immunity Flashcards
what is immunity
-the way in which an organism protects itself against pathogenic viruses is known as an immune response
-body monitors constant exposure
what is natural immunity
present at birth
passive: antibodies transferred from mother at birth
active: direct contact with pathogens stimulates immune system to produce antibodies
-first line of defence against pathogens is the external barrier
-skin
-first line of defence against pathogens
-reflexes
-if it occurs the first response is inflammation and fever
what is acquired immunity
-pathogens have penetrated the body tissues and are actively destroyed and the body stores a memory of response
-protein molecules known as antigens occurs as markers on the surface
-the white blood cells (leukocytes) recognise the pathogen and immediately destroy them by the white blood cells
passive: body injected with antibodies
active: vaccinated with a dead or weaker form of pathogen
what is lymphocytes
occurs in lymph glands, spleen, blood
2 types: b lymphocytes and t lymphocytes
what are b lymphocytes
-have receptor proteins on their surface which attach to specific antigens on the surface of the pathogen
-recognition that they foreign
-multiplies and produces millions of new b lymphocytes
-the new ones produce antibodies (1000 p/s) and are released into the blood
-caused pathogen to burst
what are t lymphocytes
-recognise and destroy body cells that are infected by a virus
-viruses hide in infected host cells
-with the aid of the receptor proteins, recognises and destroys them
what are phagocytes
-large white blood cells that can change shape
-produced in red bone marrow
-they engulf pathogens by the process of phagocytosis
-antibodies produced by b lymphocytes facilitate the process
what is immunisation and vaccinations
-immunisation (vaccinations) is the administration of a vaccine by means of an injection or orally to develop immunity to a disease
-a vaccine consists of a dead of weakened form of pathogens, this stimulates the body
