term 2 year 11 biology

summarise the innate immune system

its the second line of defence, triggered after the breach of the first.rapid…non learned response, found in all animals, plants, invertebrates, fungi

what is phagocytosis

white blood cells such as ‘phagocytes’ carry out a process of endocytosis…neutrophils and macrophages reconigse and bind to the surface receptors of bacteria, englufing and destroying them

what are neutrophils and macrophages

white blood cells that are found everywhere mainly in the the lymphatic system. they respond to chemical signals when tissues become damaged/infected

what are natural killer cells (NK)

provides protection agaisnt cells infected or changed by cancer . reconigses protein markers as non self on cells that need to be destroyed…realeases cytokines which are cell signalling molecules …attacking in number and punching holes through cells that need to be destroyed

what is the complement system

group of 30 proteins that are secreted… in active untill they bind to receptors on the surface of pathogens bringing out a cascade effect: stimulating a range of chemicals and affects….pathogen is then destroyed by phagocytes…binding to mast cells stimulating them to release histamine

what are interferons

can be secreted by cells that are infected by viruses, having been mass produced using DNA tech, can be used to treat genital warts but can cause heart problems, tells immune cells to attack when needed

features of inflammatory response

occurs at wound site where injuries have incurred/ pathogens may have entered. induces swelling, heat, redness and pain

process of inflammatory response

macrophages and neutrophils bind to the antigen at the wound site secreting cytokines… mast cells realease histamine… histamine causes blood vessels to widen at the wound site bringing extra white blood cell supply… these white blood cells engulf the microbes

what are natural killer T cells

release chemicals like perferin, part of adaptive immune system

state the role of mast cells in the inflammatory response

mast cells are important as they release histamine which widens blood vessels allowing for more pentration

what does the second line of defence consist of

complement system, inflammatory system, natural killer cells, macrophages and nuetrophils, phagocytosis

what are primary lymphatic organs

Bone marrow (b cells) and thymus gland (t cells)

what are the seconday lymphatic organs

lymph nodes, spleen, tonsils

what is the major histocompatibility complex (mhc)

set of protein markers found on the surface of cells. there are two different groups of protein markers… non self and self

what are lymphocytes

all blood cells come from bone marrow and in this instance B cells remain and mature in bone marrow. T cells mature in the thymus gland

B lymphocytes

orginate in bone marrow and mature there, release a specific antibody which is a protein molecule that can bind to one specific antigen neutralizing it

T lymphocytes

posses receptors on the surface of their membranes that can bind to antigens or a fragment of an antigen

killer T cells

‘cytotoxic’ T cells indentify infected cells and destroy them

helper T cells

these activate killer T cells and certain B cells, provide memory for memory T cells

memory T cells

repsonsible for quicker larger responses

what is active immunity

exposure to pathogen/antigen, exposure to a vaccine ( bodys own response)

passive immunity

mother providing antibodies eg breast milk, protection agaisnt snake bike venom ( recieving antibodies from an external source)

what are the physical barriers for pathogens

ear wax, eye blinking, lysozyme, tough waterproof skin, high Ph stomach acid, sneezing/coughing to expell pathogens, mucus in respiratory system expelling pathogens, blood clotting to form scabs

what are biofilms

most bacteria exist in colonies known as biofilms, these are usually resistant to bacteria.

how do viruses spread in the body

they use host cells nucleic acids and organelles to produce new patricles

what bacteria can survive the stomach acid ph2

heliobacter pylori can survive, reprodue and cause stomach olsars

what is the difference between antiseptics , disenfectants and antibiotics

antiseptics kill microbes on the outside of the body, disenfectants kill microbes on surfaces, floors, toilets. antibiotics help kill pathogens inside the body

methods of disease transmission

body fuilds, animals, contaminated food, droplet infection, sneezing/coughing

what is a difference between viruses and bacteria

bacteria are living and grow, viruses cant grow/non living without a host

define non-infectious disease

cannot be transmitted, faulty genes, cancer

define infectious disease

are caused by pathogens and viruses, once inside a host body a pathogen may cause disease by destroying cells, releasing toxins

types of pathogens

fungi, protista, parasites, prions, viruses

define cytokines

small proteins important in cell signalling

why is the innate immune system rapid and non specific

its non specific because it has no reconigtion of a specific antigen, rapid because it has lots of blood cells ready for action

how can binding of complement molecules to pathogens increase their chance of destruction

it makes pathogens more reconigsible to phagocytotic cells

main difference between adaptive and innate immune response

innate is non specific and faster while adaptive is specific and slow

difference between primary and secondary response

primary occurs at first cobtact while secondary occurs with the second exposure to the same antigen

what does pus consist of

dead pathogens, dead white cells and other celluar debris

what is humoral immunity

• Mediated by: B-cells.

• Mechanism: Produces antibodies that circulate in the blood and lymph.

• Targets: Extracellular pathogens (e.g., bacteria) and their toxins.

• Response Time: Quick.

• Function: Neutralizes pathogens by binding to them, making them easier targets for phagocytes and other immune cells 

what is cell mediated immunity

• Mediated by: T-cells.

• Mechanism: Does not produce antibodies. Instead, it relies on T-cells to directly attack infected cells.

• Targets: Intracellular pathogens (e.g., viruses, some bacteria) and cancer cells.

• Response Time: Delayed compared to humoral immunity.

• Function: T-cells recognize and destroy infected cells, and activate other immune cells like macrophages 

why is non self reconigtion so important in defence agaisnt disease

non self reconigtion by binding is an important part as this binding by macrophages stimulates them to release cytokines which then stimulate a range of effects to boost the immune system

booster injections are often needed agaisnt a pathogen, why is this?

memory cells may die over long period of times but the booster injection would stimulate more of them to be produced and stored incase of infection

how do vaccines provide protection?

vaccination can stimulate B and T lymphocytes producing memory cells that are stored in the spleen and lymph nodes

whats a difference between the primary and secondary response

the primary response is slower and produces less antibodys than the secondary response