Lecture 8: Intestinal Transport and Liver Physiology

Question 1

Secretory fluids from accessory organs, stomach, and intestine itself take up a

Answer 1

Substantial fraction of ECF volume

Question 2

Enterosystemic cycle

Answer 2

Daily exchange of several times total volume of body water

Question 3

Net movement of fluid into and out of intestinal lumen every 24 hours

Answer 3

Enterosystemic cycle

Question 4

Where are the major reabsorptive sites?

Answer 4

Distal SI + LI

Question 5

What kind of eater has the largest volumes of secretions

Answer 5

Herbivores

Question 6

Apical membrane has what channels

Answer 6

Cl channels

Question 7

When Cl goes into the lumen, what follows, and what follows after?

Answer 7

Na follows Cl, water follows NaCl

Question 8

What transporters does basolateral membrane have?

Answer 8

Na+/K+ ATPase
Na+/K+/2Cl co-transporter

Question 9

Cl channels are normally

Answer 9

Closed

Question 10

What will Cl channels open in response to?

Answer 10

Hormones and neurotransmitters binding basolateral membrane

Question 11

What does cholera cause

Answer 11

Secretory diarrhea

Question 12

What routes for fluid and electrolyte absorption

Answer 12

Transcellular and paracellular

Question 13

What determines the route taken

Answer 13

Permeability of tight junctions between enterocytes

Question 14

What locations are tight junctions “tight”

Answer 14

Stomach and colon

Question 15

What locations are tight junctions “leaky”

Answer 15

Duodenum and jejunum

Question 16

When tight junctions are leaky, is it easier or harder for fluid and ions to move paracellular?

Answer 16

Easier

Question 17

Fluid absorbed is always

Answer 17

isosmotic

Question 18

What is the major site for Na+ absorption

Answer 18

Jejunum

Question 19

What transporter is used for Na absorption in jejunum?

Answer 19

Na-dependent co-transporters

Question 20

Ileum net absorption or secretion of NaCl?

Answer 20

Absorption

Question 21

What transporter is in the enterocyte apical membrane of ileum?

Answer 21

Cl-/HCO3-

Question 22

What transporter is in the enterocyte basolateral membrane?

Answer 22

Cl- transporter

Question 23

Apical membrane of colon has what channels?

Answer 23

Na and K channels

Question 24

Synthesis of Na+ channels in colon is induced by

Answer 24

Aldosterone

Question 25

Synthesis of Na+ channels in colon is induced by aldosterone, which leads to absorption of what and secretion of what

Answer 25

Increased absorption of Na Increased secretion of K+

Question 26

Fecal concentrations of K+ in

Answer 26

Herbivores

Question 27

Why are fecal concentrations of K+ in herbivores

Answer 27

K+ high in forages

Question 28

Loss of large volumes of ECF-type fluid from GIT leads to (ECF volume, intravascular volume, arterial blood pressure)

Answer 28

All decrease

Question 29

Large loss of volumes of ECF-type fluid from GIT leads to what receptors being stimulated?

Answer 29

Baroreceptors to restore BP

Question 30

High K+ losses in ECF =

Answer 30

Hypokalemia

Question 31

Circulatory collapse is an issue associated with

Answer 31

Severe diarrhea

Question 32

High HCO3 losses relative to Cl losses can lead to

Answer 32

Hypochloremic metabolic acidosis with normal anion gap

Question 33

Loss of bicarb from GIT signals what to the kidneys

Answer 33

To reabsorb NaCl (because Na usually lost from GIT with bicarb lost)

Question 34

What is activated when bicarb is lost from GIT and Na needs to be reabsorbed

Answer 34

RAAS activated -> Stimulates Na/H exchanger

Question 35

Decreased surface area (cause of diarrhea) can be due to

Answer 35

Infections Inflammation of SI

Question 36

Osmotic diarrhea can be due to

Answer 36

Non-absorbable solutes

Question 37

Secretory diarrhea can be due to

Answer 37

Excessive secretions of fluid by crypt cells which permanently activates adenylyl cyclase and cAMP levels high

Question 38

Excessive secretions of fluid by crypt cells activate? Leading to?

Answer 38

Adenylyl cyclase; High cAMP levels

Question 39

Liver receives portal blood from

Answer 39

Stomach, SI, LI, pancreas, spleen

Question 40

Functions of liver

Answer 40

- Process absorbed substances - Synthesis and excretion of bile acids - Bilirubin production and excretion - Metabolism of nutrients - Detoxification and excretion of waste products

Question 41

Bile equation/formation

Answer 41

Cholesterol > Bile acids > Conjugate with glycine or taurine > Bile salts

Question 42

Mononuclear phagocyte system removes ______ _____

Answer 42

Senescent RBC

Question 43

Mononuclear phagocyte system degrades ________

Answer 43

Hemoglobin

Question 44

Mononuclear phagocyte system degrades hemoglobin > _______

Answer 44

Biliverdin

Question 45

Mononuclear phagocyte system degrades hemoglobin > Biliverdin > _______

Answer 45

Bilirubin

Question 46

Bilirubin binds

Answer 46

Albumin in blood

Question 47

Bilirubin binds albumin in blood > _____

Answer 47

Liver

Question 48

Bilirubin binds albumin in blood > Liver > conjugated to

Answer 48

Glucuronic acid

Question 49

Conjugated bilirubin excreted in ____ AND secreted in ____

Answer 49

Urine; bile

Question 50

Conjugated bilirubin excreted in urine and secreted in bile --> ______ and ____

Answer 50

Terminal ileum and colon

Question 51

Conjugated bilirubin excreted in urine and secreted in bile --> terminal ileum and colon --> deconjugated to ______ AND ____ + _____

Answer 51

urobilinogen AND urobilin + stercobilin

Question 52

Which bilirubin deconjugation is excreted in feces

Answer 52

urobilin and stercobilin

Question 53

Some of this bilirubin conjugation goes back to the liver

Answer 53

urobilinogen

Question 54

Increased destruction of RBC and build up of unconjugated bilirubin

Answer 54

Jaundice

Question 55

Jaundice can be due to what 2 things

Answer 55

Obstruction of bile duct Liver disease

Question 56

Use glycerol + glucogenic AA to synthesize glucose AFTER stored glycogen exhausted

Answer 56

Gluconeogenesis

Question 57

Occurs after meal --> Synthesizing glycogen [highly branched chains of glucose]

Answer 57

Glycogenesis

Question 58

Glycogen

Answer 58

Highly branched chains of glucose

Question 59

Breakdown of glycogen to release glucose --> Stimulated by glucagon and epinephrine

Answer 59

Glycogenolysis

Question 60

Liver synthesizes what kind of amino acids

Answer 60

Non-essential

Question 61

Liver modifies amino acids using

Answer 61

Glucogenic AA to make glucose

Question 62

What plasma proteins does liver synthesize

Answer 62

Albumin, clotting factors

Question 63

Liver converts ammonia to

Answer 63

urea

Question 64

What does liver do in lipid metabolism for fatty acids

Answer 64

Fatty acid oxidation (energy)

Question 65

Liver synthesizes what as far as lipid metabolism goes

Answer 65

Lipoproteins, cholesterol, phospholipids, bile acids, HDLs, LDLs

Question 66

What stimulates glycogenolysis?

Answer 66

Glucagon and epinephrine

Question 67

First pass metabolism

Answer 67

Liver receives ALL substances absorbed from the GIT

Question 68

In liver, bacteria are phagocytized by

Answer 68

Hepatic Kupffer cells

Question 69

Liver modifies toxin to be; for

Answer 69

Water soluble for excretion in urine or bile

Question 70

Phase I reactions include

Answer 70

Oxidation/reduction/hydrolysis/cyclization reactions

Question 71

Phase II reactions include

Answer 71

Conjugation reactions (solubilize compound; transferases)