Module 11: Digestive System Flashcards
Overview of Digestion
Alimentary canal extends from the mouth to the anus
- main organs of digestion
- accessory organs of digestion
Mechanisms involved in digestion
- ingestion
- digestion
*mechanical and chemical
- secretion
- absorption
Wall of the Digestion Tract
mucosa/mucous membrane
- stratified epithelium or simple epithelium
Submucosa
- connective tissue containing blood vessels and nerves
Muscularis
- skeletal muscle
- smooth muscle (inner) and longitudinal smooth (outer)
- Circular, longitudinal, and oblique layers *stomach only
Serosa
- outermost covering of the digestive tract
*visceral and parietal peritoneum
*mesentery
Mouth: structure of oral cavity
Roof of mouth
- hard palate
- soft palate
Uvula
Floor of mouth
- tongue - papillae
Lingual Frenulum
Mouth: teeth
Types of teeth
- incisors, canines or cuspids, premolars or bicuspids, molars or tricuspids
- deciduous (baby) teeth
-permanent teeth
Typical tooth
- crown
-neck
- root
Mouth: salivary glands
saliva
- serous-type saliva
- mucous-type saliva
Parotid glands
- serous-type saliva contains sodium bicarbonate to neutralize bacterial acids
Submandibular glands
- serous-type and mucus-type saliva
Sublingual glands
- mucus- type saliva
Pharynx
Structure
- nasopharynx
- oropharynx
- laryngopharynx
Function
- nasopharynx
- oropharynx and laryngopharynx
*deglutition (swallowing)
*regulation - voluntary and involuntary
Esophagus
Function
- propulsion of food into the stomach by peristalsis
Upper esophageal sphincter (UES)
- controls passage of food from laryngopharynx into esophagus
- helps prevent air from entering esophagus during respiration
Lower esophageal sphincter (LES) or cardiac sphincter
- prevents backflow of acidic stomach contents
Stomach
Structure
- fundus, body, pylorus
- muscularis
*peristalsis
- mucosa
- pyloric sphincter muscle
Function
- liquefaction (mechanical digestion)
- partial digestion of proteins and lipids (chemical digestion)
Small intestine
Structure
- duodenum, jejunum, ileum
Function
- intestinal secretions and digestions
* intestinal glands; pancreatic and liver secretions
- Absorption
*circular folds (plicae), intestinal villi, blood capillaries, lacteals
- Motility
*peristalsis and segmentation
Liver and Gallbladder
Structure
- liver
*located in the upper right section of abdominal cavity and extends over into the left side
- Gallbladder
*located on the undersurface of the liver
- Ducts
*common hepatic duct
*cystic duct
*common bile duct (CBD)
Liver, Gallbladder and bile
Function
- liver
*secretes bile
*removes bile pigments from hemoglobin
- Gallbladder
*concentration and storage of bile
-Bile
*emulsification of lipids
*elimination of cholesterol from the body
Pancreas
Exocrine and Endocrine gland
- located behind stomach in a space created by the c-shape of the duodenum
Pancreatic digestive juice
- digests carbohydrates, proteins, and lipids
Pancreatic islets or islets of Langerhans
- secrete hormones of the pancreas (insulin and glucagon)
Large intestine
Lower or terminal portion of the digestive tract
subdivisions of large intestine
- cecum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum and anal canal; anus is the external opening
Function
- microbiome
-absorption or water, salts, and vitamins
- increased/decreased motility
- defecation
Appendix
Vermiform appendix
- directly attached to the back of the cecum
- maintains a normal intestinal microbiome
- appendicitis
*McBurney Point
Peritoneum
Continuous serous membrane lining the abdominal cavity and covering abdominal organs
- parietal peritoneum
- visceral peritoneum
*peritoneal space
*retroperitoneal
Extensions
- mesentery
- greater omentum
Glossary: Absorption
Passage of a substance through a membrane, such as skin or mucosa, into blood
Glossary: alimentary Canal
principal tubelike structure of the digestive system extending from mouth to anus- sometimes called the gastrointestinal (GI) tract
Glossary: Amylase
Enzyme that digests carbohydrates
Glossary: Anal Canal
terminal portion of the rectum
Glossary: Anus
distal end or outlet of the rectum
Glossary: Appendicitis
Inflammation of the vermiform appendix
Glossary: Ascending colon
Portion of the colon extending from the cecum to the hepatic flexure
Glossary: Barrett Esophagus
Condition related to untreated gastroesophageal reflux disease; may develop precancerous changes in the esophageal lining
Glossary: Bicuspid
Tooth type with a large flat surface and two or three grinding cusps; also called premolars
Glossary: Bile
Substance that reduces large lipid globules into smaller droplets of lipid that are more easily broken down
Glossary: Body
unified and complex assemble of structurally and functionally interactive components (as in human body); the main or central part of a structure (as in cell body or body of an organ)
Glossary: Bolus
a small, rounded mass of masticated food and saliva to be swallowed
Glossary: Canine tooth
relating to a dog, as in the canine tooth with the longest crown and the longest root, which is located lateral to the second incisor; it serves to pierce or tear food being eaten; the canine tooth is also called a cuspid tooth (having a single cusp or point) or eye tooth (roughly aligned with each eye)
Glossary: Catalyst
Chemical that speeds up reactions without being changed itself
Glossary: cecum
blind pouch; the pouch at the proximal end of the large intestine
Glossary: Cementum
Hard dental tissue that covers the root and neck of each tooth
Glossary: Cholecystectomy
The surgical removal of the gallbladder