The document discusses energy demand and supply as well as the integration of major metabolic pathways for energy metabolism. It outlines several key metabolic pathways including glycolysis, fatty acid oxidation, degradation of amino acids, the citric acid cycle, oxidative phosphorylation, the hexose monophosphate shunt, gluconeogenesis, and glycogen metabolism. It then describes how different organs specialize in carbohydrate, lipid, and protein metabolism both during fed and starved states to regulate energy supply and demand at the organism level.

1. By
Dr Shraddah Bharath
PG Student
ESIC-MC & PGIMSR
Banglore - 10

3. ENERGY DEMAND AND SUPPLY
• It is estimated that one can consume as much
as 100times his/her basal requirements.

4. INTEGRATION OF MAJOR METABOLIC
PATHWAYS OF ENERGY METABOLISM.
1. GLYCOLYSIS
2. FATTY ACID OXIDATION
3. DEGRADATION OF AMINO ACIDS
4. CITRIC ACID CYCLE
5. OXIDATIVE PHOSPHORYLATION
6. HEXOSE MONOPHOSPHATE SHUNT
7. GLUCONEOGENESIS
8. GLYCOGEN METABOLISM

7. CITRIC ACID CYCLE

12. OVERVIEW OF INTEGRATION OF METABOLIC
PATHWAYS OF ENERGY METABOLISM

13. REGULATION OF METABOLIC PATHWAYS

14. ORGAN SPECIALIZATION AND METABOLIC INTEGRATION
• DURING WELL-FED STATE
ORGANS CARBOHYDRATE
METABOLISM
LIPID
METABOLISM
PROTEIN
METABOLISM
LIVER
(CENTRAL
METABOLIC
CLEARING
HOUSE)
GLYCOLYSIS
GLYCOGENESIS
HMP SHUNT
GLUCONEOGENESIS
SYNTHESIS OF
FATTY ACIDS
AND
TRIACYLGLYCEROL
DEGRADATION OF
Aas &
PROTEIN
SYNTHESIS
ADIPOSE
TISSUE
(ENERGY
STORAGE
TISSUE)
15KG TAG 
STORED IN A
NORMAL
ADULT MAN
GLYCOLYSIS
HMP
SYNTHESIS OF
FATTY ACIDS
AND
TRIACYLGLYCEROL

15. ORGANS CARBOHYDRATE
METABOLISM
LIPID
METABOLISM
PROTEIN
METABOLISM
SKELETAL
MUSCLES
(METABOLISM
IS VARIABLE)
RESTING
MUSCLE 
30% OF O2
CONSUMPTION
STRENOUS
EXCERSISE 
90%
GLUCOSE UPTAKE
GLYCOGEN
SYNTHESIS
UPTAKE OF FATTY
ACIDS  IMPORTANT
SOURCES OF FUEL
FOR SKELETAL
MUSCLES
INCORPORATION OF
AAs INTO PROTEINS
IS HIGHER.
BRAIN ABOUT 120g OF GLUCOSE
IS UTILIZED PER DAY BY AN
ADULT BRAIN
FATTY ACIDS
INSIGNIFICANT AS
THEY DO NOT CROSS
BBB
DURING WELL-FED STATE

16. GLUCOSE
GLUCOSE
GLUCOSE
GLUCOSE
LIVER
ADIPOSE
GLUCOSE
BRAIN
MUSCLE

17. •METABOLISM IN STARVATION
ORGANS CARBOHYDRATE
METABOLISM
LIPID METABOLISM PROTEIN
MET.
LIVER
(ACTS AS
BLOOD
GLUCOSE
BUFFERING
ORGAN)
GLUCONEOGENESIS
GLYCOGEN
DEGRADATION
FATTY ACID OXIDATION
KETONE BODIES
SYNTHESIS
ADIPOSE
TISSUE
GLUCOSE UPTAKE &
ITS METABOLISM
DEGRADATION OF
TAG
FATTY ACID GLYCEROL

18. METABOLISM IN STARVATION
ORGANS CARBOHYDRATE
METABOLISM
LIPID
METABOLISM
PROTEIN MET.
SKELETAL
MUSCLE
GLUCOSE UPTAKE
& ITS METABOLISM
FATTTY ACIDS & KETONE
BODIES  UTILISED BY
SK MUSCLE AS A FUEL
SOURCES
STARVATION (>3WKS) 
INCREASED KB IN Bd
CIRCULATION
EARLY PERIOD
STARVATION 
MUSCLE PROTEINS
DEGRADED INTO AAs
 UTILISED BY LIVER
PROLONGED
STARVATION 
PROTEIN BREAK
DOWN REDUCED
BRAIN STARVATION FOR FIRST
2WKS  BRAIN IS
MOSTLY DEPENDENT ON
GLUCOSE (SUPPLIED BY
LIVER
GLUCONEOGENESIS)
>3WKS  INCREASED IN
PLASMA KETONE
BODIES BY THIS TIME
BRAIN DEPENDS ON KB
FOR ENERGY NEEDS

19. KETONE BODIES
KETONE BODIESKETONE
BODIES
KETONE
BODIES
GLYCEROL,
AMINO
ACIDS
GLUCOSE
GLUCOSE
LIVER
ADIPOSE
BRAIN
MUSCLE