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111 Cards in this Set
- Front
- Back
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Aspirin inhibits what? |
Prostaglandins |
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Prostaglandins |
cause Bicarb and mucous secretion |
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Ethanol and vinegar have what effect in the stomach |
These are acids they disrupt mucus barrier |
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Hunger Contractions are caused by ? |
a decrease in blood glucose low glucose detected by Hypothalamus Vagal efferents increase contractions |
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Mucus functions |
Lubricate cause fecal particles/bacteria to adhere to each other Amphoteric (acid/base) Protect stomach lining |
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Canaliculus |
In parietal cells in both secreting and non-secreting Canaliculi chamber is short in non-secreting |
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Alkaline Tide |
Bicarb leaves the cell and enters the ICF as Cl- enters the cell in an antiport system. This causes fluid leaving the stomach to be very basic usually not the case in other organs. |
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Functions of H+ |
1. bacteriostatic 2. Pepsin activator 3. Fe 3+ to Fe 2+ 4. Hydrolysis of proteins (especially collagen) |
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Why stomach is crucial for blood formation. |
Stomach HCl secretion allows iron uptake (For hemoglobin) and intrinsic factor by Parietal cells (for erythroblast formation) |
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What secretes Intrinsic Factor? |
Parietal Cells |
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What secretes Gastric lipase? |
Chief cells |
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What does stomach absorb? |
NOT water *Lipid soluble molecules like ethanol and aspirin |
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Gastrin Functions |
Increase HCl and pepsinogen formation Increase Motility Trophic Effect (gastric, SI, and pancreas mucosa) |
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Stomach PH during a meal? |
Eventhough more total Hydrogen is secreted after eating, the pH increases slightlydue to the buffering power of food. |
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Stomach epithelial cells are protected by Hydrogen by: |
Mucus Bicarbonate And mucosal membrane is impermeable to H+ |
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Control of mucus and Bicarbonate secretion by? |
Tactile stimulation Chemical stimulation Neurons releasing PGE2 |
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Intrinsic factor B12 is carried in the blood how? |
Transcobalamin |
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HCl secretion needs what? |
ACH (parasympathetics) Gastrin Histamine affecting its H2 receptor |
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What secretes Histamine? |
Enterochromaffin Like cells ELC |
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Cephalic Phase |
Vagus feed forward reflex (10-30%) Smell, taste, anticipate, favorite foods (more) |
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Gastric phase |
50-70% Local nervous secretory reflexes Vagal reflexes Gastrin stimulation |
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Intestinal Phase |
5% Nervous and Hormonal Mechanisms |
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What pH stimulates somatostatin release? |
stomach pH lower than 3.5 enhances somatostatin release and inhibits parietal cell and gastrin secretion. |
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Enterogastric reflex |
Reflexes from duodenum to stomach that slow gastric secretion and emptying Acidic Hypertonicity Lipids > Protein > Carbs Distension |
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Enterogastric reflex what happens as chyme enters the duodenum |
CCK blocks G-receptors Secretin inhibits stomach secretion and motility |
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If intestines were removed what effect would this have on gastric secretion and motility? |
BOTH would increase due to lack of negative feedback from duodenum and nervous system = termed "dumping syndrome" |
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What triggers vomiting center? |
Labryinthine receptors (inner ear) Touch receptors Mechano/Chemo in stomach and duodenum Retching area |
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Chemical trigger zone is acted by what? what does it stimulate? |
Stimulates vomiting center 1. Tylenol-3 (Codeine) 2. Ipecac (alkaloid) 3. H. chorionic gonadotropin "morning sickness" |
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Ipecac --> Tylenol-3 --> |
alkaloid (also effects mechano/chemoreceptros in stomach and duodenum, NO LONGER Recommended) Codeine |
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Small intestine Lamina Propria contains |
Lymphoid tissue, macrophages and 80% of body lymphocytes, IgA secretions |
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Segementation Contractions Peristalic contractions |
Mixing VIP,NO (relax) and Ach (contract) , one direction movement. |
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ICC |
located near myenteric plexus they decrease in frequency From D -> J -> I |
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Transit times Chyme reaches pelvic colon when? 25% of chyme in colon When? |
12 hours 72 hours |
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Transit times Chyme leaves stomach when? Chyme reaches cecum when? |
2 hours 4 hours |
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Brunner's gland |
secrete Bicarbonate and Mucus |
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Crypts of Lieberkuhn |
Epithelial cells that secrete watery solution |
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Most water absorption in the Small intestine involves aquaporins or paracellularly? |
Paracellulary |
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Hormones of Small intestine |
Secretin CCK GIP/GDIP (glucose-dependent insulinotrophic peptide) because it stimulates insulin secretion (Feed forward) and does not inhibit gastric emptying |
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Pancreatitis |
gallstones occludes duct malignancy and common in alcoholics |
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Acinar cells secrete what? Duct cells secrete what? |
Acinar --> enzymes (influenced by CCK) Ducts --> bicarb (influenced by Secretin) |
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Acinar cells are under the control of what? |
Hormone CCK (From duodenal mucosa) Enteric nervous system Vagus nerve |
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Tongue protrusion reflex |
Stimulate pharyngeal region --> sensory afferent to solitary tract nucleus --> Hypoglossal nucleus --> Alpha efferent fibers leave to cause tongue to protrude. |
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Tongue retrusion reflex |
Stimulate tongue or soft palate Trigeminal spinal tract nucleus --> hypoglossal nucleus --> alpha efferent fibers |
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Phases of swallowing |
Voluntary, pharyngeal, esophageal |
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Voluntary phase of swallowing |
Prep with saliva bolus undergoes physical (sized-shaped) Chemical changes (reduction-period) Bolus moved by tongue to pharynx (oral phase) |
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Pharyngeal phase of swallowing |
Tonsillar pillars and posterior pharyngeal wall have sensory receptors; soft palate moves upward; initial peristaltic pressure wave sets off complex reflexes |
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NO in the intrinsic (enteric) nervous system |
is made by enteric nerves and release as a neurotransmitter |
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Phospholipase A2 |
Converts Lecithin --> Lysolethicin + FA (Phospholipid) |
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Amylopectin gets digested into what by alpha amylase |
Maltotriose and Maltose and Alpha-limit dextrin *majority starch of plants* |
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Amylose gets digested into what by alpha amylase |
Maltotriose and Maltose |
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Trypsin activates what enzymes |
self or by Enteropeptidase Chymotrypsinogen Proelastase Procarboxypeptidase |
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Cholesterol esterase |
Converts cholesterol ester --> cholesterol + FA |
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Surface area is increased by what |
1. Valves of Kerckring 'picae circulares' 2. Villi 3. Microvilli |
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many small molecules are absorbed how? |
solvent drag |
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Intrinsic factor B12 is absorbed how? |
endocytosis |
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Bile salts, glucose, and AA are absorbed how? |
active transport |
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Fructose is absorbed how? |
Facilitated diffusion |
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Most all proteins, carbs, and fats are absorbed by the |
mid-jejunum |
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Types of Dietary Carbs and percentages |
Starches (amylose and amylopectin) - 60% Sucrose (glucose and fructose) - 30% Lactose (glucose and galactose) - 10% |
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Why can't humans digest cellulose? |
has beta 1-4 bonds |
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Maltase Isomaltase |
Maltase =glucoamylase Isolmaltase = alpha 1-6 dextrinase |
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Maltose is hydrolyzed by what into what? |
Glucoamylase (maltase) into 2 glucose molecules |
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Sucrose is hydrolyzed by what into what? |
sucrase into glucose and fructose |
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Sucrose vs Sucralose |
Same structure but sucralose (Splenda) has Cl instead of OH |
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Lactose is converted into what by what? |
Lactase into galactose and glucose |
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Absorption rates of Glucose and galactose |
Glucose 1.0 and galactose is 1.1 |
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Glucose vs Fructose transporter |
Sodium dependent mucosal glucose transporter-1 (SGLT-1) facilitated transport (GLUT5) |
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T/F The understanding of co-transport of glucose and Na+ and osmotic movement of H20 has allowed the use of a simple sugar, salt, and water solution to treat cholera that has saved millions of lives each year |
True |
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Gut membrane that is leaky in infants |
movement of peptides/polypeptides into circulation causes allergy reactions. Human colostrum has IgA but can't reach circulation (unlike cows) |
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Polypeptides/peptides that reach circulation by endocytosis |
then exocytosis during B12 uptake (example allergic foods like peanuts, eggs,..) |
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Primary bile salts |
cholic acid and chenodeoxycholic acid |
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Secondary bile salt |
deoxycholic acid |
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Bile salts conjugated with what increases solubility? |
Taurine and glycine (charged AA) |
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How is bilirubin transported in plasma? |
by albumin |
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Hepatic cells that uptake bilirubin do what? |
Create Billirubin diglucuronide by Glucuronyl transferase the gets exocytosed. |
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The breakdown of bilirubin in feces and urine |
Feces- Stercobilin Urine - urobilin |
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What causes bile secretion? |
CCK contracting gallbladder and relaxing sphincter of oddi (VIP/NO) |
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How is bile concentrated in the gall bladder? |
Na is actively absorbed by the gallbladder epithelial cells. Water follows Na, which concentrates the bile up to 15x |
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CCK actions |
Gallbladder --> contraction Pancrease --> acinar secretions Stomach --> reduce emptying Sphincter of Oddi --> relax |
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Co-lipase function |
makes it possible for lipase to get through bile salt coating of the fat droplet |
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Micelles contain |
1.Mono (50%) and some diglycerides 2. Free FA 3. Cholesterol 4. Lysolecithin 5. Bile salts (primary/secondary) |
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VIllikinin |
Hormone that is released into circulation to cause lymphatic smooth muscle to contract. Other mechanism is lymphatic pump (muscle) by stretch |
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Where are bile salts reabsorbed? Ion absorption? |
Terminal ileum Jejunum and ileum |
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Divalent ions |
poorly absorbed
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Intestinal and Colon absorption |
7000 ml (78%) 1900 ml (21%) |
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Parotid/Sublingual/Submandibular glands have what cell types |
Serous Mucous Mixed |
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Serous vs Mucous |
amylase, acinar cells spherical mucin, acinar cells tubular |
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Mixed type gland and demilunes |
demilunes - lysozyme mixed type gland - tubuloalveolar with mucous cells along tubules and serous cells at distal ends |
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Parotid Sublingual Basal and Stimulated secretion % |
0 --> 60 80 --> 30 20 --> 10 |
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Sympathetic innervation of salvary gland comes from the |
superior cervical ganglion |
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Vagus is what % efferent and what % afferent |
10-20% efferent 80-90% afferent Sympathetics 50-50 |
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Glossopharyngeal nerve 9 |
Inferior salivatory nucleus --> otic ganglion --> parotid |
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Facial nerve 7 to lacrimal glands |
Lacrimal --> pterygopalatine ganglion --> lacrimal |
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Facial nerve 7 to submandibular/sublingual gland |
Superior salivatory nuclei --> submandibular ganglion --> submandibular and sublingual |
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Striated ducts |
Na+ and K+ exchange occurs in striated ducts also secrete glycoproteins/proteins (but acinar mainly do this 85%) |
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Total salivary secretion is how much a day? |
500-1500 ml/day |
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Plasma mOsm of Na/K/Cl/HCO3- |
143.3 - Na 4.1 - K 100.9 - Cl 27.5 HCO3- Total 296 mOsm |
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Primary saliva leaving acinar cells is similar to: |
plasma |
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Composition of saliva |
water electrolytes Mucous (mucin 1 and 2) GF (NGF and EGF) Numerous proteins (immunoglobulins) and Glycoproteins Digestive enzymes (amylase and lingual lipase) (IgA --> 87%) |
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Mucin Glycoprotein 1 |
High MW enable to coat on hard/soft tissues (slippery material on teeth) |
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Mucin Glycoprotein 2 |
Physiochemical properties enable it clump bacteria together |
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NGF made where and what Nervous system does it effect? |
Submandibular and other body organs Stimulates Sympathetic nervous system |
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Epidermal Growth Factor from saliva |
Wound healing in saliva into circulation - maintains ileal mucosa - aids in healing ulcers - role in liver regeneration |
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sIgA |
sIgA is main immunoglobin found in secretion, critical role in oral/GI immunity Secretory component protects it from being degraded by proteolytic enzymes produced by plasma cells (Then endocytosis --> exocytosis) |
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Ptyalin |
alpha amylase by acinar cells |
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Lingual lipase |
by lingual von Ebner's gland cells |
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Lysozyme |
Found in saliva breaks peptidoglycan wall of gram + bacteria |
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Lactoferin |
Binds iron bacteria need and is bacteriostatic |
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Salivary peroxidase |
(lactoperoxidase) antimicrobial oxidative enzyme |
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Statherin |
protein prevents calcium phosphate precipitation in saliva helps maintain high calcium level for remineralization |
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Salivary Histidine-rich proteins |
antimicrobial and antifungal proteins secreted by lingual serous glands
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