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42 Cards in this Set
- Front
- Back
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The four basic processes of the digestive system |
1) Motility 2) Secretion 3) Digestion 4) Absorption |
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Layers of digestive tract Mucosa |
lines side surface of tract
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Layers of digestive tract Submucosa |
elastic layer with lots of blood vessels and lymphatic |
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Layers of the digestive tract Muscularis externa |
smooth muscle |
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Layers of the digestive tract Serosa |
outer covering |
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MOUTH |
palate: arched part of mouth cavity and the soft palate is what collapses in sleep apnea Teeth: Chewing and breaking up food *mechanical digestion* Mix food with saliva |
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PHARYNX |
-Where mouth cavity and nasal passages meet -tonsils are here -swallowing occurs here (bolus of food) |
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Sphincters in the esophagus |
Gastroesophageal sphincter: prevents contents of stomach from splashing up into esophagus (if this opens then you get acid reflux) Pyloric: end of stomach and beginning of small intestine (gradually over a period of hours allows chyme to enter small intestine) |
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STOMACH |
-food storage until it can be emptied into small intestine -Churns up food into chyme *mechanical digestion* -Some chemical digestion of proteins |
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Mucosa of the stomach secretes several Things: |
-Mucus -HCL -Enzymes -Intrinsic Factor -Gastrin |
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Pyloric Sphincter allows chyme to enter the small intestine |
-This is controlled by hormones (Secretin and Cholecystokinin) -These hormones act in stomach lining and inhibit contractions -Hormones are released by small intestine in response to: Fat, Acid, and Hypertonicity |
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Peptic ulcer |
Erosion of the stomach wall Mucus barrier does't work great Acid and enzymes attack lining of stomach WHY? because Bacterium Helicobacter pylori infects lining of stomach Treatment: antacids and antibiotics |
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Accessory organs of the digestive system |
Pancreas Liver gallbladder |
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PANCREAS |
Mixed organ: has both endocrine and exocrine functions Endocrine are islet of Langerhans for glucagon and insulin Exocrine cells secrete things that move through a duct into small intestine |
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Enzymes for protein digestion |
Made as inactive precursors that are activated in the lumen of the small intestine: Trypsinogen= trypsin for cutting proteins into amino acid chains Chymotryposinogen= Chymotrypsin for same thing Procarboxypeptidase= carboxypeptididase for chopping amino acids off of one end of amino acid chains |
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Enzyme for carbohydrate digestion |
Pancreatic Amylase: digests polysaccharides to maltose |
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Enzyme for fat digestion |
Lipase: clips fatty acids off of glycerol |
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Regulation of pancreatic secretion |
-Secretin hormone increases secretion -Cholyecystokinin increases secretion |
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LIVER |
Largest organ Functions: makes blue salts (which aid in digestion of fats), Detoxifies drugs and poisons |
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Bile Salts |
-Bile Salts are made from the lipid cholesterol -They aid in digestion of fats by breaking up large fat droplets into smaller ones -The are amphipathic (part hydrophobic part hydrophilic) -Made continuously in the liver -Stored in the Gall bladder |
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Gall stones |
80% cholesterol and 20% bilirubin some people get and we don't know why can cause pain and can be passed but sometimes need surgery to remove the gallbladder |
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SMALL INTESTINE |
-Function is to finish digestion and abrsrob nutrients into the body (most important site of digestion and absorption) -Three parts: duodenum, jejunum, ileum -lots of projections in wall of small intestine and folds |
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LARGE INTESTINE |
-No digestion here
-Mostly reabsorbs water from chyme reaching it -what remains after all that liquid absorbed is feces -Contains lots of bacteria |
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Colorectal cancer |
-wall of colon becomes cancerous -Polyp is growth of cancer cells growing into large intestine -If left, can keep growing and change over time Colonoscopy: flexible light and camera inserted through anus to examine colon |
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Celiac disease/ Gluten problems |
-Gluten is two proteins in wheat/rye/barely that associate together (when you bake the bubbles that form when you use a leavening agent form stringy strands that trap bubbles -Some people are allergic to gluten (there immune system recognizes it as an antigen to respond to and initiates inflammation -Symptoms: bloating, diarrhea, constipation, pale, foul-smelling or fatty stool irritability, depression |
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Fecal transplant for Clostridium difficile infections |
C. difficile is bacterium in most peoples gut, often times after antibiotic treatment, C. difficile becomes the dominant bacterial species which is bad- causes diarrhea and does NOT stop until normal microbes are restored |
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KIDNEY |
Functions: maintaining water balance and plasma volume in body regulating ion balance in the body Excreting water soluble |
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Urinary system |
-kidneys -ureters -urinary bladder -urethra |
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Kidney |
Renal cortex (outer part) Renal medulla (inner part) |
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The Nephron |
This is the functional unit of the kidney. The kidney is mostly lots and lots of nephrons all packed together |
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The Nephron is just a tube: |
-Bowmans capsule -Proximal tubule -Loop of Henle (depending and ascending) -Distal tubule -Collecting duct |
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Filtration in the Nephron |
-blood enters glomerulus at pretty high pressure
-fluid leaks out of pores in capillary and between cells of bowman capsule -all cells and proteins stay in capillaries only plasma leaves This fluid is called filtrate |
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Reabsorption in the Nephron |
of 180L of filtrate, 178.5L is reabsorbed by the peritubular capillaries *filtration requires no energy and is nonselective Whatever is left in the nephron is waste and water 1.5L of urine a day but this is an average Color of urine gives indication of how much water is going out |
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Secretion in Nephron |
Secretion is active transport of stuff out of blood/tissue fluid and into the nephron
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Urine |
whatever is filtered and not reabsorbed is filtered and not reabsorbed, plus whatever is secreted into nephron |
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**SEE NOTES FOR DETAILS OF ALL THREE |
flirtration, reabsorption, and secretion in the Nephron |
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Glucose reabsorption |
Active transport by transporter protein
Tm (maximum amount that can be transported if every transporter protein is being used Tm for glucose is 375 mg/min any higher glucose level and excess stays in urine Untreated diabetics can have blood glucose in excess of this so glucose appears in urine
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Potassium secretion |
most (98%) of potassium is intracellular but concentration in ECF is important! esp for neurons and muscles *see notes for how it works |
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drug secretion |
some drugs are actively secreted into the filtrate uses ATP and a membrane pump ( ex. penicillins) |
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Regulation of water balance in the Kidney |
-kidney makes urine of different concentrations -all due to the osmotic gradient in kidney from cortex to medulla -80% of water is reabsorbed prior to fluid reaching the distal tubule and collecting duct. The 20% left can stay in urine or be reabsorbed |
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Vasopressin |
antidiuretic hormone that is made in the hypothalamus and stored in posterior pituitary When water needs to be conserved, vasopressin is released |
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Aquaporins |
water channels Vasopressin causes aquaporins to be inserted into the luminal membrane of these cells |
