Recognising Structures in the Gas Exchange System Trachea Trachea cross-section A tracheal cross-section shows the large lumen which air has to travel through The innermost cells of the trachea are...
Recognising Tissues in the Gas Exchange System Cartilage Cartilage micrograph Cartilage – electron micrograph The cartilage in the trachea has a ‘glassy’ appearance due to its translucent protoplas...
Distribution of Tissues in the Gas Exchange System Cartilage is a strong and flexible tissue found in various places around the body One place is in rings along the trachea, called Tracheal rings T...
The Human Gas Exchange System Gas exchange takes place in the human thorax. This is a collection of organs and tissues in the chest cavity The main structures of the human gas exchange system Thora...
Heart Action: Initiation & Control Control of the basic heartbeat is myogenic, which means the heart will beat without any external stimulus This intrinsic rhythm means the heart beats at aroun...
The Cardiac Cycle The contraction of the heart is called systole, while the relaxation of the heart is called diastole Atrial systole is the period when the atria are contracting and ventricular sy...
The Walls of the Heart The muscular walls of the atria are thinner than those of the ventricles When the atria contract, the thin muscular walls do not generate much pressure, but enough to force b...
Mammalian Heart Structure Heart structure The human heart has a mass of around 300g and is roughly the size of a closed fist The heart is a hollow, muscular organ located in the chest cavity It is ...
The Bohr Shift Changes in the oxygen dissociation curve as a result of carbon dioxide levels are known as the Bohr effect, or Bohr shift When the partial pressure of carbon dioxide in the blood is ...
