Digestive system Is a disassemble line to break nutrients down into forms that can be used by the body
|
|
- Mavis Heath
- 7 years ago
- Views:
Transcription
1 Digestive system Is a disassemble line to break nutrients down into forms that can be used by the body for cells to perform metabolic reactions the cells need oxygen and organic molecules that can be broken down to release the energy in there bounds the digestive system provides these organic molecules digestive processes 1. ingestion 2. propulsion voluntary swallowing involuntary peristalsis alternate eaves of smooth muscle contraction and relaxation 3. mechanical digestion chewing and mixing food segmentation- rhythmic local contractions of intestines 4. chemical digestion food to monomers using digestive enzymes 5. secretion release of water, acids, enzymes, and salts 6. absorption end products from GI tract into blood or lymph 7. excretion or defecation elimination of indigestible substances digestive system is separated into two main groups 1. the alimentary canal or gastrointestinal tract includes mouth pharynx esophagus stomach small intestine large intestine 2. accessory digestive organs includes teeth tongue gallbladder salivary glands liver pancreas histology of alimentary canal 1
2 from the esophagus to the anal canal the walls of the GI tract are made of four layers or tunics mucosa submucosa muscularis externa serosa or adventitia 1. mucosa is the moist epithelial membrane that lines the lumen of the GI tract functions 1. secretion of mucus, digestive enzymes, and hormones 2. absorption of digestive produces 3. protection against infectious diseases three layers of the mucosa 1. epithelium oral cavity, pharynx, and esophagus stratified squamous most of remaining simple columnar epithelium lots of goblet cells produces mucous liberates food protects against enzymes some sites (stomach small intestine) contain glands that produces 1. digestive enzyme 2. hormone from secreting cells called enteroendocrine cell coordinate activates of digestive tract and accessory glands 2. lamina propria underlies the epithelium is loose areolar connective tissue contains 2
3 1. capillaries and lymphatic vessels for nutrients and absorption 2. lymph nodules for protection 3. sensory nerve endings 4. smooth muscle (very thin) 3. muscularis mucosae thin layer of smooth muscle adds strength and some movement 2. submucosa moderately dense connective tissue contains with much elastic fibers 1. blood and lymphatic vessels traveling to lamina propria 2. lymph nodules 3. glands 4. nerve fibers produces the submucosal nerve plexus regulates the activity of glands in the mucosa and submucosa layer 3. muscularis externa is an inner circular layer and outer longitudinal of smooth muscle also contains myenteric nerve plexus regulates the contraction of smooth muscle responsible for peristalsis to propel foodstuff in 4. serosa is the outermost protective layer of organs located the abdominopelvic cavity is the visceral peritoneum mesothelium prevents organs from sticking to each other not seen in oral cavity, pharynx, esophagus they have an adventitia is fibrous connective tissue no epithelium 3
4 oral cavity digestive processes occurring in the mouth 1. analysis of materials before swallowing 2. mastication (chewing of food) 3. lubrication mixing with mucus and salivary secretions 4. limited digestion by saliva saliva salivary amylase breakdown of polysaccharides into smaller fragments salivary lipase breakdowns triglycerides only works at low ph so works in the stomach 97% water moistens food lysozyme destroys bacteria IgA antibodies blocks infection mucin which forms thick mucus when water is added lubricates food growth factors release of saliva secretion of saliva are controlled by ANS salivatory nuclei of the medulla oblongata sends actions potentials down the facial and glossopharyngeal nerves to stimulate salivation both sympathetic and parasympathetic nervous system stimulates salivation thus always have a flow phases of saliva release: 1. oral phase chemoreceptors most strongly stimulated by acidic substances pressure receptors presence of food in mouth 4
5 Absorption of oral cavity very little if any absorption occurs in the mouth some lipid soluble substances results in the activation of the parasympathetic nervous system to produce abundant watery saliva rich in enzymes 2. cephalic phase thought, sight, smell of food also stimulates the parasympathetic nervous system to produce abundant watery saliva rich in enzymes sympathetic stimulation results in the production of a smaller viscous saliva with little enzyme content due to constriction of blood vessels feeding the glands stomach functions: 1. function is primarily as a food storage organ 50 ml empty 4 liters extremely full will extend nearly to the pelvis 2. also mechanically breaks up food particles 3. liquefies the food to produce chyme 4. some limited digestion of proteins and lipids 5. helps sterilize the food acidity of stomach actions of digestive enzyme pepsin histology of stomach stomach is lined by a simple columnar epithelium is a secretary sheet produces a carpet of mucus to protect the stomach for acid 5
6 the epithelium is organized into shallow depressions called gastric pits pits are lined with columnar epithelium called mucous epithelium release mucin cell at base of pit undergo mitosis to replace cells at the base of a gastric pit will be two or three gastric glands cells of gastric glands 1) mucous neck cells located at the top of the gland where it opens into the pit produces mucin 2) parietal cells produce intrinsic factors required for the absorption of B12 by the intestine B12 need to produce RBC Release drops as you age increasing chances of pernicious anemia produce HCL 1. CO2 diffuses into cell from blood 2. carbonic anhydrase produces H and HCO3 3. H/K ATPase pump out H in exchange for K 4. Cl shifts into cell as HCO3 goes to blood alkaline tide function of HCL kills micros denatures proteins breaks down plant cell wall activates pepsin converts Fe3 to Fe2 can be absorbed 3) chief cells produce pepsinogen is converted to pepsin by HCL 6
7 function of pepsin pepsin digests proteins to shorter peptide chains produce rennin and gastric lipase in infants milk digestion 4) enteroendocrine cells produces hormones gastrin produced by G cells stimulates secretion by parietal cells and chief cells somatostatin produced by D cells weekly inhibits gastrin release 5) regenerative cells located at the base of the gland undergoes mitosis to replace old cells Digestive process of the stomach begin with the production of a gastric secretion gastric secretion contains mucus, acid, enzymes, and hormones regulation of gastric secretion release is controlled by both nervous and hormonal mechanisms three overlapping phases cephalic, gastric, and intestinal 1. cephalic phase directed by CNS to prepare the stomach to receive food occurs before food enters the stomach triggered by sight, smell or thought of food PNS nerve fibers traveling down the vagus nerve stimulates the mucous cells, chief cells, parietal cells, and G cells 2. gastric phase 7
8 occurs once food has reached stomach results from 1)neural stretch reflexes 2)gastrin stimulation most important stimuli of the gastric phase are distention, peptides and low acidity neural response distention of stomach by the food activates local stretch reflexes stimulate the parietal cells to make HCl and the chief cells to release pepsinogen and stimulate the G cells to release gastrin hormonal response gastrin released do to low acidity and peptides and by stretch gastrin effects 1. gastrin stimulates the release of pepsinogen from chief cells 3. intestinal phase starts when chyme enters the SI 2. main effect of gastrin is the simulation of HCl from the parietal cells more acid = more gastrin which = more acid (positive feedback loop) gastrin release is inhibited when ph drops lower then 2 this stimulates release of somatostatin and provides a negative feed back control main function is to control the entrance of acidic chyme into the duodenum neural response 8
9 regulation of gastric emptying stretch on SI receptors by the chyme inhibits gastrin production by the stomach hormonal response four hormones are involved gastrin released from the small intestine if ph of chyme is 3 or above stimulates gastric secretion secretin released from the SI if ph of chyme is less than 3 inhibits gastric secretion cholecytokinin (CCK) gastric inhibitory polypeptide (GIP) released from SI due to the presence of fatty acid and lipids in the chyme both inhibit gastric secretions periodic gastric emptying must be closely regulated by neural reflexes and by hormones too fast and chyme is not formed too slow and stomach too acidic regulation is primarily accomplished by controlling the opening and closing of the pyloric sphincter stimulation of gastric emptying 1. stretch of the stomach mildly relaxes the pyloric sphincter 2. gastrin released form the stomach due to stretch acid and amino acids relaxes the pyloric sphincter inhibition of gastric emptying 1. stretch and chemical receptors (acid, amino acids and lipid) in the small intestine activate neural reflexes that slow gastric emptying by contracting the pyloric sphincter 9
10 2. hormones of small intestine acid, amino acids and lipid in the small intestine also stimulate the release of secretin, CCK and GIP from the small intestine inhibit emptying by contracting the pyloric sphincter small intestine site of most digestion and almost all absorption averages 10 feet in a living person (21 in a cadaver) and is 1 inch in diameter three regions 1. duodenum smallest region 10 inches is retroperitoneal receives: 1. stomach contents acid chyme 2. pancreatic juice digestive enzymes and bicarbonate solution 3. bile fat emulsifiers and waste products site where ducts from gall bladder and pancreas enter have a common entry point called the common bile ducts controlled by a valve called the sphincter of Oddi closed between meals 2. jejunum 3 feet long more digestion then absorption 3. ileum 6 feet long more absorption then digestion 10
11 to perform the roles of digestion and absorption there are specializations to increase surface area intestine 1. plica circulares deep folds of the inner surface (submucosa) of the intestine their shape causes the chyme to spiral not found in the distal half of the ileum 2. villi fingerlike projections of the mucosal surface of the 3. microvilli tiny projections of the plasma membrane of the epithelial cells (absorptive cells) also called the brush borders has brush border enzyme mostly for carbohydrates and proteins become progressively smaller in more distal regions of SI histology of small intestine cells of the mucosal epithelium cells of the villus simple columnar cells called absorptive cells contain brush borders mirovilli 1. produce digestive enzymes brush border enzymes 2. contain transporters for nutrient uptake goblet cells secretes mucus intestinal crypts also called intestinal glands start at the base between two villi secret intestinal juice cell types absorptive cells goblet cells enteroendocrine cells secretes hormones S cells = secretin, CCK cells= CCK G cell = gastrin paneth cells 11
12 secretes lysozyme and is phagocytic contains the epithilial cells that renew the old cells Peyer s patches mucosa-associated lymphoid tissue (MALT) structures of the submucosa duodenal glands or Brunner s glands secrete an abundant alkaline mucus neutralize stomach acid lymphatic nodules like Peyer patches more numerous closer to large intestine intestinal secretion 1. largely water and mucus 1.8 liters per day mainly secreted by duodenal glands and goblet cells water is necessary for acid hydrolysis most comes in to SI by osmosis 2. is enzyme poor most enzymes of SI are brush border enzymes 3. is slightly alkaline to buffer acid release of SI secretions cephalic phase ANS parasympathetic stimulation stimulates release of secretions before food arises mucus will protect the walls from enzymes sympathetic stimulation inhibits release of mucous so get duodenal ulcers intestinal phase local reflexes distention by the acid chyme 12
13 irritation of the intestinal wall by the acid chyme hormones gastrin, CCK and secretin released due to the presence of acid, amino acids and lipid small intestine is the site of most chemical digestion this requires 1. brush border enzymes 2. juices from the gall bladder 3. juices from the pancreas pancreas produces enzymes that break down all categories of foodstuff the enzymes are delivered to the duodenum by two pancreatic ducts. The larger one which fuses with the bile duct to form the common bile duct controlled by a valve called the sphincter of Oddi the smaller one (accessory duct) empties directly into the small intestine physiology of pancreas endocrine pancreas islets of Langerhans beta cells release insulin alpha cells release glucagon exocrine pancreas organized into small clusters of glandular epithelial cells called acini composition of pancreatic juice produce about 1.5 qt. Per day 1. mainly water 2. electrolytes most is sodium bicarbonate 3. is alkaline ph8 this is to neutralize the acid chyme from stomach provides optimal environment for enzymes 4. enzymes 13
14 most are release in inactive form proteases trypsinogen is activated to trypsin by enterokinase enterokinase is a brush border enzyme procarboxypeptidase = carboxypeptidase chymotrypsinogen = chymotrypsin proelastase= elastase starch enzymes pancreatic amylase lipid enzymes pancreatic lipase DNA and RNA enzymes nucleases regulation of pancreatic secretion 1. neural stimulation parasympathetic activity during cephalic phase of gastric secretion stimulates section of pancreases 2. hormone control due to food in the small intestine 1. CCK (released in response to fats in SI) stimulate the release of pancreatic enzymes 2. secretin (released in response to HCL in SI) stimulate pancreatic duct cells to release bicarb rich juice liver and gallbladder functions of the liver carbohydrate metabolism- maintaining normal blood glucose lipid metabolism- produce lipoproteins which traffic lipids amino acid metabolism- deaminate amino acids removal of waste products vitamin storage mineral storage drug inactivation phagocytosis and antigen presentation 14
15 Kupffer's cells plasma protein synthesis removal of circulation hormones removal of antibodies removal and storage of toxins- bilirubin for example synthesis and secretion of bile liver s role in digestion is the production of bile for export to the duodenum bile is a yellow-green alkaline solution its role in digestion is as a fat emulsifier (meaning it breaks up fat into tiny particles) gallbladder is storage organ for bile composition of bile 1. bile salts 1. cholesterol derivatives mostly cholic acid and chenodeoxycholic acid 2. emulsify fats breaks them up into many small droplets 3. help the absorption of fats and cholesterol bile salts are recycled by the enterohepatic circulation 1. bile salts are reabsorbed by a specific transporter by distal part of SI 2. return to the liver by the hepatic portal vein 3. transported to gall bladder for release 2. phospholipids important in fat emulsification and absorption 3. bile pigments most is bilirubin -- a waste product of heme bacteria breakdown to urobilinogen which gives feces a brown color 4. cholesterol 5. electrolytes mostly sodium bicarbonate 15
16 regulation of bile release into SI cephalic phase parasympathetic impulses via the vagus simulate release not real strong stimulator hormonal phase 1. CCK stimulates gallbladder contraction and relaxation of sphincter of Oddi of the common bile duct is released due to presence of fats in the chyme entering the SI 2. Secretin released by intestinal cells due to presence acid in the chyme entering the SI stimulates the bile duct cells to produce a watery bicarbonate-rich juice large intestine about 5 feet long and 2.5 inches in diameter four regions cecum the ileocecal sphincter allows material in from the ileum 2.4 inches long off to the side of the cecum is the appendix 3 inches long colon about four feet long ascending, transverse, descending, and sigmoid rectum about 8 inches long final 3cm is the anal cannel histology not as complicated as the small intestine no villi no plicea circulares few glands epithelium simple columnar with numerous goblet cells columnar cells are also called absorptive cells mainly absorb water muscularis 16
17 longitudinal muscles are thickened into three conspicuous longitudinal bands called taeniae coli contraction forms a series of pouches called haustra functions of the large intestine chemical digestion in the large intestine the finial stage of limited chemical digestion occurs here by bacteria 1. ferment some of the indigestible carbohydrates flatus hydrogen sulfide (H2S), H2, N2, CO2, methane (CH4) two amines indole and skatole together with H2S = odor of flatus and feces the 2. synthesize B complex vitamins and most vitamin K B vitamins necessary for some enzymes and DNA production K necessary for formation of clotting proteins by liver absorption water very important some electrolytes vitamins vitamin K released from bacteria required to synthesize four clotting factors biotin required for the mitochondria to convert pyruvate (from anaerobic glucose metabolism) to oxaloacetate during aerobic metabolism vitamin B5 (pantothenic acid) is a component of coenzyme A (CoA) required for fats, polysaccharides, and proteins to enter the citric acid cycle remaining bile salts for production of steroid hormones and some neurotransmitters 17
18 elimination of fecal material (defecation) Chemical digestion and absorption 1. catabolic process 2. breakdown foodstuff into their monomers which can be absorbed 3. accomplished by enzymes intrinsic enzymes found on surface (brush border) secreted enzymes from accessory glands 4. enzymatic breakdown is called hydrolysis part of a water molecule is added to each broken bond the diet mainly contains carbohydrates, proteins, and fats digestion of carbohydrates carbohydrates in the diet 1) starch, most of the digestible dietary carbohydrate are long glucose polymers 2) glycogen not much in diet digested like starch are glucose polymers 3) sugars disaccharides sucrose lactose small amount of maltose monosaccharides glucose galactose fructose these are ready to be absorbed (monomers) 4) cellulose can not be digested = dietary fiber all carbohydrates must be broken down into monomers mostly glucose fructose galactose 18
19 digestion of carbohydrates starches these are quickly absorbed 1. salivary amylase works in mouth and center of food while in stomach 2. pancreatic amylase breaks down starches into smaller pieces. Only takes 10 minutes to work in small intestine yields 1. maltose (two glucoses) 2. 3 to 9 glucose chain polymers (oligosaccharides) 3. dextrinase and glucoamylase found on brush border of SI works on small glucose polymers made of three or more sugars yeilds the sugars glucose and maltose 4. maltase found on the brush border of SI splits maltose into two glucose molecules sugars (disaccharides) major dietary sugars are sucrose (glucose + fructose) lactose (glucose + galactose) maltose (glucose + glucose) disaccharides are digested by brush border enzymes of SI 1. maltase breaks down maltose to two glucose molecules 2. sucrase breaks down sucrose to glucose and fructose 3. lactase breaks down lactose to galactose and glucose absorption glucose is absorbed 1) transcellular by sodium-glucose transport proteins secondary active transport coupled to sodium ions 19
20 2) paracellular by solvent drag galactose is absorbed 1) transcellular by galactose-sodium transport proteins secondary active transport coupled to sodium ions 2) paracellular by solvent drag fructose is absorbed 1) transcellular by facilitated diffusion that is not sodium coupled fructose is quickly converted to glucose inside the cell so there is always a strong gradient 2) paracellular by solvent drag protein digestion 1. stomach 1. pepsinogen secreted by chief cells cleaved to pepsin by acid 2. works in acidic conditions ph 1.5 to 3.5 stops in small intestine 3. attacks bonds involving tyrosine and phenylalanine so get smaller polypeptides and some free amino acids from terminal tyrosine and phenylalanine digests 10 to 15% of dietary protein into shorted polypeptides particularly effective in digesting collagen which is poorly digested by other enzymes prepares meat for other enzymes 2. small intestine 1. pancreatic enzymes trypsin chymotrypsin reduces size of polypeptides by attacking internal peptide bonds so have many smaller peptides carboxypeptidase removes single amino acids from the carboxyl end (-COOH) 20
21 2. brush border enzymes carboxypeptidase removes single amino acids from the carboxyl end aminopeptidase and dipeptidase removes single amino acids from the amine end (-NH2) these work best in neutral ph absorption there are specific amino acid-sodium transport proteins transporters for each class of amino acids classes are neutral charged amino acids positively charged amino acids negatively charged amino acids there are also specific sodium dependent transporters for some di and tripeptides once in the cell they are broken down infants can absorb proteins by pinocytosis allows IgA from breast milk to inter blood stream intact absorbed proteins also may triggers some food allergies lipid digestion almost all occurs in the small intestine very small amount by salivary lipase fats (triglycerides) are insoluble in water so enzymes can not get at them and form large droplets bile salts from gallbladder act as detergents bile salts have a polar end with combines with water and a nonpolar end which combines with the fats bile salts pull off small droplets from larger thus emulsifies fats this increases surface area of the droplets so enzymes can get at them 21
22 pancreatic lipases can now cleave two fatty acid chains leaving fatty acids and monoglycerides absorption lipase activity breaks down the triglycerides the fatty acids and monoglycerides combined with phospholipids from bile and with bile salts to form even smaller micelles micelles have a core of lipids shielded from water by a surface of bile salts also in the micelle is cholesterol and fat sol vitamins the micelles come in contact with the cell surface and melt into the plasma membrane releasing the contents into the cell once inside the cell the free fatty acids and monoglycerides are resynthesized into triglycerides the triglycerides combined with phospholipids and cholesterol and are surrounded with a coat of proteins to form a spherical particle called a lipoprotein the lipoprotein formed in the guy is called a chylomicrons this occurs in the endoplasmic reticulum with final assemble occurring in the Golgi and then exported from the cell most chylomicrons go to lacteals some to capillaries the chylomicrons enter the blood stream and lipoprotein lipase found on the surface of capillary endothelium break the triglycerides down to fatty acids and glycerol with can be used by the tissue for energy or stored as fat in adipose tissue the left over chylomicrons are taken up by the liver nucleic acid pancreatic nucleases hydrolize RNA and DNA to nucleotides Brush border nucleosidase and phosphatases hydrolize nucleotides to their free base, pentose sugars and phosphate ions 22
23 absorption specific carriers of purines and pyrmidines in the SI vitamin absorption 1. fat-soluble vitamins A, D, E, K incorporated into micelles 2. water soluble vitamins are small and easily absorbed by simple diffusion except B12 which is large binds with intrinsic factor from stomach then binds to a specific receptor in the ileum is endocytocytosised electrolyte absorption sodium most absorbed coupled to active absorption of glucose and amino acids potassium moves by simple diffusion as water is absorbed potassium is concentrated and moves into cells anions like Chloride passively follow the sodium and potassium iron 1. is actively transported into the GI cells where it is stored by binding to ferritin 2. when needed it is released into the blood and bound to transferritin calcium absorption when active form of Vitamin D is present parathyroid hormone converts vitamin D to active form and stimulates kidneys to reabsorb calcium water absorption 9 liters of water enter the GI tract daily most absorbed in SI due to uptake of nutrients i.e. follows the glucose and sodium 23
24 24
Digestive System Functions
Digestive System Functions A. Gastrointestinal Processes 1. Ingestion: placing food in mouth (voluntary) 2. Propulsion: moving food through GI tract a. Peristalsis: alternating waves of contraction and
More informationThe Vertebrate (mostly human) Digestive System
The Vertebrate (mostly human) Digestive System Mouth - mastication, lubrication, digestion Pharynx and Esophagus - swallowing Stomach - some digestion Small intestine - most digestion and absorption Large
More informationChapter 15 Digestive System.
Chapter 15 Digestive System. I. The Gastrointestinal Tract. a. The digestive system mechanically and chemically breaks down food into molecules that can be absorbed into the bloodstream or lymph. Residues
More informationFunctions of the GI Tract. Chapter 18. Functions of the GI Tract (continued)
Functions of the GI Tract Chapter 18 The Digestive System Motility: Movement of of food through the GI tract. Ingestion: Taking food into the mouth. Mastication: Chewing the food and mixing it with saliva.
More informationSMALL AND LARGE INTESTINE SECRETIONS
SMALL AND LARGE INTESTINE SECRETIONS Objectives At the end of lecture student should be able to know, Digestive system Digestive system secretions Small intestine Component of small intestine Intestinal
More informationMedical Physiology Z.H.Al-Zubaydi
Lec.13 Medical Physiology Z.H.Al-Zubaydi Functions of the Digestive System The major functions of the digestive tract include the following six processes, summarized in Figure 1: 1. Ingestion Food must
More informationDigestion, Absorption. How & where?
Digestion, Absorption How & where? What happens to food? Three processes Digestion Absorption Elimination Where do they occur? GI tract Overview of Digestion GI tract Gastrointestinal (GI) tract: series
More informationGI TRACT ORGANS ACCESSORY ORGANS
Digestive System GI TRACT ORGANS Oral cavity Oropharynx Esophagus Stomach Small intestine Large Intestine Anus ACCESSORY ORGANS Salivary glands Pancreas Liver Gall bladder GI TRACT LAYERS Mucosa Submucosa
More information10.2 The Human Digestive System pg. 411
10.2 The Human Digestive System pg. 411 The human digestive system is made up of a group of organs working together. The digestive tract is made up of the mouth, esophagus, stomach, small intestine, and
More informationDigestive System Module 7: Chemical Digestion and Absorption: A Closer Look
OpenStax-CNX module: m49457 1 Digestive System Module 7: Chemical Digestion and Absorption: A Closer Look Donna Browne Based on Chemical Digestion and Absorption: A Closer Look by OpenStax This work is
More informationTHE DIGESTIVE SYSTEM Secretion Graphics are used with permission of: Pearson Education Inc., publishing as Benjamin Cummings (http://www.aw-bc.
THE DIGESTIVE SYSTEM Secretion Graphics are used with permission of: Pearson Education Inc., publishing as Benjamin Cummings (http://www.aw-bc.com) Page 1: Title Page Digestive system secretion involves
More informationThe Digestive System
The Digestive System Digestive Structures Mouth including teeth and tongue Esophagus Stomach Small intestine Large intestine Accessory structures - salivary glands, liver, gallbladder, & pancreas Digestive
More informationDivisions of Digestive System. Organs of the Alimentary Canal. Anatomy of the Digestive System: Organs of the Alimentary Canal. CHAPTER 14 p.
Divisions of Digestive System Anatomy of the Digestive System: Organs of the Alimentary Canal CHAPTER 14 p. 412-423 1. Alimentary Canal or Gastrointestinal Tract (GI)-digests and absorbs food coiled hollow
More informationOutline Digestive System
Outline Digestive System The Digestive System Digestive System Lecture Packet 19 Chapter 15 I. Function II. Layers of the GI tract III. Major parts: mouth, pharynx, esophagus, stomach, small intestine,
More informationChapter 24: DIGESTIVE SYSTEM
Chapter 24: DIGESTIVE SYSTEM I. OVERVIEW A. Gross anatomy (Fig. 24.1) and functions (Table 24.1) B. "You are what you eat." 1. The problem: Ingestion (eating) is not the same as absorption. 2. The solution:
More information5. Secretion: release of water, acids. Enzymes, buffers by digestive tract.
Digestive System CH-16 Lecture topics Functions of the digestive system: p. 488. 1. Ingestion: Taking food in 2. Propulsion: movement of food thru alimentary canal p.490. voluntary: swalloing : skeletal
More informationSpecial organ structures and functions conduct these tasks through the successive parts of the overall system.
Chapter 5 Digestion, Absorption, and Metabolism Chapter 5 Lesson 5.1 Key Concepts Through a balanced system of mechanical and chemical digestion, food is broken down into smaller substances and the nutrients
More informationThe Human Digestive System
The Human Digestive System Name: Section: Date: Page 1 of 10 Page 2 of 10 Page 3 of 10 Page 4 of 10 Page 5 of 10 Page 6 of 10 Putting it All Together Digestive Enzymes Page 7 of 10 Page 8 of 10 Page 9
More informationDigestion, Absorption. How & where?
Digestion, Absorption How & where? What happens to food? Three processes Digestion Absorption Elimination Where do they occur? GI tract Overview of Digestion GI tract Gastrointestinal (GI) tract: series
More informationChapter 49 - Nutrients and the Digestive System I. Nutrients (chemical substances necessary for organisms to grow and function properly)
Chapter 49 - Nutrients and the Digestive System I. Nutrients (chemical substances necessary for organisms to grow and function properly) 6 basic nutrients - 4 food groups (milk, meat, fruit and vegetable,
More informationMechanical digestion: physical breaking of food chewing by teeth churning by stomach segmentation by intestines (= mixing food) p.611/ Fig. 22.
The Digestive System 1. Describe the general functions of the digestive system Ingestion: Taking food in Propulsion: movement of food thru alimentary canal voluntary: swalloing involuntary: peristalsis
More informationChapter 17 Digestive System. Alimentary Canal. Movements of the Tube
Chapter 17 Digestive System Functions of Digestive System ingestion mechanical digestion chemical digestion propulsion absorption defecation Consists of the alimentary canal and accessory organs 1 Alimentary
More informationThe Digestive System. You are what you eat!
The Digestive System You are what you eat! Try to label the diagram (PENCIL!!) What is Digestion? Digestion: the breakdown of large macromolecules (proteins, fats, carbohydrates) into smaller molecules
More informationDigestive system Review
Digestive system Review 1. Distinguish between chemical digestion and mechanical digestion. The physical breakdown of food begins in the mouth with two types of processes. The mouth is a complex structure
More informationChapter 48. Nutrients in Food. Carbohydrates, Proteins, and Lipids. Carbohydrates, Proteins, and Lipids, continued
Carbohydrates, Proteins, and Lipids The three nutrients needed by the body in the greatest amounts are carbohydrates, proteins, and lipids. Nutrients in Food All of these nutrients are called organic compounds,
More informationThe Digestive System. Chapter 16. Introduction. Histological Organization. Overview of Digestive System. Movement and Mixing of Digestive Materials
The Digestive System Chapter 16 Introduction Structure of the digestive system A tube that extends from mouth to anus Accessory organs are attached Functions include Ingestion Movement Digestion Absorption
More informationDigestive system. Dr. Carmen E. Rexach Physiology Mt San Antonio College
Digestive system Dr. Carmen E. Rexach Physiology Mt San Antonio College Functions Motility ingestion mastication deglutition peristalsis Secretion exocrine endocrine Digestion Absorption Tunics Innervation
More informationDigestive System Notes
Digestive System Notes Structure Function Relation Mouth cavity Mechanical digestion by teeth; chemical digestion of starch by saliva. Salivary glands Three pairs of glands which secrete saliva containing
More informationThe Digestive System. Chapter 14. The Digestive System and Body Metabolism. Metabolism. Organs of the Digestive System. Digestion.
Chapter 14 The Digestive System The Digestive System and Body Metabolism Digestion of ingested food of nutrients into the blood Metabolism Production of Constructive and degradative cellular activities
More informationDigestion. What we ll cover. Main stages of digestion. Digestion: A Closer Look. A Tour of the Human Digestive System. Mechanical digestion
Digestion What we ll cover What are the digestive system structures and their functions? Where does carbohydrate, protein and fat digestion and absorption occur? What are the 3 accessory organs of digestion?
More informationDIGESTIVE SYSTEM Five Basic Processes The Gastrointestinal tract (alimentary canal)
DIGESTIVE SYSTEM Five Basic Processes 1. Ingestion - eating 2. Movement of the food along the G.I. tract. 3. Digestion- chemical and mechanical breakdown of food. 4. Absorption of the breakdown products
More informationSEER Training Modules
http://training.seer.cancer.gov/anatomy/digestive/ WiRED International wishes to thank the National Cancer Institute for use of this information. SEER Training Modules Introduction to the Digestive System
More informationTHE GI TRACT IS A CONTINUOUS MULTILAYERED TUBE EXTENDING FROM THE MOUTH TO THE ANUS THAT IS SUPPORTED AND PARTIALLY COVERED BY THE PERITONEUM.
THE GI TRACT IS A CONTINUOUS MULTILAYERED TUBE EXTENDING FROM THE MOUTH TO THE ANUS THAT IS SUPPORTED AND PARTIALLY COVERED BY THE PERITONEUM. OVERVIEW OF THE DIGESTIVE SYSTEM Two groups of organs compose
More informationChapter 15 Digestion and Nutrition
Chapter 15 Digestion and Nutrition Digestive System: Digestion refers to the mechanical and chemical breakdown of foods so that nutrients can be absorbed by cells. Consists of the canal which is all of
More informationThe Digestive System. Chapter 15
The Digestive System Chapter 15 Introduction Digestion refers to the mechanical and chemical breakdown of food so the nutrients can be absorbed by cells Carried out by the digestive system Consists of
More informationThe Digestive System
The Digestive System Objectives Name and locate the digestive organs and the accessory organs of digestion. List the general function of the digestive system and the function of each organ. Define mechanical
More information1. Essay: The Digestive and Absorption Processes of Macronutrients
Jenny Kim Professor Rosario Nutrition: Macronutrients Project June 26, 2014 1. Essay: The Digestive and Absorption Processes of Macronutrients Whenever we eat, the foods we ingest in our bodies undergo
More information26. Digestive System
26. Digestive System Your body needs food for two primary purposes: growth and maintenance. Molecules and atoms in the food you eat are generally used to either build new molecules in your body or to provide
More informationBiology 2402 Anatomy &Physiology II - Digestive system notes - Ch. 15
Biology 2402 Anatomy &Physiology II - Digestive system notes - Ch. 15 Digestive system processes the food used as fuel and nutrients for the body. Composed of a tube through the body (digestive tract,
More informationDigestive System AKA. GI System. Overview. GI Process Process Includes. G-I Tract Alimentary Canal
Digestive System AKA G-I Tract Alimentary Canal Overview GI System Consists of Mouth, pharynx, esophagus, stomach, small intestine, large intestine, anus About 30 in length Accessory Organs Teeth, tongue,
More informationPhysiology of Digestive system II
Small Intestine Physiology of Digestive system II Motility of small intestine: Distention of the Small Intestine Elicits Mixing Contractions Called Segmentation Contractions. These are concentric contractions
More informationEating, pooping, and peeing THE DIGESTIVE SYSTEM
THE DIGESTIVE SYSTEM Ingested food is not technically in the body until it is absorbed so it needs to be: Mechanically and chemically reduced Transported by the blood to the cells Large portions are not
More informationThe Digestive System. - teeth, tongue, gall bladder, and glands (salivary glands, liver, pancreas).
The Digestive System I. Overview A. Organs of the digestive system. 1. Alimentary canal (GI Tract): - continuous muscular tube, open at both ends. - digests food, absorbs digested fragments. 2. Accessory
More information1. gustatory cells: Surface cells in the throat and on the taste buds in the mouth that transmit
Chapter 3 Digestion and Absorption Key Terms 1. gustatory cells: Surface cells in the throat and on the taste buds in the mouth that transmit taste information. 2. absorption: The movement of substances
More informationI. The basic function of the digestive system is
Chapter 15, Digestive System - ANATOMY OF THE DIGESTIVE SYSTEM I. The basic function of the digestive system is. This process is called. II. List 2 other names for the digestive tract: A. B. III. The digestive
More information8. Be able to label a diagram of an earthworm. Know the function of each of the major parts of the earthworm.
Review for Unit Test: The Digestive System 1. Know the meaning of these terms: heterotrophs digestion peristalsis microvilli autotrophs chemical digestion chyme lacteal intracellular digestion mechanical
More informationDigestive System Why is digestion important? How is food digested? Physical Digestion and Movement
Digestive System The digestive system is made up of the digestive tract a series of hollow organs joined in a long, twisting tube from the mouth to the anus and other organs that help the body break down
More informationCHAPTER 23 DIGESTIVE
CHAPTER 23 DIGESTIVE nutrition requires : getting nutrients digesting nutrients transporting nutrients Digestive System musculo-skeletal digestive circulatory Digestive System alimentary canal ~ gastrointestinal
More informationDigestive System Digestive Tract
Digestive System Digestive Tract Dept. of Histology and Embryology 周 莉 教 授 Introduction of digestive system * a long tube extending from the mouth to the anus, and associated with glands. * its main function:
More informationDigestive System. Gross Anatomy and Physiology
Digestive System Gross Anatomy and Physiology I. Introduction A. Base Function: Working with the circulatory system the digestive system provides the body with fuel. B. Main players: 1. Digestive tract:
More informationWeds 5/20/15. Membranes - finish last lecture outline. Digestive System Nutrition Types of digestion & digestive systems Vertebrate digestive system
Membranes - finish last lecture outline Weds 5/20/15 Digestive System Nutrition Types of digestion & digestive systems Vertebrate digestive system structures and functions // accessory organs mechanism
More informationSmall & Large Intestines
Small & Large Intestines Small Intestine: principal site for digestion of food and absorption of the products of digestion Large Intestine: reabsorption of water and elimination of undigested food and
More informationThe Gastrointestinal System It consists of: The digestive tract Mouth Pharynx Oesophagus Stomach Small intestine Large intestine
The Gastrointestinal System It consists of: The digestive tract Mouth Pharynx Oesophagus Stomach Small intestine Large intestine The digestive organs Teeth Tongue Salivary glands Liver Gall bladder Pancreas
More informationAlimentary canal (gastrointestinal or GI tract) continuous coiled hollow tube
The Digestive System and Body Metabolism Gross Anatomy Function The Digestive System Functions Ingestion taking in food Digestion breaking food down both physically and chemically Absorption movement of
More informationDigestive System. Digestive System. Digestive tract. Accessory organs. Digestive System Overview
Digestive System Digestive System The process of chemically and physically breaking down foods into simpler forms that can be absorbed is called digestion. The digestive system can be divided into two
More informationEach gland has at least one duct that takes saliva to the oral cavity.
kufa university Physiology College of Nursing first year student Ass. Lect :- Hisham Qassem M. Lecture No :-3 The Digestive System Digestive system consists of: 1. Gastrointestinal Tract (GIT). 2. Accessory
More informationChapter 2 Digestion and Absorption Chapter Outline
Chapter 2 Digestion and Absorption Chapter Outline I. Anatomy of the Digestive Tract A. The Digestive Organs 1. Mouth to the Esophagus 2. Esophagus to the Stomach 3. The Small Intestine 4. The Large Intestine
More informationFunctions of the digestive system
Digestive system Functions of the digestive system Digestion-mechanical and chemical breakdown of material Motility-movement of material from the oral cavity to the anus-swallowing / peristalsis Secretion-exocrine
More informationDigestion in the small and Large Intestines
9.5 Digestion in the small and Large Intestines Do some foods keep you feeling full for a long time? Do you ever feel that after eating certain foods, you are hungry again in a short time? Some foods stay
More information23.4 Digestive System
23.4 Digestive System The Pancreas & Pancreatic Regulation Regulation of Bile Secretions The Small Intestine The Large Intestine Pancreas Location Mostly retroperitoneal Deep to greater curvature of stomach
More informationAP Biology. What do animals need to live? Animal Nutrition. Nutritional requirements. How do animals get their food? Different diets; different lives
Animal Nutrition What do animals need to live? Animals make energy using: food food oxygen Animals build bodies using: food for raw materials amino acids, sugars, fats, nucleotides O 2 ATP energy for synthesis
More informationBIO 202 Digestive System Part I Overview and Mouth to Stomach
1 BIO 202 Digestive System Part I Overview and Mouth to Stomach Function of the Digestive System Ingestion Taking food and water into the mouth Break down the food Mechanical digestion: chewing, mixing,
More informationII. General Characteristics of the Alimentary Canal
Human Anatomy & Physiology 17 Be sure to watch the Video: The Digestive System. Digestive System URLs http://www.emc.maricopa.edu/faculty/farabee/biobk/ BioBookDIGEST.html http://yahooligans.yahoo.com/reference/gray/244.html
More informationTHE DIGESTIVE SYSTEM
THE DIGESTIVE SYSTEM What is digestion? Digestion is the process of breaking down food so that it's small enough to be absorbed and used by the body for energy or in other bodily functions. Digestion involves
More informationContinuing Education Independent Study Series
Continuing Education Independent Study Series Professional Development Manager Association of Surgical Technologists Englewood, Colorado Association of Surgical Technologists Publication made possible
More informationChapter 22: Digestive System
Chapter 22: Digestive System Converts food into raw materials necessary for cell maintenance and growth Digestive System: Main Divisions of Digestive System: 1) Alimentary Canal (gastrointestinal tract)
More informationThe Excretory and Digestive Systems
The Excretory and Digestive Systems 38.2 The Process of Digestion Organs of the Digestive System The digestive system includes the: Mouth Pharynx Esophagus Stomach Small and large intestine. Other structures
More informationMammalian Physiology. Gastrointestinal System: Digestion and Absorption
Mammalian Physiology Gastrointestinal System: Digestion and Absorption 1UNLV UNIVERSITY OF NEVADA LAS VEGAS PHYSIOLOGY, Chapter 33 Berne, Levy, Koeppen, Stanton Objectives Describe the digestive secretions
More informationDigestive system. Dr. Carmen E. Rexach Anatomy 35 Mt San Antonio College
Digestive system Dr. Carmen E. Rexach Anatomy 35 Mt San Antonio College Oral cavity Alimentary Canal Accessory organs teeth salivary glands liver gall bladder pancreas appendix Components Functions Motility
More informationAbsorption and Transport of Nutrients
Page1 Digestion Food travels from mouth esophagus stomach small intestine colon rectum anus. Food mixes with digestive juices, moving it through the digestive tract Large molecules of food are broken into
More informationThe Digestive System 24-1
The Digestive System 24-1 Overview of GI tract Functions Mouth---bite, chew, swallow Pharynx and esophagus---- transport Stomach----mechanical disruption; absorption of water & alcohol Small intestine--chemical
More informationHuman Anatomy & Physiology II with Dr. Hubley
Human Anatomy & Physiology II with Dr. Hubley Practice Exam III Name: Instructions This exam consists of 50 questions. You may write on the exam itself, but be sure to answer all your questions on a Scantron
More information17. The Digestion and Absorption of Food. Regulation of Gastrointestinal Processes
chapter C H A P T E R 17 _ The Digestion and Overview: of the Gastrointestinal Organs Structure of the Gastrointestinal Tract Wall Digestion and Absorption Carbohydrate Protein Fat Vitamins Water and Minerals
More information1. Which substances in the small intestine of humans serve to increase the surface area for absorption?
Digestion Review 1. Which substances in the small intestine of humans serve to increase the surface area for absorption? (a.) intestinal glands (b.) villi (c.) pseudopodia (d.) cilia (e.) flagella 2. The
More informationii. Palatine tonsils - located between glossopalatine arch and pharyngopalatine arch iii. Function: guide food and air to laryngopharynx III.
Digestive System I. Introduction I. Tube from mouth to anus, 30 ft. long II. Greatest portion below diaphragm III. Function: digestion and absorption II. Cross section through the coelom (body cavity)
More informationIntegumentary System Digestive System. Outline. Integumentary System 11/4/2008. Week 11 BA & BP November 4, 2008 Nadia Arora, ND
Integumentary System Digestive System Week 11 BA & BP November 4, 2008 Nadia Arora, ND Outline Integumentary system and body membranes Types of body membranes and their function General structure and main
More informationGeneral Structure and Function of the Digestive System
General Structure and Function of the Digestive System Do Now Why does food have to be digested before cells can use it? What are the typical four layers of the digestive tract wall? What is the name of
More information2) Digestion the breakdown of. There are two types of digestion: Mechanical and Chemical. 3) Absorption when the nutrients enter into the blood.
The Digestive System Video on the digestive system (5 min) The digestive system is responsible for the breakdown of the we eat so that it can be absorbed into the. There are four main stages of the digestive
More informationChapter 25. The Small Intestine (The Absorption of Nutrients)
hapter 25 The Small Intestine (The Absorption of Nutrients) Small Intestine nearly all chemical digestion and nutrient absorption occurs in small intestine the longest part of the digestive tract 2.7 to
More informationName Digestive System and Body Metabolism Notes Ch 14
Name Digestive System and Body Metabolism Notes Ch 14 Digestion Breakdown of ingested food Absorption of nutrients into the blood Metabolism Production of cellular energy ( ) Constructive and degradative
More informationThe Digestive System. The organ system that processes food, extracts nutrients from it, and eliminates the residue.
The Digestive System The organ system that processes food, extracts nutrients from it, and eliminates the residue. Digestive System The digestive system allows your body to obtain substances required to
More informationTopic 4: Digestion and Nutrition
Topic 4: Digestion and Nutrition THE CONTENTS OF FOOD Food contains nutrients: Nutrients include: 1. 2. 3. 4. 5. Nutrients must be small enough to enter our cells. If they are too large they must be digested
More informationChapter 25: Metabolism and Nutrition
Chapter 25: Metabolism and Nutrition Chapter Objectives INTRODUCTION 1. Generalize the way in which nutrients are processed through the three major metabolic fates in order to perform various energetic
More informationThe digestive system, also called the gastrointestinal
exercise 8 Chemical and Physical Processes of Digestion Objectives 1. To define digestive tract, accessory glands, digestion, hydrolases, salivary amylase, carbohydrates, proteins, lipids, bile salts,
More information10.1 The function of Digestion pg. 402
10.1 The function of Digestion pg. 402 Macromolecules and Living Systems The body is made up of more than 60 % water. The water is found in the cells cytoplasm, the interstitial fluid and the blood (5
More informationDigestion. Processing of food Types. Mechanical (physical) Chemical. Chew Tear Grind Mash Mix. Catabolic reactions Enzymatic hydrolysis
Digestive System Digestion Processing of food Types Mechanical (physical) Chew Tear Grind Mash Mix Chemical Catabolic reactions Enzymatic hydrolysis Carbohydrate Protein Lipid 2 Digestion Phases Ingestion
More informationThe Digestive System
16 The Digestive System FOCUS: The function of the digestive system is to take in food, break it down into smaller compounds, and absorb those compounds so that the body can use them. This process provides
More informationChapter 25. The Stomach Microscopic Anatomy and Gastric Function
Chapter 25 The Stomach Microscopic Anatomy and Gastric Function Gross Anatomy of Stomach Diaphragm Lesser omentum Lesser curvature Pyloric region: Antrum Pyloric canal Pylorus Pyloric sphincter Fundic
More information1. The diagram below represents a biological process
1. The diagram below represents a biological process 5. The chart below indicates the elements contained in four different molecules and the number of atoms of each element in those molecules. Which set
More informationDigestive System Lecture 5 Winter 2014
Digestive System Lecture 5 Winter 2014 This lecture tells the story of the Flow of Matter from Food to Cells. The pictures are only there to help you visualize structures don t worry about names of structures
More informationLab 18 The Digestive System
Lab 18 The Digestive System Laboratory Objectives Identify on a diagram, model or cadaver the parts of the digestive system and accessory organs. Describe the general histology of the digestive system.
More informationh. Large intestine 3
(1) General features (a) Large intestine is last organ of digestive tract proper divided into 3 or 4 regions cecum appendix in humans colon rectum 1 b) No villi lumenal epithelium has microvilli This brush
More informationDigestive System. Student Learning Objectives: Structures to be studied: Introduction
Digestive System Student Learning Objectives: Identify the primary structures of the digestive system. Describe the use of various important nutrient materials in the body. Structures to be studied: Oral
More informationCHAPTER 17: DIGESTIVE SYSTEM. 2. Distinguish between mechanical digestion and chemical digestion.
CHAPTER 17: SYSTEM OBJECTIVES 1. Define the term digestion and explain its significance. 2. Distinguish between mechanical digestion and chemical digestion. 3. Discuss the five digestive processes that
More informationHorse Science: The Digestive System of the Horse Page 3
Horse Science: The Digestive System of the Horse Page 3 The digestive system of the horse is different from that Mastication (chewing) is the mechanical reduction of of the other farm animals. Although
More informationLAB 3: DIGESTION OF ORGANIC MACROMOLECULES
LAB 3: DIGESTION OF ORGANIC MACROMOLECULES INTRODUCTION Enzymes are a special class of proteins that lower the activation energy of biological reactions. These biological catalysts change the rate of chemical
More informationLearning Objectives. Introduction to Medical Careers. Vocabulary: Chapter 16 FACTS. Functions. Organs. Digestive System Chapter 16
Learning Objectives Introduction to Medical Careers Digestive System Chapter 16 Define at least 10 terms relating to the digestive Describe the four functions of the digestive Identify different structures
More informationIntroduction. Digestive System. Physiology. Anatomy. Physiology. Alimentary Canal. Chapter 21
Chapter 21 Digestive System Susan G. Salvo Introduction Digestive process is a disassembly line Digestive system provides processes in which proteins, carbohydrates, and fats are broken down and used a
More information22 Digestive System. Taft College Human Physiology
22 Digestive System Taft College Human Physiology Functions of the Digestive System (4 Basic Functions of Digestion) 1. Ingestion - food intake. 2. Digestion - process of reducing foods to their constituent
More informationOVERVIEW OF LIPID METABOLISM
VERVIEW F LIPID METABLISM Date: September 20, 2005 * Time: 8:00 am 8:50 am * Room: G202 Biomolecular Building Lecturer: Steve Chaney 515A Mary Ellen Jones Building stephen_chaney@med.unc.edu 9663286 *Please
More information