Factors for Prevention & Control of Common Diseases Prevention & control of cholera Cholera occurs when people do not have access to effective?sanitation?facilities?and?access to clean wate...
Transmission of Common Diseases Transmission of cholera Cholera is caused by the?bacterium?Vibrio cholerae The disease is?water-borne?(the bacterium lives in water) and?food-borne This means the di...
Infectious Diseases A disease is an?illness or disorder?of the?body or mind?that leads to?poor health Each disease is associated with a set of?signs and symptoms Infectious diseases are caused by?p...
Gas Exchange Processes The exchange of oxygen and dioxide occurs between the alveoli and the capillaries in the lungs Oxygen and carbon dioxide are exchanged in a process of simple diffusion; (pass...
The Gas Exchange System: Structure & Functions Ciliated epithelial cells, goblet cells and mucous glands play vital roles in maintaining the health of the gas exchange system Cartilage, smooth ...
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...
