Flashcards
Test 4: Part 2
Cards in this deck (83)
- 1What is coprophagia?Eating of feces
Some species do this to recover the vitamin Bs that the colon can't absorb - 2What accounts for up to 10% of our caloric intake?The absorption of small fatty acids in the large intestine that are produced by bacteria fiber digestion
- 3How is the digestive system controlled?Both neural and hormonal control
- 4What is the Enteric NS?Nervous system of the digestive system that controls glands, muscles, and motility
- 5What determines the length of digestion in the stomach?Amount and type of food
Detected by stretch and chemoreceptors
Carbohydrates - fast (<1hr)
Proteins - intermediates
Fats - slow (up to 6 hr) - 6What is CCK?Hormone secreted by the small intestine when fat or acid-rich chyme from the stomach enters
Causes the gallbladder to contract, sending stored bile to the small intestine
Causes pancreas to release digestive enzymes
Slows stomach emptying so chyme can be neutralized and emulsified a little at a time
Stimulates satiety - 7What is secretin?"first hormone"
Release by small intestine is stimulated by the presence of acid
Circulates and stimulates pancreas to secrete bicarbonate for neutralization (SI not as well protected as the stomach) and so the enzymes work best (neutral/alkaline)
Slows down stomach emptying - 8What are the two types of incretins? What do they do?GIP and GLP
Stimulate insulin secretion
Secreted in response to glucose in the small intestine - 9Who doesn't respond to GIP?People with NIDDM because of lack of receptors
- 10What does GLP do?Inhibits acid secretion and stomach-emptying
Increases satiety
Increases insulin, decreases glucagon - 11Hormones don't play a role in ______ motility. Control is via _________ and _______.Large intestine
Enteric NS and ANS - 12What can stimulate/inhibit defecation?Anxiety can do both!
Coffee stimulates - 13What is the innate immune system?System that provides an immediate, non-specific response
Found in all plants and animals - 14What is the adaptive immune system?System that is activated to specifically attack pathogens that evade/survive the innate response
Specificity is carried into the future by immunological memory - 15What is immunological memory?System that carries specificity into the future which enables faster, stronger attack next time that pathogen is seen
How vaccinations work! - 16What are PAMPs?Pathogen-associated molecular patterns
Include LPS (lipopolysaccharide) from gram- membranes and peptidoglycan from gram+ walls and double-stranded RNA from viruses
Trigger phagocytosis by the innate system - 17What are PRRs?Pattern recognition receptors
Receptors in innate system cells that recognize the PAMPs common to many microbes - 18What are neutrophils?WBCs that are produced in the marrow
Mobile, short-lived, and the 1st to arrive at infection sites (within minutes), biggest component of pus
Attracted by cytokines and exit the bloodstream by diapedesis - 19What's the most abundant type of WBC?Neutrophils
- 20What are macrophages?Derivatives of monocytes
Mobile, long-lived phagocytes - 21What are organ-specific phagocytes?Phagocytes that are often tethered and found in the liver, spleen, lymph nodes, lungs, and brain
- 22Fever is part of innate immunity. How?It is induced by pyrogens released by WBCs in response to PAMPs
Increases body temp above the optimal growth temp for many microorganisms
Leads to release of heat shock proteins - 23What are heat shock proteins? What is their role?Family of proteins released in stressful conditions that cause production of inflammatory cytokines
Cytokines increase metabolism which increases production and activity of phagocytes, speeds up multiplication of lymphocytes, increases antibody and cytokine production, and increases WBC release by marrow - 24What are interferons?Polypeptides that are produced by virus-infected cells to boost immune activity
Activate Natural Killer Cells
Confers short-acting, non-specific resistance to viral infection on nearby cells - 25What are natural killer cells? (NKCs)WBCs that are activated by interferons
- 26What is the purpose of the complement system?To help clear pathogens and bad cells from the body and to work with adaptive immunity
- 27How does the complement system work?When activated, the system initiates an enzyme cascade that results in the formation of MACs to kill pathogenic cells
- 28What are MACs?Membrane attack complexes
Large pores formed by complement proteins that perforate and lyse pathogenic cells - 29What are antigens?Molecules that can elicit an immune response
Immune system can distinguish self from non-self antigens and NORMALLY only makes antibodies against nonself - 30What are lymphocytes?A class of WBCs that include T cells, B cells, and natural killer cells
Produced by the thymus, spleen, and lymph nodes - 31What are T cells?Cells produced by the thymus that provide cell-mediated immunity
Constitute 65-85% of lymphocytes in blood
Attack infected host cells, cancer cells, and foreign cells - 32What are B cells?Lymphocytes that secrete antibodies into blood and lymph which provide humoral immunity
Have antibodies on their surface that are receptors for antigens
When bound to the antigen, they are stimulated to divide and secrete antibodies - 33What happens when B cells divide?Some become plasma cells, some become memory cells
- 34What are plasma cells?Cells derived from B cells that produce about 2000 antibodies per second
Provide active immunity - 35What are memory cells?Cells derived from B cells that provide a rapid, strong antibody response to subsequent exposures to an antigen
- 36What is the complement cascade?A process triggered by the binding of B cells to antigens
B cells and their products serve as signals for MACs and phagocytes to carry out killing - 37What are antibodies?Proteins called immunoglobulins
5 types, basic structure is a "Y" - 38What are the 5 types of antibodies?IgG, IgE, IgM, IgA, and IgD
- 39What is Fab?The variable region of antibodies at the tips of the "Y" arms that binds antigens and confers antibody specificity
- 40What is Fc?The stem part of the "Y" that is constant among different antibodies
Activates other parts of the immune system - 41How many antibody molecules does each person have?10^20
(With a few million different specificities) - 42What is antigen specificity based on?Shape
An antibody binds to an antigen that fits into its binding pocket - 43What is opsonization?Labeling of a pathogen for phagocytosis or complement attack
Antibodies do this because they can't kill on their own - 44What do antibodies use opsonization on?Gram negative bacteria, viruses, and host cells recognized as non-self
- 45What are MHCs?The Major Histocompatibility Complex
4 gene complex on Chromosome 6
Produce cell surface proteins that display self peptides normally made by a cell or non-self peptides normally originating from a pathogen
Are on the surface of all the body's cells EXCEPT mature RBCs - 46What forms the basis for histocompatibility typing?MHC genes have multiple alleles, creating many possible MHC types
Basis of organ compatibility - 47What do MHCs produce?2 types of antigen-presenting proteins: Class 1 and Class 2
- 48What are class-1s?Antigen-presenting molecules produced by MHCs in all cells except RBCs
Display peptides normally made by a cell on the cell's surface
Interacts with CD8 coreceptor on killer Ts which (normally) recognize these peptides as self and leave them alone - 49What happens if a killer T's antigen is presented by a class-1 protein?The killer T takes out the cell with the help of the complement system because it indicates it's a bad self cell
Killer Ts have to have found a class 1 with a foreign antigen to bind to the cell - 50What happens if killer Ts respond to self antigens?They are (normally) deleted or inactivated
- 51What are class-2s?Antigen-presenting proteins produced by MHCs that are expressed by professional antigen-presenting cells
- 52What are pro APCs?Professional antigen-presenting cells
Include macrophages, dendritic cells, and B cells
Phagocytize antigens then digest them into small pieces (epitopes) which are presented by class-2s on their surface - 53What do pro APCs have on their surface?Class-1 and Class-2 proteins
- 54Which cells can activate a killer or helper T that has never seen its antigen before? How?Dendritics
When a naive helper T binds to its antigen and a class-2 MHC, a dendritic cell activates it with ILs which leads to secretion of antibodies, memory cells, and plasma cells - 55What is CD4?A coreceptor on helper Ts that interacts only with class-2s on dendritic cells
- 56What do activated helper Ts do?Stimulate other cells with ILs
- 57What are NKCs?Natural killer cells
Lymphocytes that can kill virus-infected and tumor self cells that are opsonized and lack class-1 MHC antigens - 58How do intracellular microbes and tumors become resistant to killer T actions? What kills them then?They down-regulate class-1 molecules
NKCs recognize these cells and attack them with MACs, granzymes, and perforins - 59What is affinity maturation?When a B cell binds to an antigen, it undergoes programmed point mutations of its variable region genes at a rate 10^6x higher than normal
If the new Bs bind longer and tighter to the epitope, they will divide more and survive longer, so this fine-tunes the shape of the Fab antigen pocket (binds epitope better)
The better-fit Bs become plasma and memory cells - 60What is immunological tolerance?The ability to produce antibodies against non-self while tolerating self
BEGINS at about 1 month of life - 61Where does T cell tolerance first develop? B cell?Thymus
Marrow - 62What is AIRE?Autoimmune regulator
A transcription factor in the thymus that causes the thymus to express peptides produced by most other tissues, creating a profile of self-antigens - 63What happens to new Ts that bind to the selfs produced by AIRE?They are deleted!
- 64Why do dendritics migrate to the cortex of the thymus?To help present self-antibodies to developing Ts for potential deletion in the event that they bind to selfs
- 65What happens to B cells in marrow that bind selfs?They undergo receptor editing, meaning they reshuffle gene expression to make new receptors
If it still bind self, they will undergo apoptosis - 66What is peripheral tolerance?Outside the thymus, naive T cells that recognize self-antigens undergo apoptosis (clonal deletion), usually in the lymph nodes
And/or Ts, Bs that bind selfs are inactivated and circulate without function until they die (ANERGY) - 67What are autoreactive Ts?Killer Ts that attack self-antigens
- 68Which self-antigens are normally hidden from the blood? What happens if the body has exposure to these?Lens protein in the eye, those in joints, etc.
Exposure results in production of autoantibodies and attack from autoreactive Ts - 69What is FAS?A surface receptor on killer Ts that increases during infection
- 70What is FAS ligand?Produced by killer Ts a few days after an infection begins
Binds to FAS and triggers apoptosis of the killer Ts - 71What are Tregs?Suppressor T cells
Cells that shut down immune attack after a disease to deter autoimmunity
Secrete cytokines that suppress other immune cell activity - 72What happens if you have a deficiency of Tregs?Severe autoimmunity, immunopathology, and allergy
- 73What is the primary antibody response?On first exposure to a pathogen, there is a latency of 5-10 days before specific antibodies are made, then antibody levels decline after a few weeks
Induced by vaccines - 74What is the secondary antibody response?A response caused by subsequent exposure to the same antigen that causes much more rapid and sustained antibody production
- 75What is passive immunity?Protection produced by transfer of antibodies from a donor to a recipient
Used to treat snakebite, rabies, tetanus, and hepatitis - 76How does passive immunity occur with babies?Occurs naturally before and after birth (most in breastmilk)
Some antibodies from the mother pass the placenta to the fetus during pregnancy and provide passive immunity - 77What is colostrum?Produced by a mother during the first 2-3 days of nursing
Contains her antibodies and gives her immunity to the infant - 78When does a specific immune response develop? When do vaccines take?1 month
15 months - 79What happens when you have an autoimmune disease?Autoreactive T cells are formed and B cells produce autoantibodies
- 80What happens in Hashimoto's?Antibodies attack thyroglobulin which is normally hidden from immune surveillance
- 81What happens in thrombocytopenia?Platelets are destroyed because they combine with the victim's medications
An example of a self-antigen that is otherwise tolerated with a foreign antigen that is not - 82What happens in rheumatoid arthritis?Antibodies are produced that are directed against other antibodies
- 83What happens in Type I diabetes to make it autoimmune?Self-antigens are presented to a helper T by a class-2 molecule causing them to be activated