Roll of skeletal muscle in starvation

Question 1

Are glucose requirements of muscle high or low during starvation?

Answer 1

They are low due to very low insulin levels.

Question 2

During the first couple weeks of starvation, muscle uses fatty acids from places in the liver as fuels, what are these places?

Answer 2

Adipose tissues & ketone bodies.

Question 3

Beyond 2 weeks of starvation, muscle only uses what as fuel and what happens to ketone bodies ?

Answer 3

Fatty acids. KBs are spared for other tissues, promoting KB in the blood so parts of the brain can utilise them.

Question 4

Starvation causes protein degradation causing muscle wastage, the resulting amino acids are used for gluconeogenesis…

Answer 4

because the brain utilises KB when KB in the blood is high enough, there is less need for the liver to perform gluconeogenesis. In effect of this, muscle protein degradation is paused as blood (glycerol and lactate) are sufficient to meet the gluconeogenic needs of the liver.

Question 5

Tell me about the brain in starvation.

Answer 5

First few weeks brain is dependant on glucose. Later, as KB rises, it can adapt to using ketone bodies for 2/3s of its caloric requirements- reducing the need for glucose consumption.

Question 6

What is metabolic disease?

Answer 6

Inborn errors of metabolism. Inborn error = an inherited genetic disorder which is either autosomal recessive or X-linked.
Majority are due to defects in single genes.

Question 7

Garrods hypothesis.

Answer 7

A= substrate excess
C= product deficiency
D= toxic or interfering metabolite.

Question 8

Major categories of inherited metabolic diseases.

Answer 8

Disorders of; mitochondrial function, amino acid, carbohydrate & peroxisomal metabolism, lysosomal storage diseases & miscellaneous (not exhaustive).

Question 9

Types of Inherent metabolic Diseases.

Answer 9

TYPE 1- Silent disorders
TYPE 2 - acute metabolic crises.
TYPE 3 - neurological deterioration.

Question 10

Describe type 1 - silent disorders

Answer 10

Not life-threatening, untreated could lead to brain damage developmental disabilities. Examples include IMDs associated with the metabolism of the aromatic acids.

Question 11

Describe phenylketonuria (PKu)

Answer 11

Inability of the body to use the essential amino acid phenylalanine. Characterised by elevated blood phenylalanine levels.

Question 12

What are the 3 phenotypes of PKU?

Answer 12

Classic PKU,
Varient PKU,
Mild hyperphenylalanemia (HPA)