Digestive System. What happens to the donut you ate for breakfast this morning?

Transcription

1 Digestive System What happens to the donut you ate for breakfast this morning?

2 Free Tutoring and Extra Credit!!!

3 Digestive System: Is the basic process of breaking down the food you eat into individual components that you body can use for energy. Proteins turn to amino acids Carbohydrates to monosaccharides Your In & Out Double Double to a LOT of fatty acid

4 Carbohydrates

5 Basic Digestive Anatomy of The Human Body

6 Phases of Digestion 1. Ingestion 2. Movement 3. Mechanical and Chemical Digestion 4. Absorption 5. Elimination

7 The Alimentary Canal (Gi Tract) Tube within a tube Direct link/path between organs Structures Mouth Pharynx Esophagus Stomach Small intestine Large Intestine Rectum

8 Step 1: The mouth! Teeth mechanically break down food into small pieces. Tongue mixes food with saliva (contains amylase, an enzyme which helps break down starch). Epiglottis is a flap-like structure at the back of the throat that closes over the trachea preventing food from entering it. That would be very bad! The soft palate closes off the nasal cavity. The actual act of swallowing is called deglutition The food you are eating is called the bolus when it is in the mouth The large paratoid salivary glands, sublingual, and submandible release saliva.

9 Swallowing: 3 stages Voluntary Oral Stage (you're in control) Pharyngeal Stage (soft palate lifts, you cannot breathe) Esophageal Stage (smooth muscle contracts and relaxes to push the bolus through the esophagus) SPECIAL TERM Peristalsis : The process of contraction and relaxation of circular smooth muscle that pushes food through the alimentary canal!

10 The Esophagus Approximately 10 long Functions include: 1. Secrete mucus 2. Moves food from the throat to the stomach using muscle movement called peristalsis If acid from the stomach gets in here that s heartburn.

11 The Stomach Fact: Food in the stomach is actually called Chyme Major Functions of the Stomach Storage of ingested food and mechanical breakdown of ingested food by gastric juice Disruption of chemical bonds in food material by acid and enzymes Kills most bacteria using the acid Production of intrinsic factor, a glycoprotein required for absorption of vitamin B12 in small intestine

12 The Stomach The stomach has a PH of about 1-2. (Battery acid is 1) Mucus is the reason our stomachs don t digest themselves. Pepsin helps break down proteins into very small chains of amino acids called peptides The stomach is controlled by both the nervous system and endocrine system.

13 The Small Intestine

14 The Small Intestine The Duodenum The segment of small intestine closest to stomach 25 cm (10 in.) long Mixing bowl that receives chyme from stomach and digestive secretions from pancreas and liver Functions of the duodenum To receive chyme from stomach To neutralize acids before they can damage the absorptive surfaces of the small intestine

15 The Small Intestine The Jejunum Is the middle segment of small intestine 2.5 meters (8.2 ft) long Is the location of most Chemical digestion Nutrient absorption Small villi

16 The Ileum The final segment of small intestine 3.5 meters (11.48 ft) long Ends at the ileocecal valve, a sphincter that controls flow of material from the ileum into the large intestine

17 The Small Intestine Nutrients from the food pass into the bloodstream through the small intestine walls. Absorbs: 80% ingested water Vitamins Minerals Carbohydrates Proteins Lipids

18 Accessory Organs: Not part of the alimentary canal but still play a HUGE role in digestion.

19 The Liver The MOST COMPLICATED organ in the digestive system. Main job is to produce bile which is responsible for breaking down fats, is stored in the gall bladder, and then released into the small intestine. The hepatocytes form 99% of the liver and do A LOT of things. The liver has 6 main functions: - 1. Bile Production 2. Storage of nutrients (glycogen when blood sugar is too high) 3. Nutrient interconversion (glucose to glycogen) 4. Synthesis (proteins used in blood clotting) 5. Phagocytosis (eat the bad guys) and 6. Detoxification (alcohol)

20 Gallbladder Stores bile from the liver, releases it into the duodenum of the small intestine. Fatty diets can cause gallstones

21 The Pancreas Produces digestive enzymes to digest fats, carbohydrates and proteins Regulates blood sugar by producing insulin and glucagon

22 The Large Intestine About 5 feet long Accepts what small intestines don t absorb Rectum (short term storage which holds feces before it is expelled). Absorb the water and concentrate the waste in one place 100 trillion bacteria (over 3 pounds) in large intestine break down carbs, kill harmful bacteria, and do many other wonderful things for your body.

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25 The End.