Morfofisiología I: Metabolismo de Carbohidratos

General Information

• Course: Morfofisiología I, Programa de Medicina
• Institution: Universidad Nacional Experimental "Francisco de Miranda"
• Location: Extensión Barinas
• Instructor: Daniela Canelón
• Topic: Carbohydrate Metabolism, Glycogenolysis, and Glycogenogenesis
• Members: A list of student names is given.

Carbohydrate Metabolism

• This is a metabolic pathway responsible for oxidizing glucose, with fructose and other dietary carbohydrates being parts of this.
• The product of this pathway is pyruvate, which is essential for protein and lipid synthesis through the formation of acetyl-CoA.
• This process is important for the overall metabolism.

Glycogenolysis Process

• Glycogenolysis is the process of breaking down glycogen into glucose for energy.
• This starts in the mouth with the enzyme amylase, breaking down complex sugars into monosaccharides.
• Amylase is an enzyme that catalyzes the breakdown of the 1-4 linkages in glucose and glycogen.
• This enzyme is mainly produced in salivary and pancreatic glands.
• Glucose enters the body and is broken down by amylase into simpler sugars.
• The process involves the breakdown of glycogen molecules into glucose molecules.
• There are different types of monosaccharides and disaccharides involved including: glucose, galactose, fructose, maltose, lactose, and sucrose.

Glycogenolysis Mechanisms

• Glycogen is broken down by specific enzymes through a process called hydrolysis.
• Hydrolysis uses water molecules to break the bonds.
• Phosphorolysis is the process that uses phosphate groups to break the bonds of glycogen.
• Glycogen phosphorylase is one key enzyme in glycogenolysis.
• Other notable enzymes include: debranching enzymes, phosphoglucomutase, and glucose-6-phosphatase.

Glycogenolysis Regulation

• Liver: Regulation is primarily controlled by glucagon and adrenalines and also influenced by insulin levels.
• Muscle: Is predominantly influenced by the activation of glycogen phosphorylase by AMP and calcium and inhibition by glucose-6-phosphate and insulin.

Glycogen Storage Diseases

• Certain diseases, such as Cori's Disease and Pompe's Disease are linked to deficiencies in enzymes crucial for glycogenolysis.
• These diseases can lead to glycogen buildup in different tissues, affecting normal bodily functions.

Glycogenogenesis

• This is the synthesis of glycogen, a crucial anabolic pathway catalyzed by insulin.
• It happens in the liver and muscles and involves several steps.
• This pathway is triggered after a meal when blood sugar levels are elevated, especially high-carbohydrate meals.
• Gluconeogenesis is essential for the storage of glucose as glycogen when the body has excess glucose.

Glycogenogenesis Stages

• This process has five main stages involved in the synthesis and branching of glycogen.
• The first stage is the phosphorylation of glucose to glucose-6-phosphate.
• The second stage is the isomerization of glucose-6-phosphate to glucose-1-phosphate.
• The third stage involves the activation of glucose-1-phosphate to UDP-glucose.
• The fourth step involves the addition of glucose molecules to the growing glycogen chain.
• The fifth and final stage involves the branching of the glycogen chain for increased storage capacity.

Importance of Glycogenogenesis

• Glycogenogenesis plays a crucial role in storing excess glucose in tissues like the liver, muscles, and red blood cells.
• It provides a readily available energy source when blood glucose levels are low.
• The liver's glycogen stores help maintain consistent blood glucose levels.
• This is vital for bodily functions and energy demands.

Glycogen Metabolism Disorders

• Disorders like Van-Creveld and Hers Disease result from defects in glycogen metabolism due to enzyme deficiencies affecting glycogen storage.
• This will be reflected in issues relating to the regulation of blood glucose levels, potentially leading to health concerns.

Regulation of Glycolysis and Gluconeogenesis

• Glycolysis and gluconeogenesis are regulated by hormones (glucagon, insulin) and allosteric effectors to maintain blood glucose balance and energy reserves.
• These mechanisms are critical to ensure the body has enough energy to meet its needs.
• Substrate availability, product inhibition, allosteric regulation, and hormonal controls are crucial components in the regulation of these pathways.

Este cuestionario evalúa los conceptos fundamentales del metabolismo de carbohidratos, incluyendo la glucogenólisis y la glucogénesis. Se centra en los procesos metabólicos que convierten el glucógeno en energía, así como la importancia del piruvato en la síntesis de proteínas y lípidos.