Digestive System Flashcards
Layers of GIT wall (inner to outer)
Mucosa, Submucosa, Circular Smooth Muscle Layer, Longitudinal Smooth Muscle Layer, Serosa
Gastrointestinal smooth muscle function as what?
Syncytium
“Brain of the Gut”
Enteric Nervous System
How many neurons are there in the ENS?
100 million
Two plexus of ENS
Submucosal and Myenteric Plexus
Other name of Submucosal Plexus
Meissner’s Plexus
Outer plexus that lies between longitudinal and circular muscle layer
Myenteric / Auerbach
Inner Plexus that lies at submucosa
Submucosal / Meissner
Slow, undulating changes in the RMP of GI smooth muscle
Slow Waves
Electrical pacemakers of smooth muscle cells
Interstitial cells of Cajal
Threshold potential of GI muscle
-40 mv
Plexus for GI mobility
Myenteric / Auerbach
Does myenteric plexus has a inhibitory function?
YES
Factors that depolarize GI membrane
(1) Stretching of muscle, (2) Stimulation of Acetylcholine, (3) Stimulation of specific GI hormones
Slow acting channels present in the GI membrane
Calcium-Sodium Channels
Wave that occur automatically when RMP becomes more positive than -40 mv
Spike Potentials
RMP of GIT
-50 to -60 mv
Plexus for GI secretion and local blood flow
Submucosal / Meissner
Intensity of slow wave
5-15MV
“True Action Potential”
Spike Potentials
What initiates spike potential?
Slow waves
PSNS or SNS: excitation of GIT
PSNS
PSNS or SNS: Thoracolumbar
SNS
PSNS or SNS: inhibition of GIT
SNS
PSNS or SNS: Craniosacral
PSNS
Factors that hyperpolarize the membrane
(1) Effect of NE and Epi, (2) Stimulation of sympathetic nerves
True or False: Slow waves do not cause calcium ions to enter the smooth muscle fiber
True (only sodium ions)
Myenteric plexus is useful in inhibiting what structure?
Spinchter
Sphincter that controls emptying of stomach into the duodenum
Pyloric Sphincter
What accounts for the long duration of AP in the GIT membrane?
Slow opening and closing of Ca-Na channels
Sacral division of PSNS that supplies GIT
S2-4
Thoracolumbar division of SNS that supplies GIT
T5-L2
Cranial division of PSNS that supplies GIT
CN X
Sphincter that controls emptying from the small intestine into the cecum
Sphincter of ileocecal valve
Reflexes that control GIT secretion, peristalsis, mixing contractions and local inhibitory effects
Reflexes integrated entirely within the gut wall
Reflex that send signals from the stomach to cause evacuation of the colon
Gatrocolic Reflex
Reflex from the colon to inhibit emptying of ileal contents to the colon
Colonoileal reflex
Reflex that signals general inhibition of entire GIT
Pain Reflex
Reflex that produce the powerful colonic, rectal and abdominal contractions
Defecation reflex
Reflex signals from the colon and small intestines to inhibit stomach motility and stomach secretion
Enterogastric reflex
Three GIT Reflexes
Entire wall gut, Prevertebral Sympathetic Ganglia, Spinal Cord & Brainste,
Who acts as passageway of reflex signals from the stomach and duodenum to control gastric motility
CN X
80% composition of CN X
Afferent Nerve FIber
What hormones does G cells secretes?
Gastrin
Hormones that promote pancreatic secretion of bicarbonate
Secretin & Cholecystokinin
What hormones does M cells secretes?
Motilin
Hormones that is secreted during fasting
Motilin
Hormones that inhibits appetite
CCK
What hormones does S cells secretes?
Secretin
Hormones that stimulates growth of gastric mucosa
Gastrin
What hormones does I cells secretes?
Cholecystokinin
Hormones that stimulates insulin release
Gastric Inhibitory Peptide
Hormones that growth of exocrine pancreas
Cholecystokinin
What hormones do K cells secrete?
Gastric Inhibitory Peptide
Hormones that stimulates gastric acid secretion
Gastrin
Hormones that inhibits gastric acid secretion
Gastric Inhibitory Peptide & Secretin
Hormones that increase gastrointestinal motility
Motilin
Hormones that stimulates gallbladder contraction
Cholecystokinin
Hormones that inhibits gastric emptying
Cholecystokinin
What neutralizes the acid in the GIT
Bicarbonate
Movements in GIT that cause food to move forward along the the tract at an appropriate rate
Propulsive movements
Movements in GIT that keeps the intestinal contents thoroughly mixed
Mixing Movements
Inherent property of many syncytial smooth muscles
Peristalsis
Usual stimulus for intestinal peristalsis
Distention of the gut
What initiates a peristaltic movement?
Contractile ring
How long does the contractile ring lasts before dying out?
5-10 cm
Peristaltic reflex + anal direction of movement of peristalsis
Law of the gut
What allows food to be propelled more easily toward the anus
Receptive Relaxation
What structure helps in churning the bolus
Sphincter
What causes chopping and shearing of intestinal contents?
Local intermittent constrictive contractions
Addition of H2O to catalyze complex food particles into simple and smaller unit
Hydrolysis
Anterior border of the oral cavity
Oral Vestibule
How many force can a molar generate?
200 lbs (90 kg)
Teeth from cutting
Incisor
Floor of the oral cavity
Tongue
Roof of the oral cavity
Palate
Teeth for grinding
Molar
Innervation of Muscle of Mastication
CN V3 (maxillary division)
Important for digestion of all foods
Chewing
What initiates rebound contraction of chewing reflex?
Jaw drop
What initiates chewing reflex?
Presence of bolus in the mouth
Posterior border of the oral cavity
Palatoglossal arch
Rate of digestion is dependent with ______ exposed to the digestive enzyme
Total surface area
pH level of saliva
6-7
Digestive enzyme in the oral cavity that helps digest lipids
Linguial Lipase
Digestive enzyme n the oral cavity that helps digest carbohydrates
Salivary Amylase (Alpha amylase)
Other name of Salivary Amylase
Pfyalin
Largest extrinsic salivary glands
Parotid Gland
Duct present in submandibular gland
Warton’s duct
What kind of saliva does sublingual gland?
Serous and Mucus
Duct present in parotid gland
Stensen Duct
What kind of saliva does parotid gland?
Serous
Duct present in Sublingual gland
Duct of Rivinus
Location where parotid duct drains its saliva
2nd maxillary molar
What kind of saliva does submandibular gland?
Serous and Mucus
The location where Warton’s duct drains its saliva
Lingual Frenelum
How many saliva is produced in intrinsic salivary gland?
20%
Intrinsic salivary gland
Buccal, Labid, Palatin
Location where duct of Rivinus drains its saliva
Tongue
How many saliva is produced in extrinsic salivary gland?
80%
Condition of parotid gland caused by paramyxovirus
Mumps
Saliva is release at constant rate
Intrinsic Salivary Gland
Saliva is released based on stimuli
Extrinsic Salivary Gland
Normal range of saliva released per day
800-1500 mL
Type of cells for lubrication and protection
Mucous
Type of saliva that contains alpha-amylase
Serous
Three stages of Ingestion
Voluntary, Pharyngeal and Esophageal
What is the movement of the tongue when the individual swallows the bolus from their mouth?
Upward and backward against the palate
Innervation of tongue muscles
CN 12
Tongue muscles for formation of central through
Intrinsic tongue muscle
Tongue muscle for upward and backward motion
Extrinsic and Backward motion
Direction of bolus in oropharynx
Downward
What CN detects bolus in the mouth and moves uvula upward?
CN X
Direction of bolus in nasopharynx
Upward
Direction of bolus in larynx
Downward and Anterior
Muscle that contracts to close nasopharynx
Levator veli palatini
Two structures in closing of larynx
Vocal cords & Epiglottis
What muscle elevate pharynx and pull larynx upward?
Outer longitudinal muscle
What muscle compresses the upper esophageal sphincter?
Cricopharyngerous
What muscle helps with pharyngeal peristalsis?
Inner circular muscle
What muscle pulls larynx upward and outward?
Suprahyoid
What causes primary peristalsis in the esophageal stage?
Simply a continuation of pharyngeal peristalsis
Secondary peristalsis in the esophageal stage occurs when?
When primary peristalsis fails
Disease with aganglionic neurons of myenteric plexus with megacolon affectation
Hirschsprung’s Disease
Location of stomach
Left Side
Two glands of the stomach
Oxyntic and Pyloric
Oxyntic cells are responsible for how many percentages of secretion?
80%
Where does Vitamin B12 absorption happen?
Ileum
“Chief cells” in the Oxyntic gland
Peptic cells
Parietal cells secrete what chemicals?
Hydrochloric acid and Intrinsic Factor
The pyloric gland secretes what hormone?
Gastrin
“Oxyntic cells” in the Oxyntic gland
Parietal cells
Peptic cells secret what molecule?
Pepsinogen
Glycoprotein for Vitamin B12 absorption
Intrinsic Factor
Protein that helps with digestion of protein
Pepsinogen
The resulting mixture of bolus and digestive juices that passes down the gut
Chyme
What condition is due to an intrinsic factor deficiency?
Pernicious Anemia
What structure increases the total surface area in the stomach?
Rugae
How many bolus can be stored in the stomach
0.8-1.5 L of food
What produces retropulsion mixing movement in the stomach?
Pyloric Sphincter
What produces the rhythmical peristaltic contraction during hunger contraction?
Body of the stomach
The condition where the lower esophageal sphincter is partially open?
GERD
What worsens GERD?
Stress
Five factors that increase gastric emptying
(1) Increase distention (2) Hormones (3) Size and Temperature (4) Disease/Surgery (5) PSNS
Two factors that decrease gastric emptying
(1) Duodenal Factors (2) Hormonal Feedback
Two hormones that increase gastric emptying
Gastric and Motilin
Succession of Emptying
Carbs > Lipids > Proteins
Reflex stimulates inhibition of the pyloric pump
Enterogastric reflex
Two hormones that decrease gastric emptying
CCK and GIP
Five causes of duodenal inhibition of gastric emptying
O, DIBA: (1) Osmolality of CHyme (2) Distention of duodenum (3) Irritation (4) Breakdown of products (5) Acidity of Chyme
Three parts of Small Intestine
Duodenum, Jejunum, Ileum
Location in the small intestine that has most chemical digestion
Duodenum
Structures present in Jejunum
Villi and microvilli
Function of microvilli
Increase surface area
Location in the small intestine that has most absorption
Jejunum
The longest part small intestine
Ileum
Structure in the duodenum that release mucus that is bicarbonate rich
Brunner’s gland
Mixing contraction of the small intestine
Segmentation
Chyme travel time in Small Intestine
3-5 hrs
Rate of propulsion in the small intestine
Slow movement for absorption
A reflex that intensifies peristalsis in the ileum and forces chyme through the ileocecal valve to the cecum
Gastroileal Reflex
How much water and electrolytes are absorbed in the jejunum?
95%
A reflex in the small intestine due to distention that excites the myenteric plexus
Gastroenteric Reflex
What other substances are absorbed in jejunum?
Ions, carbs, fat, and proteins
What prevents the backflow of fecal contents from the colon into the small intestine?
Ileocecal valve
Powerful and rapid peristalsis occurs during diarrhea
Peristaltic Rush
The small Intestine digestive enzyme that breakdown proteins?
Peptidases
The enzyme that catalyzes maltose in the small intestine
Maltase
Monosaccharide of sucrose
Fructose + Glucose
The enzyme that catalyzes lactose in the small intestine
Lactase
The enzyme that catalyzes maltose in the oral cavity
Alpha-amylase
Monosaccharide of maltose
Glucose + Glucose
The enzyme that catalyzes sucrose in the small intestine
Sucrase
What type of transport does glucose use?
Secondary Active Transport (Sodium-Glucose Co-transport)
Monosaccharide of lactose
Galactose + Glucose
What type of transport does fructose use?
Facilitated Diffusion
The small Intestine digestive enzyme that breakdown triglyceride?
Intestinal Lipase
Monosaccharide of triglyceride
Fatty Acids + Glycerol
“Duct of Wirsurg”
Main Pancreatic Duct
11 parts of hepatobiliary tree
(1) Liver, (2) R&L hepatic duct, (3) Common Hepatic Duct, (4) Cystic Duct, (5) Common Bile Duct, (6) Gallbladder, (7) Pancreas, (8) Main Pancreatic Duct, (9) Accessory Pancreatic Duct, (10) Ampulla of Vater and (11) Sphincter of Oddi
“Duct of Santorini”
Accessory Pancreatic Duct
A visceral organ that has an exocrine and endocrine function
Pancreas
How much does the endocrine function of the Pancreas have?
1% (Islet of Langerhans)
How much does the exocrine function of the Pancreas have?
99% (Acini)
Cells that produce glucagon
Alpha
Beta cells produce what substance?
Insulin
Cells that produce somatostatin
Delta
What enzyme catalyzes trypsinogen to trypsin?
Enterokinase
Trypsin catalyzes what products?
Chemotrypsin, Carboxypolypeptidase, Proelastase
Carbs or Fats or Proteins: Pancreatic Amylase
Carbs
Carbs or Fats or Proteins: Pancreatic Lipase
Fats
Carbs or Fats or Proteins: Trypsin
Proteins
Carbs or Fats or Proteins: Chemotrypsin
Proteins
Are trypsin and chemotrypsin active in pancreas?
NO
What substance breakdown red meat?
Elastase
What condition results from dysfunctional trypsin inhibitor at pancreas?
Acute pancreatis
It neutralizes the acid chyme from the stomach to the duodenum?
Pancreatic Bicarbonate
The pancreatic secretion that increases gastric motility
Acetylcholine
Hormones that activates the pancreas to stimulate pancreatic bicarbonate
CCK & Secretin
The second-largest organ in the body
Liver
The functional unit of liver
Lobule
The secretion that emulsifies fat
Bile
What structure stores and secretes bile?
Gallbladder
Liver cells that produce bile
Hepatocytes
The hormone that stimulates the gallbladder to contract and relaxation the sphincter of Oddi
CCK
Site in GIT where the feces is formed
Large Intestine
Chyme time travel in the large intestine
72 hours
Two functions of the large intestine
(1) 5-10% absorption H20 and electrolytes (2) storage of fecal matter
The portion of the large intestine that is for absorption
Proximal 1/2
Chyme at cecum
Fluid
Chyme at the transverse colon
Mushy
Chyme at the sigmoid colon
Semi-solid
Good bacteria in the proximal 1/2 of the large intestine that aids the formation of vitamin K
Colon Bacilli
What substance does colon bacilli digest?
Cellulose
Chyme at the ascending colon
Semi-fluid
Chyme at the descending colon
Semi-mushy
Mixing movement of the large intestine
Haustrations
Three longitudinal strips of muscle in the large intestine
Teniae colli
Chyme at Rectum
Solid
Storage colon
Distal 1/2
Propulsive movements in the large intestine
Mass Movement
What type of peristalsis is present in the large intestine that results in longer relaxation time
Modified Peristalsis
Two reflexes that aid mass movements
Gastrocolic and Duodenocolic Reflex
What structure is present in the large intestine that adheres feces together?
Crypts of Lieberkun
True or False: Large intestine has a digestive enzyme
False
What structure gives greater storage and aids added resistance in the large intestine?
Sharp angulation of anus
EAS is controlled by what?
Pudendal Nerve
During defecation reflex, IAS and EAS are in what state?
Relaxed
True or False: Feces is 1/4 water and 3/4 solid
False
What makes feces color brown?
Stercobilin and Urobilin
Composition of flatus
Oxygen, nitrogen, carbon dioxide, hydrogen, and methane
________ not produced in the gut, but a component of environmental air.
Nitrogen
Five signals of defecation
(1) Take a deep breath (2) Closure of glottis (3) Abdominal wall contraction (4) Pelvic Floor Relaxation (5) Outward pull of the anal ring
The anal sphincter which can be voluntarily controlled
External
Vitamin deficiency: (+) Pernicious Anemia
Vitamin B12
Vitamin A
Retinol
Vitamin K
Mequinone
Vitamin deficiency: (+) Scurvy
Vitamin C
Vitamin deficiency: (+) Hemorrhage
Vitamin K
Vitamin B12
Cyanocobalmin
Vitamin B2
Riboflavin
Vitamin deficiency: (+) Pellagra
Vitamin B3
Vitamin B1
Thiamine
Vitamin deficiency: (+) Rickets (child)
Vitamin D
Vitamin deficiency: (+) Beri-beri
Vitamin B1
Vitamin C
Ascorbic Acid
Vitamin deficiency: (+) night blindness
Vitamin A
Vitamin B2 deficiency
Dementia, Diarrhea, Dermatitis
Vitamin B6 deficiency
Seizures, Dermatitis
Vitamin D deficiency in adults
Osteomalacia
Vitamin deficiency: (+) Hemolytic Anemia
Vitamin E
Vitamin E
Tocophorol
Vitamin D
Calciferol
Vitamin B6
Pyridoxine
Niacin
Vitamin B3
Vitamin is an essential role in blood clotting
Vitamin K
Vitamin that is for wound healing
Vitamin C
Fat-soluble vitamins
ADEK
Vitamin that regulates the circulating levels of calcium and phosphorus
Vitamin D
Vitamine act as an antioxidant, preventing oxidative stress and protecting fatty acids in your cell membranes from free radicals.
Vitamin E
