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Spring 2021 Patho > GI Part 2 > Flashcards

GI Part 2 Flashcards

1
Q

Liver

Contributes ____ _____ to digestion

Important for _____ digestion and absorption

Two types of cells make up liver (2)

A

bile salts

fat

Hepatocytes

Kupffer Cells

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2
Q

Bile Composition

1) Aqeuous _____ fluid
2) Organic compounds - bile ____, ch_____, l____, bi_____

Play a major role in aiding fat digestion through Fat ______

Secreted into the ______

A

1) Aqueous Alkaline fluid
2) Bile salts, cholesterol, lecithin, bilirubin

Emulsification

duodenum

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3
Q

Action of Bile

=

Amphipathic Structure =

A

When bile salt interacts with fat they create lipid emulsion droplets through the process of intestinal mixing, large droplets of fat get broken up into smaller droplets (large bc they accumulate together when in an aqueous solution and try to exclude water bc its hydrophobic like salad dressing)

One end is lipohilic (lipid soluble) and one end is water soluble

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4
Q

Emulsification Through Bile Salts

Taking large droplets of fat and creating small droplets prevents any ______ bc once the bile salts surround the individual droplets and bury their _______ ends into the oil and point their _____ soluble ends to the solution

  • Important effects: gives ____ enzyme better ______ to fat by increasing surface area
  • Having very little bile doesn’t mean you can’t break down fat, but it _____ the amount of fat you can digest
A

recombining, hydrophibic ends in oil, water solube ends towards solution

  • Lipase, access
  • limits
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5
Q

Bile Formation and Transport

Bile is produced by the ______

Bile salts are converted from _____ and added aqueous solution leaves through the liver through the (1)

  • (1) sphincter between bile duct and duodenum
    • When we are not actively digesting fat, sphincter is tightly _____ -> so bile that’s produced by the liver tends to back up into the (1) and is ____ there
A

Liver

cholesterol, Common bile duct

  • Sphincter of Oddi
    • ​closed, gallbladder, stored
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6
Q

Hormones Secreted When we Eat Fat

(2)

A

CCK

Secretin

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7
Q

Actions of CCK and Secretin

CCK (3)

Secretin (1)

A
  1. Stimulates liver to produce bile
  2. Relaxes and opens up sphincter of Oddi
  3. Contracts the gallbladder
  4. Stimulates liver to produce bile
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8
Q

Positive Feedback Loop of Bile

__% of bile is reabsorbed at the terminal portions of the ____ ____ and goes back to the liver

  • When bile salts come back to liver -> very strong signal for liver to? -> more bile enters duodenum -> more gets reabsorbed, etc
  • What shuts off this loop?
A

50%, small intestine

  • strong signal for liver to make even more bile
  • When fat digestion is complete, CCK and Secretin no longer released, sphincter of Oddi constricts, gallbladder relaxes and bile no longer enters duodenum and gets reabsorbed, and any bile produced by liver in the interim gets stored in the gallbladder
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9
Q

Micelle

______ core

______ shell

Surrounds free fatty acids and monoglycerides

  • Bile Salt
    • ​Water soluble _____ points towards _____
    • Lipid soluble _____ points towards _____
  • Lecithin
    • ​Water soluble _____ points towards ______
    • Lipid soluble _____ points towards ______
A

Hydrophobic core

Hydrophillic shell

  • Bile Salt
    • ​Tail towards outside
    • Head towards center
  • Lecithin
    • Head towards outside
    • Tail towards center
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10
Q

Small Intestine Segments

(3)

Small intestine is where all _____ and _____ of food is going to be completed

Majority of w_____, e_____, and m_____ asborption happens in the small intestine

Small intestine uses (1) as both mixing and propulsion movements

A

Duodenum

Jejunum

Ileum

digestion, absorption

water, electrolytes, minerals

segmentation contractions

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11
Q

Motility in the Small Intestine

Small Intestine uses ________ as both mixing and propulsion movements

In addition to mixing, segmentation enhances ___ that food comes in contact with intestinal wall to enhance ______

A

Segmentation

SA, absorption

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12
Q

Segmentation

Smooth muscle contraction depends upon stimulation from ______ cells

Intensity of contraction depends on:

  • degree of _______
  • presence of ______
  • _____ ____ activity (ie ____ input)

How does it propel food? Ans: ______ of segmentation ______ down the length of the Small Intestine

A

pacesetter

  • distension
  • gastrin
  • extrinsic nerve (vagal)

Frequency declines down length of intestine (creates slow movement forward)

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13
Q

Digestion and Absorption

____anatomy - Adaptations for digesetive and absorptive functions

Membrane-bound ______

_____ ______ membrane contains three categories of membrane bound digestive enzymes

  1. (1)
  2. (1)
  3. (1)
A

Microanatomy

enzymes

Brush Border

  1. Enterokinases
  2. Disaccharidases
  3. Aminopeptidases
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14
Q

Membrane Bound Digestive Enzymes (Notes)

Aminopeptidase = ______ enzyme

Enterokinase = ______ enzyme -converts _____ into _____

Disaccharidases = breaks down disaccharides into ______ (3)

A

Proteolytic

Proteolytic, trypsinogen -> trypsin

monosaccharides (maltose, sucrose, lactose)

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15
Q

Membrane Adapted for Absorption

(1) Folds of mucosa that enhances the absorptive surface area

(1) Each individual cell along the vili has these on their apical surface which is termed the (1)

Villi and Microvilli increases _____ _____ available for digestion by ____ times

Note: Anything that compromises our absorptive surface area can greatly affect n____ and hy____

A

Villus

Microvilli - Brush Border Membrane

surface area 600x

nutrition and hydration

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16
Q

Interior Structure of Vili

Highly adapted to take up food, water, electrolytes, etc

  • Capillaries =
  • Central Lacteal =
A
  • Where amino acids and monosaccharides are first absorbed
  • Lymphatic vessel where fat that has been absorbed by small intestine initially enters then drains into veins that feed into liver
17
Q

Brush Border Enzymes

Disaccharidases (3)

Disaccharides they digest (3)

Broken down into which monosaccharides (3)

A

Maltase -> Maltose -> 2 Glucose

Sucrase -> Sucrose -> Glucose and Fructose

Lactase -> Lactose -> Glucose and Galactose

18
Q

Brush Border Enzymes

(1) The prominent brush border enzyme that’s going to break down (1) fragments into individual (1) that are then absorbed

Which then activates _____, _____, and _____ (from last lecture)

A

Aminopeptidase -> Polypeptide Fragments -> Amino Acids

Trypsin, Chymotrypsin, Carboxypeptidase

19
Q

Fat digestion

Introduction of bile salts and pancreatic lipase in Duodenum

  • Production of Lipid _____ - combination of triglycerides and bile salts
  • Pancreatic Lipase breaks down triglycerides to from the (1) which represents what?*
  • Micelles cross the brush border enzyme and once it does, monoglycerides and fatty acids reform triglycerides bc for it to eventually enter bloodstream has to be packaged into a thing called a (1) (LDL, HDL) in this case first one that is formed is the (1) lipoprotein that enters the (1) and make its way to the circulation
A
  • Lipid Emulsification
  • MICELLES REPRESENT THE ABSORBABLE FORM OF DIGESTIVE FAT
  • Lipoprotein, Chylomicron, Central Lacteal
20
Q

Large Intestine

By the time we reach the large intestine, should have digested and absorbed all of the food -> if not bacteria are going to thrive off it

  • (1) waste that is left
    • However before feces leaves the body we want to ____ a certain amount of water, electrolytes, and minerals
    • Moves from terminal portions of the ileum through ______ valve into the _____ -> ______ colon -> ______ colon -> _____ colon -> ______ colon -> _______ -> ____ sphincters
A
  • Feces
    • ​absorb
    • Ileocecal valve -> cecum -> ascending -> transverse -> descending -> sigmoid -> rectum -> anal sphincters
21
Q

Large Intestine Structure

  • Internal Anal Sphincter = ______ muscle through autonomic and enteric nervous system, is it voluntary?
  • External Anal Sphincter = ______ muscle, is it voluntary?
  • (1) band of connective tissue that runs down length of colon
  • (1) Circular compartments - indentatations are bands of muscle
A
  • smooth muscle, not voluntary
  • skeletal muscle, voluntary so we can choose when to relax and defecate
  • Taenia coli
  • Haustra
22
Q

Motility in the Large Intestine

2 forms of Motility

  1. Motility through (1) AKA (1) - desiged to _____ feces and enhance _____ with colon wall to enhance absorption
  2. (1) AKA (1)
A
  1. Segmentation Contraction (Haustral Contractions), MIXING MOVEMENT, enhance contact
  2. Peristalsis (Mass Movements)
23
Q

Haustral Contractions

  • ____ and _____ movement
  • Result of autonomous ______ of colonic smooth muscle
  • Frequency ___-___ /hour
  • ______ movement*
  • Controlled by local _____ via intrinsic nerve plexuses
A
  • Slow and Nonpropulsive
  • rhythmicity
  • 2-3/hr
  • Mixing
  • reflexes
24
Q

Mass Movements

  • _______ Movement*
  • Occurs __-__ times per day - usually after
  • Drives feces __-___ length of colon in a few ____
  • Stimulation - ______ reflex - via ______
A
  • Propulsive Movement
  • 3-4
  • 1 - 3/4, seconds
  • Gastrocolic reflex - Gastrin
  • Very strong and can drive feces down entire colon within seconds*
  • We have about 3-4 mass movements per day, usually after meals, strongly stimulated by gastrin*
25
Q

The Defecation Reflex

  • Stimulated by ______ on ____ wall
  • Stretch receptors in the rectal wall cause _______ of the (1)
  • (1) - when voluntarily relaxed allows defecation
A
  • Distension, rectal
  • relaxation, Internal Anal Sphincter
  • External Anal Sphincter
26
Q

Consequence of Delayed Defecation

  • If defecation is delayed too long, mass movements ____ down, internal sphincter _____ so feces can move ____ out of the _____ and decrease ______, can lose _____ to defecate
  • Consequence =
A
  • slow, contracts, back out of rectum, decrease distension, lose desire to defecate
  • As long as feces stays in the colon, more and more water is absorbed, feces becomes hard -> risk of CONSTIPATION
27
Q

What’s so great about fiber?

  • Aids in ______ in a few ways
    • Adds ______ to chyme and eventually feces
    • Increases the ______ of chyme
  • Too much of a good thing =
A
  • Digestion
    • Volume
    • Osmolarity
  • Osmotic diarrhea - osmolarity too high
28
Q

Diarrhea

Causes

  • Rapid Colonic motility - no time to absorb water like with bacterial _____ ( want to get it out)
  • Osmotic Diarrhea: undigested material through _____ deficiencies (ie (1), (1) is something we don’t digest and raises the osmolarity of stool) -> retain too much ____ and cause osmotic bacteria
A
  • Toxins
  • enzyme deficiencies ie lactose intolerance, fiber, water

Spring 2021 Patho (14 decks)

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