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The Digestive System: Marco Sesar Per. 5 - Coggle Diagram
The Digestive System: Marco Sesar Per. 5
Functions
Digestion of food for metabolism
Absorption of food for metabolism
Mastication
Chewing Movement
Segmentation
Mixing/churning movement
Peristalsis
Wave/rippling movement
Small Intestine
Absorbs-water, vitamins, minerals, carbohydrates/proteins, and fats
Large Intestine
Absorbs-water, vitamin K, and B complex
Primary Processes
Motility/Propulsion
Mixing and movement of food (muscles)
Secretion
release of mucus, acid, bile, and enzymes to aid digestion
Digestion
physical (teeth) and chemical (enzymes) breakdown of food into nutrients
Absorption
Taking in of nutrients
Ingestion
Eating
Elimination/Defication
removal of waste and undigested food from the body
Major Organs
Mouth
Function
To receive food and begins mechanical digestion by mastication; chemical digestion also occurs
Chews and lubricates food with saliva
Saliva contains enzymes that starts chemical digestion
Moves food (bolus) to pharynx
The oral cavity is the chamber between the palate and tongue
The narrow space between the teeth, cheeks, and lips is called the vestibule
Anterior opening called oral orifice
Structure
Uvula
A downward projections of soft palate
Muscle
Floor
Formed by tongue and its muscles
Roof
Formed by hard and soft palate
Lips
Keep food in mouth
Teeth
Breaks down food
Tongue
Muscle
Moves and mixes food with saliva (food+saliva= bolus)
Cheeks
Form the lateral walls of the mouth and involved in expressions and chewing
Lips
Highly mobile structures that surround the mouth opening
Are sensitive to help judge the temperature and texture of foods.
Tongue
A thick, muscular organ covered by mucous membrane with taste buds within papillae; it is attached to the floor of the mouth by the lingual frenulum
The papillae also provide friction for moving food around in the mouth
Palate
Forms the roof of the oral cavity and has an anterior hard palate and posterior soft palate
The soft palate and uvula function to close off the nasal cavity during swallowing
Associated with the palate in the back of the mouth are palatine tonsils, which, because they are lymphatic tissue, help to protect the body against infection
Pharyngeal tonsils are located on the posterior wall of the pharynx, above the border of the soft palate
Teeth
Two sets of teeth develop in the sockets within the maxillary and mandibular bones
Through the actions of chewing, teeth breaking food into smaller pieces, beginning mechanical digestion
Each tooth consists of a crown and a root, and is made of enamel, dentin, pulp, cementum, nerves, and BV running through root canals
Teeth: incisors, cuspids, bicuspids, and molars
Incisors- cut
cuspids- tear and shred
bicuspid- crush and grind
Molars- crush and grind structures of a typical tooth
Salivary Glands
Secret saliva, which moistens and dissolves food particles, bind them, together, allows tasting, helps to cleanse the mouth and teeth, and begins carbohydrate digestion
Contain serous cells that produce a watery fluid with salivary amylase and mucous cells that produce lubrication and binding mucous
Receive parasympathetic stimulation that triggers the production of a large volume of saliva at the sigh or smell of food
Parotid glands
lying in front of the ear are the largest of the major salivary glands, they secrete a clear, watery fluid (serous) rich in amylase
Submandibular Glands
Located on the floor of the mouth, secret a more viscous fluid (serous and mucous)
Sublingual Glands
Inferior to the tongue, are the smallest of the major salivary glands and secrete a saliva that is thick and stringy (mucous)
Esophagus
Pharynx
Is a cavity lying behind the mouth
Structure
Connects the nasal and oral cavities with the larynx and esophagus
Is divided into the nasopharynx (top), oropharynx (middle), and largyngopharynx (bottom)
Epiglottis (a flap of cartilage)
Closes so food goes into esophagus
Function
Passageway for food and air from mouth to esophagus
Deglutition
Swallowing
Swallowing food passes from oropharynx into larngopharynx
Is a muscular tube leading to the stomach
A straight, collapsible, passageway leading to the stomach, through a diaphragm opening (esophageal hiatus)
Mucous glands are scattered throughout the submucosa of the esophagus and produce mucus to moisten and lubricate the inner lining of the tube
The lower esophageal (cardiae) sphincter helps to prevent regurgitation of the stomach contents into the esophagus
Function
Connects pharynx to stomach
Passageway only for food
Digestive function= propulsion
Moves food by peristalsis
Peristalsis-rhythmic wavelike contraction by musclaris layer of wall
Connects the stomach at lower esophageal sphincter
Circular ring of muscle
Sphincter can lead to acid reflex
Stomach
Structure
J shaped, muscular organ, can hold about 1lt
Thick mucous membrane
Cardia and the Fundus
enlarged opening next to esophagus (upper section; temporary storage
Cardiac sphincter seperates fundus from esophagus
Body
Central main part
Phyloric sphincter
lower narrow section
Phyloric sphincter seperates pylorus from duodenum
Inside lined with rugae(gastric folds of the mucosa and submucosa)
Function
3 layers of smooth muscle mix food into a tiny particle
Chemical digestion (mechanical-churning)
Glands secrete gastric juices: HCI, pepsin, intrinsic factor
HCI (secreted by Parietal cells) kills bacteria and denatures/digests proteins
Pepsin
Breaks peptide bonds in protein (secreted by Chief cells)
Intrinsic factor secreted by parietal cells, helps sm intestine absorb Vitamin B12
Mixing and holding chamber
Mucous cells produce mucus (protects stomach lining)
Forms chyme from food
Soupy mixture of macerated food and gastric juices
Food exits through Pyloric sphincter
Very little absorption
Small quantities of water and certain salts, alcohol, and some lipid soluble drugs.
Small Intestine
Tube approx. 7m long, 2cm in diameter; fills most of the abdominal cavity; connects stomach to large intestine.
Functions
Mechanical digestion
Segmentation and peristalsis
Back and Forth movement
Mixes and breaks down chime (food+ gastric juices)
Chyme+secretions from pancreas and liver+ intestinal juices
Chemical Digestion
Intestinal glands secrete intestinal juices
Absorption
Of water and nutrients (90%)
Villi and Microvilli
Increase surface area for absorption
Lacteals
Lymphatic capillaries; fat absorption into lymph
Sections
Duodenum
Most "fixed" in place
Chem. digestion
Liver-bile- fats
Pancrease-pancreatic juices
Carbs, proteins, and fats
Jejunum
Absorption
Circular folds to increase surface area
Ilium
Absorbs vitamins and bile salts
Ileocecal sphincter (valve) joins small intestine to large intestine cecum
Pancreas
Location: Behind stomach, closely associated with small intestines
Function
Pancreatic juice (made by pancreatic acinar cells) into duodenum
Enzymes
Digest all 4 nutrients
Trypsin, chymotrypsin, carboxypeptidase-protein
Lipase-lipids
Protease-protein
Amylase- carbohydrates
Gall Bladder
Stores excess bile for liver
Location: Under surface of liver
Connected to the cystic duct which joins to the hepatic duct-merge to common bile duct
Function
concentrations and stores bile produced in the liver, to release into small intestine (duodenum)
Large Intestine
1.5 m(5ft) long, wider diameter than sm. intes.
Separated from sm. intest. by ileocecal valve (sphincter
No villi present
Slow movement
Starts at ileocecal valve and ends at anus
Function
Gut Bacteria as E.coli live here
Digestion by bacteria
Synthesizes of Vitamin K, Vitamin B complex
Digestion of cellulose
Undigested food called fecal matter leaves the ileum and enters the cecum through the ileocecal shincter
Absorption of water and salt
Form, store, eliminate feces.
Bacteria ferment remaining carbs and release H, CO2 and Ch3 producing gas
Break down remaining proteins to amino acids
Decompose the bilirubin in bile to give feces their brown color
In a 24 hour period, feces are turned in stool in about 3-10 hours
Subdivisions
Sigmoid colon
S shaped
Descending colon
Transverse colon
Bend called left colic fixture
Ascending colon
Bend called Right colic fixture
Right side
Retroperitoneal
Cecum
Pouch like area (site of appendix)
Rectum
Near coccyx
Anal Canal (Anus)
Interior anal sphincter
Exterior anal sphincter
Appendix
Vermiform appendix-worm like structure ~9cm
Vestigial organ-noldeboted function
Near R hip bone
Contains lymphatic tissue
Attaches to cecum
3 in below ilececal valve
Many become inflamed resulting in appendicitis
Rectum
Liver
Largest internal organ
Functions
Helps maintain concentration of blood glucose levels, metabolizes proteins, stores glycogen, iron, Vitamin A,D, B12
Responsible for many metabolic activities (carbohydrates, lipids, proteins)
Removes toxic substances from blood
Synthesizes lipoproteins, phospholipids, cholesterol
Converts carbohydrates and prtoeins to fat and breaks down amino acids, forming urea, to synthesize plasma proteins and clotting factors
Concert amino acids to other amino acids
Filters blood-removing damaged RBC's and foreign substances, removes toxins
Functions for digestion: secrete bile into duodenum
Bile
Water
Cholesterol, electrolytes, bile pigments and bile salts
Bile pigments are break down products from RBCs
Bile is secreted by hepatic cells
Bile Salts
Emulsify (break up) fats
eliminates cholesterol
Bilirubin and Biliverden
Bile is a fat emulsifier, break up fats into smaller particles
Have digestive function
Lack of bile salt can lead to poor lipid absorption and vitamin deficiencies
Digestive Enzymes
Pepsin-protein-peptide
Carbohydrates(mouth and small intestine)
Protease-peptide-amino acids
Polysaccharides-dissacharides and monosacharides
Amylase-poly-di
Dissacharides-monosaccharides
Maltase-glucose
Lactase-glucose and galactase
Sucrase-glucose and fructose
Nucleic acid- nucleotides
Nuclease-nucleodtides
Lipids-small intestine
Fats-fatty acids
Lipase-fatty acids and glycerol
Functions
Growth, blood coagulation, healing, diseases, digestion, reproduction, and many other functions.
Location of Digestion and Absorption of Each Macromolecule
The digestion of most macromolecules occur in the small intestine
Intestinal enzymes produced by brush-border cells further breakdown proteins and carbs into their monomers
Enzymes of SI
Peptidases
Reduce peptides to amino acids
Sucrase
Reduces sucrose (cane sugar) to glucose and fructase
Lactase
reduces lactose (milk sugar)
Maltase
Reduces maltose to glucose
Intestinal lipase
Reduces fats into fatty acids and glycerol
Enzymes of Pancreas
Protease-protein
Trypsin, chymatrypsin, carboxypeptidase-protein
Lipase- lipids
HCI in stomach destroys amylase and stops carb digestion
Enzymes digest all 4 nutrients
Nuclease-nucleic acids
Sodium bicarbonate rich
Neutralizes
Layers of GI Tract
Mucosa
Mucous membrane produces mucus for reduction of friction and protections
Epithelium
Varies by location
Nonkeratinized stratified squamous in mouth, esophagus, and anus
Protection against friction
Simple columnar in intestine for absorption and secretion
Lamina Propria
Areolar CT. contains blood and lymphatic vessels, and lymph node for nourishment and immunity
Muscularis mucosae
Two thin layers of smooth muscles
Submucosa
Autonomic nerve supply
Areolar CT containing major BV
Many elastic fibers to retain shape
Submucosal plexus
Glands and lymphatic tissue
Muscularis
Muscle Layer
2 layers of smooth muscles to allow peristalis and segmentation
Inner circular layer
Squeeze, decrease size of lumen; in some areas act as sphincter or valves
Outer longitudinal layer
shortens intestine
Mouth, pharynx, superior esophagus, and anal sphincter-voluntary muscle
Also external and sphincter is skeletal muscle
Myenteric plexus-nerves
Serosa
Outer covering of the Gi Tract
Serous membrane
Composed of thin layer of areolar CT and simple squamous epithelium
Produces serous fluid for lubrication
Covers the outside of abdominal organs
Attaches the digestive tract to the wall of the abdominopelvic cavity by forming folds called mesenteries
Disorders
Hepatitis
Hepatitis or inflammation of liver
Usually due to to one of six hepatitis viruses
Nonviral causes include drug toxicity, and wile mushroom poisoning
In the U.S. 40% are due to HVB which is transmitted via blood transfusion, contaminated needles or sexual contact.
Cirrhosis
Is a chronic inflammation of the liver usually resulting from alcoholism or chronic hepatitis
Liver transplants are the only clinically proven effective treatment for patients with end-stage liver disease
Jaundice
Yellow skin discoloration due to excessive amounts of bile in blood
Various Causes- gallstone or diseased liver, hepatitis, tumor, etc.
If a gallstone blocks the common bile duct feces will be white and skin yellow
Gall stone
Blocks bile duct
Obstruction of common hepatic duct