Biomed Test #3 Review

lymphatic vessels

drainage system that transports lymph back to cardiovascular system; lymph capillaries -> lymphatic collecting vessels -> ducts (right lymphatic/thoracic)

lymph nodes

filters lymph before it re-enters blood through lymphocytes and macrophages

lymph

excess interstitial fluid

spleen

right below heart, filters/cleans blood, blood reservoir

thymus

right beneath sternum, produces and trains T-cells, peaks during youth

tonsils

in throat, traps and removes bacteria entering airways

Peyer's patches

in wall of small intestine, protects intestine from infection

appendix

lower right side of abdomen, protects intestine from infection

innate defenses

respond immediately to anything non-self

surface membrane barriers

skin and mucous membranes, physical barriers that produce sebum, acid mantle, mucus, gastric juice, saliva, and tears to kill bacteria

natural killer cells (NKC)

recognize virus and cancer infected cells and release chemicals to kill them

perforin

found in NKCs, creates pores in target cells so chemicals can get through

neutrophils

most common white blood cell, first responders to injury, phagocytic, produce pus when they die

inflammatory response

cardinal signs: redness, heat, pain, swelling (edema)

damaged cells release histamine to dilate blood vessels, prostaglandins increase blood flow, and pyrogens increase temperature all to assist with repair

histamine

a chemical that causes blood vessel dilation, and helps deliver platelets and attract phagocytes

pyrogens

a chemical that triggers heat increase

complement proteins

always circulating, lyse antigens (complement fixation)

interferons

proteins released by virus infected cells to protect healthy cells

adaptive defenses

focuses on particular foreign substances, antigen-specific, systemic (response circulates throughout the body), has memory (e.g. vaccines)

lymphocytes

respond to specific antigens, develop self-tolerance (difference between self and non-self)

B-lymphocytes

part of humoral response, produce antibodies, mature in bone marrow

T-lymphocytes

part of cell-mediated response, no antibodies, mature in thymus

antigen-presenting cells (APCs)

engulf antigens and then present fragments of them to activate T cells

e.g. dendritic cells, macrophages, B lymphocytes

humoral immunity

antibody mediated, involves B cells

clonal selection

B lymphocytes activated by an antigen selecting its matching receptor, triggers mass production of plasma and memory B cells

plasma B cells

produce antibodies for 4-5 days before dying

memory B cells

live longer to preserve immunological memory, respond to same antigen if it returns

active immunity

B cells encounter antigens and produce antibodies to attack them, forms immunological memory

passive immunity

antibodies obtained from others, temporary protection

antibodies

immunoglobins, bind to antigen to neutralize/mark it for destruction

complement fixation

antibodies activate complement proteins to destroy pathogens, either by flagging or lysing them

neutralization

antibodies bind to certain sites on exotoxins or viruses to physically prevent it from doing harm

agglutination

antibody-antigen reaction that causes clumping of cells

preciptation

cross-linking reaction in which antigen-antibody complex settles out of solution

cellular immunity

cell mediated, involves T cells (require double recognition and antigen to be presented to them - can't bind to free antigens)

effector T cells

activated T cells that engage in direct combat against antigen, can be cytotoxic or helper

cytotoxic T cells

directly kill infected or abnormal cells through attaching and inserting a toxic chemical (perforin or granzyme) into the diseased cell

helper T cells

release cytokines to recruit other cells such as macrophages and B cells

regulatory T cells

releases chemicals to suppress activity of T and B cells, stop immune response/prevent uncontrolled immune activity

memory T cells

live longer to preserve immunological memory, initiates immune response if antigens reappear

autograft

tissue transplanted from one site to another on the same person

isograft

tissue graft from a genetically identical person (identical twin)

allograft

tissue taken from a person other than an identical twin

xenograft

tissue taken from a different animal species (never successful)

allergies

abnormally aggressive immune response to an otherwise harmless antigen

immediate (acute) hypersensitivity

almost immediate flood of histamines that trigger reactions such as hives and anaphylaxis (rare, but deadly), can be treated with antihistamines or an epipen

delayed hypersensitivity

caused by T cells (which trigger cytokines and macrophages), takes around 1-3 days to appear, allergic contact dermatitis (e.g. poison oak), can be treated with topical/oral treatments

autoimmune diseases

caused by the body's self-tolerance breaking down and attacking its own cells/tissues, e.g. rheumatoid arthritis, multiple sclerosis, type 1 diabetes

immunodeficiencies

any abnormality of immune cell production/function causing an insufficient immune response

severe combined immunodeficiency disease (SCID)

congenital (present from birth), immune system is basically nonfunctional (can't protect itself from pathogens)

AIDS

caused by HIV which specifically attacks helper T cells, crippling the immune response over time (B cells can't make antibodies effectively and cytotoxic T cells can't coordinate attacks)

COVID-19

name of disease

SARS-CoV-2

virus that causes COVID-19

coranvirus

family of viruses SARS-CoV-2 is in

RT-PCR test

tests for pieces of the virus's RNA genome, results take a day to a week, few false negatives

angiten test

tests for pieces of viral proteins (antigens), takes an hour or less, more false negatives because the protein pieces can be difficult to detect (unless they are in large amounts)

mutations (and effects)

mistakes made in copies of a virus's genome causing genetic variation, can be beneficial or harmful to the virus's survival

vaccines

train immune system to develop immunity through exposure to safe versions of pathogens (e.g. an inactive virus, antigen proteins, or a virus's mRNA/DNA)