Digestive System & Nutrition

Digestive & Nutrition System
By: Lisa Alison & Alyssa PoncePeriod 5

Function
First your food must be digested, resulting in chemical breakdown of foods and the absorption of the resulting nutrients by cells. Then the food breaks large pieces into smaller ones without altering their chemical composition Lastly the food gets reverted into simpler chemicals for the body to use..

Major Orangs: Alimentary Canal and Mouth
The Major Organs are all consisted in the alimentary canal. The major organs that make up the alimentary canal are the mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum, and anus.

Mouth -The mouth hangs inferior towards the diaphragm in the upper left portion of the abdominal cavity.It receives food and begins digestion by mechanically reducing the size of the solid particles and mixing them with saliva.

Pharynx
It is located posterior towards the mouth from which the tubular esophagus leads to the stomach. Together there are three parts to the pharynx. The nasopharynx is the first part of the pharynx it aides in having a passage way for breathing and a way to communicate with the nasal cavity. The second part is the oropharynx it is posterior to the soft palate, and inferior to the nasopharynx. The oropharynx helps creates a passageway for food to move downward and a passage way to move air to and from the nasal cavity. The last part is the laryngopharynx it is located inferior towards the oropharynx and it creates a passageway towards the esophagus.

The function of the pharynx is to contain the nasal and oral cavities with the larynx and esophagus

Esophagus
The esophagus is found between the pharynx and the stomach. It begins at the base of the pharynx then it penetrates through the opening It helps in containing peristalsis which pushes the food consumed towards the stomach

Stomach
The stomach hangs inferior to the diaphragm in the upper left portion of the abdominal cavity. The stomach secretes acid and enzymes. Which mixes food with secretions to begin enzymatic digestion of proteins.

Large and Small Intestine
The small intestine starts at the large intestine then extends to the pyloric sphincter. The small intestine mixes food with bile and pancreatic juice. Final enzymatic breakdown of food molecules; main site if nutrient absorptionThe large intestine starts at the right side of the abdominal cavity where the ilium is met that joins the cecum then it crosses obliquely to the left, and descends into the pelvis. The large intestine absorbs water and electrolytes to form feces

Rectum and Anus
The Rectum and Anus are both a part of the large intestine. Along with the cecum, colon, and anal canal. The rectum lies next to the sacrum. They aid in absorbing water and electrolytes to form chyme and to form and hold feces.

Accessory Organs : Salivary Glands
The Salivary Glands are found on the tongue they secrete saliva which contains enzymes that initiate break down of carbohydrates. There are three types of Major Salivary Glands called Parotid glands, Submandibular glands, and Sublingual Glands. The Parotid Glands is the largest of the salivary glands it creates a clear watery fluid called amylase. The Submandibular glands is located on the floor of the mouth it secretes a more vicious fluid than Parotid. Sublingual glands are the smallest glands they secrete thick and sticky secretions.

Liver
The Liver is found in the upper right quadrant of the abdominal cavity inferior to the diaphragm, partially surrounded by ribs, which extends out towards the fifth intercostal space to the lower margin of the ribs. The livers functions is producing bile which emulsifies fat

Gallblader
The Gallbladder is associated with the liver. The Gallbladder is a pear shape sac located on a depression in the livers inferior surface. The gallbladder functions in storing bile and introduces it into small intestine

Pancreas
The Pancreas is found right across the stomach however it is slightly hidden from view. The Pancreas produces and secretes pancreatic juice, containing digestive enzymes and bicarbonate ions, into small intestine

Description of Alimentary Canal
The alimentary canal is a muscular tube that passes through to bodys ventral cavity. Specialized in certain regions to carry on particular functions, but the structure of its wall, how it moves food, and its innervation are similar throughout its length. There are three parts to the tube the Mucosa/Mucous Membrane is the beginning to where the food you put into your mouth is secreted with mucus and digestive enzymes. Then it travels through the submucosa which is carried into the plexus from where they carried away absorbed materials. The last part is the serosa/ serous layer it helps secretes fluids, moistens and lubricates tubes.

How contents of the Alimentary canal are moved and mixed
The alimentary canal goes through two movements which, are propelling and mixing movements. The mixing happens when smooth muscles in small segments of the tube contract rhythmically. When the stomach reaches a full capacity they form full waves of muscular contractions move along its walls from one end to the other. It creates a wave like motion called peristalsis. Then it creates a ring of contraction that later pushes the food ahead.

Organs and Enzymes
Salivary Enzyme Amylase Salivary Amylase is found in the salivary gland, used to split starch and glycogen disaccharides the first step towards the chemical digestion of carbohydrates.Gastric EnzymePepsin is an enzyme that is found in the gastric glands. Pepsin is an enzyme that is used for starting up a chemical digest.

EnzymeSourceDigestive ActionSalivary Enzyme AmylaseSalivary GlandsBegins Carbohydrate digestion by breaking down starch and glycogen to disaccharides NucleasesPancreasBreaks down nucleic acid into nucleotides EntrokinaseMucosal CellsConverts trypisongen into trypsinIntestinal lipaseMucosal CellsBreaks down fats into fatty acids and glycerol

Importance of Carbohydrates, Lipids, and Proteins
Carbohydrates are needed for supplying energy for cellular processes.Lipids supply energy for cellular processes and for building structures like cell membranes. Proteins can have control of metabolic enzymes rates, clotting factors, elastin and collagen of connective tissues, plasma proteins that regulate and water balance.

Absorption
Vitamins are Water and Fat- Soluble. They can be absorbed into they can also be spread through cellular metabolism. An example for Water- Soluble Vitamins would be Vitamin B and C. While Vitamin A and C are Fat-SolubleMinerals can be absorbed into organic materials such as teeth and bonesFoods can be absorbed in the body as nutrients, carbohydrates, lipids, and proteins.

Normal VS Athlete Diet
Athletes require large amounts of carbohydrates because of the fuel source they provide, these usually cause obesity if eaten in large quantities, but since athletes have a lot of physical activity they are able to maintain weight. They also require protein because of the many functions they provide. A normal diet must have even amounts of carbohydrates to prevent obesity, plenty of proteins and even amounts of lipids as well so to not retain only fat.

Diseases and Sicknesses
Achalasia- Failure of the smooth muscle to relax at some junction in the digestive tube, such as between the esophagus and stomach.Achlorhydria- Lack of hydrochloric acid in gastric secretions.Anorexia Nervosa- Self- StarvationAphagia- Inability to swallowCirrhosis- Condition in which liver cells degenerate and the surrounding connective tissues thicken.

Answers to Beginning Activity
L- Salivary Glands You have 10 minutes to study for the QuizA- EsophagusK- LiverB and J- GallbladderD- PancreasH- AnusG- RectumC and I- StomachF- Large Intestine