Digestive System test Flashcards
Function of digestive system:
Function of the digestive system is to break down the foods you eat, release their nutrients, and absorb those nutrients into the body
Small intestine is where the majority of digestion occurs, where most of the released nutrients are absorbed into the blood or lymph
Four layers of the alimentary canal
Mucosa
Submucosa
Muscularis
Serosa
Function of the alimentary canal?
Gastrointestinal (GI) tract or gut
Main function of the organs of the alimentary canal is to nourish the body
What does the mucosa consist of?
Innermost lining of the alimentary canal
Epithelium, which is in direct contact with ingested food
lamina propria, a layer of connective tissue analogous to the dermis
In addition, the mucosa has a thin, smooth muscle layer, called the muscularis mucosa
What does the submucosa consist of ?
Immediately beneath the mucosa
Dense connective tissue
Blood & lymphatic vessels: transport absorbed nutrients
Submucosal glands: release digestive secretions
What does the Muscularis consist of ?
Third layer of the alimentary canal
Muscle (skeletal or smooth) layer of the alimentary canal wall
Double layer of smooth muscle: an inner circular layer and an outer longitudinal layer
Contractions of these layers promote mechanical digestion, expose more of the food to digestive chemicals, and move the food along the canal
Peristalsis
What does the submucosa consist of ?
Superficial to the muscularis
layer of loose connective tissus
Present only in the region of the alimentary canal within the abdominal cavity
Serve to hold the alimentary canal in place near the ventral surface of the vertebral column
Which organs are supported by a layer of adventitia rather than serosa?
Mouth
Pharynx
Esophagus
What is the function of Peyer’s patches?
These lymphocyte clusters are particularly substantial in the distal ileum where they are known as Peyer’s patches
Alimentary canal is exposed to foodborne bacteria and other foreign matter and immune system has evolved a means of defending against the pathogens encountered within it
Gastrointestinal (GI) Tract
Mouth to anus
Mouth and anus open to the external environment
Food and wastes within the alimentary canal are technically considered to be outside the body
What is the function of accessory digestive organs?
Aid in the breakdown of food
The mouth, the teeth and tongue begin mechanical digestion
Salivary glands begin chemical digestion
Once food products enter the small intestine, the gallbladder, liver, and pancreas release secretions- bile and enzymes- essential for digestion
What tissue is the mouth, pharynx, esophagus, and anal canal lined with?
Non-keratinized, stratified squamous epithelium, which provides protection
What tissue is the stomach and intestines lined with?
Simple columnar epithelium, which secretes and absorbs
What cells secrete mucus and fluid into the lumen?
Goblet Cells
What cells secrete hormones into the interstitial spaces between cells
Enteroendocrine cells
What is the Lamina Propria lined with?
Loose connective tissue
Blood and lymphatic vessels: transport nutrients absorbed through the alimentary canal to other parts of the body.
Serves an immune function by housing clusters of lymphocytes, making up the mucosa-associated lymphoid tissue (MALT)
What is the Peritoneum?
Digestive organs within the abdominal cavity are held in place by the peritoneum
Broad serous membranous sac made up of squamous epithelial tissue surrounded by connective tissue
What are the 2 regions of the Peritoneum?
Parietal peritoneum: lines the abdominal wall
Visceral peritoneum: enveloping the abdominal organs
Mechanical digestion along the gastrointestinal tract:
Mouth: chewing
Esophagus: Peristalsis
Stomach: Churning & Maceration- (mixing wave)
Small intestine: peristalsis & segmentation
Large intestine: peristalsis
What are the 6 digestive processes?
- Ingestion
- Propulsion
- Mechanical digestion
- Chemical digestion
- Absorption
- Defecation
What processes occurs throughout most of the alimentary canal?
Propulsion
In which part of the alimentary canal does most digestion occur?
Proximal small intestine
Peristalsis:
Series of wave-like muscle contractions that move food through the digestive tract
Segmentation:
Divides and mixes the chyme by alternating between backward and forward movement of the gastrointestinal tract (GI) contents.
What is the function of liver?
Produces bile salts, which emulsify lipids, aiding their digestion and absorption
What is the function of Gallbladder?
Stores, concentrates, and releases bile
What is the function of Pancreas?
Produces digestive enzymes and bicarbonate help neutralize acidic chyme and provide optimal environment for enzymatic activity
What is the structure and function of gastric pits?
Gastric pits lead to gastric glands that secrete gastric juice
Vast number of gastric pits dot the surface of the epithelium, entry to each gastric gland, which secretes a complex digestive fluid referred to as gastric juice
What are the structures in small intestine that increase absorption of nutrients?
3 features of the mucosa and submucosa are unique
- Circular folds
- Villi
- Microvilli
Absorptive surface of the small intestine is vastly enlarged by the presence of circular folds, villi, and microvilli
What is the role of bacterial flora?
Bacteria live within the large intestine and are referred to as the bacterial flora
More than 700 species of these bacteria are nonpathogenic commensal organisms that cause no harm as long as they stay in the gut lumen
Many facilitate chemical digestion and absorption, and some synthesize certain vitamins, mainly biotin, pantothenic acid, and vitamin K
What is the role of bile?
Lipids are hydrophobic, i.e. they do not dissolve in water
Bile is a mixture secreted by the liver to accomplish the emulsification of lipids in the small intestine
Location of the pancreas:
Lies transversely in the retroperitoneum behind the stomach
Mix of exocrine (secreting digestive enzymes) and endocrine (releasing hormones into the blood) functions
What are the major ducts that carry bile in the pancreas & gallbladder?
- Small ducts accumulate the bile produced by hepatocytes
- Bile flows first into bile ductules and then into bile ducts
bile ducts unite to form the larger right and left hepatic ducts, which themselves merge and exit the liver as the common hepatic duct - Duct then joins with the cystic duct from the gallbladder, forming the common bile duct through which bile flows into the small intestine
The common hepatic duct and the cystic duct join to form the common bile duct.
What is chemical digestion?
Large food molecules (for example, proteins, lipids, nucleic acids, and starches) must be broken down into subunits that are small enough to be absorbed by the lining of the alimentary canal
This is accomplished by enzymes through hydrolysis
What cells produce both hydrochloric acid (HCl) and intrinsic factor
Parietal Cells
What secretes pepsinogen: inactive proenzyme form of pepsin.
Chief Cells
What are the 3 brush boarder enzymes?
- Hydrolyze sucrose
- Lactose
- Maltose
What breaks down lactose into one molecule of glucose and one molecule of galactose?
Lactase
What breaks down maltose into two glucose molecules?
Maltase
What splits sucrose into one molecule of fructose and one molecule of glucose?
Sucrase
What is water absorption driven by?
concentration gradient of the water
Where does water absorption occur?
90% of the water is absorbed in the small intestines
Much of the remaining water is then absorbed in the colon
ALT:
Alanine transaminase
AST:
Aspartate transaminase
GI:
Gastrointestinal
IBD:
Inflammatory bowel disease
IBS:
Irritable bowel syndrome
LFT:
Liver function Test
Hemoccult test:
Feces are placed on paper containing the chemical guaiac, which reacts with hidden blood.
Used to test for colon cancer
Liver function tests:
Measurement of the liver enzymes and other substances in the blood
Stool culture:
Feces are placed in a growth medium to test for microorganisms
Anal:
Pertaining to anus
An/o- anus
al- pertaining to
Appendectomy:
Surgical removal of appendix
append/o- appendix
ectomy- surgical removal
Appendicitis:
Inflammation of appendix
appendic/o- appendix
itis- inflammation
Cholesystectomy:
Surgical removal of gallbladder
cholecyst/o- gallbadder
ectomy- surgical removal
Colostomy:
New opening of colon
col/o- colon
stomy- a new opening
Colonoscopy:
Visual examination of colon
colon/o- colon
scopy- visual examination
Duodenal:
pertaining to duodenum
Douden/o- duodenum
al- peratining to
Esophageal:
pertaining to esophagus
Esophag/o- esophagus
eal- pertaining to
Gastralgia:
Stomach pain
gastr/o- stomach
algia- pain
Hepatomegaly:
enlargement of liver
Hepat/o- liver
megaly- enlargment
Ileostomy:
Surgical opening of ileum
ile/o- ileum
stomy- surgical opening/ new opening
Gastrojejunostomy:
Surgical opening of the stomach jejunum
Gastr/o- stomach
jejun/o- jejunum
stomy- new surgical opening
oral:
pertaining to mouth
or/o- mouth
al- pertaining to
Pancreatitis:
Inflammation of pancreas
Pancreat/o- pancreas
itis- inflammation
Pharyngeal:
Pertaining to pharynx
pharyng/o- pharynx
eal- pertainning to
Proctoscopy:
Visual examination of anus and rectum
proct/o- anus & rectum
scopy- visual examination
Rectocele:
Hernia of rectum
cele- hernia
rect/o- rectum
Sigmoidoscopy:
Visual examination of sigmoid colon
Sigmoid/o- sigmoid colon
scopy- visual examination
Stomatitis:
Inflammation of mouth
Stomat/o- mouth
itis-inflammation
Cholelithiasis:
Condition of gallstones
chol/e- gall
lithiasis- presence of stones
Cirrhosis:
Chronic disease if the liver with degeneration of liver cells
Cirrh/o-tawny, orange-yellow
osis- abnormal condition
Colonic Polyposis:
Condition in which polyps protrude from the mucous membrane lining of the colon.
Pertaining to abnormal condition of polyps in the colon
colon/o- colon
al- pertaining to
ployp/o- polyp
osis- abnormal condition
Diverticulosis:
Abnormal condition of small pouches or sacs in the wall of the intestine
osis- abnormal conditon
Gastroesophageal reflux disease:
A condition in which contents of the stomach flow back to the esophagus
Hepatitis:
Inflammation of the liver
Inflammatory bowel disease:
Inflammation of the terminal portion of the ileum or inflammation of the colon.
Irritable bowel syndrome:
Signs and symptoms are cramping, abdominal bloating, constipation, and diarrhea
Hepatocellular carcinoma:
Cancer of the liver
Jaundice:
Yellow-orange coloration of the skin
