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UNIT 4 ANIMALS

UNIT 4 ANIMALS. STRUCTURE & FUNCTION. Ingestion : taking in/eating of food Digestion : breaking down food (mechanically/chemically) into nutrients Absorption : taking in of nutrients by cells = transport of products into circulatory system and to the rest of the body

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UNIT 4 ANIMALS

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  1. UNIT 4 ANIMALS STRUCTURE & FUNCTION

  2. Ingestion: taking in/eating of food • Digestion: breaking down food (mechanically/chemically) into nutrients • Absorption: taking in of nutrients by cells = transport of products into circulatory system and to the rest of the body • Elimination: removal of undigested solid wastes Four stages of food processing

  3. 10.2 The Path of Digestion

  4. Mouth  Esophagus  Esophagialsphyncter  Stomach  Phyloric sphincter  Small intestine  Large intestine  Rectum  Anus Pathway of Digestion

  5. The smell or sight of food can trigger salivary glands to produce saliva • Saliva contains Amylase (Carbohydrase) • Saliva is responsible for: 1) stimulating taste buds 2) lubricating food 3) chemical digestion (amalyse) • The mouth is also responsible for the breakdown of food. This creates more surface area to facilitate chemical digestion Digestion - Mouth

  6. What is this called? Food going down the esophagus has a new name, bolus. Contraction and relaxation of the smooth muscle down the esophagus moves the bolus down to the stomach. This movement is called peristalsis. The cardiac sphincter opens to allow the bolus of food to enter the stomach. Esophagus

  7. Esophagus Esophagus:muscular tubethrough which food passes from mouth to stomach Peristalsis Peristalsis:wave-like muscular contraction in esophagus Esophagus – Peristalsis

  8. The stomach functions under low acidity • Food is broken down through: 1. The HCl 2. Churning of the stomach 3. Pepsin (protease that functions under low pH) • Food leaves the stomach through the pyloric sphincter Stomach

  9. The stomach is very acidic so why does it not eat itself? • Food stimulates the production of gastric juice • The stomach produces mucus (basic) which prevents the acidity of the stomach from harming the lining. • Pepsin is activated by gastric juices. Protection of the Stomach Lining

  10. Composed of 3 parts: • Duodenum • Jejunum • Ileum • Consists of proteases, lipases, and carbohydrases • Majority of nutrients are absorbed into the circulatory system • Chyme leaves the S. I. through the ileocecal valve Small Intestine

  11. Villi and Microvilli of the Small Intestine

  12. Pancreas • Secretes ~1 L of pancreatic fluid/day containing carbohydrases/lipases/proteases into the duodenum • Secretes bicarbonate into duodenum to counter balance acidity from stomach • Allows enzymes secreted by pancreas to function because they need a more neutral pH The role of accessory organs

  13. Liver • Secretes bile to emulsify fats • Amino acids are processed Gallbladder • Stores bile • Release into duodenum when needed (after mealtime!) The role of accessory organs

  14. Enzymes – pg 416

  15. Billions of anaerobic bacteria break down material further, producing vitamins (B12, K) • Main function is to absorb water (~90%) • The leftover matter forms feces which are pushed by muscular contractions (peristalsis again!) into the rectum and out the anus through the anal sphincter. Transverse Descending Sigmoid Ascending Rectum Large Intestine Anus

  16. Digestive Organs Accessory Organs Esophagus Stomach Liver Small Intestine GallBladder LargeIntestine Pancreas Rectum Accessory Organs & The Digestive Tract Anus

  17. Digestion time varies depending on the individual • For healthy adults, it's usually between 24 and 72 hours • After you eat, it takes about six to eight hours for food to pass through your stomach and small intestine • Elimination of undigested food residue through the large intestine usually begins after 24 hours How long does it take?

  18. Jejunum • Ileum • Transverse colon • Ascending colon • Descending colon • Peristalsis occurs here… • Mouth • Esophagus • Liver • Stomach • Pancreas • Large Intestine • Small Intestine • Duodenum • Sphincters • Gallbladder • Anus • Salivary glands • HCL • Pepsin • Bile • Amylase Digest this!

  19. Trace the torso of a teammate on the chart paper provided • Using as many words from the board as you can, draw and label the organs of the digestive system as best you can. • Clearly label where mechanical and chemical digestion occur • Add in digestive enzyme… Digest this!

  20. Section 10.2: Pages 411-418 • Fill out handout • Questions: • Pg. 417 - #17, 18 • Pg. 418 - #2, 3, 5, 6, 10, 12 HW

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