Digestive System PDF

DIGESTION AND NUTRITION UNIFYING THEMES ★ animals must take in sufficient amounts of specific substances or they develop diseases and die ★ an animal’s anatomy and physiology are tied closely to its diet and nutrient needs. The Food Guide Pyramid The Key to a...

DIGESTION AND NUTRITION UNIFYING THEMES ★ animals must take in sufficient amounts of specific substances or they develop diseases and die ★ an animal’s anatomy and physiology are tied closely to its diet and nutrient needs. The Food Guide Pyramid The Key to a Balanced Diet! DIGESTIVE SYSTEM DIGESTIVE SYSTEM  FUNCTIONS OF DIGESTIVE SYSTEM 1. Ingestion - Consuming food 2. Digestion - breakdown the ingested food into smaller molecule ○ Carbohydrate ○ Protein ○ Lipids 3. Absorption - passage of nutrients into the blood 4. Metabolism - converting nutrients into raw materials for the production of cellular energy (ATP) 5. Elimination - removing indigestible waste PARTS AND FUNCTION  DIGESTIVE SYSTEM GASTROINTESTINAL ACCESSORY TRACT/ALIMENTARY ORGANS CANAL GASTROINTESTINAL TRACT Digestion ▪Breaking down of food into smaller pieces ▪Chemical and mechanical breakdown of the large molecules of food into smaller molecules. MOUTH BUCCAL CAVITY/ORAL CAVITY ▪Mechanical digestion - Teeth bite off and chew food into a soft pulp that is easy to swallow. ▪Chemical digestion – saliva (presence of amylase)  PALATE The palate - the arched shape of the roof of your mouth allows you to handle both digestion and respiration at the same time. Hard palate: rigid shelf against which the tongue can push food. Soft palate: the posterior oral cavity, subconsciously manipulate through a yawn, swallowing, or singing 18  UVULA Purpose: When you swallow, the soft palate and uvula move upward, helping to keep foods and liquid from entering the nasal cavity. contribute to the sound produced by snoring. 19  TONGUE Facilitating ingestion,mechanical digestion, chemical digestion (lingual lipase), sensation(of taste, texture, and temperature of food), swallowing, and vocalization. position food for optimal chewing, gather food into a bolus (rounded mass) position food so it can be swallowed 20 21  TEETH Function: chew food Humans have two sets: 1. Deciduous (baby or milk) teeth 20 teeth are fully formed by age two 2. Permanent teeth Replace deciduous teeth between the ages of 6 to 12 A full set is 32 teeth, but some people do not have wisdom teeth. 22 23 What are wisdom teeth? 24 Wisdom teeth Wisdom teeth are known in clinical and dental terms as the third set of molars. They usually erupt between the ages of 17 and 24 years old. On average, humans have four wisdom teeth, few individuals only develop one or two wisdom teeth, however, in certain cases they may never develop, and sometimes they are missing. 25 26 Wisdom teeth Not everyone has wisdom teeth. A study shows that up to 35% of people have missing wisdom teeth. There are two main reasons why some individuals have no wisdom teeth: They are present but still haven’t erupted yet. The lack of wisdom teeth is related to genes. 27 28 29 Wisdom teeth A study carried out at Princeton University shows evolution has a large role to play in the absence of wisdom teeth. The study shows that the expanding brain size over hundreds and thousands of years meant that the head was no longer large enough to accommodate a larger brain and an extra set of teeth. https://www.drmichaels.com/blog/why-are-some-of-us-born-without-wisdom-teeth#:~:text=There%20ar e%20two%20main%20reasons,teeth%20is%20related%20to%20genes. 30 31 32 33 ESOPHAGUS ▪ The esophagus is a muscular tube. It takes food from the mouth to the stomach. ▪ It moves food by a series of wave-like muscle contractions called peristalsis. How long does it take for food to reach the stomach? 35 How long does it take for food to reach the stomach? 1-2 s = liquid 2-4 s=semi-solid 7-8 s= solid 36 37 38 39 STOMACH ▪ The stomach has thick muscles in its wall. These contract to mash the food into a water soup called chyme. ▪ The stomach lining produces strong digestive juices (HCl). 41 43 45 SMALL INTESTINE ▪ The nutrients are broken down small enough to pass through the lining of the small intestine, and into the blood. ▪ Nutrients are carried away to the liver and other body parts to be processed, stored and distributed. 48 50 51 52 53 54 55 56 57 LARGE INTESTINE ▪ Water reabsorption. ▪ The remains are formed into brown, semi-solid feces, ready to be removed from the body. 60 61 62 63 RECTUM ▪ Rectum’s job to receive stool from the colon, to let the person know that there is stool to be evacuated, and to hold the stool until evacuation happens.  ANUS ▪It lets you know whether the contents are liquid, gas, or solid. The anus is surrounded by sphincter muscles that control movement of stool. BRISTOL STOOL CHART 67 1 MOUTH ESOPHAGUS 2 STOMACH 3 SMALL INTESTINE 4 5 LARGE INTESTINE RECTUM 6 7 ANUS 68 ACCESSORY ORGANS 73 76  LIVER ▪It stores some nutrients, and releases them into the blood according to the activities and needs of the body (helps the body maintain homeostasis) WHAT IS HOMEOSTASIS? 78 ANSWER: “Homeostasis is the state of steady internal chemical and physical conditions maintained by living systems.” 79  LIVER ▪Produces bile. ▪Detoxifies chemicals and metabolizes drugs.  LIVER ▪ It’s estimated that your liver can produce 27 to 34 fluid ounces of bile each day. 82 GALL BLADDER ▪Temporary storage of bile. 84 PANCREAS ▪Produces pancreatic juices which help to digest food. ▪-releases hormones: insulin and glucagon 86 HOW DOES INSULIN WORKS? 87 88 APPENDIX ▪ The appendix is a narrow, finger-shaped pouch that projects out from the colon. ▪ Vestigial organ  SALIVARY GLANDS 11 8 LIVER 9 GALL BLADDER PANCREAS 10 APPENDIX 90 How will you rate your understanding of the lesson? 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