SEHS UNIT 3 ENERGY SYSTEMS - 3.2 Carbohydrates and Fats Metabolism

Metabolism

All the biochemical reactions that occur within an organism.

Anabolism

Energy requiring reaction whereby small molecules are built up into larger ones

Aerobic catabolism

Chemical reaction that breaks down complex organic compounds into simpler ones, with the net release of energy

Anaerobic catabolism

The breakdown of complex chemical substances into simpler compounds, with the release of energy, in the absence of oxygen.

Glycogen

Storage form of glucose

The major storage sites for glycogen

Muscles and liver

The major sites of triglyceride storage

Adipose tissue and skeletal muscle

The role of insulin in the formation of glycogen and the accumulation of body fat. (1 step of 7)

After eating a meal there is an increase of glucose in the blood

The role of insulin in the formation of glycogen and the accumulation of body fat. (2 step of 7)

Insulin is a hormone secrete by the pancreas in response to elevated blood glucose

The role of insulin in the formation of glycogen and the accumulation of body fat. (3 step of 7)

Insulin helps to lower the elevated blood sugar levels

The role of insulin in the formation of glycogen and the accumulation of body fat. (4 step of 7)

Insulin speeds up the diffusion of glucose into the cells

The role of insulin in the formation of glycogen and the accumulation of body fat. (5 step of 7)

Excess glucose is converted into glycogen, it is removed from the bloodstream and stored in the liver and muscles.

The role of insulin in the formation of glycogen and the accumulation of body fat. (6 step of 7)

Insulin stops fat from being used as an energy source, so insulin is preventing the body from breaking down lipids and glycogen.

The role of insulin in the formation of glycogen and the accumulation of body fat. (7 step of 7)

Insulin promotes the accumulation of fat by stimulating the body to store fat in the adipose tissue

Glycogenolysis

The breakdown of glycogen back into glucose (and its release into the blood)

Lipolysis

The breakdown of stored fat into glucose

Glucagon

A hormone complementary to insulin. Secreted by the pancreatic when blood glucose levels lower. It stimulates glycogenolysis to raise blood glucose levels.

Adrenaline

A hormone released into the bloodstream in response to physical or mental stress (fight or flight)

Glucagon during fasting

Blood glucose levels will drop.

Glucagon is a hormone, released from the pancreas

This stimulates glycogenolysis and lipolysis and

Accelerates the conversion of glycogen to glucose in the liver

Glucagon during exercise

Glucose is being used to release energy (aerobic respiration) and therefore blood glucose levels drop.

Glucagon is a hormone, released from the pancreas

This stimulates glycogenolysis.

And accelerates the conversion of glucose in the liver.

Adrenaline during fasting

Blood glucose levels will drop.

Adrenaline is released as part of a sympathetic nervous system response.

This accelerates the conversion of glycogen to glucose in the liver.

Adrenaline during exercise

There is an increased demand for glucose within the skeletal muscle cells for respiration to occur.

Adrenaline is released as part of a sympathetic nervous system response.

This accelerates the conversion of glycogen to glucose in the liver.

The role of insulin and muscle contraction on glucose uptake during exercise (1 of 5 steps)

There is an increased demand for glucose to allow respiration to occur, as insulin and muscle contraction stimulates the uptake of glucose from the blood

The role of insulin and muscle contraction on glucose uptake during exercise (2 of 5 steps)

During exercise however insulin levels decrease, this allows an increase in glycogenolysis

The role of insulin and muscle contraction on glucose uptake during exercise (3 of 5 steps)

Stored glycogen in the muscles is the primary energy source for strenuous, prolonged exercise. This is why glycogenolysis occurs as opposed to insulin, allowing the diffusion of blood glucose.

The role of insulin and muscle contraction on glucose uptake during exercise (4 of 5 steps)

Blood glucose diffusion still occurs as inulin increases a cells permeability to glucose and so speeds up the uptake of glucose from the blood and skeletal muscles

The role of insulin and muscle contraction on glucose uptake during exercise (5 of 5 steps)

As inulin levels fall, glucagon and adrenaline increase, resulting in more glycogenolysis, releasing more glucose from glycogen stores.