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BIO 176 LAB + LEC > The Digestive System Part 2 > Flashcards

The Digestive System Part 2 Flashcards

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1
Q

what does the PANCREAS + LIVER + GALLBLADDER all have in COMMON?

A

ACCESSORY ORGANS associated with the SMALL INTESTINE (DUODENUM)

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2
Q

describe the LIVER

A
  • important for the DIGESTIVE FUNCTION IN TERMS OF PRODUCTION OF BILE
  • in the URQ
    • BILE: FAT EMULSIFIER
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3
Q

describe the GALLBLADDER

A

the CHIEF FUNCTION in terms of STORAGE OF BILE

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4
Q

describe the PANCREAS

A
  • supplies most of the ENZYMES needed to DIGEST CHYME
  • also supplies BICARBONATE to NEUTRALIZE STOMACH ACID
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5
Q

describe the CHARACTERISTICS OF THE LIVER

A
  • REDDISH IN COLOR due to being BLOOD RICH
  • the LARGEST GLAND IN THE BODY
  • weighs around 3 POUNDS—WEDGE SHAPE
    • the LESSER OMENTUM ANCHORS IT TO STOMACH
  • right under the DIAPHRAGM
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6
Q

describe the DUCTS (BILARY TREE)

A
  • LEFT AND RIGHT HEPATIC DUCT
    • drain the RIGHT AND LEFT SIDES OF LIVER
    • coverage at COMMON HEPATIC DUCT:
      • connects to GALLBLADDER (CYSTIC DUCT)
        • union is known as COMMON BILE DUCT (BILIARY DUCT)
        • empties into the SMALL INTESTINE
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7
Q

what are the LOBES OF THE LIVER?

A
  • consists of FOUR PRIMARY LOBES;
    • RIGHT
    • LEFT
    • CAUDATE (inferior view)
    • QUADRATE (inferior view)
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8
Q

what are the LIGAMENTS OF THE LIVER?

A
  • FALCIFORM LIGAMENT:
    • separates the LARGER RIGHT and SMALLER LEFT LOBES
  • ROUND LIGAMENT (LIGAMENTUM TERES)
    • remnant of the FETAL UMBILICAL VEIN
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9
Q

describe the HEPATIC ARTERIES

A
  • BV that SUPPLIES OXYGENATED BLOOD to the LIVER
  • supplies 25% of the ARTERIAL BLOOD TO THE LIVER/as well as HALF OF ITS OXYGEN SUPPLY
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10
Q

describe the HEPATIC PORTAL VEIN

A
  • vessel located in the ABDOMINAL CAVITY—formed from UNION OF the SUPERIOR MESENTERIC & SPLENIC VEINS
  • channels blood from the GI TRACT and SPLEEN to the CAPILLARY BEDS IN THE LIVER
  • supplies of over 75% of the VENOUS BLOOD TO THE LIVER/as well as HALF OF ITS OXYGEN SUPPLY
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11
Q

describe the HEPATIC PORTAL SYSTEM

A
  • connects the CAPILLARIES of the GI TRACT with the CAPILLARIES IN THE LIVER
  • NUTRIENT RICH BLOOD LEAVES the GI TRACT—first brought to the LIVER FOR PROCESSING before being sent to the HEART
    • known as the FIRST PASS EFFECT
  • all empty into the CENTRAL VEIN FIRST!!
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12
Q

what are some other FUNCTIONS of the LIVER other than creation of BILE?

A
  • METABOLISM of CARBS, LIPIDS, and PROTEINS
  • processing of DRUGS AND HORMONES
  • creation of ANGIOTENSIONOGEN
  • raises our BP
  • renin-angiotensin aldosterone mechanism
  • creation of INSULIN-LIKE GROWTH FACTOR; IGF-1 (polypeptide protein hormone—childhood growth)
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13
Q

describe the HISTOLOGY OF THE LIVER

A

composed of HEPATOCYTES + BILE CANALICULI + HEPATIC SINUSOIDS

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14
Q

describe the LIVER LOBULES

A
  • has HEXAGONAL STRUCTURAL + FUNCTIONAL UNITS; made from HEPATOCYTES
    • have rough and smooth ER
    • lots of MITOCHONDRIA—just very active cells; to help produce BILE
    • processing of BLOODBORNE NUTRIENTS
  • filter and process NUTRIENT-RICH BLOOD
  • move OUTWARD FROM CENTRAL VEIN
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15
Q

describe BILE SECRETION

A

secretion of BILE through TINY CANALS called BILE CANALCULI—runs between HEPATOCYTES to the BILE DUCT & branches in the PORTAL TRIADS

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16
Q

what is the PORTAL TRIAD?

A
  • BRANCH OF HEPATIC ARTERY
    • supplies OXYGEN CONTENT
  • BRANCH OF HEPATIC PORTAL VEIN
    • brings in NUTRIENT RICH BLOOD
  • BILE DUCT
    • receives BILE FROM THE BILIARY CANALICULI
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17
Q

function of STELLATE MACROPHAGES

A
  • also known as HEPATIC MACROPHAGES/KUPFFER CELLS) within LIVER SINUSOIDS
  • REMOVES DEBRIS OR OLD WBCs
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18
Q

what are the LIVER (HEPATIC) SINUSOIDS?

A

heavily FENESTRATED LEAKY CAPILLARIES between the HEPATIC PLATES

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19
Q

describe BILE and BILE SALTS

A
  • composition and ENTEROHEPATIC CIRCULATION
  • YELLOW-GREEN + ALKALINE SOLUTION CONTAINING;
    • BILE SALTS:
      • cholesterol derivatives that FUNCTION IN FAT EMULSIFICATION & ABSORPTION
      • recycled by through REABSORPTION through the ILEUM
        • reused back into NEWLY-FORMED BILE 😄
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20
Q

what is BILIRUBIN?

A
  • pigment formed from HEME
  • broken down into STERCOBILIN—BROWN DISCOLORATION TO FECES
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21
Q

describe the CHARACTERISTICS OF THE GALLBLADDER and its FUNCTIONS

A
  • GALLBLADDER:
    • THIN-WALLED MUSCULAR SAC
    • on the VENTRAL SURFACE OF THE LIVER
    • around 3-4 inches in length
  • FUNCTIONS:
    • stores and concentrates BILE by absorbing WATER AND IONS
    • contains HONEYCOMB FOLDS to allow for EXPANSION AS IT FILLS
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22
Q

what are GALLSTONES?

A
  • PRODUCTION OF GALLSTONES:
    • known as CHOLELITHIASIS
    • see a HIGH CHOLESTEROL DIET and TOO LITTLE BILE SALT
    • BLOCKAGE OF BILIARY TREE (asymptomatic until then)
      • leads to a BACKUP OF BILE
      • PAIN—in URQ
  • gets worse when eating FATTY FOODS
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23
Q

describe the PANCREAS – and FUNCTION

A
  • GLAND THAT LIES POSTERIOR TO THE STOMACH

FUNCTIONS:

  • produces ENZYMES that begins to DIGEST CARBS, PROTEINS, FATS, and NUCLEIC ACIDS—ACINAR CELLS (99%)—EXOCRINE FUNCTION!!
    • secretion of PANCREATIC JUICE
  • produces SODIUM BICARBONATE which BUFFERS STOMACH ACID
  • PRODUCTION OF INSULIN through ISLETS OF LANGERHANS (1%)—ENDOCRINE FUNCTION!!
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24
Q

describe the ACTIVATION OF PANCREATIC PROTEASES in the SMALL INTESTINE

A
  • PANCREATIC JUICE COMPOSITION:
    • BICARBONATE
    • PROTEASES (PROTEINS)
      • only activated within the SI—don’t want AUTODIGESTION OF PANCREAS

TYPES:
- TYPES:
- TRYPIN
- CHYMOTYPSINOGEN
- PROCARBOXYPEPTIDASE
- all eventually BREAK DOWN PROTEINS

all first INACTIVE FORMS and then are ACTIVATED IN THE DUODENUM to PROTECT PANCREASE FROM DIGESTNG ITSELF

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25
Q

what is the SIGNIFICANCE OF ENTEROPEPTIDASE?

A
  • has ENTEROPEPTIDASE (secreted from DUODENAL EPITHELIAL CELLS)
    • ACTIVATES THE PROTEASES!!
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26
Q

what are the CORRESPONDING PROTEASES (INACTIVE AND ACTIVE FORMS) in the DUODENUM?

A

TRYSINOGEN (INACTIVE) > TRYPSIN
CHYMOTRYPSINOGEN > CHYMOTRYPSIN
PROCARBOXYPEPTIDASE (INACTIVE) > CARBOXYPEPTIDASE

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27
Q

why is the DUODENUM so IMPORTANT?

A
  • where BILE DUCT & PANCREATIC DUCT unites in WALL
    • FUSES TOGETHER as the HEPATOPANCREATIC AMPULLA
28
Q

describe the FUNCTION OF THE AMPULLA and the HEPATOPANCREATIC SPHINCTER

A
  • AMPULLA:
    • opens into DUODENUM via the MAJOR DUODENAL PAPILLA
  • HEPATOPANCREATIC SPHINCTER:
    • controls ENTRY OF BILE and PANCREATIC JUICE into DUODENUM
29
Q

How are the BILE AND PANCREATIC SECRETIONS REGULATED?

A
  • BILE & PANCREATIC JUICE SECRETIONS:
    • both stimulated by NEUTRAL & HORMONAL CONTROLS
  • HORMONAL CONTROLS;
    • includes ENTEROGASTRONES; CHOLECYSTOKININ (CCK) & SECRETIN
30
Q

describe the SMALL INTESTINE

A
  • the MAJOR ORGAN OF DIGESTION & ABSORPTION
  • around 2-4 m long (7-13 ft long)
    • from the PYLORIC SPHINCTER to the ILEOCECAL VALVE (where it joins the LARGE INTESTINE)
  • diameter; 2.5-4 cm (1.0-1.6 inches)—has a SMALLER LUMINAL SIZE VS. LARGE INTEST.
31
Q

describe the SUBDIVISONS OF THE SMALL INTESTINE or what are they? (3)

A
  • DUODENUM
    [DUODENAL JEJUNAL JUNCTION]
  • JEJUNUM
  • ILEUM
    [ILEOCECAL JUNCTION—where SMALL INTESTINE and LARGE INTESTINE MEET]
32
Q

describe the DUODENUM

A
  • mostly retroperitoneal; around 25.0 cm (10 in)
  • CURVES around the HEAD OF THE PANCREAS
  • NUTRIENT IRON
33
Q

describe the JEJUNUM

A
  • around ~2.5 m (8 ft long); ATTACHES POSTERIORLY by the MESENTRY
  • MAJORITY OF NUTRIENTS takes PLACE HERE (with exceptions of course)—ABSORPTION
34
Q

describe the ILEUM

A
  • around ~3.6 m (12 ft long); attaches POSTERIORLY by MESENTRY—joins the LARGE INTESTINE at the ILEOCECAL VALVE
  • NUTRIENT VITAMIN B12—in TERMINAL ILEUM
  • WATER & LIPIDS—SMALL INTESTINES
35
Q

what is the BLOOD SUPPLY of the SMALL INTESTINE?

A
  • SUPERIOR MESENTERIC ARTERY—BLOOD SUPPLY
  • VEINS (carries NUTRIENT-RICH BLOOD):
    • drains into SUPERIOR MESENTERIC VEINS
    • goes into HEPATIC PORTAL VEINS
      • then into LIVER
36
Q

what is the NERVE SUPPLY OF THE SMALL INTESTINE?

A
  • PARASYMPATHETIC INNERVATION—VAGUS NERVE
  • SYMPATHETIC INNERVATION—THORACIC SPLANCHNIC NERVES
37
Q

what are some MODIFICATIONS the SI has for ABSORPTION?

A
  • CIRCULAR FOLDS:
    • increases the SA for DIGESTION & ABSORPTION in the SMALL INTESTINE
  • VILLI
    • has LACTEAL IN BETWEEN—helps to ABSORB DIGESTED FOOD into the CAPILLARY AND LACTEAL
  • MICROVILLI
    • contains ENZYMES (BRUSH BORDER)—continues DIGESTIVE PROCESS for CARBS and PROTEINS
38
Q

function of ENTEROCYTES

A
  • forms the BULK OF EPITHELIUM (SIMPLE COLUMNAR)
  • ABSORBS NUTRIENTS and ELECTROLYTES in the BILII
  • secretes INTESTINAL JUICE in the CRYPTS
39
Q

function of PANETH CELLS

A

secretes DEFENSINS and LYSOZYMES + ANTIMICROBIAL AGENTS

40
Q

describe INTESTINAL JUICE

A

provides a VEHICLE FOR ABSORPTION for SUBSTANCES from CHYME as they come in contact with VILLI

41
Q

describe BRUSH BORDER ENZYMES

A
  • found on the SURFACES OF THE MICROVILLI of ABSORPTIVE CELLS + BREAKS DOWN FOOD PRODUCTS
  • MAJOR STIMULUS for PRODUCTION—HYPERTONIC or ACIDIC CHYME
42
Q

describe the REGULATION OF CHYME ENTRY

A
  • CHYME entering DUODENUM; typically HYPERTONIC (chyme delivery has to be SLOW)
  • CHYME:
    • must be mixed with BILE and PANCREATIC JUICE = continues DIGESTION
43
Q

what controls the movement of food into the duodenum?

A

the enterogastric reflex

44
Q

how does food MOVE in the SMALL INTESTINE?

A
  • SEGMENTATION:
    • the MOST COMMON MOTION of SMALL INTESTINE
    • initiated by INTRINSIC PACEMAKER CELLS
    • helps with MIXING and MOVING CONTENTS toward ILEOCECAL VALVE
  • PERISTALSIS;
    • has HORMONE MOTILIN—increases WAVES OF PERISTALSIS
45
Q

describe the SUBDIVISIONS of the LARGE INTESTINE

A
  1. CECUM
  2. APPENDIX
  3. COLON
    1. ascending
    2. transverse
    3. descending
    4. sigmoid
  4. RECTUM
    1. 3 rectal valves
  5. ANUS
    1. 2 sphincters
46
Q

what are the THREE UNIQUE FEATURES of the LARGE INTESTINE?

A
  1. TENIAE COLI:
    1. THREE BANDS of LONGITUDINAL SMOOTH MUSCLE in the MUSCULARIS
  2. HAUSTRA:
    1. POCKETLIKE SACS caused by tone of TENIAE COLI
  3. EPIPLOIC APPENDAGES:
    1. fat-filled pouches of VISCERAL PERITONEUM
47
Q

describe the HISTOLOGY OF THE LARGE INTESTINE

A
  • HISTOLOGY:
    • made up of SIMPLE COLUMNAR EPITHELIUM (except the ANAL CANAL)
    • has NO CIRCULAR FOLDS, VILLI, and BRUSH BORDERS
    • MUCOSA:
      • much more THICKER and CRYPTS —contains many GOBLET CELLS
48
Q

describe C. DIFFICILE

A
  • CLOSTRIDIUM DIFFICILE:
    • an ANTIBIOTIC-ASSOCIATED DIARRHEA;
      • accounts for 14,000 deaths per year
    • type of an ANAEROBIC BACTERIUM that carries in INTESTINE
    • when antibiotics kill other bacteria; BROAD SPECTRUM ANTIBIOTIC THERAPY
      • begins to FLOURISH and CAUSE PSUEDOMEMBRANOUS COLITIS (the INFLAMMATION OF THE COLON)
        • leads to BOWEL PERFORATION and SEPSIS
49
Q

describe the DIGESTIVE PROCESS

A
  • DIGESTIVE PROCESS:
    • residue remains in LARGE INTESTINE around 12-24 hours
    • NO FOOD BREAKDOWN—except by ENTERIC BACTERIA
    • VITAMINS (made by bacterial flora) + WATER + ELECTROLYTES (Na + Cl)
  • FUNCTIONS:
    • propulsion of FECES to ANNUS—DEFECATION
    • colon not essential for life
50
Q

defintiion of HAUSTRAL CONTRACTIONS

A
  • has SLOW SEGMENTING MOVEMENTS
  • sequentially CONTRACTS in RESPONSE TO DISTENSION
51
Q

defintiion of GASTROCOLIC REFLEX

A
  • GASTROCOLIC REFLEX:
    • initiated by the PRESENCE OF FOOD in STOMACH
    • activates THREE to FOUR SLOW POWERFUL PERISTALTIC WAVES per DAY IN COLON (MASS MOVEMENTS)
52
Q

describe how the LOW FIBER DIET can influence the DIGESTIVE PROCESS

A
  • an begin to NARROW THE COLON and cause STRONG CONTRACTIONS that INCREASES PRESSURE ON WALLS
    • results in DIVERTICULA—HERNIATIONS OF MUCOSA
53
Q

definition of IBS

A
  • IBS:
    • functional GI DISORDER
    • recurring abdominal pain, stress, etc…
54
Q

definition of IBD

A
  • CROHN’S + ULCERATIVE COLITIS
    • ulceration of the GI TRACT (CONT.)
    • have SKIP LESIONS—areas of inflammation and normal areas (CROHN’S)
55
Q

definition of ABSORPTION

A
  • ABSORPTION:
    • process of MOVING SUBSTANCES from the LUMEN OF THE GUT into the BODY
    • have TIGHT JUNCTIONS to let substances to PASS THROUGH
      • ENTER THROUGH APICAL MEMBRANE
      • EXIT THROUGH BASOLATERAL MEMBRANE
56
Q

what are the SIMPLEST FORMS OF MONOSACCHARIDES?

A
  • around 60% are DIGESTIBLE as STARCH
  • all want them into their SIMPLEST FORMS!!
    • SUCRASE > SUCROSE > GLUCOSE + FRUCTOSE
    • LACTASE > LACTOSE > GLUCOSE + GALACTOSE
    • MALTASE > MALTOSE > GLUCOSE
57
Q

describe the PATHWAY OF DIGESTION OF CARBS

A
  • all starts at the ORAL CAVITY with SALIVARY AMYLASE
  • follows into PANCREAS with PANCREATIC AMYLASE
  • follows into BRUSH BORDER within SI
  • COTRANSPORTED across the APICAL MEMBRANE of ABSORPTIVE EPITHELIAL CELLS—mostly by SECONDARY ACTIVE TRANSPORT with Na+
  • exit across the BASOLATERAL MEMBRANE by FACILITATED DIFFUSION
58
Q

describe LACTOSE INTOLERANCE

A
  • have DEFICIENT AMOUNTS of LACTASE and CAN NOT CONSUME LACTOSE
    • remaining UNDIGESTED LACTOSE—the creation of an OSMOTIC GRADIENT in the INTESTINE
      • prevents WATER FROM BEING ABSORBED; diarrhea
      • can start pulling water from the INTERSTITIAL SPACE into the INTESTINAL LUMEN
59
Q

what can LACTOSE INTOLERANCE CAUSE?

A
  • BACTERIAL METABOLISM (undigested solutes):
    • production of LARGE AMOUNTS OF GAS
    • results of BLOATING + FLATULENCE + CRAMPING PAIN
60
Q

describe PROTEIN DIGESTION

A
  • PROTEIN DIGESTION:
    • use of DIGESTIVE ENZYMES to BREAKDOWN
    • broken down into LARGE POLYPEPTIDES > SMALL POLYPEPTIDES > PEPTIDES > AMINO ACIDS
  • PROCESS:
    • begins in STOMACH due to PEPSIN (inactive form—PEPSINOGEN)
    • follows into PANCREAS—pancreatic enzymes
    • follows into BRUSH BORDER ENZYMES
61
Q

describe LIPID DIGESTION

A
  • have to undergo EMULSIFICATION;
    • large lipid globule is BROKEN DOWN INTO SMALLER ONES)
    • TRIGS are now exposed with PRETREATMENT WITH BILE SALTS
  • BILE:
    • has the necessary BILE SALTS in order for the EMULSIFICATION PROCESS TO OCCUR
62
Q

describe the LIPID DIGESTON PATHWAY

A
  • DIGESTION:
    • PANCREATIC LIPASES begin to HYDROLYZE TRIGLYCERIDES yielding MONOGLYCERIDES and FREE FATTY ACIDS
  • MICELLE FORMATION:
    • consists of FATTY ACIDS + MONOGLYCERIDES + BILE SALTS to move contents into EPITHELIAL CELLS
    • have a BILIARY SALT—coated with LECITHIN
  • DIFFUSION:
    • FATTY ACIDS + MONOGLYCERIDES start to DIFFUSE from the MICELLEs into EPITHELIAL CELLS
  • CHYLOMICRON FORMATION:
    • FATTY ACIDS + MONOGLYCERIDES —are now RECOMBINED and PACKAGED with other FATTY SUBSTANCES + PROTEINS = CHYLOMICRONS
  • CHYLOMICRON TRANSPORT:
    • leaves EPITHELIAL CELLS via EXOCYTOSIS—enter LACTEALS and carried away from the INTESTINE IN LYMPH
63
Q

describe NUCLEIC ACID DIGESTION

A
  • can contain DNA AND RNA—all starts with PANCREATIC NUCLEASES
  • also have BRUSH BORDER ENZYMES —breaks down nucleic acids even more
    • products transported by the EPITHELIUM VILLI OF THE SI
64
Q

describe ABSORPTION of MONOSACC in SMALL INTEST

A
  • MONOSACCHARIDES:
    • carbs are digested except with cellulose—use of FACILITATED DIFFUSION
    • SECONDARY ACTIVE TRANSPORT:
      • with GLUCOSE and GALACTOSE
    • LEAVING CELL:
      • use of FACILITATED DIFFUSION
65
Q

describe ABSORPTION of AMINO ACIDS in SMALL INTEST

A
  • AMINO ACIDS:
    • ABSORBED through ACTIVE TRANSPORT or SECONDARY ACTIVE TRANSPORT (around 99% are ABSORBED)
    • LEAVE THROUGH SIMPLE DIFFUSION
66
Q

describe ABSORPTION OF LIPIDS in SMALL INTEST

A
  • LIPIDS:
    • ABSORBED THROUGH SIMPLE DIFFUSION (95%)
    • LEAVE THROUGH SIMPLE DIFFUSION
67
Q

where does the DIGESTIVE SYSTEM arise from?

A

the ENDODERM

BIO 176 LAB + LEC (20 decks)

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