defences in animals Flashcards
whats innate immunity
bodys first and second line of defence, rapid but non specific
whats adaptive immunity
the bodys third line of defence
specific immune response that develops over time and establishes immunological memory
what are primary defences
prevent the entry of pathogens into the body in the first place
they are non specific so prevent entry if any pathogen
steps of blood clotting (primary response)
- damage to tissue exposes collagen
- collagen activates platelets
3.platelets bind to collagen and release clotting factors e.g. thromboplastin
4.platelets also form a plug at the wound
5.thromboplastin triggers an enzyme cascade - thrombokinase (triggered by thromboplastin) and the calcium convert prothrombin into enzyme active thrombin
6.calcium ions and prothrombin (protein) are present in the blood - there is soluble fibrinogen found in the blood plasma
9.active thrombin converts soluble fibrinogen into the insoluble fibrin
10.fibrin fibres form a mesh and attach to platelets in plug
11.RBC and platelets get stuck in fibrin mesh and clot is formed
what is converted into insoluble fibrin fibres (which are polymerised)
fibrinogen through active thrombin (enzyme)
what happens in the skin repair process (primary response)
-when a blood clot dries it forms a scab
-as this dries it shrinks and pulls the edges of the broken skin together to form a seal
what occurs under a scab during the skin repair process (primary response)
-fibrous collagen is deposited to give the new tissue strength
-stem cells in the epidermis divide forming new cells
-these cells migrate to the edges of the cut and differentiate into new skin cells
-new blood vessels grow to supply oxygen and nutrients to the new tissue
what does mucus contain (primary response)
lysozymes which can destroy bacterial and fungal cell walls
where are mucus membranes found and why
-found where the membranes are once cell thick as they are more easily infected by pathogen
-airways ,gut, genitals ,anus, ears and nose
what’s an expulsive response (primary response)
sudden ejection of pathogens from the gut or pathogen-laden mucus from the gas exchange system
-e.g. coughing, sneezing, throwing up, diarrhoea
What is inflammation
A localised response to pathogen, damage or irritants characterised by pain, heat, redness and swelling
Inflammation process
-Presence of microorganisms detected by specialised mast cells
-mast cells release histamines and cause blood vessels to dilate (vasodilation)
-raised temp helps prevent pathogens reproducing
-histamine makes capillary walls more permeable so blood plasma, phagocytes and WBCS are forced out to create tissue fluid which causes swelling and pains
-cytokines released by mast cells attract phagocytes which remove pathogens by phagocytosis
-if widespread can cause a rash
How does vasodilation cause redness and heat
Due to more blood flowing to the infection
What do tears contain
Lysozymes
What is the ear canal lined by
Wax which traps pathogens
What does the epidermis consist of
Keratinocytes (cells) produced at the base of the epidermis by mitosis
Migrate to the surface of the skin and dry out cytoplasm, replaced by keratin
Known as keratinisation
Defence in the female reproductive system
Mucus plug in the cervix and by maintaining relatively acidic conditions
