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20 Cards in this Set
- Front
- Back
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What is hypoxic drive? How does it relate to Ephyzema or Smoking
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Hypoxic drive is a mechanism that increases breathing rate when oxygen is low. However, under normal circumstances, a healthy person will never feel it's effects, as it only kicks in when oxygen is below 40% of normal. Emphyzema and smoking both create scar tissue and gunk in the lungs, and may be bad enough to trigger this
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What is meant by ventilation-perfusion?
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Ventilation-perfusion refers to the fact that the body reroutes blood supply to better (more efficient) air sacs so that more O2 transfers to the blood
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What is a sphincter?
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A sphincter is nothing more than a valve in your body - it keeps stuff going in only one direction.
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The digestive tract has 6 different sphincters - what are their names, and where are they?
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1. Upper esophageal sphincter - located at the top of the throat/roof of the mouth
2. Lower esophageal sphincter (aka Cardiac/Gastroesophogeal/Cardioesophogeal sphincter) - located between the esophagus and the stomach 3. Pyloric sphincter - located between the stomach and the small intestine 4. Illeosecal sphincter - located between the illeum and secum (small and large intestines) 5. and 6. Internal and External anal sphincters, located at the end of the large intestine - External is voluntarily controlled, internal is not |
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There are five enteric reflexes - list them
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1. Cephalo-gastric reflex
2. Gastro-enteric reflex 3. Gastro-iliac reflex 4. Entero-gastric reflex 5. Cephalo-gastric response |
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What is the Cephalo-gastric reflex?
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The cephalo-gastric reflex is a signal from the brain to the stomach to start action: make acid, make enzymes, start churning, make gastrin
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What is gastrin?
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Gastrin is a hormone, not an enzyme - it is produced by the stomach and acts on the stomach via positive feedback to produce more acid, more enzymes, and opens the pyloric sphincter
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What is the Gastro-enteric reflex?
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The gastro-enteric reflex is a signal from the stomach to the small intestine to make enzymes and start pushing (make room)
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What is the Gastro-iliac reflex?
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The gastro-iliac reflex is a signal from the stomach to the large intestine to push and to open the ileocecal valve
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What is the Entero-gastric reflex?
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The entero-gastric reflex is a signal from the small intestine to the stomach to "stop" and to close the pyloric sphincter, which also produces the hormone CCK (cholecytokinin)
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What is CCK and what does it do?
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CCK (cholecystokinin) is a hormone that releases bile and decreases cephalo-gastric response (less hungry, reduces appetite, feeling "full"), and takes about 20 minutes to respond - it is produced by the entero-gastric reflex as a response to stretch receptors and/or the presence of fat
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What is bile? Where is it in your body?
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bile - made in liver, stored in gallbladder, released into small intestine - helps break down fat (like soap/detergent), emulsifies it, make smaller pieces (doesn't actually digest it)
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What is a stretch reflex? How does it relate to alcohol?
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stretch reflex - all digestive organs respond to expansion, reacting in the following three ways, progressing down the list as the stretch becomes more urgent
1. Digest food -> Full feeling 2. Push -> Full feeling 3. Vomit Alcohol irritates lining of stomach, and initiates the stretch reflex |
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What is fiber? What happens if you have too much? Too little?
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Fiber=cellulose=plant cell walls - non-digestible by mammals
increases speed of intestines excess->diarrhea, no time to absorb water too little->constipation, too much water absorbed |
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How is the acid level of the small intestine modified? How does secretin figure in to this?
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too much acid in small intestine=
a. close pyloric sphincter (no more acid) b. release hormone secretin, goes to pancreas, release buffer (bicarbonate) to reduce acidity |
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For the mouth:
Is it involved in physical digestion, chemical digestion, or nutrient absorption? What is the local pH level (normally)? What enzymes are present, if any (list sources and substrates)? |
The mouth performs both physical and chemical digestion, but no nutrients are absorbed.
The pH within is approximately 7. Two enzymes are present: Salivary amylase, breaks down starches to glucose and monosacharides, produced by the salivary glands. Lingual lipase, breaks down fats to fatty acids, produced by the tongue |
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For the esophagus:
Is it involved in physical digestion, chemical digestion, or nutrient absorption? What is the local pH level (normally)? What enzymes are present, if any (list sources and substrates)? |
The esophagus is not involved in physical digestion, chemical digestion, or nutrient absorption. (It's "just a tube".)
The pH within is approximately 7. No enzymes are present. |
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For the stomach:
Is it involved in physical digestion, chemical digestion, or nutrient absorption? What is the local pH level (normally)? What enzymes are present, if any (list sources and substrates)? |
The stomach is involved in both physical and chemical digestion, but is not technically involved in nutrient absorption (although alcohol, aspirin, and various other pharmaceuticals can be absorbed here)
The pH within is about 2. Three enzymes are present: Pepsin, breaks down protein/peptides into amino acids, produced by the stomach Rennin (double n separate from renin-angiotensin system, aka Rennet), curdles milk (only infants have this, adults don't), made by stomach Gastric lipase, breaks down fat into fatty acids, made by stomach Also contains hydrochloric acid Hydrochloric acid (not an enzyme), which kills bacteria (acting as a barrier) and dissolves things |
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For the small intestine:
Is it involved in physical digestion, chemical digestion, or nutrient absorption? What is the local pH level (normally)? What enzymes are present, if any (list sources and substrates)? |
The small intestine is involved in physical and chemical digestion as well as nutrient absorption.
The pH within is approximately 8. Three brush border enzymes are present to break down sugars, all produced by the small intestine: Lactase, breaks down lactose (milk sugar) Sucrase, breaks down sucrose. Maltase, breaks down maltose The small intestine also contains brush boarder pepsidases, which act to break proteins down to amino acids. Three other enzymes are present, all produced by the pancreas: Pancreatic amylase, breaks starches down to sugars (disacharides), which are then further broken down by the other sugar enzymes Pancreatic lipase, which breaks fat into fatty acids Trypsin, which breaks protein into amino acids. |
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For the large intestine:
Is it involved in physical digestion, chemical digestion, or nutrient absorption? What is the local pH level (normally)? What enzymes are present, if any (list sources and substrates)? |
The large intestine is not involved in digestion, but does absorb some nutrients (water, vitamins, and electrolytes [salt])
The pH within is approximately 8. No enzymes are present. |
