Brain Metabolism
Objectives
1. Metabolism in the Brain - energy metabolism and ammonia
handling
2. Oxygen Consumption
3. Glucose Metabolism
4. Cerebral blood flow
5. Cerebrospinal fluid
Metabolic Systems
Aerobic and Anaerobic
Aerobic - presence of oxygen
Anaerobic - absence of oxygen
Ionic transport in the neurons mainly to transport Na+ and
Ca2+ to the outside and K+ to the inside
this is done by the sodium
potassium ATPase pumps
Brain Metabolism 1
, BRAIN METABOLISM
this is the sum of chemical changes that occur within the
tissues of the brain consisting of anabolism (biosynthesis)
and catabolism
basically, it is the buildup and breakdown of molecules
for utilization by the brain
this is important because the brain is a very important
aspect in the functioning of the body
The brain has a low energy reserve
the brain expends so much energy that it is not able to
store energy. This means that energy needs to be constantly
supplied to the brain
The energe is needed to maintain the ionic gradient across
nerve membranes. (putting Na+ and Ca2+ outside and bringing K+
inside)
GLUCOSE is the main fuel and source of energy. lactate is
also used
Brain depends more on aerobic metabolism
Hypoxia to the brain for more than 10 sec causes
unconsciousness. this is because the brain depends almost
entirely on aerobic metabolism which means that oxygen is
needed at all times
Glucose enters the brain via the GLUT-1 receptors in the
cerebral capillaries
insulin is not required for cerebral cells to utilize
glucose
glucose enters the glia and neurons by pass through GLUT 3
and GLUT 5 transporters
Brain Metabolism 2
Objectives
1. Metabolism in the Brain - energy metabolism and ammonia
handling
2. Oxygen Consumption
3. Glucose Metabolism
4. Cerebral blood flow
5. Cerebrospinal fluid
Metabolic Systems
Aerobic and Anaerobic
Aerobic - presence of oxygen
Anaerobic - absence of oxygen
Ionic transport in the neurons mainly to transport Na+ and
Ca2+ to the outside and K+ to the inside
this is done by the sodium
potassium ATPase pumps
Brain Metabolism 1
, BRAIN METABOLISM
this is the sum of chemical changes that occur within the
tissues of the brain consisting of anabolism (biosynthesis)
and catabolism
basically, it is the buildup and breakdown of molecules
for utilization by the brain
this is important because the brain is a very important
aspect in the functioning of the body
The brain has a low energy reserve
the brain expends so much energy that it is not able to
store energy. This means that energy needs to be constantly
supplied to the brain
The energe is needed to maintain the ionic gradient across
nerve membranes. (putting Na+ and Ca2+ outside and bringing K+
inside)
GLUCOSE is the main fuel and source of energy. lactate is
also used
Brain depends more on aerobic metabolism
Hypoxia to the brain for more than 10 sec causes
unconsciousness. this is because the brain depends almost
entirely on aerobic metabolism which means that oxygen is
needed at all times
Glucose enters the brain via the GLUT-1 receptors in the
cerebral capillaries
insulin is not required for cerebral cells to utilize
glucose
glucose enters the glia and neurons by pass through GLUT 3
and GLUT 5 transporters
Brain Metabolism 2
