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Digestive System. Organs of Digestion Four components of digestion: ComponentRole IngestionThe taking in of nutrients DigestionBreak down of molecules.

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Presentation on theme: "Digestive System. Organs of Digestion Four components of digestion: ComponentRole IngestionThe taking in of nutrients DigestionBreak down of molecules."— Presentation transcript:

1 Digestive System

2 Organs of Digestion Four components of digestion: ComponentRole IngestionThe taking in of nutrients DigestionBreak down of molecules into complexes AbsorptionTransport complexes to body tissues EgestionRemoval of indigestible materials

3 k -

4 Digestive tract = Alimentary Canal Alimentary Canal = Open ended muscular tube around 7meters long.

5 Two types of digestion Physical Digestion: Breaking up food using force eg. Teeth chewing, Stomach churning Chemical Digestion: Breakdown of food using chemical reactions. eg. Stomach acid,

6 Beginning of Digestion Chewing: Physical digestion that mixes food with saliva produced by the salivary glands. The chewing and mixing with saliva creates a food bolus Function of saliva: 1) Activate taste buds 2) Lubricate food so it slides easily down the esophagus. 3) Contains the digestive enzyme amylase 4) Dissolves food particles which can activate the taste buds

7 Amylase Enzyme Amylase Enzyme: Breaks down starches to smaller-chain sugars, dextrins

8 Teeth and Their Structure Comparing Different types of teeth for different animals. Understanding Human Teeth Carnivores: All teeth are wedge shaped (no flat molars) Teeth come together in a scissors like motion for tearing meat off the bone and breaking bones. Large canines for holding onto prey

9 Carnivore Teeth jk

10 Teeth and Their Structure Herbivores: Flat like incisors. Large flat grinding molars

11 Teeth and Their Structure Omnivores (Bear, Pig): Multipurpose teeth. -carnivore-like: Sharp incisors, Wedge like premolars, large canines -Herbivore-like: Slightly flattened grinding molars in the very back

12 Teeth and Their Structure Humans: Mainly herbivorous teeth. Some minor modifications -Omnivore-like: Sharp incisors, -Herbivore-like: Flat grinding molars in the back. Reduced canines

13 Teeth and Their Structure Humans: Mainly herbivorous teeth. Some minor modifications -Omnivore-like: Sharp incisors, -Herbivore-like: Flat grinding molars in the back. Reduced canines

14 Oral Cavity to Stomach After food is chewed and mixed with saliva: Esophagus: A muscular tube that runs from the mouth to the stomach Peristalsis: The muscular contractions that occur in the esophagus pushing food towards the stomach.

15 Peristalsis k

16 Stomach Stomach: A acid filled, muscular, mucus lined sack Function: 1)Storage of food (1.5 L) 2)Initial digestion of proteins

17 Stomach Sphincter: A circular muscle that controls the passage of materials Cardiac Sphincter: Controls the amount of food that enters the stomach. Prevents stomach acid from leaking into the esophagus. Heartburn: cardac sphincter allows some stomach acid to leak into esophagus and break down the esophagus wall

18 Stomach Sphincter: A circular muscle that controls the passage of materials Cardiac Sphincter: Controls the amount of food that enters the stomach. Prevents stomach acid from leaking into the esophagus. Heartburn: cardac sphincter allows some stomach acid to leak into esophagus and break down the esophagus wall

19 Stomach Pyloric Sphincter: Regulates the amount of food entering the small intestine from the stomach.

20 Cells in the Stomach Wall CellFunction Mucous Cell Secrete a protective mucous lining Parietal Cell Secrete Hydrochloric acid Peptic Cell Secretes a protein digesting enzyme, Pepsinogen.

21 Pepsin Pepsinogen (inactive form): gets converted to pepsin (active form) once it reaches the acid. Pepsin (active): breaks Protein chains into smaller chains called Peptones

22 Rennin Rennin: Slows the passage of milk through the digestive tract. This increases the time allowed for it to breakdown (more nutrients can be extracted) Adults: Cannot function in the acid stomach of an adult. Baby: Allows the milk to curdle (forms solid clumps) Solids move through the digestive tract at a slower pace.

23 Assignment Questions:


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