The whole process can takes approximately 40-50 hours.
Metabolism – the chemical reactions which take place in the body.Dietary minerals are generally trace elements, salts, or ions such as copper and iron. Some of these minerals are essential to human metabolism.Vitamins are organic compounds essential to the body. They usually act as coenzymes or cofactors for various proteins in the body.Water is an essential nutrient and is the solvent in which all the chemical reactions of life take place.
Carbohydrates: simple sugars & complex sugars.
For most enzymes the optimum temperature is about 30°C.Many are a lot lower, cold water fish will die at 30°C because their enzymes denature.A few bacteria have enzymes that can withstand very high temperatures up to 100°C.Most enzymes however are fully denatured at 70°C.
Secretion of saliva is under control of the autonomic nervous system, which controls both the volume and type of saliva secreted. This is actually fairly interesting: a dog fed dry dog food produces saliva that is predominantly serous, while dogs on a meat diet secrete saliva with much more mucus. Parasympathetic stimulation from the brain, as was well demonstrated by Ivan Pavlov, results in greatly enhanced secretion, as well as increased blood flow to the salivary glands.
Most animals have three major pairs of salivary glands that differ in the type of secretion they produce:parotid glands produce a serous, watery secretionsubmaxillary (mandibular) glands produce a mixed serous and mucous secretionsublingual glands secrete a saliva that is predominantly mucous in characterThe basis for different glands secreting saliva of differing composition can be seen by examining salivary glands histologically. Two basic types of acinar epithelial cells exist:serous cells, which secrete a watery fluid, essentially devoid of mucusmucous cells, which produce a very mucus-rich secretionAcini in the parotid glands are almost exclusively of the serous type, while those in the sublingual glands are predominantly mucus cells. In the submaxillary glands, it is common to observe acini composed of both serous and mucus epithelial cells.
Lubrication and binding: the mucus in saliva is extremely effective in binding masticated food into a slippery bolus that (usually) slides easily through the esophagus without inflicting damage to the mucosa. Saliva also coats the oral cavity and esophagus, and food basically never directly touches the epithelial cells of those tissues.Solubilizes dry food: in order to be tasted, the molecules in food must be solubilized.Oral hygiene: The oral cavity is almost constantly flushed with saliva, which floats away food debris and keeps the mouth relatively clean. Flow of saliva diminishes considerably during sleep, allow populations of bacteria to build up in the mouth -- the result is dragon breath in the morning. Saliva also contains lysozyme, an enzyme that lyses many bacteria and prevents overgrowth of oral microbial populations.Initiates starch digestion: in most species, the serous acinar cells secrete an alpha-amylase which can begin to digest dietary starch into maltose. Amylase is not present, or present only in very small quantities, in the saliva of carnivores or cattle.Provides alkaline buffering and fluid: this is of great importance in ruminants, which have non-secretory forestomachs.Evaporative cooling: clearly of importance in dogs, which have very poorly developed sweat glands - look at a dog panting after a long run and this function will be clear.
Evaporative CoolingAs the liquid forms a gas, the remaining liquid contains less energy (in other words, the molecules are moving more slowly), which means it is cooler. This can cool the skin and, therefore, the blood supply under the skin.By panting, dogs (and other animals such as gazelles and birds) use evaporative cooling to lower their body temperature. Some saliva on the tongue evaporates, while some cools. The saliva comes into contact with blood vessels in the tongue, which effectively cools the blood. This cooler blood then travels to cool organs.Oral HygieneRemoves food particles, keeps food from getting trapped and stuckContains antibacterial agents such as secretorylgA and lysosome LgA =Lysosome =
Rugae or gastric foldsThe rugae allow the stomach to stretch, to increase volume.
HypothalamusRegulates satiety Negative feed back system with use of nerves and hormones Stretching of stomach wall, sends signals to brain to taper off eatingHormone ghrelin triggers a hunger response, so this is decreased.OvereatingOccurs when your not paying attention to body signals, eating more than physically required.When your not enjoying food, your overeating (mechanical eating)Feeling sluggishFeeling bloated, stretched stomach.
gastric gland, any of the branched tubules in the inner lining of the stomach that secrete gastric juiceand protective mucus.There are three types of gastric glands, distinguished from one another by location and type of secretion. The cardiac gastric glands are located at the very beginning of the stomach; the intermediate, or true, gastric glands in the central stomach areas; and the pyloric glands in the terminal stomach portion. Both the cardiac and pyloric glands secrete mucus, which coats the stomach and protects it from self-digestion by helping to dilute acids and enzymes.Stomach EnzymesPepsin is the main gastric enzyme. It breaks proteins into smaller peptide fragmentsGelatinase, degrades type I and type V gelatin and type IV and V collagen, which are proteoglycans in meat.Gastric amylase degrades starch, but is of minor significance.Gastric lipase is a tributyrase by its biochemical activity, as it acts almost exclusively on tributyrin, a butter fat enzyme.Pepsin enzyme is secreted by gastric glandsRenin enzyme change the liquid milk to solidAcid: Hydrochloric acid is secreted from parietal cells into the lumen where it establishes an extremely acidic environment. This acid is important for activation of pepsinogen and inactivation of ingested microorganisms such as bacteria.
The stomach does do some absorption too.Some medicines (i.e. aspirin), water and alcohol are all absorbed through the stomach.
Intestines are 17 to 35 feet. Majority of that is small intestine.
Shortest part of the intestine (15 inches in humans).Regulates release of chyme via hormones (secretin & cholecytokini)
Bile a complex fluid containing water, electrolytes and bile acids, cholesterol, phospholipids and bilirubin. Up to 800ml is made by daily, by humans.Functions: bile acids / salts allow for the breakdown and absorption of fats, including fat-soluble vitamins. The bile can contain waste products (bilirubin) which is then eliminated with the feces.Bilirubin – waste product of catabolism of red blood cells.Pancreatic JuiceSecreted by the pancreasVarious enzymes (proteases, lipases, and amyliase) including trypsinogen, chymotrypsinogen, elastase, carboxypeptidase, pancreatic lipase, nucleasesand amylase.maltase cleaves maltose into two molecules of glucoselactase cleaves lactose into a glucose and a galactosesucrase cleaves sucrose into a glucose and a fructose
Gallstones form when cholesterol and other things found in bile make stones. They can also form if the gallbladder does not empty as it should. People who are overweight or who are trying to lose weight quickly are more likely to get gallstones.Symptoms:-mild pain in the pit of your stomach or in the upper right part of your belly. Pain may spread to your right upper back or shoulderblade area. Sometimes the pain is more severe. It may be steady, or it may come and go. Or it may get worse when you eat.-May have fever and chills.
There are two distinct sources that supply blood to the liver:Oxygenated blood flows in from the hepatic artery.Nutrient-rich blood flows in from the hepatic portal vein.The liver holds about 13 percent of the body's blood supply at any given moment. The liver consists of two main lobes, both of which are made up of thousands of lobules. These lobules are connected to small ducts that connect with larger ducts to ultimately form the hepatic duct. The hepatic duct transports bile produced by the liver cells to the gallbladder and duodenum (the first part of the small intestine).FunctionsBile production (carries waste, breaks down waste)Blood Regulation (remove waste, produces proteins for plasma, regulates blood clotting, regulate amino acid levels in blood)Waste Regulation (remove waste from blood, conversion of ammonia to urea waste product of protein digestion) Metabolic activity (glucose into glycogen, production of proteins/cholesterol for fat transportationProcessing of hemoglobin for use of its iron content (The liver stores iron.)
Contains Islets of Langerhans, which are cells that release:Glucagonraises the level of glucose (sugar) in the bloodInsulin stimulates cells to use glucoseSomatostatinmay regulate the secretion of glucagons and insulin
Lacteals:Vessels (capillary) of lymphatic systemAbsorbs fats, which form a milky substance referred to as chyle (lymph, fats, and fatty acids)Absorbs glycerol Lacteals merge into larger vessels At thoracic duct, chyle is dumped into blood stream.Liver takes overBlood VesselsAbsorb glucose and amino acids
Can be about 2-4 m.Villi are shorter.Cecum is the beginning of the large intestine. Receives waste materials which will become fecal matter.Separated from the small intestine by the ileocecal valve
Takes about 16-32 hours for passage through large intestine. About 1.5L of chyme passes through the valve.Vitamins are absorbed – K, B12, thiamine, and riboflavin K – important for blood clotting B12 - Thiamine - Riboflavin - Vitamins are made by colonic bacteria. Mucus also protects epethilial cells.
Normal feces are roughly 75% water and 25% solids. The bulk of fecal solids are bacteria and undigested organic matter and fiber. The characteristic brown color of feces are due to stercobilin and urobinin, both of which are produced by bacterial degradation of bilirubin. Fecal odor results from gases produced by bacterial metabolism, including skatole, mercaptans, and hydrogen sulfide.
The digestive system .pptm
Digestive System: group
of organs which
chemically, so it can be
absorbed into the
Processing of food takes
place across the
alimentary canal in
Events taking place can be classified as:
The stages are:
Ingestion: Food enters into the system.
Digestion: Break down of food into simpler forms,
allowing for absorption. Is both mechanical & chemical.
Absorption: The movement of nutrients into the
circulatory system. Means nutrients have entered into
Egestion / Excretion: The elimination of waste
materials. Any food material not processed is eliminated
as fecal matter.
After ingestion, carries food
through digestion until
Food is moved through the
canal via smooth muscle
Various enzymes will enter
into the tube at different
points to process food
The digestive system
processes nutrients into more
Nutrients: any material
needed by an organism to live
Think of nutrients as providing
the building materials &
energy to make and sustain
Nutrients can be classified as:
Materials used by
for growth &
help carry out
Macronutrients are broken down into 3 basic
and in life
Known as lipids
Used in making
Breakdown of food into simpler forms by chemical
Carbohydrates are broken down into simple sugars
Proteins are broken down into peptides and amino
Fats become emulsified, eventually forming fatty acids
Chemical digestion is made possible by biological
catalysts referred to as enzymes which are
The release of
Saliva secretion is
under the control of
It is produced by the
Produced by the salivary gland.
Saliva is a mixture
of water, mucus,
Binding of Food
into a Bolus
Other functions, can include evaporative
cooling and oral hygiene depending on
Food Leaves The Mouth
The tongue shapes
the food into a bolus
The bolus is pushed
into the esophagus
A muscular tube
which connects the
pharynx to the
Made of smooth
contraction of smooth
muscle pushing food
down into stomach.
DIGESTION & THE
A muscular bag (3
layers) lined with
place as the food
Rugae allow the stomach to stretch…
The stomach has the ability to stretch.
Allows for increase
in stomach volume
As the stomach fills, receptors send impulses
to the brain to indicate “fullness”
Gastric glands in the stomach wall release gastric
juice, so the stomach contains:
released for the chemical
digestion of proteins
The stomach is lined with protective mucus.
The digested bolus is now called chyme, and is
slowly released into the small intestine.
The movement of chyme
is regulated by sphincter
Note: some absorption
Secretions released include
stored in the
An alkaline mixture
secreted by the
which can lead to
the formation of
Final portion of the
Leftovers (waste) are
through the cecum
into the large
Main function is the
absorption of water &
electrolytes from the
Mucus is secreted,
binding the dehydrated
waste into feces.
50 hours, egestion
occurs at which point
Waste materials are
eliminated in the form
Final portion of large intestine, which is a temporary
storage area for feces.
When full, the
feces to pass
anus exiting the