What is involved in the non-specific resistance first line of defense
- intact skin: Upper layer of skin is stratified squamous, tightly bound so it blocks out microbs, Skin is arid (dry) and acid (low pH) does not support micro organisms.
- Microbial inhabitants: Ecoli covers our skin to keep pathogenic bacteria from entering system, Good bacteria lives in our body cavities –> their presence discourages pathogenic bacteria (the gut and vagin)
- Mucous Membrane: consists of cells that release/ produce mucous, Mucous trap and immobilizes microbs from entering system
- exocrine glands: secrete lysosomes (tears and saliva) which degrade bacterial cell wall
- Urine: low pH (acidic) flushes out bacteria, the quicker the process of urination bacteria get eliminated
- Diarrhea: if there are substances that shouldnt be in the digestive tract (pathogens), body will sacrifice water to flush it out
What are the stem cells in bone marrow?
- monocyte
- basophil
- neutrophil
- eosinophil
- lymphocyte (3rd line of defense)
Monocytes–>_____—-> Phagocytosis
Monocytes–> macrophages (can recognize any microb/cell that should not be in our system, called “search and destroy cells,” shreds cells into pieces)—> Phagocytosis: process of eating cell and using digestive enzymes to shred cell
Lymphatic vessel function in the lymphatic system
to collect plasma fluid that leak into your tissues from the bloodstream and return it to the circulatory system
The second line of defense includes nonspecific substances and cell activities, the 2nd line is activated when….
microbs cross the 1st line of defense and start affecting tissue
The molecules include interferons and proteins of the complement system. What are interferons and what do they do?
interferons interfere with the life cycle of the virus by limiting the rate of infection
What is included in the 2nd line of defense?
compliment proteins (which travel as single plasma)
What are complement proteins (second line of defense)
the complement system is a set of plasma proteins that enhance nonspecific and specific defenses
About 20 kinds of complement proteins circulate in the blood in inactive form: what are their characteristics?
- these proteins are activated in a cascading fashion *
- Some form pore complexes which cause the pathogen to lyse and die
- some activate proteins which promote inflammation
- some attract phagocytes to the scene to ingest the invaders
what are viruses?
all are parasites. They have infectious particles. They also have nucleic acids but do not know what to do. They cannot transcribe/ translate. They have no machinery. They kill cells/ infect cells by puncturing them. Infect cells by making cells replicate them.
Function of histamine?
to orchestrate inflammation, and makes capillaries “leaky”
What are neutrophils
the most abundent leukocytes, phagocytize bacteria, detect bacterial invaders–> kills by phagocytosis.
what are Eosinophils
they secrete enzymes that punch holes in parasitic worms, detect single and multicelled parasites
What are basophils
they secrete histamine which promotes leakage of fluid out of capillaries, which sustains inflammation, tiny leukocytes.
Where are macrophages formed?
they are formed from immature cells called monocytes
What are macrophages
these leukocytes are slower to act but can engulf and digest just about any foreign agent or damage tissue
The inflammatory response starts when microbs start affecting tissue.
What do the inflammatory response results include?
-Localized warming,redness,swelling, and pain are signs of inflammation that occur at the site of damage or invasion
-Microorganisms invade a tissue and kill and damage cells
-Mast cells release histamine(makes capillary leaky) and heparin (makes plasma more fluid), which stimulates vasodialation and capillary permeability
- fluid seeps from blood vessels causing swelling and delivery of infection-fighting proteins
-complement proteins attack invaders as clotting factors wall off inflamed area
- some leukocytes are also squeezed out of the “leaky” capillaries
Macrophages secrete interleukins and prostaglandins which are communication signals among leukocytes, but in addition prostoglandins can signal the brain the reset its “thermostat” to cause fever
What are mast cells made up of?
Loose connective tissue
What are the lymphatic organs?
- tonsils: give quick local response
- lymph node: expands when there is infection, projector cells go through mitosis to protect
- Thymus gland: houses leukocytes
- Spleen: largest lymphatic organ & *filters dead or mutated red blood cells
Interleukin-1 induces ____
drowsiness
Macrophages secrete
interleukins and prostaglandins-> which communicate with white blood cells
What are the function of prostoglandins
- Increase the temperature
- to signal messages to white blood cells
- High temperature can cause denaturation of proteins, hence must bring down temp. –> more WBC produced to get rid of microbs
- once concentration of microbs go down-> bod returns to normal temperature
What are the functions of specific responses-> immune system?
- goes after the very microb that causes the infection
- creates memory, for the next time you get infected by a microb so it can kill them fast
- memory cell: immunization
T lymphocytes arise from stem cells in the bone marrow and then travel to the ______ where the helper T and _____ cells complete their development by aquiring T-cell receptors (TCRs)
Thymus gland; Cytotoxic T (natural killer) cells
