Sec 31.1: Pathogens and Human Illness Flashcards
What is an infectious disease?
It is one that can be passed from one person to another, caused by “germs”
What is a noninfectious disease?
It is one that cannot be passed from a sick person to another, caused by genetics or lifestyle
What is the Germ Theory? Who proposed it?
Louis Pasteur proposed the Germ Theory, which proposed that specific microorganisms caused diseases
What are pathogens?
Disease-causing agents
What did Joseph Lister do?
He created the antiseptic technique by cleaning surgical tools before surgery, which decreased patient deaths
What did Robert Koch do?
He experimented with injecting pathogens into healthy animals, and came up with Koch’s postulates
What is the purpose of Koch’s postulates?
They are conditions pathogens must meet to declare that they cause a disease
What are Koch’s postulates?
- The pathogen thought to cause the disease must be present in every case in which the disease is found.
- The pathogen must be isolated and grown outside the body in a pure, uncontaminated culture
- Healthy animals injected with the pure culture must develop the disease
- The pathogen must be reisolated and cultured from the newly sick animals and must be identical to original pathogen
What are the 5 types of pathogens?
Bacteria, Viruses, Fungi, Protozoa, and Parasites
How do bacteria cause illness?
By releasing chemicals toxic to the host or destroying healthy body cells
How do viruses cause illness?
By taking over a healthy cell, forcing it to stop normal activities, and produce more viruses
How do fungi cause illness?
By piercing healthy cells and taking their nutrients (usually present in warm and damp areas)
How do protozoa cause illness?
By feeding on healthy cells to complete their life cycle
How do parasites cause illness?
By growing and feeding on host, either draining its resources or killing it
How can illness enter the body?
Through direct or indirect contact
