Digestive Part II Flashcards
What is clinically indicated when the lower esophageal sphincter fails to close adequately after food enters the stomach & contents reflux into the esophagus?
Gastroesophageal Reflux Disease (GERD)
This can be associated with esophageal cancer?
GERD
How many amino acids are considered essential because they cannot be produced in the body and must be part of our diet?
9
What is the form fat is usually found in the human diet?
Triacylglycerol (TAG)
What are the smaller components fat must be hydrolyzed into in order to be absorbed?
Free Fatty Acids
Monoglycerides
What are some of issues that arise concerning the aging GI System?
- Hiatal Hernia
- Gastritis
- Peptic Ulcer Disease
- Appendicitis
- Gallbladder Problems
- Acute Pancreatitis
- Janundice/Cirrhosis
What is the reflex that is triggered by distention of the stomach while eating/immediately after triggers mass peristalsis in the colon?
Gastrocolic Reflex
The Gastrocolic Reflex is usually triggered how long after eating?
30-45 minutes
This reflex is activated with entry of feces into the rectum that causes distention, increased signals to descending & sigmoid colon (via myenteric plexus) increases peristalsis pushes fecal matter to anus and cause anal sphincter to relax?
Intrinsic Myenteric defecation reflex
What is the nerve impulse pathway for the defecation reflex pathway?
- Sensory impulses to sacral spinal cord triggered by stretch receptors (mechanoreceptors) in rectum
- Motor impulses travel along parasympathetic nerves to descending & sigmoid colon, rectum & anus
The motor impulses trigger a contraction of what muscle in regards to defecation?
Longitudinal rectal muscles
Voluntary contractions of diaphragm & abdominal muscles along with parasympathetic stimulation cause what to relax?
internal Anal Sphincter
What sphincter is completely voluntary and if it is relaxed feces exits the anus if constricted defecation is postponed?
External Anal Sphincter
What factors affect the frequency of Bowel Movements?
Diet
Health
Stress
The normal (typical) range of number of Bowel movements daily & weekly are?
1-3 per day
3-4 per week
What is defined by increase in frequency, volume, or fluid content caused by increased motility & decreased absorption by the intestines?
Diarrhea
Name some of the reasons for excessive motility of the intestines?
Lactose Intolerance
Stress
Microbes that irritate mucosa
What is defined by Infrequent or difficult defection caused by decreased motility of the intestines?
Constipation
What happens as feces remains in the colon for longer periods of time?
Excessive water reabsorption/absorption causing feces to become dry & hard
Name some of the causes of constipation?
- Delaying defecation
- Spasms of the colon
- Insufficient fiber or water in diet
- Lack of exercise
- Emotional stress
- Drugs (Narcotics)
Name some of the treatments for constipation?
Laxatives (habit forming)
Increasing Fiber
Increasing exercise
Increasing Water
What portion of the digestive tract is considered to be the terminal portion?
Large Intestine
What is the overall function of the Large Intestine?
- Complete process of absorption
- Produces vitamins (Vit. K & Biotin)
- Forms feces
- Excretes feces from body
What are the four major regions extending from ileum to anus?
Cecum
Colon
Rectum
Anal Canal
What is the length & diameter of the large Intestine?
approx. 5 feet long
approx. 2.5 in diameter
What is the Large Intestine attached to?
Posterior Abdominal wall by the Mesocolon (peritoneal fold)
This is the opening from the ileum to the large intestine & allows materials to pass from small intestine into the large intestine?
Ileocecal Sphincter (Value)
This is inferior to the ileocecal valve & is a small pouch (approx. 2.4 in long)?
Cecum
What is attached to the cecum & is approx. 3in long?
Appendix (vermiform appendix)
This is proceeded by obstruction of the lumen by chime, fecolith, foreign body, carcinoma, stenosis, or kinking, & characterized by high fever, elecvated WBC, neutrophil count >75%?
Appendicitis
What are the four portions of the colon?
Ascending
Transverse
Descending
sigmoid
This portion of the colon lies retroperitoneal, ascend on the right side of abdomen to lower border of the liver?
Ascending Colon
What is the abrupt left turn of the colon called at the transition of the ascending to transverse colon?
Right Colic (Hepatic) Flexure
This portion of the colon lies in the peritoneal & crosses the abdomen until on the left side it makes an abrupt turn inferiorly?
Transverse Colon
What is the abrupt inferior turn of the colon called at the transition of the transverse colon to descending colon?
Left Colic (Splenic) Flexure
This portion of the colon lies retroperitoneal and descends on left side to the level of the iliac crest?
Descending Colon
This portion of the colon lies in the peritoneal & begin near left iliac crest, projects medially to midline & terminates at the rectum (about 3rd sacral vertebra)?
Sigmoid Colon
What is the name of the digestive tract that is the last 8 inches, lies anterior to sacrum & coccyx with the terminal 1inch being called the anal canal?
Rectum
What are the folds created by the mucous membrane of the anal canal arranged longitudinally called?
Anal Columns
What is contained within the anal columns?
Arteries & veins
The opening of the anal canal is the anus and has two sphincters, what are they named?
Internal anal sphincter
External anal sphincter
This anal sphincter is made up of smooth muscle and we have involuntary control over it?
Internal Anal Sphincter
This anal sphincter is made up of skeletal muscle and we have voluntary control over it?
External Anal Sphincter
At the anus, what can be caused by Pregnancy, hard stool, pushing too hard?
Hemorrhoids
What are the four layers of the Large Intestine walls?
Serosa
Muscularis
Submucosa
Mucosa
This layer has Omental appendices that attach to teniae coli?
Serosa
What are Omental Appendices?
Small pouches of visceral fat attached to the teniae coli
The Muscularis layer; External & Internal smooth muscle layers run in which directions?
External: Longitudinal
Internal: Circular
What are the portions of the Muscularis layer that are thickened, forming three bands?
Teniae Coli
The Teniae Coli contract causing what to occur with the large intestine?
Gather together like pouches (Haustra)
What gives the colon it’s “puckered” appearance?
Haustra
What is not found within the large intestine?
Plicae (circular folds) or villi
This clinical finding arises from the mucosal layer of the colon & usually are benign growth, asymptomatic, but if symptoms occur usually cause diarrhea, blood in feces, &/or mucus being discharged from the anus?
Polyps
What sphincter is normally partially closed to regulate material transitioning from ileum to cecum, the Gastroileal reflex intensifies peristalsis in the ileum & forces material through this sphincter?
Ileocecal sphincter
What does the hormone gastrin secreted into bloodstream by the stomach help do?
Relax the Ileocecal Sphincter
What is the term given to the build up of material in the cecum & up the ascending colon until distension occurs triggering contraction of walls forcing material forward?
Haustral Churning
What is the rate in which peristalsis occurs in the large intestine?
3-12 per minute
This is the final type of movement in the colon & is a strong peristaltic wave that starts at middle of transverse colon & pushes material from colon into rectum?
Mass Peristalsis
On average many people have to evacuate bowels within what time frame after eating?
30-45 minutes
What is secreted by the cells of the colon & what is not secreted?
Mucus is secreted
Enzymes are not secreted
What provides for chemical digestion in the colon?
bacteria
The bacteria ferment remaining carbohydrates and this process releases what?
Hydrogen, Carbon Dioxide, & Methane Gases
What is the term that describes excessive gas?
Flatulence
What gives feces its odor?
Bacteria breaking down protein into indole & Skatole
Bacteria help decompose this into stercobilin & it gives feces its brown color?
Bilirubin
How much of the remaining water is absorbed & excreted by the large intestine?
0.5-1.0L enter
900mL absorbed
100mL excreted
How long does Chyme remain in the large intestine on average?
3-10 hours
The chyme becomes a solid or semisolid due to water absorption/reabsorption and it is then called what?
Feces
What does feces chemically contain?
Water Epithelial Cells Bacteria Product of bacterial decomposition Unabsorbed digested materials Indigestible parts of food
What do lipids first have to undergo prior to digestion beginning on them?
Emulsification
This is produced in the liver & secreted into the small intestine where it mixes with lipids pulling them apart?
Bile
What enzyme starts to digest the emulsion droplets still in the lumen of intestine into FFA & MG?
Pancreatic Lipase
These are 200 times smaller than emulsion droplets?
Micelles
Micelles transport FFAs & MGs where?
Apical Surface of the enterocytes to be absorbed
Resynthesized FFAs & MGs into TAGs are packaged with cholesterol, vitamins, & proteins (apolipoproteins) into what?
Chylomicron
These are so large that they cannot enter blood capillaries & have to enter a lacteal & get transported to the subclavian veins to be circulated?
Chylomicrons
What are some of the functions of Cholesterol?
Found in every cell -Essential for hormone production Testosterone, progesterone, aldosterone -Used to make Vit. D -Part of Bile
The stomach serves as what?
Mixing chamber
Holding Chamber
What is the most distensible part of the GI tract & the mucosa lies in rugae?
Stomach
What is occurring to food (bolus) in the stomach?
- Carbs stop breaking down due to amylase being deactivated by stomach acid
- Lipids begin to break down (activation of lingual lipase)
- Proteins begin to break down
- Semisolid bolus converted to liquid
- Some absorption
What are the 4 main regions of the Stomach?
Cardia
Fundus
Body
Pyloric (divided into three parts)
What are the three parts of the Pyloric region of the stomach?
Pyloric Antrum (connects the body to stomach) Pyloric Canal (Leads to third region) Pylorus (connects duodenum via pyloric sphincter)
What is the Histology (Layers) of the stomach?
Serosa
Muscularis (3 layers of smooth muscle)
Submucosa
Mucosa
This layer of the stomach on the greater curvature of stomach continues as greater omentum & on lesser curvature projects upward towards the liver as lesser omentum?
Serosa
What are the three layer of smooth muscle that make up the Muscularis layer of the stomach?
Outer Longitudinal Layer
Middle Circular Layer
Inner Oblique Layer (only in stomach)
What kind of tissue makes up the Submucosa of the Stomach?
Connective Areolar Tissue
What are the three layers of the Mucosal Layer of the Stomach?
Muscularis Mucosae (Smooth Muscle) Lamina Propria (Connective Areolar Tissue) Mucosa (Simple Columnar Epithelial Cells)
What are the simple columnar epithelial cells of the mucosa layer of the stomach called?
Surface mucous Cells
The Surface Mucous Cells form columns of secretory cells open into the lumen surface (gastric pits) these are called?
Gastric Glands
What are the three types of exocrine gland cells that are found in Gastric Glands?
Mucous Neck Cells/Mucous Cells
Chief Cells
Parietal Cells
Which cells secrete mucous?
Mucous Cells/ Neck Cells
These cells secrete pepsinogen & gastric Lipase?
Chief Cells
These cells secrete hydrochloric acid & intrinsic factor?
Parietal Cells
What is the importance of Intrinsic factor?
Needed to aid in absorption of Vitamin B12/Cyanocobalamin