4B A&P and Pathology of the Small Intestine (Part 2)

Question 1

What is emulsification?

Answer 1

Taking big globules of fat and dispersing them into smaller droplets

Question 2

What is responsible for emulsification?

Answer 2

Bile

Question 3

What is the benefit of emulsification?

Answer 3

Increasing surface area of exposed of fat

Question 4

After emulsification, which two pancreatic enzymes begin digestion on the emulsified fat droplets?

Answer 4

Pancreatic lipase and his friend colipase

Question 5

What are micelles?

Answer 5

Lipids coated with bile acids to protect and sequester it from water, so the lipids could travel thru the water

Question 6

Where do micelles go after they form?

Answer 6

To the brush border

Question 7

How do the micelles get inside the brush border cells?

Answer 7

They merge with the phospholipid bilayer of the brushborder and the fatty contents are uptaken into the inside of the absorptive enterocyte

Question 8

What happens to the fatty products brought into the cells from the micelles?

Answer 8

Inside they cell they get repackaged with protein-coated chylomicrons

Question 9

What happens to the chylomicrons?

Answer 9

They go to the lymph vessels - lacteals (lymphatic capillaries) first, then thoracic ducts before going into the blood when the lymph empties into the subclavian veins

Question 10

Which is bigger lacteals or blood capillaries?

Answer 10

Lacteals (lymphatic capillaries)

Question 11

Where does the thoracic duct empty into the venous circulation?

Answer 11

At the juncture of the jugular and subclavian veins

Question 12

What is Lipemia? When does it occur?

Answer 12

Lipid in the blood.

W/in an hour after eating a fatty meal

Question 13

What is the half-life of chilomicrons?

Answer 13

Less than 60 minutes, so plasma usually becomes clear within a few hours

Question 14

What is the fate of chilomicrons?

Answer 14

Removed from blood as they pass thru the capillaries of adipose tissue and the liver

Question 15

What enzyme does adipose tissue and the liver contain large quantities of?

Answer 15

Lipoprotein lipase

Question 16

Where is lipoprotein lipase especially active?

Answer 16

In the capillary enthothelium

Question 17

What does lipoproteinn lipase do?

Answer 17

Hydrolyzes the TGs of chylomicrons into FAs and glycerol, which diffuse into adipocytes (storage) & hepatocytes (re-packaged into lipoproteins and exported to blood)

Question 18

Can tissues use the contents of chylomicrons?

Answer 18

Yes, sir!

Question 19

What are the five general types of lipoproteins?

Answer 19

Chylomicrons
VLDL
IDL
LDL
HDL

Question 20

Where are chylomicrons synthesized?

Answer 20

By the enterocytes of the small intestine.

Question 21

What lipoproteins does the liver synthesize?

Answer 21

VLDL, IDL, LDL and HDL

Question 22

What do VLDLs contain?

Answer 22

High TGs, moderate cholesterol and phospholipids

Question 23

What do IDLs contain?

Answer 23

Moderate TGs, cholesterol and phospholipids

Question 24

What do LDLs contain?

Answer 24

Low TGs, high cholesterol and phospholipids

Question 25

What do HDLs contain?

Answer 25

Lows TGs, cholesterol and phospholipids

Question 26

What are the only two lipoproteins routinely monitored clinically to screen for atherosclerosis, MI and stroke risk, and heart disease?

Answer 26

LDL-C and HDL-C

Question 27

What are the most effective drugs currently in use for treating elevated LDL-C?

Answer 27

Statins (Lipitor, Crestor, Lescol, Mevacor, etc)

Question 28

What are the adverse effects of statins?

Answer 28

Myopathy

Question 29

What is Myalgia? Myositis? Rhabdomyolysis?

Answer 29

Myalgia is muscle pain/weakness w/o inreased creatine kinase VS Myositis also includes elevated CK. Rhabdomyolysis has very high CK (>10 times the upper normal limit), increased serum creatinine, often with dark urine and myoglobinuria

Question 30

What does dark urine and myoglubinuria indicate?

Answer 30

Muscle damage

Question 31

T/F all statins have been associated with myopathy?

Answer 31

T

Question 32

How many pts out of 10 report having muscle complaints?

Answer 32

1 in 10

Question 33

What are risk factors for myopathy?

Answer 33

Being elderly, small size, high statin dose, liver or renal disease, diabetes, uncontrolled hypothyroidism, and interacting medications

Question 34

What was the first lipid lowering agent?

Answer 34

Niacin (Vit B3)

Question 35

What are the three basic preparations of niacin?

Answer 35

Immediate release, sustained release, and extended release

Question 36

What is no-flush niacin? Does it work?

Answer 36

Inositol hexaniacinate/niacinamide. No, it is worthless

Question 37

What is the mechanism of action of Niacin?

Answer 37

Reduces production of VLDL, which leads to a secondary reduction of LDL

Question 38

What is the most potent agent for raising HDL?

Answer 38

Niacin

Question 39

Is intolerance to Niacin common?

Answer 39

Yes, only 50-60% of pts may be able to take full doses

Question 40

What are the adverse effects of Niacin? How can this be mitigated?

Answer 40

Flushing. Take ASA or NSAIDs 30-45 minutes prior to each niacin dose (blunts this prostaglandin-mediated effect)

Question 41

Why are Bile Acid binding resins taken?

Answer 41

Some take when statins do not lower the LDLs enough

Question 42

What do Bile Acid binding resins do?

Answer 42

Bind bile acids in your gut

Question 43

What happens if you bind bile acids with resins?

Answer 43

Can't emulsify fats, means you can't digest/absorb fat as well

Question 44

Do resins affect HDL or TGs?

Answer 44

No, not much. Will lower LDLs

Question 45

What happens if you don't breakdown/absorb fat?

Answer 45

It stays in your gut and becomes part of the stool

Question 46

What are the consequences of fat remaining in stool?

Answer 46

Constipation

Question 47

What can relieve constipation and bloating?

Answer 47

Increased dietary fiber or fiber supplement (Metamucil)

Question 48

What are the drug interactions of bile binding resins?

Answer 48

``` Interfere with: Fat soluble vitamins. Folate Thiazides Tetracyclines Warfarin Propanolol Penicillin ```

Question 49

What is one way of avoiding some of the drug-drug interactions of resins?

Answer 49

Take resins a few hours AFTER taking the affected medications

Question 50

All H2O absorption in the small intestine is what type?

Answer 50

Passive and secondary to solute movement

Question 51

What stimulates water absorption in the small intestine?

Answer 51

Solutes such as Na+, glucose, amino acids

Question 52

How is most K+ absorbed?

Answer 52

Passively when luminal [K+] rises b/c of absorption of water (solvent drag)

Question 53

Where does calcium absorption occur? What is it primarily regulated by?

Answer 53

In the Duodenum and jejunum. | Regulated by Vitamin D3

Question 54

What does vitamin D do?

Answer 54

Stimulates synthesis of Ca++binding proteins called calbindins in enterocytes

Question 55

How are fat soluble vitamins (ADEK) absorbed in the small intestine?

Answer 55

Similar to fat

Question 56

How are more water-soluble vitamins absorbed in the small intestine?

Answer 56

By simple diffusion

Question 57

What water soluble vitamin requires intrinsic factor?

Answer 57

B12

Question 58

What cells absorb IF-B12 complexes across the brush border?

Answer 58

Ileal cells

Question 59

What does atrophy of gastric mucosa result in?

Answer 59

Deficiency of IF and acid secretion that causes VitB12 deficiency

Question 60

Where do peristaltic contractions occur?

Answer 60

Esophagus, stomach, and small intestine

Question 61

How long does it take chyme to move across the entire Small Intestine via peristalsis?

Answer 61

3-5 hours

Question 62

What is segmentation?

Answer 62

A series of contractile and relaxation periods that mechanically digests food

Question 63

What is peristalsis and segmentation controlled by?

Answer 63

Autonomic nervous system - SNS generally inhibit, while paraSNS generally excite muscular activity