Intestinal Transport & Liver Physiology

Question 1

The enterosystemic fluid cycle is what?

Answer 1

daily exchange of several times total volume of water
- net movement both into and out of the intestinal lumen every 24 hours

Question 2

Why is the enterosystemiic fluid cycle important?

Answer 2

to reabsorb secretions delivered to proximal part of the small intestine

Question 3

What has a substantial fraction of ECF volume?

Answer 3

secretory fluids from accessory organs
stomach and intestine itself

Question 4

In the enterosystemic fluid cycle, there are larger volumes of secretions in [carnivores/omnivores/herbivores]

Answer 4

herbivores

Question 5

Where are major reabsorptive sites regarding the enterosystemic fluid cycle?

Answer 5

distal small intestine
large intestine

Question 6

Epithelial cells lining intestinal crypts secrete _____ & ______

Answer 6

fluid
electrolytes

Question 7

During intestinal secretions, the apical membrane has what kinds of channels?

Answer 7

Cl-

Question 8

What does the basolateral membrane have in epithelial cells of the intestinal crypt?

Answer 8

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

Question 9

Cl- channels of the epithelial cells of the crypts are usually [open/closed], but will open to response to _____ and ________ binding the basolateral membrane

Answer 9

closed
hormones
neurotransmitters

Question 10

What does the cholera toxin cause? What does it do?

Answer 10

chloride channels to open
dumps lots of Cl-, Na+, and water

Question 11

Which routes are there for fluid and electrolyte absorption

Answer 11

transcellular
paracellular

Question 12

If the junction is tight, it tends to go the [transcellular/paracellular] route

Answer 12

transcellular

Question 13

Where are there tight junctions?

Answer 13

stomach
colon

Question 14

If the junction is leaky, it tends to go the [transcellular/paracellular] route

Answer 14

paracellular

Question 15

Where are there leaky junctions?

Answer 15

duodenum
jejunum

Question 16

What is special about the jejunum with intestinal absorption?

Answer 16

major site for Na+ absorption

Question 17

Intestinal absorption occurs via what transporters on the apical membrane? Na+ transporters are coupled with what?

Answer 17

monosaccharides
amino acids
Na+/H+ exchanger

Question 18

The ileum also absorbs ______

Answer 18

Na+

Question 19

What transporters are on the apical membrane in the ileum?

Answer 19

Na+/sugar or amino acid
Cl-/HCO3-
Na+/H+ exchanger

Question 20

In the ileum, there is an overall net absorption of ______

Answer 20

NaCl

Question 21

What channels are there in the apical membrane of the colon?

Answer 21

Na+ and K+

Question 22

The synthesis of Na+ channels is induced by ______

Answer 22

aldosterone

Question 23

Diarrhea is due to an increase loss of [Na+/K+] due to an [increased/decreased] flow rate of intestinal fluid

Answer 23

K+
increased

Question 24

The colon helps to excrete which ion?

Answer 24

K+

Question 25

What are some issues and losses associated with severe diarrhea?

Answer 25

hypercholemic metabolic acidosis with normal anion gap

Question 26

You lose a lot of ____ from the GIT which signals the kidneys to reabsorb ______

Answer 26

HCO3-
NaCl

Question 27

What does losing HCO3- from the GIT stimulate?

Answer 27

Na+/H+ exchanger
kidneys start to excrete more H+, need more NH3 for buffering

Question 28

What causes diarrhea?

Answer 28

decreased surface area for absorption
osmotic diarrhea
secretory diarrhea

Question 29

The liver receives portal blood from which organs?

Answer 29

stomach
small intestine
large intestine
pancreas
spleen

Question 30

What produces and exerts bilirubin?

Answer 30

liver

Question 31

Bilirubin production and excretion has which type of system?

Answer 31

mononuclear phagocyte

Question 32

Hemoglobin is degraded to ______ then _______

Answer 32

biliverdin
bilirubin

Question 33

Bilirubin binds to _____ in [blood/lumen/colon]

Answer 33

blood

Question 34

After bilirubin binds to albumin in blood and transports to liver, it is conducted to _____, which results in _______

Answer 34

glucoronic acid
detoxification/degradation in liver

Question 35

Conjugated bilirubin is excreted in ___ AND secreted in ______

Answer 35

urine
bile - SECRETED!!

Question 36

If secreted in bile, conjugated bilirubin travels to where to become deconjugated?

Answer 36

terminal ileum
colon

Question 37

What is conjugated bilirubin deconjugated to?

Answer 37

urobilinogen
urobilin + stercobilin

Question 38

What is jaundice?

Answer 38

accumulation of free or conjugated bilirubin

Question 39

What does jaundice result in?

Answer 39

destruction of red blood cells
destruction of bile ducts
liver disease

Question 40

Can conjugated bilirubin be excreted?

Answer 40

NO
shows up in circulation

Question 41

What aa does gluconeogenesis use to synthesize glucose after glycogen is depleted? This is in [ruminants/nonruminants]

Answer 41

glycerol
glycogenic aa
non-ruminants

Question 42

How do ruminants do gluconeogenesis?

Answer 42

continuous process of converting propionate to glucose

Question 43

Glycogenesis are highly branches chains of stored _____ and occurs [before/after] a meal

Answer 43

glucose
AFTER

Question 44

What is glycogenolysis?

Answer 44

break down glycogen to release glucose

Question 45

What stimulates glycogenolysis?

Answer 45

glucagon
epinephrine

Question 46

What are the metabolic functions of the liver?

Answer 46

carbohydrate metabolism
protein metabolism
lipid metabolism

Question 47

Protein metabolism in the liver does what?

Answer 47

synthesizes non-essential amino acids
modifies amino acids
synthesizes plasma proteins (albumin)
converts ammonia to urea

Question 48

What happens in lipid metabolism in the liver?

Answer 48

fatty acid oxidation
synthesizes lipoproteins, cholesterol, phospholipids, and bile acids