Fasting and Starvation Metabolism

What syndrome is commonly associated with starvation, particularly in children under 1 year of age?

In marasmus, which component does muscle primarily provide to the liver?

What is the primary function of fatty acyl-CoA in the context of starvation?

Which metabolic processes are primarily utilized by the brain during starvation?

What can lead to marasmus in adults?

What occurs during hepatic gluconeogenesis in response to fasting?

What is the relationship between hepatic gluconeogenesis and the urea cycle?

What happens to acetyl-CoA during starvation?

What role does oxaloacetate play in Starvation metabolism?

What is the primary source of glucose during prolonged fasting?

What process occurs simultaneously with lipolysis in adipose tissue during fasting?

Which of the following best explains the increase in ketone bodies during starvation?

What is the fate of fatty acids during the fasting state?

Fasting and Starvation Metabolism

Hepatic gluconeogenesis relies on protein degradation from muscle and triglyceride breakdown from adipose tissue.
Glucose synthesis from alanine in the liver is linked to the urea cycle, which is crucial in maintaining nitrogen balance.
Hepatic ketogenesis utilizes fatty acids derived from triglyceride degradation, leading to ketone body formation.

Starvation Process

Fatty acids are broken down via β-oxidation, yielding acetyl-CoA which enters the tricarboxylic acid (TCA) cycle for oxidative metabolism into CO2.
The presence of oxaloacetate is necessary for acetyl-CoA entry into the TCA cycle; during starvation, gluconeogenesis reduces oxaloacetate availability.
Increased acetyl-CoA levels during starvation promote the production of ketone bodies instead of continuing through the TCA cycle.

Marasmus Syndrome

Marasmus is a severe form of malnutrition prevalent in children under 1 year in developing countries, but can affect all age groups.
In marasmus, the body mobilizes fat as an energy source for ketogenesis while muscle-derived amino acids support gluconeogenesis in the liver.
The brain utilizes both glucose and ketone bodies as energy sources during this state of malnutrition.
Prolonged starvation exhausts energy and protein reserves, potentially leading to death from starvation.
Adults may experience marasmus due to diseases affecting swallowing or food access, such as throat or esophageal cancer, dementia, or stroke.

This quiz explores the metabolic processes involved in fasting and starvation. Focused on hepatic gluconeogenesis, ketogenesis, and the implications towards marasmus syndrome, it emphasizes the biochemical pathways and their significance in energy production and nutrient balance. Test your understanding of how the body adapts during periods of nutrient deprivation.