Absorptive & Postabsorptive Nutrient Utilization I

Question 1

are digestion and absorption continuous?

Answer 1

NOPE

Question 2

what are the three phases of fuel metabolism?

Answer 2

absorptive phase
postabsorptive phase
prolonged energy deficiency

Question 3

list the major fuel of the brain for each phase of fuel metabolism

Answer 3

phase I (absorptive) - glc
phase II (postabsorptive) - glc
phase III - ketones

Question 4

what fluctuates more dramatically, AA and FA levels or glc levels?

Answer 4

AA and FA

Question 5

why do glc levels have to be kept within a strict concentration?

Answer 5

basic metabolic fuel
brain uses glc almost exclusively

Question 6

which 3 metabolic fuels are channeled to depot sites during absorptive phase?

Answer 6

glc
aa
TG/FA

Question 7

what’s protein mainly used for?

Answer 7

body protein
metabolism if needed

Question 8

what’s glc mainly used for?

Answer 8

metabolism ASAP

Question 9

what’s FA mainly used for?

Answer 9

adipose +/- metabolism

Question 10

what’s the pathway where all fuels are used?

Answer 10

krebs cycle

Question 11

glc is stored as ___ in liver and muscle during absorptive phase

Answer 11

glycogen

Question 12

what’s the first step in glc processing?

Answer 12

glycolysis

Question 13

excess glc can be converted to ____ in liver

Answer 13

FA

Question 14

nitrogen is transferred to ___ -> alanine

Answer 14

pyruvate
aka transport AA

Question 15

what’s the major source of blood urea?

Answer 15

liver

Question 16

do AA get removed from circulation on first of second liver passge?

Answer 16

first

Question 17

what does the liver selectively remove AA for?

Answer 17

ones that can be used for hepatic protein and plasma protein synthesis or for liver metabolism

Question 18

most AA can be converted to ___ and ___ synthesis

Answer 18

glc and FA

Question 19

what’s the storage form of AA?

Answer 19

muscle protein

Question 20

when does a “net increase” in muscle protein occur?

Answer 20

when synthesis&raquo_space;> breakdown

Question 21

after liver deamination, keto-analogues are… (3 possibilities)

Answer 21

1. metabolized
2. enter gluconeogenesis/glycogenesis
3. enter FA synthesis

Question 22

what’s the storage form of FA?

Answer 22

triglycerides

Question 23

what do pools of FA consist of?

Answer 23

NEFA and glycerol

Question 24

where are NEFA and TG repackaged?

Answer 24

liver

Question 25

during postabsorptive phase, what do fat cells release?

Answer 25

glycerol and NEFA

Question 26

can FA be converted to glc? why?

Answer 26

nope since decarboxylation of pyruvate to acetyl CoA is irreversible

Question 27

what's derived from FA to act as alternative fuel source?

Answer 27

ketone bodies

Question 28

where can ketone bodies be used during prolonged energy deficiency?

Answer 28

brain and heart

Question 29

what two things regulate transfer of metabolic fuels into pools during absorptive phase?

Answer 29

insulin glucagon

Question 30

in order to reduce circulating glc concentrations, insulin sitm...

Answer 30

glc uptake in liver glycogen synthesis in liver/muscle FA synthesis in liver and adipose protein synthesis in liver/muscle

Question 31

how is insulin secretion stim?

Answer 31

increased levels of glc in circulation

Question 31

insulin is secreted by pancreatic __-cells

Answer 31

beta

Question 32

glucagon is secreted by pancreatic ___-cells

Answer 32

alpha

Question 33

how is glucagon secretion stim?

Answer 33

low levels of glc and/or high levels of aa

Question 34

insulin promotes glc uptake by increasing surface exposure of ___ transporters

Answer 34

GLUT 4

Question 35

insulin stim glycogen synthesis in liver by ____ of glycogensynthase (activated) and by ____ of glycogenphosphatase (inactive)

Answer 35

dephosphorylation for both

Question 36

describe what happens when glc >> aa

Answer 36

Question 37

describe what happens when glc

Answer 37

Question 38

high aa levels stim both ___ and ___ secretion

Answer 38

insulin and glucagon

Question 39

high glc levels stim mostly ___ secretion

Answer 39

insulin

Question 40

glucagon is stim by high ___ and low ___ levels

Answer 40

high aa low glc

Question 41

what does glucagon stim from aa in order to prevent hypoglycemia?

Answer 41

gluconeogenesis

Question 42

during the ____ phase, metabolic fuels are channeled to depot sites, and glc is used to maintain metabolism

Answer 42

absorptive

Question 43

during the ___ phase, metabolic fuels are mobilized from depots

Answer 43

post-absorptive

Question 44

both a ___-rich diet and the ___ phase are characterized by low glc levels

Answer 44

protein rich post-absorptive phase