Unit 5
P4- Explain the physiology of two named body systems in relation to energy metabolism in the
body
M1- Explain how two body systems interrelate to provide for the body’s energy needs
D1- Analyse how systems of the body use energy
In this task, I will be going to explain the physiology of two named body systems in relation to energy
metabolism in the body. Firstly, I will start off defining energy and metabolism.
Energy & Metabolism
Energy is used everywhere. We need energy to move, breath, digest food and regulate body
temperature etc. Energy helps our body to function. Energy isn’t just in your body it always comes
from somewhere. Energy comes from the food you eat and drink. There are many different types of
energy, this includes chemical energy, kinetic energy, potential energy, heat energy, light energy and
nuclear energy. However, the three main forms of energy for the body are chemical energy, kinetic
energy and heat energy. Chemical energy is energy stored in bonds of chemical compounds, like
atoms and molecules. This energy is released when a chemical reaction takes place. Chemical energy
is used by body systems such as the cardiovascular, respiratory and digestive system. Whereas
kinetic and heat energy are used elsewhere.
Energy is used in the body for much more than movement and muscular activity. Energy is needed to
circulate blood, it necessary for respiration, taking in oxygen and removing carbon dioxide. It is
necessary for making new cells to carry out growth and repair, and to transmit nerve impulses.
Metabolism is made from catabolism and anabolism. Metabolism is the chemical reactions in the
body’s cells that change food into energy. Our bodies need this energy to do everything from moving
to thinking to growing. Specific proteins in the body control chemical reactions of metabolism.
Thousands of metabolic reactions happen at the same time, all regulated by the body to keep our
cells healthy and working.
We all know that energy is needed in the body so that it can function. However, some activities
create energy whereas some use energy. Metabolism is a process that helps the energy that is
produced and used by all the chemical reactions to stay balanced in the body.
How does metabolism work
After we eat food, the digestive system uses enzymes to break proteins down into amino acids, turn
fats into fatty acids and turn carbohydrates into simple sugars. The body can use sugar, amino acids
and fatty acids as energy sources. These three compounds are absorbed by the blood, which carries
them to the cells. After the compounds enter the cells, other enzymes work to speed up or regulate
the chemical reactions involved with metabolising these compounds. During these processes, the
energy from these compounds can be released for use by the body or stored in body tissues
including the liver, muscles and fat.
An example of a metabolic reaction is the one that takes place when a person eats a spoonful of
sugar. Once inside the body, sugar molecules are broken down into simple molecules with the
release of energy. That energy is then used by the body for a variety of purposes, such as keeping
the body warm and building up new molecules within the body.
, Anabolism & Catabolism
Anabolism & catabolism are two types of biochemical reactions that make up metabolism.
Anabolism is all about building and storing. Anabolism builds up complex molecules from simpler
ones. Anabolism supports the growth of new cells, the maintenance of body tissues, and the storage
of energy for future use. In anabolism, small molecules including sugars, lipids, amino acids and fatty
acids change into larger, more complex molecules of carbohydrates, proteins and fat.
Alternately, catabolism is the processes that breaks down molecules into smaller units that are
either oxidised to release energy or used in anabolic reactions. So instead of amino acids becoming
proteins in anabolism, proteins will be broken down to amino acids instead. Catabolism is the
process that produces the energy that is needed to have activity in the cells. For this to happen cells
breakdown large molecules such as carbohydrates and fats to release energy. The energy created
provides fuel for anabolism, heats the body, and enables the muscles to contract and the body to
move. As complex chemical units are broken down into more simple substances, the waste products
released in the process of catabolism are removed from the body through the lungs and intestines.
Activities involved in supplying energy to the cells of the body
Activities involved in supplying energy include the cardiovascular, respiratory and digestive systems.
Firstly, the digestive system is responsible for the intake of food and water, using enzymes to
separate complex molecules into soluble materials, capable of travelling to adjourning capillaries of
the cardiovascular system. The cardiovascular system then transports these soluble materials to the
liver and body cells through the bloodstream, directed by the pumping of the heart. During this time
the respiratory system continuously refreshes the oxygen in the lungs and removes waste products
such as carbon dioxide through the breathing process. Diffused oxygen then travels through the
alveolar walls, into the bloodstream transported to the cells. This means the body cells have a
constant supply of raw materials such as glucose, other nutrients and dissolved oxygen so that the
breakdown process of glucose oxidation can take place, releasing energy to do work. This begins in
the cytoplasm and is completed in the mitochondria. The released energy is captured as chemical
energy in adenosine triphosphate (ATP).
Role of the respiratory system in energy metabolism
Once we breathe in air, this air goes through the respiratory system to the alveoli, tiny air sacs that
allow gas exchange found in the lungs. The carbon dioxide in the air is passed on from the cell to the
alveoli and the oxygen passes from the alveoli to the cell. The blood that was once deoxygenated is
now oxygenated and goes back into the heart to be pumped around the body. The respiratory
system's role in energy metabolism is bringing in oxygen into the body, which is needed to burn
nutrients to create energy.
