FIRST LINE OF DEFENCE Flashcards
what is innate immune response?
the response that available to us when we are born and is immediately available.
is innate specific or non-specific?
it is nonspecific as it react against any infection or pathogen.
first line of defence in the innate immune response consists of?
mechanical, chemical, and microbial barriers.
second line of defence in the innate immune response consists of?
specific cells and molecules.
why does barrier defences considered as innate immunity?
- non-specific action and work against wide range of pathogens
- immediate response, always present and ready to act.
- preventing entry, forms physical, chemical and biological barriers that blocks entry.
what are the first line of defences?
- skin
- lacrimal apparatus
- mucous membrane
- saliva
- epiglotis
- urine and vaginal secretions
- transferrins
what is the skin?
a semi watertight barrier made up of epidermis and dermis.
what does the epidermis consist of?
many layers of tightly packed dead and dying cells that contain keratin.
keratin is a tough protein. what does keratin do?
keratin gives strength, flexibility and semi waterproof properties to the skin.
the epidermis are continuosly _____
being sloughed off.
does the intrusion of pathogens will be localized or systemic on the skin? why?
localized. because epidermal layer have no access to blood or lymph.
what does normal flora microbes on the skin do?
blocks the growth of other microbes.
the skin____and ____with ______. eg: psoriasin.
- sythesize
- arrange proteins
- microbial activity
what is psoriasin?
Psoriasin is an antimicrobial peptide (AMP) belonging to the S100 protein family. It is secreted by keratinocytes in the skin and plays a crucial role in innate immunity by providing protection against bacterial infections, particularly against Escherichia coli. Psoriasin also has a role in inflammatory skin diseases such as psoriasis, where it is found in elevated levels.
what does the salty and acidic pH of skin perspiration do?
inhibits bacterial growth
what is sebum?
oily secretions of sebaceous gland that contains chemicals that are toxic to bacteria.
what is the conditions of the skin that are not favourable to bacterial growth
dry and temp lower than 37C
what does hair follicles and sweat glands produce?
lysozyme and toxic lipids that can kill bacteria.
what is present beneath the skin surface?
skin-associated lymphoid tissue (SALT)
what does SALT contains?
cells for killing microbes and sampling antigens on the skin to
start adaptive immune responses against them.
mucous membrane are composed of?
an epithelial layer that secretes mucus, and a connective tissue layer.
what is mucous membrane?
line body cavities that open to the outside environment that constantly sloughing cells to remove microbes.
what is the anology of mucous membrane?
sort of like a flypaper for micrbe.
what does the resident normal flora does?
inhibit potentially harmful microbes.
what does stomach mucosa secretes?
HCl and protein-digesting enzymes that could kill pathogens.
what does mucus do?
- helps defend against any intrusions through a mechanism called mucociliary escalator.
- coats the stomach wall to protect it against the acidic fluids needed for digestion.
explain mucociliary escalator.
the goblet cells of lower respiratory tract produce mucus which traps any
microorganisms that have entered the tract
the ciliated cells move the mucus up before it is swallowed or expectorated.
what is lacrimal apparatus?
a group of organs concerned with the
production and drainage of
tears.
where are tears produced and what is its function?
Tears are produced in the
lacrimal glands and constantly
flush any foreign particles into
the nasal cavity.
what does the tears contain?
lysozyme
lipocalin
IgA
what is lysozyme?
an enzyme that destroys peptidoglycan of the bacterial cell walls
what is the function of lipocalin?
inhibit the pathogens by binding irons.
what is IgA?
antibody that prevents microbial attachment and neutralizes toxin.
where does the saliva produced?
salivary glands
what is the function of saliva?
cleanse the teeth and mucous membranes of the mouth and prepare food for digestion.
what does saliva contains?
lysozyme
IgA
histatin
what is histatin?
peptide that has antifungal activity and has a role in wound repair.
what is epiglottis?
flap of tissue at the back of the throat.
what are epiglottis functions?
prevents liquids, foods and saliva from entering the lower
respiratory tract.
what is in urine that inhibits microbial growth in the urinary tract?
its acidity. it help make a hostile environment for pathogen.
what about urine and vaginal secretion that make it a defence barrier?
the flushing action of this body fluid keeps microbes from attaching to tissues.
why does vaginal secretions important?
Vaginal secretions and lactic acid produced by resident bacteria help
make the vagina more acidic, thus help prevent colonization by
potentially pathogenic bacteria.
However, as low-pH conditions allow fungal organisms to grow, yeast
infections are more common in women than in men.
urine also contains_____
lysozyme
what is normal vaginal pH?
3.8 - 4.5
what is transferrins?
blood proteins that bind iron and prevent microbes from
using it in their growth and metabolism.
explain the statement further.
it limits the availability of iron that is essential for microbial growth.
