Question

Explain the cellular and metabolic pathways involved in the uptake of glucose from the blood by muscle and adipose tissue after eating a meal. Make sure you include on your explanation the digestive organs, hormone, receptor, and transporter involved in the uptake of glucose, and the metabolic pathways activated inside the cells after glucose uptake..

please explain the physiology thoroughly.

Answer 1

Metabolism is the process in which the carbohydrates is broken down ,metabolised and used for the energy puroposes .

Carbohydrate (glucose ) can be explained in major three pathways .

1. Glycolysis

It is a metabolic process in which the glucose( 6 carbon compund ) undergoes many chemical reactions to produce the final product pyruvic acid (3 carbon compound) .

It is a cytoplasmic pathway

Glysolysis takes place in 10 steps

In this catabolic method the energy is generated through the formation of ATP and NADPH .

2ATP and 2 NADPH .= 8 ATP

It is explained in the daigram .

Glucose transportation in the body can be explained as :

The primary regulatory method by which glusose uptake take place is via insulin stimulated transport of glucose into skeletal muscle and adipose tissue ,mediated by GLUT 4.

Glut4 exist in skeletal muscle cells,adipocytes and cardiomyocytes .

INSULIN MEDIATED UPTAKE .

Insulin mediated uptake can occur through 2 pathways .

First : It involves lipid kinase phosphatadyllinositol-

3 -Kinase . Insulin binds to the receptor ,and the receptor undergoes confirmational changes which activates tyrosine kinase domain intracellularaly .

Then they undergo phosphorylation and glucose is transported .

Second :Protooncoprotien comples when insulin mediated undergoes phosphorylation and gkusoe is taken in .

NON INSULIN MEDIATED

Physical activity stimulates GLUT 4 translocation to the plasma membrane in skeletal muscle .

Coming to the metabolism ,we can break it into 4 categories .

1.Breakdown of substrates .

Glycolysis , oxidative phosphorylation , krebs cycle .

2. Storage of energy .

Glycogenosis .

3.Metobolism

Gluconeogenesis, Glycogenolysis.

4 . Side pathways such as HMP Shunt pathway .

Expalining each of the reaction .

1. Glycolysis - Already mentioned in the first para.

2. Glycogenesis

# It is the formation of primary carbohydrate glycogen , stored away in the liver and muscle cells .

3. Gluconeogenesis

# It is a metabolic pathway that results in the generation of glucose from certain non carbohydrate carbonsubstrates .

# It is a eleven enzyme catalysed reaction .

4. HMP Shunt pathway .

# The pentose phosphate pathway parallel to glycolysis .

It generates NADPH and pentoses as well as ribose -5-phosphate and they are the precursor of nucleotide synthsis .