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Digestive System Ashley Duenas Period:3 - Coggle Diagram
Digestive System Ashley Duenas Period:3
Main Organs:
Large Intestine:
~1.5 meter longer and wider diameter than small intestine by ileocecal valve.
~No villi present
~Slow movement
~Starts at ileocecal valve and ends at anus.
Functions:**
~Digestion by bacteria
~Absorption of water and salt.
~Breakdown remaining proteins to amino acids.
~Undigested food called fecal matter leaves the ileum and enters cecum through the
ileocecal sphincter.**
~Bacteria ferment remaining carbs and release hydrogen, carbon dioxide, producing gas.
Small Intestine:
~Tube approximately 7 meters filling most of the abdominal cavity.
~Connects stomach through the pyloric sphincter to the large intestine.
Functions:
~Mechanical digestion:
segmentation and peristalsis that mixes and breaks down chime.
~Chime plus secretion from pancreas, liver and intestinal juices.
~Chemical Digestion:
Intestinal glands secrete intestinal juices.
~Absorption of water and nutrients (90%).
~Microvilli and Villi:
increase surface area for absorption.
Pancreas
~Located behind stomach, closely associated with smaller intestine.
Functions:
~Secretes
pancreatic juices(
made by pancreatic acinar cells) into duodenum.
~Enzyme to digest all nutrients including protease (proteins), Lipase (lipids), Amylase (carbohydrates) and nuclease (nucleic acids).
Gall Bladder:
~Stores excess
bile
for liver.
~Located under the surface of liver
~Connected to the cystic duct which joins to the hepatic duct.
Functions:
~Concentrates and stores bile produced in the liver, to release into the small intestine (duodenum).
Liver:
~Largest internal organ, partily surrounded by the ribs.
~4 lobes with gallbladder( bile storage)
Normal functions:
~Helps maitain concentration of blood glucose levels an metabolizes proteins.
~Removes toxic substances from the blood.
~Converts carbs and proteins into fat.
Functions for Digestion:
~Secrete bile into duodenum.
~Bile: water, cholesterol, electrolytes, bile salts and bile pigments.
~ Bile salts
break up fats and eliminate cholesterol.
~Bile breaks up fats into smaller pieces.
Stomach:
~J-shaped, muscular organ about the size of a large sausage when empty and has a thick mucus membrane.
Composed of 3 parts:
~Cadia/Fundus:
enlarged opening next to esophagus; temporary storage.
~Body
: central main part.
~Pylorus:
lower narrow section
Functions:
~Mixing and holding chamber.
~3 layers of smooth muscle that mixes food into tiny particles.
~Chemical Digestion but also mechanical churning.
~Glands secrete gastric juices including HCI, pepsin and intrinsic factor
Esophagus
:
~Is a straight, collapse passageway leading to the stomach through a diaphragm opening.
~Mucous glands are scattered throughout the submucosa of the esophagus and produce mucus to moisten and lubricate the inner lining of the tube.
~The l
ower esophageal sphincter
helps prevent regurgitation of the stomach contents into the esophagus(prevents backflow).
Functions:
~Connects pharynx to stomach.
~Passageway only for food.
~Digestive function propulsion, moves food by peristalsis.
Appendix:
~Vermiform appendix worm-like structure about 9cm.
~Near right hip bone.
~Contains lymphatic tissue
~May become inflamed resulting in
appendicitis
.
~Vestigal Organ so it has no function/debated function.
Mouth:
~First portion of the alimentary canal.
~Opening for food and food enter into the mouth.
Oral cavity is composed of:
~Roof:
formed by hard/soft palate
~Uvula:
downward projection of soft palate.
~Floor:
formed by tongue and its muscles.
Other structures:
~Lips:
keep food in the mouth. and are sensory receptors towards food.
~Teeth:
breakdown the food.
~Tongue:
muscle
~Cheeks:
involved in expression and chewing
Functions:
~Mechanical digestion:
by mastication or chewing with the help of the teeth.
Chemical Digestion:
enzymes from the salivary glands/saliva.
Layers of GI Tract:
Submucosa:
Aerolar connective tissue containing many blood vessels.
~Many elastic fibers to retain shape.
~Submucosa
Plexus: autonomic nerve supply including glands and lymphatic tissue.
Muscularis
Layer: muscular layer
~Two layers of smooth muscle to allow perstalis and segmentation.
~Inner circular layer:
squeeze, decrease size of lumen; in some areas act as sphincter or valves.
~Outer longitudinal layer:
shortens intestine.
Mucosa:
produces mucus for reduction of the friction and protections.
Epithelium:
Varies by location; non-kerantinized stratified squamous in mouth, esophagus and anus for protection against friction.
~Simple columnar in intestine for absorption and secretion.
~Lamina Propia:
Aerolar connective tissue; contains blood and lymphatic vessels and lymph node for nourishment and immunity.
~Muscularis mucosae:
2 thin layers of smooth muscle
Serosa:
outer covering of GI tract .
~Serous membrane:
Composed of thin layer of aerolar connective tissue and simple squamous epithelium.
~Produces serous fluid for lubrication.
~Covers the outside of the abdominal organs.
~Attaches the digestive tract to the wall of the abdominal-pelvic cavity by forming folds called mesenteries.
Disorders:
Constipation:
is difficult or infrequent passage of stool. ~The main symptom is straining to go to the bathroom.
Stomach Flu:
Is an infection of the stomach and upper part of the small intestine. Common symptoms are diarrhea, vomiting, stomach pain, and cramps.
Jaundice:
Yellow skin discoloration due to excess amounts of bile in the blood.
GallStones:
The gallbladder is an organ attached to your intestine that stores bile. Bile can form small, hard deposits called gallstones.
~Either no symptoms or may feel nausea, vomitting and fever.
Appendicitis:
Is an inflammation of the appendix
~Causes pain in your lower right abdomen. However, in most people, pain begins around the navel and then moves.
Major Functions:
~Mechanical Digestion:
involves physically breaking down food substances into smaller particles to more efficiently undergo chemical digestion.
~Chemical Digestion:
to further degrade the molecular structure of the ingested compounds by digestive enzymes into a form that is absorbable into the bloodstream.
~Digestion, breakdown, and absorption of food for metabolism.
~For the growth of energy and repair of tissue.
Digestive Enzymes:
Proteins: Stomach & Small Intestine
Pepsin
: Stomach enzyme that serves to digest proteins.
Protease:
Breaks down proteins into amino acids.
Mouth & Small Intestine
Sucrase:
Aids in the breakdown of sucrose into glucose and fructose.
Lactase:
catalyzes the breakdown of lactose(milk sugar) into the simple sugars glucose and galactose.
Maltase:
Secreted by the intestine then converts maltose into glucose.
Amylase:
hydrolyze the glycosidic bonds in starch molecules and convert complex carbohydrates into simple sugars.
Pancreas
Nuclease:
Split nucleic acids into nucleotides.
Pancreatic enzymes
called ribonuclease and deoxyribonuclease break down RNA and DNA, respectively, into smaller nucleic acids.
Small Intestine
Lipase
: Split fatty acids off of fats and oils.
Location of digestion and absorption:
Proteins
~In order for our cells to actually absorb proteins, our body must first denature the proteins and then break them down into their
amino acid
form.
~
Mechanical digestion
of protein begins in the mouth and continues in the stomach and small intestine.
Chemical digestion
of protein begins in the stomach and ends in the small intestine.
Carbohydrates:
~Carbohydrates are not chemically broken down in the stomach, but rather in the small intestine. ~Pancreatic amylase and the disaccharidases finish the chemical breakdown of digestible carbohydrates.
~The monosaccharides are absorbed into the bloodstream and delivered to the liver.
Lipids:
~The digestive process has to break those large droplets of fat into smaller droplets and then enzymes digest lipid molecules using enzymes called lipases.
~The mouth and stomach play a small role in this process, but most enzymatic digestion of lipids happens in the small intestine.
