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The Digestive System Miranda Mora Casillas p.5 - Coggle Diagram
The Digestive System Miranda Mora Casillas p.5
Major Functions
digestion
the breakdown of food to nutrients needed by the body
Chemical digestion
breaks food to simpler chemicals that are absorbed by cells
include the help of enzymes (-ase)
Mechanical digestion
physical breaking of large food pieces into smaller pieces
Mastication: chewing movement (mouth)
Segmentation: mixing/churning movement (stomach)
Peristalsis: wave/rippling movement (esophagus, intestine)
Absorption
absorption of food for metabolism (energy and growth/ repair of tissues)
chemically digested food moves from the intestine into the blood & lymph
Major Organs
Accessory Organs
salivary glands
secrete saliva which moistens and dissolves food particles turning it into bolus
Major salivary glands
parotid glands- in front of ear, largest gland, secrete clear and watery fluid rich in amylase
submandibular glands- floor of mouth, secrete a more viscous fluid (serous & mucous)
sublingual glands- inferior to tongue, smallest gland, secrete thick & stringy saliva (mucous)
liver
largest internal organ, converts carbs & proteins to fat, secrete bile into duodenum ( bile breaks up fats and is secreted by hepatic cells
metabolic activity
tongue
thick muscular organ covered by mucous membrane
papillae provides friction from moving food around in mouth
gall bladder
stores excess bile for live, under surface of liver
teeth
break food down beginning mechanical digestion
masticate
pancreas
secrete pancreatic juice into duodenum(protease, trypsin, chymotrypsin, carboxypeptidase, lipase, amylase & Nuclease.
Alimentary Canal (GI Tract Organs)
stomach
thick mucous membrane, mixing and holding chambers
gastric juices: HCI kills bacteria & digests proteins (secreted by Parietal cells), Pepsin breaks protein (secreted by chief cells), intrinsic factor (secreted by Parietal) and helps sm. int. absorb vitamin B12, mucous cells produce mucus to protect stomach lining.
small intestine
chemical & mechanical digestion and absorbs water and nutrients (90%)
peptidases, sucrase, lactase, maltase, intestinal lipase
3 sections: Duodenum, Jejunum, Ilium- ileocecal sphincter (valve) joins sm. int. to large intestine's cecum
esophagus
leads to stomach through diaphragm opening
lower esophageal (cardiac) sphincter that prevents backflow of contents in stomach back to esophagus.
large intestine
digestion by bacteria, absorption of water and salt (electrolytes), form/store/eliminate feces.
subdivisions: Cecum, Ascending colon, transverse colon, descending colon, sigmoid colon, rectum, and anal canal (anus).
pharynx
3 parts: Nasopharynx, Oropharynx, Layngopharynx
deglutition: swallowing
epiglottis (flap) closes do food goes into esophagus& not trachea
mouth
mastication and lubricates food with saliva, moves bolus to pharynx
opening for food to enter (ingestion)
Layers of GI tract
Submucosa
Areolar CT containing major blood vessel
submucosal plexus- autonomic nerve supply
glands and lymphatic tissue
Muscularis or muscular layer
muscle layer
two layers of smooth muscles that allow Peristalsis & segmentation
Mucosa
mucous membrane- produces mucus for reduction of friction
epithelium
lamina propria- areolar CT, contains blood & lymphatic vessels and lymph node for nourishment and immunity.
Muscularis mucosae- two thin layers of smooth muscles
Serosa
Outer covering of GI tract
serous membrane-composed of thin layer of areolar CT & simple squamous epithelium
produces serous fluid for lubrication
attaches digestive tract to the wall of the abdominopelvic cavity by forming folds called mesenteries
Digestive Enzymes
DNA/RNA (pancreas)
Nuclease
breaks down nucleic acids into nucleotides
Lipids (small intestine)
Lipase
breaks down fats into fatty acids & glycerol
Carbohydrates (mouth & small intestine)
Amylase
breaks polysaccharides into disaccharides
Maltase
reduces maltose (malt sugar) to glucose
Lactase
reduces lactose (milk sugar) to glucose & galactose
Sucrase
reduces sucrose (cane sugar) into glucose & fructose
Proteins (stomach & small intestine)
pepsin
breaks protein into peptide (secreted by Chief Cells)
protease
breaks peptide into amino acids that is used as energy by the body
Location of Digestion & Absorption of each macromolecule
carbohydrates
small intestine
glucose
small intestine
Protein
stomach
water
small intestine
fats
small intestine
vitamins
small intestine (iliium)
Disorders
hepatitis
inflammation of the liver, due to one of the six hepatitis viruses
Cirrhosis
chronic inflammation of liver resulting from alcoholism or chronic hepatitis, effective treatment is only a liver transplant
appendicitis
appendix becomes inflamed
gastroesophageal reflux disease
lower esophageal ( cardiac) splinter relaxes and stomach acid goes back up the esophagus causing heart burn
gastritis
inflammation of stomach lining.