The Digestive System Part 2 Flashcards
1
Q
what does the PANCREAS + LIVER + GALLBLADDER all have in COMMON?
A
ACCESSORY ORGANS associated with the SMALL INTESTINE (DUODENUM)
2
Q
describe the LIVER
A
- important for the DIGESTIVE FUNCTION IN TERMS OF PRODUCTION OF BILE
- in the URQ
- BILE: FAT EMULSIFIER
3
Q
describe the GALLBLADDER
A
the CHIEF FUNCTION in terms of STORAGE OF BILE
4
Q
describe the PANCREAS
A
- supplies most of the ENZYMES needed to DIGEST CHYME
- also supplies BICARBONATE to NEUTRALIZE STOMACH ACID
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
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
- connects to GALLBLADDER (CYSTIC DUCT)
7
Q
what are the LOBES OF THE LIVER?
A
- consists of FOUR PRIMARY LOBES;
- RIGHT
- LEFT
- CAUDATE (inferior view)
- QUADRATE (inferior view)
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
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
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
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!!
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)
13
Q
describe the HISTOLOGY OF THE LIVER
A
composed of HEPATOCYTES + BILE CANALICULI + HEPATIC SINUSOIDS
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
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
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
17
Q
function of STELLATE MACROPHAGES
A
- also known as HEPATIC MACROPHAGES/KUPFFER CELLS) within LIVER SINUSOIDS
- REMOVES DEBRIS OR OLD WBCs
18
Q
what are the LIVER (HEPATIC) SINUSOIDS?
A
heavily FENESTRATED LEAKY CAPILLARIES between the HEPATIC PLATES
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 😄
- BILE SALTS:
20
Q
what is BILIRUBIN?
A
- pigment formed from HEME
- broken down into STERCOBILIN—BROWN DISCOLORATION TO FECES
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
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
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!!
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
25
what is the SIGNIFICANCE OF ENTEROPEPTIDASE?
- has **ENTEROPEPTIDASE (secreted from DUODENAL EPITHELIAL CELLS)**
- **ACTIVATES THE PROTEASES!!**
26
what are the CORRESPONDING PROTEASES (INACTIVE AND ACTIVE FORMS) in the DUODENUM?
TRYSINOGEN (INACTIVE) > TRYPSIN
CHYMOTRYPSINOGEN > CHYMOTRYPSIN
PROCARBOXYPEPTIDASE (INACTIVE) > CARBOXYPEPTIDASE
27
why is the DUODENUM so IMPORTANT?
- where BILE DUCT & PANCREATIC DUCT unites in WALL
- **FUSES TOGETHER as the HEPATOPANCREATIC AMPULLA**
28
describe the FUNCTION OF THE AMPULLA and the HEPATOPANCREATIC SPHINCTER
- AMPULLA:
- opens into **DUODENUM via the MAJOR DUODENAL PAPILLA**
- HEPATOPANCREATIC SPHINCTER:
- controls **ENTRY OF BILE and PANCREATIC JUICE into DUODENUM**
29
How are the BILE AND PANCREATIC SECRETIONS REGULATED?
- **BILE & PANCREATIC JUICE SECRETIONS:**
- both stimulated by NEUTRAL & HORMONAL CONTROLS
- H**ORMONAL CONTROLS;**
- includes ENTEROGASTRONES; CHOLECYSTOKININ (CCK) & SECRETIN
30
describe the SMALL INTESTINE
- 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
describe the SUBDIVISONS OF THE SMALL INTESTINE or what are they? (3)
- DUODENUM
[DUODENAL JEJUNAL JUNCTION]
- JEJUNUM
- ILEUM
[ILEOCECAL JUNCTION—where SMALL INTESTINE and LARGE INTESTINE MEET]
32
describe the DUODENUM
- mostly retroperitoneal; around 25.0 cm (10 in)
- CURVES around the HEAD OF THE PANCREAS
- **NUTRIENT IRON**
33
describe the JEJUNUM
- around ~2.5 m (8 ft long); ATTACHES POSTERIORLY by the MESENTRY
- **MAJORITY OF NUTRIENTS takes PLACE HERE (with exceptions of course)—ABSORPTION**
34
describe the ILEUM
- 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
what is the BLOOD SUPPLY of the SMALL INTESTINE?
- **SUPERIOR MESENTERIC ARTERY—BLOOD SUPPLY**
- **VEINS (carries NUTRIENT-RICH BLOOD):**
- drains into **SUPERIOR MESENTERIC VEINS**
- **goes into HEPATIC PORTAL VEINS**
- **then into LIVER**
36
what is the NERVE SUPPLY OF THE SMALL INTESTINE?
- **PARASYMPATHETIC INNERVATION—VAGUS NERVE**
- **SYMPATHETIC INNERVATION—THORACIC SPLANCHNIC NERVES**
37
what are some MODIFICATIONS the SI has for ABSORPTION?
- **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
function of ENTEROCYTES
- forms the **BULK OF EPITHELIUM (SIMPLE COLUMNAR)**
- **ABSORBS NUTRIENTS and ELECTROLYTES in the BILII**
- secretes INTESTINAL JUICE in the CRYPTS
39
function of PANETH CELLS
secretes DEFENSINS and LYSOZYMES + ANTIMICROBIAL AGENTS
40
describe INTESTINAL JUICE
provides a VEHICLE FOR ABSORPTION for SUBSTANCES from CHYME as they come in contact with VILLI
41
describe BRUSH BORDER ENZYMES
- found on the **SURFACES OF THE MICROVILLI of ABSORPTIVE CELLS + BREAKS DOWN FOOD PRODUCTS**
- MAJOR STIMULUS for PRODUCTION—HYPERTONIC or ACIDIC CHYME
42
describe the REGULATION OF CHYME ENTRY
- CHYME entering DUODENUM; typically HYPERTONIC (chyme delivery has to be SLOW)
- CHYME:
- **must be mixed with BILE and PANCREATIC JUICE = continues DIGESTION**
43
what controls the movement of food into the duodenum?
the enterogastric reflex
44
how does food MOVE in the SMALL INTESTINE?
- 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
describe the SUBDIVISIONS of the LARGE INTESTINE
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
what are the THREE UNIQUE FEATURES of the LARGE INTESTINE?
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
describe the HISTOLOGY OF THE LARGE INTESTINE
- 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
describe C. DIFFICILE
- 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
describe the DIGESTIVE PROCESS
- DIGESTIVE PROCESS:
- residue remains in L**ARGE INTESTINE around 12-24 hours**
- **NO FOOD BREAKDOWN—except by ENTERIC BACTERIA**
- **VITAMINS (made by bacterial flora) + WATER + ELECTROLYTES (Na + Cl)**
- FUNCTIONS:
- propulsion o**f FECES to ANNUS—DEFECATION**
- colon **not essential for life**
50
defintiion of HAUSTRAL CONTRACTIONS
- has **SLOW SEGMENTING MOVEMENTS**
- sequentially CONTRACTS in RESPONSE TO DISTENSION
51
defintiion of GASTROCOLIC REFLEX
- GASTROCOLIC REFLEX:
- initiated by the P**RESENCE OF FOOD in STOMACH**
- **activates THREE to FOUR SLOW POWERFUL PERISTALTIC WAVES per DAY IN COLON (MASS MOVEMENTS)**
52
describe how the LOW FIBER DIET can influence the DIGESTIVE PROCESS
- an begin to NARROW THE COLON and cause S**TRONG CONTRACTIONS that INCREASES PRESSURE ON WALLS**
- results in **DIVERTICULA—HERNIATIONS OF MUCOSA**
53
definition of IBS
- IBS:
- **functional GI DISORDER**
- recurring abdominal pain, stress, etc…
54
definition of IBD
- **CROHN’S + ULCERATIVE COLITIS**
- ulceration of the GI TRACT (CONT.)
- have SKIP LESIONS—areas of inflammation and normal areas (CROHN’S)
55
definition of ABSORPTION
- 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
what are the SIMPLEST FORMS OF MONOSACCHARIDES?
- 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
describe the PATHWAY OF DIGESTION OF CARBS
- 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
describe LACTOSE INTOLERANCE
- 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
what can LACTOSE INTOLERANCE CAUSE?
- BACTERIAL METABOLISM (undigested solutes):
- production of **LARGE AMOUNTS OF GAS**
- **results of BLOATING + FLATULENCE + CRAMPING PAIN**
60
describe PROTEIN DIGESTION
- 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
describe LIPID DIGESTION
- 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
describe the LIPID DIGESTON PATHWAY
-
- DIGESTION:
- P**ANCREATIC 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
describe NUCLEIC ACID DIGESTION
- 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
describe ABSORPTION of MONOSACC in SMALL INTEST
- 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
describe ABSORPTION of AMINO ACIDS in SMALL INTEST
- AMINO ACIDS:
- ABSORBED t**hrough ACTIVE TRANSPORT or SECONDARY ACTIVE TRANSPORT** (around 99% are ABSORBED)
- **LEAVE THROUGH SIMPLE DIFFUSION**
66
describe ABSORPTION OF LIPIDS in SMALL INTEST
- LIPIDS:
- A**BSORBED THROUGH SIMPLE DIFFUSION (95%)**
- **LEAVE THROUGH SIMPLE DIFFUSION**
67
where does the DIGESTIVE SYSTEM arise from?
the ENDODERM
