MCAT Immune and digestive system

location of blood storage and activation of B-cells (plasma cells)

b-cells that produce antibodies as part of adaptive immunity

a place for cells to communicate and mount attack also where B-cells get activated

gut associated lymphoid tissue

• lymph nodes - filter lymph and site where immune responses can be mounted
• BM - site of immune cell production
• T-is the site of tcell maturation
• Spleen - storage area for blood and lymph and site of mounting immune responses

• granualcytes - granules released by exocytosis and are effective against bact,fungi,patho
• agranualcytes - absence of granuels

• lymphoid SC
• myeloid SC

• NK
• T cell (helper T and cytotoxic)
• B cell (plasma)

• granulocyte (dendritic neutrophil) monocyte (macrophage)
• eosinophil
• basophil (mast cell)
• megakaryocyte (platelets)
• erythroid (erythrocytes)

• antibacterial enzymes (defensins) are found on skin
• sweat has antimicrobial properties

number of pro that act on non specific defense against bacteria

• classical pathway - binding of AB to patho
• alternative pathway - no need for antibodies

• proteins that prevent viral replication and dispersion of viral and cellular proteins from nearby cells that are produced by cells that have been infected with the virus
• decrease permeability of these cells so the virus cant infect as well
• unregulate MHC class 1/2 to increase antigen presentation and better detection of infected cells

• phago invaders through endocytosis
• digest invader
• presents pieces of invader to other cells using MHC which binds to a patho pep and carries it to cell surface

chemical substances that stim inflammation and recruit additional immune cells to area

**helps to monitor health of cells, if they are invaded by a virus then they will present an unfamiliar protein on their surface

• MHC 1 pathway that binds antigens from inside of the cells
• certain intracellular pathogen can be killed by Cytotoxic to prevent infection of other cells

molecules (macro) that display professional antigens that they pick up from phago cells from the environment

• antigens are presented outside of the cell
• can activate adaptive and innate system

• toll like receptors
• recognize the category of the invader and allows specific cytokines to recruit the right type of immune cells

nonspecific lymphocyte, detect down regulation of MHC and induce apop

• most common leukocyte in blood
• phago,macro,target bact
• follow the bact using chemotaxis
• can detect when a bact has been opsonized (marked with AB from b-cell)

the sensing of certain products given off by bact and migrate neutro to the cells

the marking of bacteria wih AB from B-cell

• involved in allergic reactions
• release a large amount of histamine

vasodilation and increase blood vessel leakiness allowing immune cells to be released to move out of blood stream and into tissue

• least amount
• involved in allergic reactions

• presents antigens from patho
• attack those that present displayed antigens

• bind to specific antigen, ab might attract other leuko to phago antigen (opsonization)
• AB can cause agglutinate to be phago
• AB can block ability of patho to invade tissue to neutralize it

• secreted into body fluids
• binding of antigen to b cell casing activation of the cell
• AB are bound to antiens on surface of the mast cell, degranulation occurs causing histamine and an inflammatory rxn

forms large insoluble complexes to be phago

• 2 heavy and 2 light chains
• disulfide linkages hold them together
• antibinding region (look or antibind site) at the end of the variable domain
• constant region (domain) is where NKC,maco,mono,eosino have receptors for and can activate a compliment cascade

• why does it take so long to initiate a AB response 2
• specific poplypep sequences will bind to one specific antigen sequence
• b-cell undergoes hypermutation  to find the best match antigen to bind to with high affinity (clonal selection)

• 5 antibody isotopes
• IgM,D,E,G,A

• isotope switching
• cell can change which isotype of the AB they produce when stim by specific cytokines

mem b cells wait for a response that has occurred before so they can act on it

secondary response - the immune response for the pathogen

sites where b-cells proliferate and mature in the lymph nodes

• lymphatic vessels at the center of villus in the small intestine
• receives fats packaged into chylomicrons by intestinal mucosal cells for support

lymphatic fluid carrying many chylomicrons that has a white fluid appearance

swelling due to fluid collecting in tissue where oncotic blood pressure decreases and less water is driven back into tissue

one way vessels that become larger as they move to the center of the body, they carry lymphatic fluid and join to comprise a large thoracic duct in posterior chest that delivers fluid into the left subclavian vein (near heart)

• fluid leaves the bloodstream and goes into tissues at the capillaries. Hydrostatic and oncotic pressure helps to determine the amount of fluid that leaves the tissue.
• oncotic pressure of blood draws water back into vessel at end of venuel when hydrostatic pressure decreases
• venuel end has less net pressure pushing fluid out, so small amount of fluid remains in the tissue

• maturing only cells that can respond to the presentation of antigen on MHC
• **don't respond to mhc undergo apop because it can not recog the periphery**

causing apop in cells that are self reactive (activated

• helper (CD4+)/cytotoxic (CD8+)
• suppressor/regulatory cells
• memory

release lymphokines that help to recruit other immune cells such as macro,cyto,plasma

directly kill virally infected cells by injecting toxic chems that promote apop into effected cells

• express CD4+ and foxp3
• tone down the IR once infection has been contained and then turn off self reactive lymphocytes to prevent autoimmune diseases (self tolerance)

• macro engulf bac and release inflame mediators
• cells digest and present antigens of pathogen on surface for MHC II
• cytokines released attract neutro/macro/inflam cells (neutro) resulting in releasing histamine and leaky capillaries
• dendritic cells go to nearest lymph node to present antigen to B-cell to create plasma and mem cells
• the AB goes into the blood stream to go to infected area while the nearest lymph node activates T-cells (CD4). CD4+ comes in 2 types, Th1 and Th2. Th1 cells release interferon gamma which activates macro and increase ability to kill bact. Th2 cells help to activate B-cells
• pathogen has been eliminated, plasma cells die, but mem T and B cells remain

• infected cell produce interferons that reduce the ability of the other cells to become infected. The infected cell also produces intracellular proteins on their surface with MHC 1
• CD8 recognize MHC1 with antigen complex as being foreign and will inject toxins in cell to promote apop
• MHC is not common on the cell once the virus has infected it so NKC will recognize its absence and will help cause apop

pro and carbo on surface of every cell in body that helps to signal to immune cells that the cell is not threatening and should not be attack

when the immune system fails at detecting between self and foreign cells so they attack the good cells

immune system are hypersensitive to antigens and become overactivated when antigens are encountered

ex:glucocorticoids that have immunosuppressive qualities

immune system that is stim by natural or artificial paho to produce AB against it specifically

results from the transfer of AB to an individual only

oxidation of glucose and fatty acids for energy (metabolism)

nutrients are obtains from food occurs within the lumen of alimentary canal

mouth t anus sectioned off by sphincters or circular smooth muscles that can contract to allow compartmentalization of function

• mechanical
• chemical

physical breakdown of food particles

enzymatic cleavage of chem bonds into particles that can be absorbed starch,carbo,lipids (transportation of products of digestion from the digestive tracts into circulatory system to distribute to tissues and cells)

mouth>pharynx>esophagus>stomach>small intestine>large intestine>rectum

provide enzymes and lubrication needed to aid in the digestion of food

collection of 10^6 neurons that governs the function of the gastrointestinal sysem. Trigger peristals/rhythmic contractions of the gut to move materials through the system

all glands of the body are innervated by ParaNS except sweat

hydrolyzing starch into smaller sugars

catalyzes the hydrolysis of lipids

• nasopharynx (behind nasal cavity)
• oropharynx (back of the mouth)
• laryngopharynx (above vocal cords)

(upper esophageal sphincter) is where swallowing is initiated, as peristalsis occur, the bolus goes down the stomach toward the lower esophageal sphincter (cardiac sphincter) where it relaxes and opens to allow the passage of food

• fundus
• body
• antrum
• pylorus

responds to signals from vagus nerve of paraNS which are activated by the brains response to sight,taste,and smells

• mucous
• chief
• parietal