Homeostasis. The biological definition of homeostasis is âthe tendency of an organism or cell to regulate its internal environment and maintain equilibrium, usually by a system of feedback controls, so as to stabilize health and functioningâ.ositive feedback mechanisms. A positive feedback mechanism is the exact opposite of a negative feedback mechanism. With negative feedback, the output reduces the original effect of the stimulus.
Bacteria produce disease in one of two general ways; some bacteria damage the cells and tissues of the infected organism directly by breaking down the cells for food, other bacteria release toxins (poisons) that travel throughout the body interfering with the normal activity of the host. Pathogens.
1 Viruses-Viruses are extremely small and consists of DNA with a protective coating of protein. 2  Diseases caused by viruses include influenza, the common cold, measles, yellow fever, and hepatitis. 3  Bacteria-Bacteria are small microorganisms. 4  They can cause diseases such as tuberculosis, cholera, typhoid fever, and tetanus. Bacteria-Bacteria are small microorganisms. 2  They can cause diseases such as tuberculosis, cholera, typhoid fever, and tetanus. 3  Parasites-Parasites are organisms that live off their hosts. 4  Some parasitic diseases include malaria, sleeping sickness, and scabies. 5  Fungi-Fungi are microorganisms such as yeasts and molds.