Learn: Energy Systems in Applied Anatomy and Physiology

Welcome!Today we'll explore energy systems in the human body. You'll learn about how energy is produced for physical activity, and how your body adapts to different types of exercise. Let's get started!

What are Energy Systems?Energy systems provide the body with the energy it needs to perform physical activities. They work by breaking down food molecules like carbohydrates, fats, and proteins into energy. This energy is stored in a molecule called ATP (adenosine triphosphate).

The ATP-PC SystemThe ATP-PC system is an immediate energy system that uses stored phosphocreatine (PC) to quickly generate ATP without using oxygen. It provides energy for short, high-intensity activities like sprinting or weightlifting. However, this system only lasts for about 10 seconds before the stores run out.

The Glycolytic SystemThe glycolytic system produces energy through the breakdown of glucose (sugar). It is a short-term energy system and does not require oxygen initially. However, it produces lactic acid, which can lead to fatigue. This system is typically used for medium-duration activities lasting up to 2 minutes, such as a 400m run.

The Aerobic SystemThe aerobic system uses oxygen to break down glucose and fat to produce energy over a long duration. It is slower than the other systems but is efficient for activities that last longer, like running a marathon or cycling for hours.

Energy ContinuumThe energy continuum explains how the body switches between energy systems depending on the intensity and duration of activity. Short, intense activities rely on the ATP-PC system, while longer activities use the glycolytic and aerobic systems.

What is EPOC?EPOC (Excess Post-Exercise Oxygen Consumption) refers to the additional oxygen the body uses after exercise to recover and return to its resting state. It helps remove lactic acid and replenish oxygen stores in the muscles.

What is Oxygen Deficit?Oxygen deficit occurs at the start of exercise when the body needs more oxygen than it can supply. The aerobic system takes time to become fully active, leading to an oxygen shortfall. During this time, the body relies on anaerobic systems for energy.

Training Adaptations for Energy SystemsTraining improves the efficiency of energy systems. For example, aerobic training increases VO2 max (maximum oxygen uptake), which helps delay fatigue and the onset of the lactate threshold. This means your body can work harder and longer before tiring.

Review Time!Great work! You've learned about energy systems, oxygen deficit, EPOC, and training adaptations. Now let's test your understanding with a few review questions.

Well done!You've completed the lesson on energy systems. Keep practising to understand how your body produces energy during exercise, and you'll be ready to tackle the exam questions on this topic!