Adenosine Triphosphate (ATP)

Adenosine triphoshate (ATP) is the bodies universal currency for energy. In fact it is the only fuel that the body can use. It is responsible for all muscle contraction, repair and growth of tissues. Structure of Adenosine Triphosphate (ATP) ATP is comprised of one adenosine molecule and and three phosphate molecules. When one of the phosphate […]

The respiratory system

The respiratory system is responsible for the intake of oxygen and the removal of carbon dioxide from the body. The main components  of the respiratory system are the lungs, the diaphragm and the intercostals. The location of the lungs The lungs are located in the thoracic cavity, behind the sternum and the ribcage.  The direction of […]

The blood

Our blood carries oxygen and nutrients to be delivered to the body tissues, and waste to be removed from the body. It is composed of the following components. Red blood cells Contains haemoglobin which binds to oxygen. White blood cells Part of our immune system that fights infection. Destroy bacteria and other harmful organisms. Platelets […]

Structure and function of blood vessels

Blood vessels are the bodies blood transportation network. There are different types of blood vessels and they all differ in size, structure and function. Blood vessels Structure Function Arteries Thick muscular walls. Found deep beneath the skin surface.  Subdivide into smaller arteries called arterioles. Withstand high blood pressure Generally carry oxygenated blood (except for the […]

Blood pressure

Blood pressure can be defined as the measure of the force that is applied to the walls of the arteries as the blood runs though them. We measure blood pressure in millilitres of mercury (mmHg). A blood pressure reading has two numbers. The first number represents the systolic blood pressure (BP when the heart is […]

Structure of the heart

The heart is made up of cardiac muscle and divided into four chambers.  Atria (upper two chambers) The upper two chambers of the heart are called the right and left atrium. Both chambers receive blood via the veins. Ventricles (lower two chambers) The bottom two chambers of the heart are the right and left ventricles. […]

The ‘All or None’ Law

Motor Units Before we discuss what the ‘all or none law’ is you must first understand what a motor unit is. A motor unit is made up of a single motor neuron and all the muscle fibres it innervates.  Innervation ratio Motor units also vary in size, small motor units stimulate just a handful of […]