in saliva? • Salivary Amylase Enzyme that begins digestion of carbohydrates

  10. Pharynx

  11. Pharynx • Commonly call the throat • Intersection of GLOTTIS and opening of the esophagus (gullet) is found here • EPIGLOTTIS is a flap that closes the glottis when the act of swallowing occurs (Closes the Trachea)

  12. Esophagus

  13. Esophagus • Does any digestion occur here? • What is the word that describes the movement that pushes the food down toward the stomach? • Connects PHARYNX and the STOMACH • Peristalsis – wave-like contractions of smooth muscles that push food down toward the stomach • Cardiac Sphincter – esophagus and stomach connect

  14. Stomach

  15. Stomach • J Shaped organ that Stores and digests food. • GASTRIC JUICES - pH of 1-2 • Enzyme: pepsin which acts on proteins. • HCl is needed to activate pepsin from its inactive form pepsinogen. • Gastrin – Horomone secreted to regulate gastric juices. • Mucus covers the inner lining to prevent the acid from eating the tissue. • The PYLORIC SPHINCTER or pylorus connects the stomach to the small intestine and closes off the stomach at its posterior end.

  16. Small Intestine

  17. Small Intestine • Most breaking down of macromolecules occurs here. • 6 meters in length • Smaller diameter than the large intestine • Divided into 3 sections: • Duodenum (first 25 cm) • Jejunum • Ileum

  18. Digestion in Small Intestine • Acid chyme enters duodenum • Intestinal wall releases a hormone – SECRETIN-signal pancreas to release a basic solution to neutralize the acid. • CHOLECYSTOKININ (CCK)- released to signal the gall bladder to release bile and the pancreas to release digestive enzymes • ENTEROGESTRONE-secreted to slow down peristalsis

  19. Absorption and Distribution of Nutrients • VILLI – small finger-like projections that increase the surface area • MICROVILLI – even smaller finger-like projections on the VILLI • LACTEAL – large lymph vessel found on each villus (Absorbs FAT) • Capillaries – small blood vessels found on each villus (Absorbs all nutrients EXCEPT Fat)

  20. Villi and Microvilli

  21. Accessory Organs

  22. Small Intestine Accessory Organs • Pancreas, Liver, and Gall Bladder • Add digestive enzymes, juices, and hormones to the small intestine • These chemicals help break down protein, fat and carbohydrates

  23. Liver, Pancreas, and Gall Bladder • Liver produces bile which is needed to help digest fat. • Gall bladder stores the bile. • Pancreas (Endocrine and Exocrine function) produces enzymes need to finish digesting the main organic foods. It also produces insulin.

  24. Pancreas and Gall Bladder

  25. LIVER • Regulates the contents of the blood. • All blood contents enter the Liver via the HEPATIC PORTAL VEIN.

  26. Large Intestine Alone

  27. Large Intestine (Colon) • Main function of the COLON is to reabsorb water from the small intestinal material. • CECUM – T junction that connects the colon to the small intestine • APPENDIX – attached at the end of the cecum. • Stores solid waste in the area called the rectum. • Bacteria (E. coli) live in this area of the body. • Produce odor, and Vitamin K

  28. Large Intestine w/Small

  29. Elaborate • Is Terry Better? • You will relate two different types of cloth (Terry and Cotton) to the increased surface area of the small intestine. • Goldfish Swallowing • You will write a creative story describing what happens to a goldfish in three distinct parts. Part 1: As it passes your lips to the cardiac sphincter. Part 2: As it passes through the cardiac sphincter until it reaches the place where the duodenum becomes the jejunum. Part 3: From the jejunum until it exits the body.

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