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56 Cards in this Set
- Front
- Back
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what makes up the GI system?
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The ailimentary tract, accessory organs
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When does food come in contact with tissues?
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Most of the time it doesn't due to mucous membranes however ulcers are the exception
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What are the functions of the digestive system? 5 of them
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ingestion: entering material food into the digestive tract.
mechanical process: crushing shearing food physically to increase surface area so that enzymes can act upon them digestion: hydrolysis secretion: release of water acids enzymes buffers salts absorption: moving electrolytes vitamins and water into the interstitial fluid excretion: removal of mostly bacteria, and byproducts.or the wastes through urination |
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Digestive tract vs accessory organs
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-oral cavity, pharynx, esophagus, stomach, sm int lg int
- teeth tongue glandular organs salivary glands liver pancreas |
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What are messentaries?
Which 2 are related to the stomach? Which is involved with the liver? The small int? The large int? |
1. double sheetes of peritoneal membrane.
2. The lesser omentum and greater omentum: the former stabilizes position and gives access for blood vessels the latter has adipose tissue that conforms the shape and cushions as well as utilization of that fat for energy 3. the falciform ligament stabilizes the position of the liver to the diaphragm and abdominal wall 4. the mesentery proper stabilizes yet allows movement: the duodenum is fused to the anterior portion and is considered retroperitoneal 5. mesocolon tranverse mesocolon and sigmoid mesocolon the ascending descending and rectum are all retroperitoneal |
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A potential complicaton of any surgery in which the peritoneal cavity is opened is called
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peritonitis painful condition and can be caused due to physical dmg, chem irritation, bacterial invasion
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The inner lining of the digestive tract is mucous membrane consisting of epithelium, lamina propria is called
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the mucous membrane
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Why is it that cancer radiation and anticancer drugs that inhibit mitosis of cancer cells as well as neighboring cells have such a profound affect on the digestive tract?
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The digestive tract has epithelial cells same as the skin that constanty undergo mitosis to replenish lost dmgd cells. The life span in the esophagus is 2-3 days lg int 6 days.
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in the villi the lamina propria is connected to a sheet of muscle called the muscularis mucosae what are two muscular layers that make up this structure?
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Longitudinal muscle and circular muscle
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In the submucosa, which is a layer of dense irregular ct there lies nerves and fibers of scattered neurons what is this called? what is it responsible for?
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submucosal plexus; sensory neurons, parasympathetic ganglionic neurons, sympathetic postganglionic fibers.
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in the muscularis externa there are two layers of muscles' the circular and longitudinal muscles, there is also a plexus btw these two layers what is that?
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the myenteric plexus
para: rest and digest stimulate the muscles to move symp: inhibit those muscles |
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The digestive tract has a serious membrane called the serosa that covers most of the muscularis externa, however where is there no serosa?
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oral cavity, pharynx, esophagus, rectum they have the adventitia
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The alternate contractions of the longitudinal muscles and circular muscles provide the motion of squeezing toothpast... what is this process called?
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peristalsis
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Similar to peristalsis there are areas of the small int and lg int that undergo cycles of contraction that churn and fargment the bolus mixing it with intestinal juices but does not push it in any one direction. what is this proesss called
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segmentation
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Describe and name the 3 regulating factors that control digestive functions: 3 mechanisms
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Neural mechanisms:short and long reflexes and sensory reflexes and myenteric reflexes of the enteric nervous system
Hormonal mechanisms: 18 digestive hormones that aid digestion Local Mechanisms: Local messengers like prostaglandins, histamines can stimulate other cells to do shit. |
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What does the tongue do besides lick ears?
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1. mech processing by compression, abrasion distortion: helps form bolus
2. manipulate and prepare for swallowing 3 senses via touch temp taste |
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extrinsic vs intrinsic muscles of the tongue
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former performs all macro movements latter coordinates w the former to assist in precise movements. innervated via N XII hypoglossal CN
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saliva composition?
which part is responsible for lubricating? what are 4 functions? Where is it made/ |
99.4% water and .6% is enzymes mucins ab and electrolytes
mucins lubricate -lubricates mouth -moisetens -dissolve chemicals that can provide sensory info about the material from the taste buds -salivary amylase and lingual lipase digest a little, or start to. 75% is made from submandibular gland 25% from parotid |
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Mumps virus
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targets salivary gland especially parotid: usually 5-9 years of age
can cause sterility diabetes and affect Nervous system: however it's been eliminated in the US |
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Fauces
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border of oro cavity and pharynx similar to internal nares
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3 parts of the pharynx and which the food pass through?
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nasopharynx
oropharynx laryngopharynx food passes through the oropharynx and laryngopharynx to the esophagus |
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What is the opening in the diaphragm in which the esophagus goes through?
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Esophageal hiatus anterior to vertebra T7
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3 phases of deglutition
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-oral stage voluntary swallow or spit
-pharyngeal phase: involuntary in the oropharynx the bolus is moved to the esphagus -esophageal phase also involuntary perisalsis |
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What are 5 secretions of the stomach?
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-parietal cells- HCL
-cheif cells- pepsinogen *together they make up gastric juice about 1500ml a day and HCL converts pepsiongen to pepsin intrinsic factor- glycoprotein that absorbs vit B12 by -gastrin by g cells stimulates secretion of parietal and cheif cells -somatostatin by the pyloric glands' D cells inhibit gastrin HCL- H+ ions made by CO2+H2O> H2CO3, the acid dissolves to make H+ions while the HCO3- is traded for Cl- which makes HCL |
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3 phases of gastic activity
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1. Cephalic phase
2. Gastic phase: 3. Intestinal phase |
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Gastritis and peptic ulcers what are they? how are they caused?
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superficial inflammation of the gastric mucosa, develop from drugs, alcohol aspirin, smoking severe emotional or physical stress can lead to the erosion of the gastric lining.
While many ulcers are caused by the strep bacteria (90%) overall only 10% of the population suffer, and out of those that suffer 90% are dueodenal |
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What does the low ph in the stomach do with digestion?
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It kills stuff
it activates enzymes breaks down CT in meat and cell walls in plants it activates pepsin |
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cephalic phase
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think smell hear food ect stomach gets ready for food. Neural preganglionic fibers innervate submucosal plexus and thus more gastric juice is produce
anger hostility increases excess amounts of gastric juice anxiety stress fear decreases |
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gastric phase
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distension of the stomach increase gastric contents and acidifies chyme. Gastrin released by g cells, histamine by mast cells and stretch receptors via neural response
Mixing waves in the muscularis externa mix the chyme with digestive enzymes Histamine stimulates secretion of acid. initially most of the ph is high however after several hours pH reaches 1.5-2 and secretion is inhibited |
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intestinal phase
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releases some of the chyme into the duodenum.
secretin reduces the acidity raising the pH also stimulates gall bladder for bile and pancreas for pancreatic enzymes CCK is released and inhibits gastric secretion of acid and enzymes enterogastric reflex causes inhibition of gastrin production and contracts the pyloric sphincter |
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What kinds of molecules are digested and absorbed in the stomach?
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initially salivary amylase and linqual lipase continue to digest carbs and lipid when pH is 4.5 ish however as it drops in pH pepsin proteins begin to digest.
Absorption does not take place because: epithelial cells covered by alkaline mucus layer, and lack transport mechanisms, and gastric lining is impermeable to water, and digestion has not been completed |
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What % is nutrient absorption in the small intestine?
What does the first half of the jejunum do? The 2nd half? |
the small int is responsible for 90% of absorption
the first half does most of the absorption the 2nd half is mostly storage |
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3 features that increase small intestine surface area
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intestinal villi
microvilli that make up the brush border plicae circulares (similar to rigae yet don't go away when stretched) |
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intestinal glands
what are some hormones/secretions/enzymes? 10 of them |
1.Enterokinase
2.GIP 3.gastrin: 4.CCK: 5.secretin: 6.mucous 7.maltase sucrase lactase 8.Dipeptidases, peptidases: 9 Vasoactive intestinal peptide 10. enterocrinin |
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Tripsin is an important hormone of the pancrease that must be activated by an enzyme to be affective what is responsible for activating that enzyme?
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enterokinase activates trypsinogen which make tripsin
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If one were to consume carbohydrates and glucose (sugars) as well as lipids and it enters the duodenum which secretions would be produced by the small intestines? And what would that enzyme do?
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1. CCK accelerates rate of all digestive enzymes, stimulates bile secretion and pancreatic juice and reduces hunger sensation in high amounts
2. & (gastric inhibitory peptide): when fats and glucose enter, inhibits gastric activity and increase insulin release, to synthesize lipids and increase glucose use by skeletal muscles |
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Gastrin two places it is secreted and what it does
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by G cells in the duodenum
and by the G cells of the pyloric antrum increases stomach motility and secretion usually in response to undigested proteins |
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CCK
what is it? |
accelerates rate of all digestive enzymes, stimulates bile secretion and pancreatic juice and reduces hunger sensation in high amounts
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Secretin
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increase secretion of bile, buffers by liver, pancrease juice. reduces gastric motility and secretory rates
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Which intestinal enzymes are found on the brush border?
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maltase sucrase lactase that are found on micro villi that break down disaccharides to monosaccharides
Dipeptidases, peptidases: found on the microvilli that break down dipeptides & tripeptides into amino acids |
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which intestinal hormone would be released to stimulate mucous production?
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enterocrinin
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Which intestinal hormone is most effective in removing absorbed nutrients out of the GI tract?
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VIP as it stimulates secretions and dilates regional capillaries.
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Which enzyme in the small intestine is responsible for utilization of the nutrients that we absorb?
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The GIP> as it releases insulin from the pancreas that utilizes the glucose
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hows the haustra related to an accordian?
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it is like the bellows of an acordian; it permits the expansion and elongation of the colon
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A pt who has a hx of bulimia nervosa suffers from erosion of the lower esophagus and is being screened for cancer. Which diseases does this person most likely suffer from, that increases his/her risk for esophageal cancer?
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GERD
Gastro Esophageal Reflux disease |
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A pt was revealed to have weakened greater and lesser omentum messentaries; the pt suffers from pain and scans reveal that the stomach is bulging into the thoracic cavity of the diaphram hiatus, what is this person suffering from?
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Hiatal hernia
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The GI tract is mostly innervated by two Autonomic and two plexus which are they?
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The sympathetic and parasympathetic
the myenteric plexus and submucosal plexus |
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Compare the internal anal sphincter with the external anal sphincter
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internal smooth involuntary
external skeletal voluntary |
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Pt suffers from distended veins at the anal orifice what may have caused this condition and what is it called?
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hemorrhoids
caused by venous pressures rising too high due to strain. |
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Colorectal cancer
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Aside from skin cancer 3rd most common both men and women,
Checking feces for blood for early screening can increase survival chances. 5 year survival rate is greater than 90% |
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Pancreatic cancer
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epidemically increasing in the USA
97% chance of dying |
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The major reason for tooth loss
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gingivitis
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What happens to carbs lipids and proteins in the stomach?
Which enzymes/hormones ? |
Lipids activated on by linqual lipase from the oral cavity yet no change
Carbohydrates are activated on by salivary amylase from the oral cavity and break into disaccharides and trisaccharides Proteins are acted on by pepsin in the stomach and break into polypeptides |
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What happens to carbs lipids and proteins in the small intestine?
Which enzymes/hormones do what? |
Carbs: Pancreatic alpha amylase breaks carbs into tri and di's, the ones salivary amylase didn't get
Fats: bile salts and pancreatic lipase breaks fats into monoglycerides fatty acids in micelles Proteins acted on by Trypsin Chymotripsin Elastase Carboxypeptidase and are converted into short peptides, and amino acids. |
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At the intestinal mucosa what happens to the carbs, proteins and lipids?
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Carbohydrates: Lactase, maltase, sucrase break down tri's and di's into monosaccharides
Lipids are in monoglycerides fatty acids and micelles, the micelles are converted to chylomicrons proteins: dipeptidases act on short peptides and convert them into amino acids, |
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Where are the fats proteins and carbs, in simpler forms transported how are they transported?
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Carbs: monosach: fascilitated diffusion into capillaries
Lipids: Chylomicrons exocytosis into lacteals Proteins: Fascilitated diffusion and co-trnasport into capillaries as amino acids. |
