Ch 8,9- Immunology & Digestive Flashcards
Composed of defenses always active against infection but lack ability to target specific invaders
Innate (nonspecific) immunity
Defenses that target a specific antigen
Adaptive or specific immunity
What structure produces all the leukocyes
Bone marrow
Stores blood and activates B-Cells (turns into plasma cells)
Spleen
_______ A division of adaptive immunity where antibodies dissolve and act in blood (rather than in cells)
Humoral Immunity
T-Cells are the agent of what type of the adaptive immunity
Cell mediated immunity
Two types of adaptive immunity
Cell mediated (T-Cells) and humoral immunity (Ab)
Provide a place for immune cells to communicate and mount an attack
Lymph nodes
Immune tissue found in close proximity to the digestive system
GALT (includes tonsils, adenoids, peyers patches, and appendix)
Site of t-cell maturation
Thymus
The procurer of leukocytes, erythrocytes, and platelets
Hematopoietic stems cells
Our first line of defense is the
Skin
Antibacterial enzymes called ________ can be found on the skin
Defensins
Several other mucous membranes like around the eye and oral cavity produce a nonspecific bacterial enzyme called
Lysozyme (Secreted in tears and saliva)
Role in GI in nonspecific immunity
Acid product, and gut flora
The ______ system consists of a number of proteins in the blood that act as a nonspecific defense against bateria
Compliment
(can be activated through a classical pathway (which requires the binding of an antibody to a pathogen) or an alternative pathway (which does not require antibodies)”
To protect against viruses, cells that have been infected with viruses produce
Interferons
Proteins that prevent viral replication and dispersion
Cause nearby cells to decrease production of both viral and cell proteins
Upregulate MHC class 1 and 3= increased antigen presentation
When a macrophage gets activated what 3 things occur
- Phagocytosis through endocytosis
- Digests invader with enzymes
- Presents peptides of invader to others cells using proteins called MHC
chemical substances that stimulate inflammation and recruit additional immune cells to the area.”
Cytokines
All nucleated cells in the body display what type of MHC molucules
MHC class 1
Often called endogenous pathway because it binds antigens from inside the cell. Allows immune system to monitor health of these calls.
________ molecules are mainly displayed by professional antigen-presenting cells like macrophages”
“MHC class II
(exogenous pathway)
because these antigens originated outside of cell
“While antibody production is the domain of the adaptive immune system, it is important to understand that cells of the innate immune system also present antigens.”
Antigen presenting cells include
Macrophages, dendritic cells, some b cells, certain activated epithelial cells
_______ is in all nucleated cells and presents endogenous antigens. _________ is in antigen-presenting cells and presents exogenous antigens.”
MHC 1, MHC-2
“Macrophages and dendritic cells also have special receptors known as _________, the best-described of which are
________
- pattern recognition receptors (PRR)
- toll-like receptors (TLR). ”
“PRRs are able to recognize the category of the invader (bacterium, virus, fungus, or parasite). This allows for the production of appropriate cytokines to recruit the right type of immune cells;”
“a type of nonspecific lymphocyte, are able to detect the downregulation of MHC and induce apoptosis in these virally infected cells. ”
Natural killer cells
“Cancer cells may also downregulate MHC production, so NK cells also offer protection from the growth of cancer as well.”
“Neutrophils can literally follow bacteria using _______—the sensing of certain products given off by bacteria and migration of neutrophils to follow these products back to the source (the bacterium itself).”
Chemotaxis
“Neutrophils can also detect bacteria once they have been marked with an antibody from a B-cell or _____
Excerpt From: Kaplan. “Kaplan MCAT Biology Review: Created for MCAT 2015 (Kaplan Test Prep).” iBooks.
opsonized
“contain bright red-orange granules and are primarily involved in allergic reactions and invasive parasitic infections.”
Eosinophils
-Release histamine=vasodilation and leaky capillaries
“contain large purple granules and are involved in allergic responses.”
Basophils
“Both basophils and _______ release large amounts of histamine in response to allergens, leading to inflammatory responses.”
Mast cells
Cells of innate immune system
Macrophages, mast cell, Granulocytes, Dendritic cells, NK cells
“B-cells mature in the _____. T-cells mature in the __________.”
Excerpt From: Kaplan. “Kaplan MCAT Biology Review: Created for MCAT 2015 (Kaplan Test Prep).” iBooks.
Bone Marrow, Thymus
“B-cells govern the ______ response while T-cells mount the ______ response.
Humoral, Cell mediated
Antibodies are also called
Immuneglobulins (Ig)
Once antigen bound to Ig what happens
Either
- Opsonization
- Agglutinate (large insoluble complexes that are phagoctizied)
- Neutralize pathogens
“For cell-surface antibodies, the binding of antigen to a B-cell causes activation of that cell, resulting in”
“its proliferation and formation of plasma and memory cells”
“when antigen binds to antibodies on the “surface of a mast cell, it causes what?
degranulation (exocytosis of granule contents), allowing the release of histamine and causing an inflammatory allergic reaction.”
“Antibodies are Y-shaped molecules that are made up of two identical _______ and two identical ________”
Heavy chains, Light chains
“Disulfide linkages and noncovalent interactions hold the heavy and light chains together”
“Each antibody has an ______ at the end of what is called the _______
antigen-binding region, variable region (domain)
“ antibodies come in five different isotypes
(IgM, IgD, IgG, IgE, and IgA).”
D-GAME
“Cells can change which isotype of antibody they produce when stimulated by specific cytokines in a process called
isotype switching.
“Upon exposure to the correct antigen, a B-cell will proliferate and produce two types of daughter cells.
Excerpt From: Kaplan. “Kaplan MCAT Biology Review: Created for MCAT 2015 (Kaplan Test Prep).” iBooks.
Plasma and memory Cells
Plasma cells produce large amounts of antibodies, whereas memory B-cells stay in the lymph node, awaiting reexposure to the same antigen.”
Initial B cell activation is called the ______ response. Takes 7-10 days. The memory cells jumping to action and producing specific atnobideis which will be rapid and robust are called ________
Primary, Secondary
“The development of these lasting memory cells is the basis of the efficacy of ____________
Vaccinations
“T-cells mature in the thymus, where they undergo both _____ and ______ selection.”
Positive, Negative
“Positive selection refers to maturing only cells that can respond to the presentation of antigen on MHC (cells that cannot respond to MHC undergo apoptosis because they will not be able to respond in the periphery).
Negative selection refers to causing apoptosis in cells that are self-reactive (activated by proteins produced by the organism itself).”
“The maturation of T-cells is facilitated by ______, a peptide hormone secreted by thymic cells.”
Excerpt From: Kaplan. “Kaplan MCAT Biology Review: Created for MCAT 2015 (Kaplan Test Prep).” iBooks.
Thymosin
“Once the T-cell has left the thymus, it is mature but naïve. Upon exposure to antigen, T-cells will also undergo clonal selection so that only those with the highest affinity for a given antigen proliferate.”
3 major types of t-cells
“helper T-cells, suppressor T-cells, and killer (cytotoxic) T-cells. ”
“CD4+ T-cells, coordinate the immune response by secreting chemicals known as
lymphokines
These molecules are capable of recruiting other immune cells (such as plasma cells, cytotoxic T-cells, and macrophages) and increasing their activity.
These molecules are capable of recruiting other immune cells (such as plasma cells, cytotoxic T-cells, and macrophages) and increasing their activity.
Lymphokines
Secreted by t helper cells
Cd4 t cells respond to antigens presented on _____, cd8 responds to antigens presented on ____
MHC II Molecules, MHC I
“CD4+ T-cells are better at fighting _______ infections, while CD8+ T-cells are better at targeting _______ infections.”
Extracellular (MHC II), Intracellular (MHC I)
Type of T Cell that also expresses cd4 but express a protein called Foxp3.
Help tone down immune response once infection contained.
Also turns of reactive lymphocytes to prevent autoimmune diseases and called
Self-Tolerance
“Similar to memory B-cells, these cells lie in wait until the next exposure to the same antigen. When activated, they result in a more robust and rapid response.”
Memory T-Cells
2 Types of CD4+ cells
TH1 and TH2
TH1 cells release interferon gamma (IFN-γ), which activates macrophages and increases their ability to kill bacteria”
Th2 cells help activate B-cells.”
TH1 cells (T-Helper Cells) release _________, which activates macrophages and increases their ability to kill bacteria”
Th2 cells help activate _______
interferon gamma (IFN-γ)
B-Cells
“In a viral infection, the virally infected cell will begin to produce _____
interferons, which reduce the permeability of nearby cells
“These infected cells also present intracellular proteins on their surface in conjunction with MHC-I”
“In the event that the virus downregulates the production and presentation of MHC-I molecules, natural killer cells will recognize the absence of MHC-I and will accordingly cause”
Apoptosis
“the proteins and carbohydrates present on the surface of every cell of the body”
Self Antigens
“when the immune system fails to make the distinction between self and foreign, it may attack cells expressing particular self-antigens, a condition known as”
Autoimmunity
“involves the elimination of T-cells that respond to self-antigens”
negative selection
“the immune system is stimulated to produce antibodies against a specific pathogen”
Active Immunity
Immunity that results from the transfer of antibodies to an individual
Passive Immunity
“small lymphatic vessels, are located at the center of each villus in the small intestine. Fats, packaged into chylomicrons by intestinal mucosal cells, enter the _______ for transport. ”
Lacteal
“B-cells proliferate and mature in the lymph nodes in collections called __________”
germinal centers
“sites where immune responses can be mounted, and in which B-cells are activated.”
“spleen and lymph nodes”
“Tears and saliva contain _______, an antibacterial compound”
Lysozymes
“MHC class I (MHC-I) is present in all nucleated cells and displays ________ (proteins from within the cell) to cytotoxic T-cells (CD8+ cells).”
endogenous antigen
“MHC class II (MHC-II) is present in professional antigen-presenting cells (macrophages, dendritic cells, some B-cells, and certain activated epithelial cells) and displays _______ (proteins from outside the cell) to helper T-cells (CD4+ cells).”
exogenous antigen
“Th1 cells secrete ________, which activates macrophages. Th2 cells ____________.”
Excerpt From: Kaplan. “Kaplan MCAT Biology Review: Created for MCAT 2015 (Kaplan Test Prep).” iBooks.
interferon gamma,
activate B-cells
“The lymphatic system connects to the cardiovascular system via the _________ in the posterior chest.”
Thoracic Duct
_________ as a part of metabolism, involves the oxidation of glucose and fatty acids for energy.”
“ The process by which these nutrients are obtained from food occurs within the lumen of the alimentary canal and is known as _________
intracellular digestion, extracellular digestion”
“physical breakdown of large food particles into smaller food particles, but does not involve breaking chemical bonds”
Mechanical Digestion
“enzymatic cleavage of chemical bonds, such as the peptide bonds of proteins or the glycosidic bonds of starches”
Chemical Digestion
“involves the transport of products of digestion from the digestive tract into the circulatory system for distribution to the body’s tissues and cells”
Aborption
“a shared pathway for both food entering the digestive system and air entering the respiratory system. ”
Pharynx
“collection of one hundred million neurons that governs the function of the gastrointestinal system. ”
Enteric Nervous System
“This system can function independently of the brain and spinal cord, although it is heavily regulated by the autonomic nervous system.”
Enteric Nervous System
“collection of one hundred million neurons that governs the function of the gastrointestinal system. ”
Hormones of the GI that stimulate feelings of hunger
“Glucagon, secreted by the pancreas, and ghrelin, secreted by the stomach and pancreas
“Leptin and cholecystokinin do the opposite, stimulating feelings of satiety”
Leptin and cholecystokinin stimulate feelings of
Satiety
“The chemical digestion of carbohydrates is initiated in the _______, but is completed in the __________.”
Mouth, Small Intestine
“ Salivary amylase (active in the mouth) and pancreatic amylase (active in the small intestine) have the same function.”
“All of the glands of the body (except sweat glands) are innervated by the”
parasympathetic nervous system.
“Salivary amylase is capable of hydrolyzing starch into smaller ________ (maltose and dextrins), while lipase catalyzes the hydrolysis of _________”
Sugars, Lipids
“The pharynx can be divided into three parts:
the nasopharynx (behind the nasal cavity), the oropharynx (at the back of the mouth), and the laryngopharynx (above the vocal cords).”
“The top third of the esophagus is composed of ________, the bottom third is composed of _________, and the middle third is a mix of both.”
Skeletal muscle, smooth muscle
“While the top of the esophagus is under somatic (voluntary) motor control, the bottom—and most of the rest of the gastrointestinal tract, for that matter—is under autonomic (involuntary) nervous control. ”
“As the bolus approaches the stomach, a muscular ring known as the ______ relaxes and opens to allow the passage of food.”
lower esophageal sphincter (cardiac sphincter
“The liver also receives all blood draining from the abdominal portion of the digestive tract through the.”
hepatic portal vein
“the liver takes up excess sugar to create glycogen, the storage form of glucose, and stores fats as _________
triacylglycerols”
The liver produces glucose for the rest of the body through ______ and _______
glycogenolysis and gluconeogenesis”
“amphipathic molecules that can emulsify fat in the digestive system”
Bile salts
“The major pigment in bile is _________, which is a byproduct of the breakdown of hemoglobin. ”
Excerpt From: Kaplan. “Kaplan MCAT Biology Review: Created for MCAT 2015 (Kaplan Test Prep).” iBooks.
bilirubin
“Bilirubin travels to the liver, where it is _________ (attached to a protein) and secreted into the bile for excretion.”
Conjugated
“The major components of bile are
- bile salts, which emulsify fats;
- pigments (especially bilirubin, from the breakdown of hemoglobin)
- cholesterol.”
2 essential proteins the liver synthesizes
Albumin (protein that maintains plasma oncotic pressure and serve as drug carrier)
and
Clotting factors
“Upon release of _____, the gallbladder contracts and pushes bile out into the biliary tree”
CCK
“Hydrolyzes specific peptide bonds; converts chymotrypsinogen to chymotrypsin”
Trypsin
activated by enteropeptidase
“Hydrolyzes specific peptide bonds; activated by trypsin”
Chymotrypsin
“Hydrolyzes terminal peptide bond at carboxy end; activated by enteropeptidase”
Carboy peptidases A and B by pancreatic acinar cells
“Hydrolyzes terminal peptide bond at amino end”
Aminopeptidase
Carboy peptidases A and B by pancreatic acing cells Hydrolyzes terminal peptide bond at carboxy end; activated by enteropeptidases”
“Hydrolyzes pairs of amino acids”
Dipeptidases
“Converts trypsinogen to trypsin and procarboxypeptidases A and B to carboxypeptidases A and B”
Enteropeptidases
“The small intestine is lined with _____, which are small, fingerlike projections from the epithelial lining”
Villi
“Each villus has many microvilli, drastically increasing the surface area available for absorption.”
“at the middle of each villus is both a capillary bed for the absorption of water-soluble nutrients and a _____, a lymphatic channel that takes up fats for transport into the lymphatic system.”
Lacteal
In intestinal absorption simple carbohydrates and amino acids ______ from the epithelial cells into the capillaries”
Diffuse
“What about fats? Small fatty acids will follow the same process as carbohydrates and amino acids by diffusing directly into the intestinal capillaries.”
“These fatty acids do not require transporters because they are nonpolar, so they can easily traverse the cellular membrane”
Triglycerides and esterified cholesterol molecules are packaged into insoluble ________”
Chylomicrons
enter the lymphatic circulation through lacteals”
Fat soluble vitamins are absorbed by _________. Water soluble vitamins are absorbed by ________
Chylomicrons,
Across Endothelial Cells directly into plasma
Water not only passes __________ but _________ to reach the blood
“transcellularly (across the cell membrane),
paracellularly (squeezing between cells)
Internal anal sphincter is under _________ control and external anal sphincter is under ______ control
Autonomic, Somatic Control
_________ involves the oxidation of glucose and fatty acids to make energy. ____________ occurs in the lumen of the alimentary canal.
Intracellular Digestion, Extracellular Digestion
“The ___________ is in the wall of the alimentary canal and controls peristalsis.”
enteric nervous system
_______ promote hunger; and _________ promote satiety.”
glucagon and gherkin, leptin and cholecystokinin,
“The stomach has four parts:
fundus, body, antrum, and pylorus.”
“secrete pepsinogen, a protease activated by the acidic environment of the stomach.”
Chief cells
“secrete hydrochloric acid and intrinsic factor, which is needed for vitamin B12 absorption.”
Parietal Cells
________ secrete gastrin, a peptide hormone that increases HCl secretion and gastric motility.”
G Cells
“After mechanical and chemical digestion in the stomach, the food particles are now called
Chyme
“are brush-border enzymes that break down maltose, isomaltose, lactose, and sucrose into monosaccharides.”
Disacharidases
“Brush-border peptidases include
aminopeptidase and dipeptidases.”
dipeptidases hydrolyze bound pairs of amino acids, called dipeptides
__________ activates trypsinogen and procarboxypeptidases, initiating an activation cascade.”
“Enteropeptidase
“stimulates the release of pancreatic juices into the digestive tract and slows motility.”
Secretin
“Acinar cells in the pancreas produce pancreatic juices that contain”
Excerpt From: Kaplan. “Kaplan MCAT Biology Review: Created for MCAT 2015 (Kaplan Test Prep).” iBooks.
bicarbonate, pancreatic amylase, pancreatic peptidases (trypsinogen, chymotrypsinogen, carboxypeptidases A and B), and pancreatic lipase.
