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ORGANIC COMPOUNDS Vocabulary 1/5 – monomer 1/6 – dehydration reaction 1/9 – chitin 1/12 - nucleotide I can…… 1/5 – Explain why carbon is unique. 1/6 – Explain why every macromolecule is different. 1/8 – List parts of an amino acid. 1/12 – Name the 3 parts of a nucleotide Decide which macromolecule each represent. Organic Compounds Organic Compounds: Compounds that contain carbon and hydrogen bonding with other atoms that build your cells and provide you energy. *Carbon is the backbone of life!!! Organic Compounds Contain the element carbon and hydrogen. Carbon is found in things that are or once were living. Carbon atoms share electrons to form covalent bonds. CARBON Why is carbon the backbone of life? Why is it special? 1. Carbon has 4 electrons in its outer shell. To satisfy the octet rule, it needs to share 4 other electrons. 2. This means that each carbon atom forms 4 covalent bonds with elements like H, O, P, & N!! What Builds This Object? Find the Macromolecules!!!! MACROMOLECULES Another level in the hierarchy of biological organization is reached when small organic molecules are joined together Macromolecules – Building of Cells Carbohydrates Lipids Proteins Nucleic Acids What Builds These Macromolecules? Macromolecule Large molecules that make up living things. They are large chains of smaller molecules or compounds. It means “giant molecule”. Organic Compounds Organic compounds are composed of hundreds to thousands of individual molecules. – The single molecules in a polymer are called monomers. Macromolecules are BIG molecules and are the building blocks of cells. Macromolecules are built by combining many single units, or monomers, into larger units, called polymers. All cells are composed of the four general types of macromolecules, although each type can serve a cell in different ways. Most macromolecules are polymers, built from monomers Three of the classes of life’s organic molecules are polymers – Carbohydrates – Proteins – Nucleic acids – LIPIDS do not have monomers!!! Monomers All macro organic molecules are made up of smaller subunits called monomers. This is just the base unit that repeats over and again. The monomers can be identical or different. Polymers Organic macromolecules are made up of repeating monomers.These chains of monomers are called polymers. Organic Compounds The long molecules formed by repeating patterns of monomers are called polymers. Condensation(dehydration) Reaction A condensation reaction is the removal of water to connect monomers. The large chain is then bonded to form a polymer. Hydrolysis Process of adding water to break apart polymers. What makes each compound different? ITS FUNCTIONAL GROUP!!!!! Functional Groups Functional group: an atom or group of atoms within a molecule that will determine how the compound will react. THEY DETERMINE THE CHARACTERISTIC OF THE MACROMOLECULE!!!! Functional groups are important for three reason; they are 1. Determine compounds function 2. the sites of characteristic chemical reactions(polar or nonpolar) 3. the basis for naming organic compounds Functional Groups Most of the useful behavior of organic compounds comes from functional groups attached to the carbons. A functional group is a special cluster of atoms that performs a useful function. Hydroxyl group - alcohols contain an -OH (hydroxyl) group Carbs HH -C-O-H H-C-C-O-H : : Functional group HH Ethanol (an alcohol) Hydroxyl Group OH Functional Groups Carbonyl Group contain a carbonyl (C=O) group Carbon double bonded to oxygen Sugars or carbohydrates O O C H CH3 -C-H Functional Acetaldehyde group (an aldehyde) O O C CH3 -C-CH3 Functional Acetone group (a ketone) Carboxyl Group contain a carboxyl (-COOH) group Acids because gives up H+ ions(vinegar) Amino Acids : Functional group : O: CH3 -C-O-H : O C O H or CH3 COOH or CH3 CO2 H Acetic acid (a carboxylic acid ) Carboxyl Group COOH Functional Groups Amino Group Nitrogen bonded to two hydrogens and carbon skeleton. Proteins or amino acids CH 3 N H CH 3 : H : : CH 3 N H CH 3 N CH 3 CH 3 Amine Group N-H2 Functional Groups Phosphate Group Phosphorus atom bonded to four oxygen atoms. ATP energy and DNA Methyl Group Carbon bonded to three hydrogens Part of DNA – nucleic acid 4 Groups of Organic Compounds 1. 2. 3. 4. Carbohydrates Proteins Lipids Nucleic Acids Carbohydrates The ratio of the Make up sugars and starches Contain a hydroxyl (OH) group Contain atoms of carbon, hydrogen, and oxygen. Monomer monosaccharides atoms is 1 C : 2 H : 1O Provide energy to the cells. Dissolve in water (hydrophilic) Polymer polysaccharides Carbohydrates *Carbohydrates are composed of C, H, and O. *Ratio: 1C:2H:1O *Function: 1. Main source of SHORT term energy. 2. Plants and some animals use it for structural purposes. Types of Carbohydrates Carbohydrates are classified according to size. • One sugar is a monosaccharide (monomer). • Two sugars make a disaccharide. • Many sugar molecules linked together form a polysaccharide (polymer). Carbohydrates Carbohydrates are made up of monomers called monosaccharides. Examples of monosaccharides: 1.glucose: plant produce during photosynthesis 2.Galactose: found in milk and diary 3.Fructose: sugar in many fruits GLUCOSE! Fructose Monosaccharide Milk Sugar Fruit Sugar Types of Carbs Carbohydrates Two monomers of monosaccharides together are called disaccharides. Sucrose is a examples of a disaccharide. MALTOSE Carbohydrates Examples of polysacchrides: 1.glycogen:stored energy 2.Starch: plant stored energy 3.Cellulose: cell walls We can not digest cellulose for energy. Our bodies use it for fiber. Herbivores have enzymes and microorganisms to help digest the cellulose. Cows have 4 stomachs. 4.Chitin: exoskeleton of insects and cell walls of fungus STARCH!!! Polysaccharide Starch is straight chain of glucose molecules with few side branches. Types of Carbs Look at the difference between these two. Think about how Plants use cellulose and animals use starch. They are shaped this way because of their use. Cellulose – straight chains Starch Branched. Lipids Class of Glycerol contains macromolecules that the hydroxyl (OH) are hydrophobic group. The three types of Fatty acids contain lipids are fats, oils, the carboxyl and waxes. (COOH) group. Contain carbon, hydrogen, and oxygen Typically contain two monomers – glycerol and fatty acids Lipids DEFINE: Large groups of organic compounds not soluble in water. Functions: 1.Store energy for LONG term. 2.Waterproof covering 3.Protection 4.Steroids – hormones 5.Warmth 6.Cell membranes Structure of lipid – Glycerol head and fatty acid chain 4 main categories of Lipids 1. 2. 3. 4. Fats & oils phosolipids Waxes steroids FAT!!! No Monomer for LIPIDS!!! Lipids Saturated & Unsaturated Fats Lipids Saturated vs. Unsaturated Saturated means that all the carbon bonds are taken. They are solid at room temperature and bad for you. Unsaturated means that there is at least one double bond with the carbon. They are liquid at room temp. and are better for you. Lipids All lipids are not soluble in water. That is why they are placed together. Saturated makes fats Unsaturated makes oils Which ones are Saturated?? Steroid - Cholesterol Phospholipid Found in cell membranes – Head is the phosphate group. • Hydrophilic – Tails are the fatty acids. • Hydrophobic Proteins Composed of carbon, hydrogen, nitrogen, and oxygen Contain amine (NH2) and carboxyl (COOH) groups MONOMER – amino acids POLYMER – polypeptide or protein Functions of Proteins Some important functions of proteins are listed below. enzymes (chemical reactions) hormones storage (egg whites of birds, reptiles; seeds) transport (hemoglobin) contractile (muscle) protective (antibodies) membrane proteins (receptors, membrane transport, antigens) structural toxins (botulism, diphtheria) Proteins Macromolecules that contain N, C, O and H. Functions: 1.Rate of cell processes. 2.Cellular structures 3.Controls substances in and out of cell. 4.Fight disease. 1. 2. 3. 4. 5. 6. 7. Examples of Proteins In Body Hemoglobin in blood Collagen Enzymes Insulin Muscles Antibodies Cell Membrane Foods with Protein Eggs, milk, meat, beans, peanut butter, yogurt, soybeans, cheese, ETC Proteins and Amino acid formation Proteins are made up of monomers of amino acids help together by peptide bonds. 3 parts of an amino acid: 1.Amino group 2.Carboxyl group 3.R group Proteins(structure) Long chains of amino acids are connected by peptide bonds which are called polypeptides. Proteins(examples of R-Groups) There are 20 different amino acids found in nature.Different proteins are determined by the type of amino acids connected together. All amino acids are the same except for the R-group. The R-group gives the amino acids different properties. Amino Acids Function of Proteins R – Group Nucleic acids Macromolecules containing the elements H, N, C, O and P. Made up of monomers of nucleotides. Nucleotides 3 parts of a nucleotide 1.Phosphate 2.Deoxyribose sugar 3.Nitrogen base 4 Nitrogen Bases 1. 2. 3. 4. Adenine Guanine Cytosine Thymine Functions of a Nucleic Acids 1. Carry genetic material 2. Carries codes to make proteins 2 Examples of Nucleic Acids 1. RNA – ribonucleic acids 2. DNA – deoxyribosenucleic acid Function of RNA Function of RNA is to make proteins from the code DNA carries. 1. Organic C ompound C arbohydrate C omposed of: Examples Function C, H, O Sugar Starch cellulose Releases energy for cells Organic C ompound Lipid C omposed of: Examples Function C, H, O Fats Oils Waxes Stores and releases MORE energy for cells C ellmembranes are made oflipids Nutrition & Digestion Balanced Diet Necessary to provide all elements and compound to make new cells, provide energy, or essential for life. Elements become energy and new cells. Metabolism – All the chemical reactions carried on by the cell – protein synthesis, respiration, DNA replication, etc. Digestion Food consists of what macromolecules? – Carbohydrates, lipids, and proteins Why is food chemically broken down? – The macromolecules are too large to pass through cell membranes – The polymers must be broken down into monomers, so that the organism can make their own polymers – ABSORPTION OCCURS IN SMLL INTESTINES!!!!! – LARGE INTESTINE REMOVES WASTES Food Processing Human digestive system Ingestion Mouth – mechanical digestion • teeth – breaking up food – chemical digestion • saliva – amylase » enzyme digests starch – mucin » slippery protein (mucus) » protects soft lining of digestive system » lubricates food for easier swallowing – buffers » neutralizes acid to prevent tooth decay – anti-bacterial chemicals » kill bacteria that enter mouth with food mouth break up food digest starch kill germs moisten food Mouth Chemical and mechanical digestion. Food is chewed (masticated) mechanically. A bolus (lump) is formed with saliva and the tongue. Swallowing (& not choking) Epiglottis – flap of cartilage – closes trachea (windpipe) when swallowing – food travels down esophagus Peristalsis – involuntary muscle contractions to move food along Pharynx The back of the throat. Larynxpassage for air, closes when we swallow. Is approximately 15cm long. Peristalsis series of involuntary wave-like muscle contractions which move food along the digestive tract Stomach Food is temporarily stored here. Gastric juices are secreted. Has layers of muscle that line the inside. Mechanically and chemically breaks down food. Stomach Functions – food storage • can stretch to fit ~2L food – disinfect food • HCl = pH 2 – kills bacteria – chemical digestion • pepsin – enzyme breaks down proteins But the stomach is made out of protein! What stops the stomach from digesting itself? mucus secreted by stomach cells protects stomach lining mouth break up food digest starch kill germs moisten food stomach kills germs break up food digest proteins store food sphincter sphincter Gastric Juices Secreted by the stomach. Acidic (pH 1.5-2.5) (HCl). Pepsin- an enzyme that breaks down large proteins into amino acids. Food is further broken down into a thin liquid called chyme. Accessory Organs Pancreas Gall Bladder Spleen Gall bladder Pouch structure located near the liver which concentrates and stores bile Bile duct – a long tube that carries BILE. The top half of the common bile duct is associated with the liver, while the bottom half of the common bile duct is associated with the pancreas, through which it passes on its way to the intestine. BILE Bile emulsifies lipids (physically breaks apart FATS) Bile is a bitter, greenish-yellow alkaline fluid, stored in the gallbladder between meals and upon eating is discharged into the duodenum where it aids the process of digestion. Pancreas An organ which secretes both digestive enzymes (exocrine) and hormones (endocrine) ** Pancreatic juice digests all major nutrient types. Nearly all digestion occurs in the small intestine & all digestion is completed in the SI. Pancreas Digestive enzymes – digest proteins • trypsin, chymotrypsin – digest starch • amylase Buffers – neutralizes acid from stomach Liver Function – produces bile • bile stored in gallbladder until needed • breaks up fats – act like detergents to breakup fats bile contains colors from old red blood cells collected in liver = iron in RBC rusts & makes feces brown mouth break up food digest starch kill germs moisten food liver produces bile - stored in gall bladder break up fats pancreas produces enzymes to digest proteins & starch stomach kills germs break up food digest proteins store food Small Intestine Most chemical digestion takes place here. Simple sugars and proteins are absorbed into the inner lining. Fatty acids and glycerol go to lymphatic system. Lined with villi, which increase surface area for absorption, one cell thick. Small intestine Function – chemical digestion • major organ of digestion & absorption – absorption through lining • over 6 meters! • small intestine has huge surface area = 300m2 (~size of tennis court) Structure – 3 sections • duodenum = most digestion • jejunum = absorption of nutrients & water • ileum = absorption of nutrients & water Duodenum 1st section of small intestines – acid food from stomach – mixes with digestive juices from: pancreas liver gall bladder mouth break up food digest starch kill germs moisten food pancreas produces enzymes to digest proteins & starch stomach kills germs break up food digest proteins store food Absorption in the SI Much absorption is thought to occur directly through the wall without the need for special adaptations Almost 90% of our daily fluid intake is absorbed in the small intestine. Villi - increase the surface area of the small intestines, thus providing better absorption of materials Absorption by Small Intestines Absorption through villi & microvilli – finger-like projections – increase surface area for absorption VILLI Large intestines (colon) Function – re-absorb water • use ~9 liters of water every day in digestive juices • > 90% of water reabsorbed – not enough water absorbed » diarrhea – too much water absorbed » constipation Large Intestine Solid materials pass through the large intestine. These are undigestible solids (fibers). Water is absorbed. Vitamins K and B are reabsorbed with the water. Rectum- solid wastes exit the body. You’ve got company! Living in the large intestine is a community of helpful bacteria – Escherichia coli (E. coli) • produce vitamins – vitamin K; B vitamins • generate gases – by-product of bacterial metabolism – methane, hydrogen sulfide Appendix Vestigial organ Rectum Last section of colon (large intestines) – eliminate feces • undigested materials – extracellular waste » mainly cellulose from plants » roughage or fiber – masses of bacteria Carb Digestion: Oral Cavity At sight or smell of food, salivary glands secrete saliva – Glycoprotein protects & lubricates lining of mouth – Antibacterial agents – Amylase to hydrolyze starch Why do you chew your food? – Easier to swallow – Expose more surface area to enzymes Tongue pushes bolus to back of oral cavity & into pharynx Carbohydrates ) . Monomer monosaccharides Polymer polysaccharides Carbohydrates *Carbohydrates are composed of C, H, and O. *Ratio: 1C:2H:1O *Function: 1. Main source of SHORT term energy. 2. Plants and some animals use it for structural purposes. Types of Carbohydrates Carbohydrates are classified according to size. • One sugar is a monosaccharide (monomer). • Two sugars make a disaccharide. • Many sugar molecules linked together form a polysaccharide (polymer). Carbohydrates Carbohydrates are made up of monomers called monosaccharides. Examples of monosaccharides: 1.glucose: plant produce during photosynthesis 2.Galactose: found in milk and diary 3.Fructose: sugar in many fruits GLUCOSE! Or ganic C ompound C ar bohydr at e C omposed of: E xampl es F unct ion C, H, O Sugar Starch cellulose Releases energy for cells Breads, pasta, potatoes, corn, sugars, lactose, etc. Energy stored in bonds of carbs Carbohydrates Two monomers of monosaccharides together are called disaccharides. Sucrose is a examples of a disaccharide. MALTOSE Carbohydrates Examples of polysacchrides: 1.glycogen:stored energy 2.Starch: plant stored energy 3.Cellulose: cell walls We can not digest cellulose for energy. Our bodies use it for fiber. Herbivores have enzymes and microorganisms to help digest the cellulose. Cows have 4 stomachs. 4.Chitin: exoskeleton of insects and cell walls of fungus STARCH!!! Carb Digestion In stomach, the carb is mixed with HCl acid to form chyme. Chyme leaves stomach and enter top part of small intestines called the duodenum. The polysaccharides are broken down into monosaccharides and absorbed into the SMALL INTESTINES wall. Human Digestion: the tum tum Why don’t we need to eat constantly? – Besides breaking down food, the stomach stores food – enough to satisfy our body for many hours What prevents gastric juice from digesting away the stomach lining? – Pepsin, an enzyme which begins the chemical digestion of protein, is secreted in the inactive form pepsinogen • Protects the gastric gland cells – Mucus helps protect the stomach lining from both pepsin and acid – However, the stomach lining must be replaced about every 3 days Carb Digestion For carbs we do not have enzymes, bacteria furthers the breakdown of carbs so they can be absorbed. Fiber is need to needs to form wastes. Helps to prevent constipation. We cannot digest cellulose(plant sugar) so it acts as fiber. Human Digestion: large intestine Colon absorbs water –approximately 90% of the 7 liters of fluid that enters the canal a day are reclaimed (most in small intestine) Remains of undigested food become more solid as water is absorbed – Feces • Consists mainly of plant fibers and prokaryotes • Diarrhea occurs when the colon is irritated and is less effective at reclaiming water • Constipation occurs when peristalsis moves the feces too slowly – Colon reabsorbs too much water and feces becomes too compacted » Diet low in plant fiber or lack of exercise Human Digestion: small intestine Capillaries that drain away from the villi converge into larger blood vessels and eventually into a main vessel that leads directly to liver Diabetes Glucose cannot be absorbed into cells because no insulin. Glucose builds up in blood and no energy production. Proteins What is protein? Protein is a complex structure containing carbon, hydrogen, oxygen, and nitrogen, and in some cases sulfur. These elements combine to form amino acids. Amino Acids Two types: 1) Essential (9) • Must be obtained from foods in the diet 2) Nonessential (11) • May be formed in the body What are some common foods that are good sources of protein? The Food Groups – High • Meat and meat substitutes (legumes) • Milk – Lower • Starch • Vegetable • Fruit • Fat Figure 6.4 Protein Digestion Chewed into piece in mouth. Digestion starts in stomach with pepsin(enzyme) Continues into the small intestines with enzyme proteases. Breakdown into amino acids. Absorbed into small intestines wall. Human Digestion: small intestine Protein digestion – Pancreas and duodenum secrete hydrolytic enzymes that break polymer into monomers (amino acids) Nucleic acid digestion – Pancreas and duodenum secrete hydrolytic enzymes which breakdown DNA & RNA polymers into • Nitrogenous bases, sugars, phosphates Lipids Class of ROLE: energy macromolecules that Cell membrane, are hydrophobic hormones, steroids, The three types of lipids are fats, oils, and waxes. Contain carbon, hydrogen, and oxygen Lipids DEFINE: Large groups of organic compounds not soluble in water. Functions: 1.Store energy for LONG term. 2.Waterproof covering 3.Protection 4.Steroids – hormones 5.Warmth 6.Cell membranes 4 main categories of Lipids 1. 2. 3. 4. Fats & oils phosolipids Waxes steroids FAT!!! No Monomer for LIPIDS!!! Lipids Lipids Saturated vs. Unsaturated Saturated means that all the carbon bonds are taken. They are solid at room temperature and bad for you. Unsaturated means that there is at least one double bond with the carbon. They are liquid at room temp. and are better for you. Which ones are Saturated?? Human Digestion: small intestine Lipid digestion – Lipids reach stomach almost completely undigested • Why? – Fats are hydrophobic – Bile salts from gallbladder coat tiny fat droplets that keep them separated from each other • Why is the separation of fats into small droplets beneficial for digestion? – More surface area is exposed, which allows the enzyme to breakdown the fats quickly Lipid digestion No lipid digestion except in small intestines. Bile from liver digests it. Lipase enzyme that breaks down lipids. Nutrition: Vitamins If one eats a balanced diet, one does not need to take vitamins – Most serve as coenzymes or are parts of coenzymes – Used over and over again in metabolic processes – Deficiencies and excessive use can cause serious problems – Water-soluble vitamins are not harmful as excess can pass in urine and feces – Excessive fat-soluble vitamins are deposited in fat and can have toxic effects Nutrition: Minerals Must obtain minerals through dietary sources Ex: calcium needed for normal functioning of nerves and muscles Ex: phosphorous is an ingredient of ATP and nucleic acids Human Digestion Nutrition Process by which organisms obtain and utilize their food. There are two parts to Nutrition: 1. Ingestion- process of taking food into the digestive system so that it may be hydrolized or digested. 2. Digestion- the breakdown of food (either chemically or mechanically) in order to utilize nutrients Types of Nutrients Micronutrients- vitamins, minerals, & water Macronutrients- proteins, lipids, carbohydrates, etc… Human digestive system GI (gastrointestinal) tract = alimentary canal Ingestion Mouth – mechanical digestion • teeth – breaking up food – chemical digestion • saliva – amylase » enzyme digests starch – mucin » slippery protein (mucus) » protects soft lining of digestive system » lubricates food for easier swallowing – buffers » neutralizes acid to prevent tooth decay – anti-bacterial chemicals » kill bacteria that enter mouth with food mouth break up food digest starch kill germs moisten food Mouth Chemical and mechanical digestion. Food is chewed (masticated) mechanically. A bolus (lump) is formed with saliva and the tongue. Swallowing (& not choking) Epiglottis – flap of cartilage – closes trachea (windpipe) when swallowing – food travels down esophagus Peristalsis – involuntary muscle contractions to move food along Pharynx The back of the throat. Larynxpassage for air, closes when we swallow. Is approximately 15cm long. Digestive Glands Groups of specialized secretory cells. Found in the lining of the alimentary canal or accessory organs. Peristalsis series of involuntary wave-like muscle contractions which move food along the digestive tract Stomach Food is temporarily stored here. Gastric juices are secreted. Has layers of muscle that line the inside. Mechanically and chemically breaks down food. Stomach Functions – food storage • can stretch to fit ~2L food – disinfect food • HCl = pH 2 – kills bacteria – chemical digestion • pepsin – enzyme breaks down proteins But the stomach is made out of protein! What stops the stomach from digesting itself? mucus secreted by stomach cells protects stomach lining mouth break up food digest starch kill germs moisten food stomach kills germs break up food digest proteins store food sphincter sphincter Gastric Juices Secreted by the stomach. Acidic (pH 1.5-2.5) (HCl). Pepsin- an enzyme that breaks down large proteins into amino acids. Food is further broken down into a thin liquid called chyme. Accessory Organs Pancreas Gall Bladder Spleen Gall bladder Pouch structure located near the liver which concentrates and stores bile Bile duct – a long tube that carries BILE. The top half of the common bile duct is associated with the liver, while the bottom half of the common bile duct is associated with the pancreas, through which it passes on its way to the intestine. BILE Bile emulsifies lipids (physically breaks apart FATS) Bile is a bitter, greenish-yellow alkaline fluid, stored in the gallbladder between meals and upon eating is discharged into the duodenum where it aids the process of digestion. Pancreas An organ which secretes both digestive enzymes (exocrine) and hormones (endocrine) ** Pancreatic juice digests all major nutrient types. Nearly all digestion occurs in the small intestine & all digestion is completed in the SI. Pancreas Digestive enzymes – digest proteins • trypsin, chymotrypsin – digest starch • amylase Buffers – neutralizes acid from stomach Liver Function – produces bile • bile stored in gallbladder until needed • breaks up fats – act like detergents to breakup fats bile contains colors from old red blood cells collected in liver = iron in RBC rusts & makes feces brown mouth break up food digest starch kill germs moisten food liver produces bile - stored in gall bladder break up fats pancreas produces enzymes to digest proteins & starch stomach kills germs break up food digest proteins store food Small Intestine Most chemical digestion takes place here. Simple sugars and proteins are absorbed into the inner lining. Fatty acids and glycerol go to lymphatic system. Lined with villi, which increase surface area for absorption, one cell thick. Small intestine Function – chemical digestion • major organ of digestion & absorption – absorption through lining • over 6 meters! • small intestine has huge surface area = 300m2 (~size of tennis court) Structure – 3 sections • duodenum = most digestion • jejunum = absorption of nutrients & water • ileum = absorption of nutrients & water Duodenum 1st section of small intestines – acid food from stomach – mixes with digestive juices from: pancreas liver gall bladder mouth break up food digest starch kill germs moisten food pancreas produces enzymes to digest proteins & starch stomach kills germs break up food digest proteins store food Absorption in the SI Much absorption is thought to occur directly through the wall without the need for special adaptations Almost 90% of our daily fluid intake is absorbed in the small intestine. Villi - increase the surface area of the small intestines, thus providing better absorption of materials Absorption by Small Intestines Absorption through villi & microvilli – finger-like projections – increase surface area for absorption VILLI Large intestines (colon) Function – re-absorb water • use ~9 liters of water every day in digestive juices • > 90% of water reabsorbed – not enough water absorbed » diarrhea – too much water absorbed » constipation Large Intestine Solid materials pass through the large intestine. These are undigestible solids (fibers). Water is absorbed. Vitamins K and B are reabsorbed with the water. Rectum- solid wastes exit the body. You’ve got company! Living in the large intestine is a community of helpful bacteria – Escherichia coli (E. coli) • produce vitamins – vitamin K; B vitamins • generate gases – by-product of bacterial metabolism – methane, hydrogen sulfide Appendix Vestigial organ Rectum Last section of colon (large intestines) – eliminate feces • undigested materials – extracellular waste » mainly cellulose from plants » roughage or fiber – masses of bacteria Digestive Homeostasis Disorders ULCERS – erosion of the surface of the alimentary canal generally associated with some kind of irritant Digestive Homeostasis Disorders CONSTIPATION – a condition in which the large intestine is emptied with difficulty. Too much water is reabsorbed and the solid waste hardens Digestive Homeostasis Disorders DIARRHEA – a gastrointestinal disturbance characterized by decreased water absorption and increased peristaltic activity of the large intestine. This results in increased, multiple, watery feces. This condition may result in severe dehydration, especially in infants Digestive Homeostasis Disorders APPENDICITIS – an inflammation of the appendix due to infection Common treatment is removal of the appendix via surgery Digestive Homeostasis Disorders GALLSTONES – an accumulation of hardened cholesterol and/or calcium deposits in the gallbladder Can either be “passed” (OUCH!!) or surgically removed Digestive Homeostasis Disorders ANOREXIA NERVOSA - a psychological condition where an individual thinks they appear overweight and refuses to eat. Weighs 85% or less than what is developmentally expected for age and height Young girls do not begin to menstruate at the appropriate age. Digestive Homeostasis Disorders HEART BURN – ACID from the stomach backs up into the esophagus. Let’s go to the Video! Digestive System Cadaver Travel Through the Digestive System