BIOS 242 Final Exam With Correct
Questions And Answers 2024
First line of defense - CORRECT ANSWERS-Skin - layer of epidermal cells is
constantly dividing and cells are move outward where they die and dry out
Form a sort of armor.
Follicle cells have associated oil (fatty acids) producing glands and sweat glands
produce salty water
There are also antimicrobial peptides produced and deposited on the skin.
Mucous membranes - single layer of cells with mucous producing cells + ciliated cells to
keep the mucous moving
Nasal hairs help capture particles, including microbes
The ciliated cells in particular keep mucous moving from the bronchus up to the pharynx
then to stomach
This ciliary (or mucosal) escalator keeps the lungs cleared
Saliva and tears wash away... - CORRECT ANSWERS-microbes - contain the
antibacterial enzyme lysozyme that degrades peptidoglycan
The flow of urine flushes the urinary tract
Acid environment of stomach and digestive enzymes/bile in intestines kill microbes
Our resident microbiota also serves to keep potentially pathogenic organisms from
setting up shop
Second line of defense - CORRECT ANSWERS-protective cells and fluids;
inflammation and phagocytosis - nonspecific
-non-specific, non-adaptive - but active, so it must also recognize self (via markers on
cells)
This includes the complement system, which is a complex series of proteins being
cleaved and which eventually either kills cells directly (MAC - macromolecular attack
complex) or marks them for phagocytosis
different compartments in our bodies - CORRECT ANSWERS-Intracellular and
extracellular - among the extracellular are:
Interstitial (between cells and tissues), circulatory, lymphatic and cerebrospinal -
separate but connected
Cells of the immune system circulate in all of the extracellular spaces.
mononuclear phagocyte system (MPS) - CORRECT ANSWERS-monocytes circulate in
blood and tissue spaces and when encountering an invader or debris differentiate into
macrophage (phagocytic cells), which are the primary vacuum cleaners in our bodies.
,The lymphatic system - CORRECT ANSWERS-drains the interstitial space, collects it,
processes what it collects, and returns the results to the bloodstream for elimination in
the urine.
The lymphatic system includes the thymus, spleen, lymph nodes, mucosal associated
lymphatic tissues (MALT)
All of these are places with significant interchange between blood and lymph
Thymus - maturation of T-lymphocytes
Spleen - mainly filters blood with removal to the lymph - allows lymphocytes to sample
blood for intruders
Lymph nodes - filters lymph - major site where lymphocytes encounter antigen
presenting cells for activation
MALT - more diffuse but similar function to nodes - GALT, SALT, etc. are subsets of
MALT named for locale
The leucocytes (cells in the blood) - CORRECT ANSWERS-white blood cells (WBC) -
all produced in the bone marrow - Hematopoiesis
Hematopoietic stems cells give rise to myeloid and lymphoid stem cells
other cells in blood - CORRECT ANSWERS-Granulocytes - named through microscopic
observation long before function known
Eosinophils - active in allergy and particularly fungal and worm infections
release digestive enzymes, inflammatory mediators such as prostaglandins and
histamine
Basophils - contain potent chemical mediators as with eosinophils - scarce - also
releases histamine
Mast cells are similar to basophils and bind IgE to stimulate allergic reactions - tissue
bound
Neutrophils are the most abundant (55 to 90% of leukocytes)
Release toxic chemicals and enzymes, inflammatory mediators and are phagocytic
Usually the first cells to encounter foreign material and set off the alarm
Agranulocytes - CORRECT ANSWERS-The monocytes circulate in the blood - large
phagocytic cells - 3 to 7% of cells in circulation
Move into the tissues and become macrophage which are the primary phagocytic cells
They also become dendritic cells and both these and macrophage are antigen
presenting cells
Lymphoid line - lymphocytes - CORRECT ANSWERS-NK cells (natural killer) do not
have specificity but recognize cells not displaying proper MHC I molecules
B-cells and T-cells
Phagocytosis - - CORRECT ANSWERS-invaders can be recognized by general
features or Pathogen-Associated Molecular Patterns - PAMPS
Toll-like Receptors (TLRs) are one class of Pattern Recognition Receptors - recognize
general types of molecules:
Peptidoglycan, lipopolysaccharide, double-stranded RNA
, TLRs are on the surface of phagocytic cells - there are intracellular PRRs and soluble
PRRs (collectins)
Inflammation - - CORRECT ANSWERS-an orchestrated series of cellular responses -
first responders produce cytokines to attract more cells
Capillaries become leaky and fluid moves into the tissues (edema)
Specific movement of WBCs into tissue is via a process called diapedesis
Fever is produced as a reaction to pyrogens and is generally beneficial
Virus infected cells produce - CORRECT ANSWERS-interferons - which signal cells to
self-destruct to prevent the spread of the infection
third line of defense (specific) - CORRECT ANSWERS-Stimulated by foreign molecules
defined as antigens - most commonly proteins and polysaccharides - also termed
immunogens
These can be intracellular (T-cell response) or extracellular (B-cell response)
T and B cells that might react with self-antigens are removed (clonally deleted)
Antigens on the surface of cells are also termed markers (a subclass of antigens)
The specific site (molecules) on the antigen that the antibodies or T-cells recognize -
CORRECT ANSWERS-the epitope
-Characterized by having molecular level specificity and creating a memory of the
response
B-cells respond by producing - CORRECT ANSWERS-antibodies
T-cells perform cell-mediated cytotoxicity, T-helper cells necessary for both responses
After being made in the bone marrow and processed in bone marrow (B-cells) or
thymus (T-cells).
They hang out mostly in secondary lymphatic tissue (spleen and lymph nodes, MALT)
Interact with antigen presenting cells (macrophage, dendrocytes, B-cells) to become
activated
Activation - CORRECT ANSWERS-involves processing of the antigens for display on
MHC class I or II cell surface molecules
-MHC I molecules are displayed on every nucleated cell in the body, MHC II on only
certain immune system cells
Extracellular antigens (picked up by phagocytosis) are processed and displayed on
MHC II molecules
Antigens produced inside the cell (ER-Golgi) are displayed on MHC I molecules
The activation of a response to most antigens requires MHC display and TH cell help
Interaction with MHC molecules also requires interaction with either CD4 (for help) or
CD8 (for cytotoxicity)
Once activated by antigenic peptides (on MHC) and TH cells the B or T cells clonally
expand (small percentage become memory cells)
Display of self-peptides on MHC I molecules is the basis for cellular recognition of "self"
and hence graft (transplant) rejection
Questions And Answers 2024
First line of defense - CORRECT ANSWERS-Skin - layer of epidermal cells is
constantly dividing and cells are move outward where they die and dry out
Form a sort of armor.
Follicle cells have associated oil (fatty acids) producing glands and sweat glands
produce salty water
There are also antimicrobial peptides produced and deposited on the skin.
Mucous membranes - single layer of cells with mucous producing cells + ciliated cells to
keep the mucous moving
Nasal hairs help capture particles, including microbes
The ciliated cells in particular keep mucous moving from the bronchus up to the pharynx
then to stomach
This ciliary (or mucosal) escalator keeps the lungs cleared
Saliva and tears wash away... - CORRECT ANSWERS-microbes - contain the
antibacterial enzyme lysozyme that degrades peptidoglycan
The flow of urine flushes the urinary tract
Acid environment of stomach and digestive enzymes/bile in intestines kill microbes
Our resident microbiota also serves to keep potentially pathogenic organisms from
setting up shop
Second line of defense - CORRECT ANSWERS-protective cells and fluids;
inflammation and phagocytosis - nonspecific
-non-specific, non-adaptive - but active, so it must also recognize self (via markers on
cells)
This includes the complement system, which is a complex series of proteins being
cleaved and which eventually either kills cells directly (MAC - macromolecular attack
complex) or marks them for phagocytosis
different compartments in our bodies - CORRECT ANSWERS-Intracellular and
extracellular - among the extracellular are:
Interstitial (between cells and tissues), circulatory, lymphatic and cerebrospinal -
separate but connected
Cells of the immune system circulate in all of the extracellular spaces.
mononuclear phagocyte system (MPS) - CORRECT ANSWERS-monocytes circulate in
blood and tissue spaces and when encountering an invader or debris differentiate into
macrophage (phagocytic cells), which are the primary vacuum cleaners in our bodies.
,The lymphatic system - CORRECT ANSWERS-drains the interstitial space, collects it,
processes what it collects, and returns the results to the bloodstream for elimination in
the urine.
The lymphatic system includes the thymus, spleen, lymph nodes, mucosal associated
lymphatic tissues (MALT)
All of these are places with significant interchange between blood and lymph
Thymus - maturation of T-lymphocytes
Spleen - mainly filters blood with removal to the lymph - allows lymphocytes to sample
blood for intruders
Lymph nodes - filters lymph - major site where lymphocytes encounter antigen
presenting cells for activation
MALT - more diffuse but similar function to nodes - GALT, SALT, etc. are subsets of
MALT named for locale
The leucocytes (cells in the blood) - CORRECT ANSWERS-white blood cells (WBC) -
all produced in the bone marrow - Hematopoiesis
Hematopoietic stems cells give rise to myeloid and lymphoid stem cells
other cells in blood - CORRECT ANSWERS-Granulocytes - named through microscopic
observation long before function known
Eosinophils - active in allergy and particularly fungal and worm infections
release digestive enzymes, inflammatory mediators such as prostaglandins and
histamine
Basophils - contain potent chemical mediators as with eosinophils - scarce - also
releases histamine
Mast cells are similar to basophils and bind IgE to stimulate allergic reactions - tissue
bound
Neutrophils are the most abundant (55 to 90% of leukocytes)
Release toxic chemicals and enzymes, inflammatory mediators and are phagocytic
Usually the first cells to encounter foreign material and set off the alarm
Agranulocytes - CORRECT ANSWERS-The monocytes circulate in the blood - large
phagocytic cells - 3 to 7% of cells in circulation
Move into the tissues and become macrophage which are the primary phagocytic cells
They also become dendritic cells and both these and macrophage are antigen
presenting cells
Lymphoid line - lymphocytes - CORRECT ANSWERS-NK cells (natural killer) do not
have specificity but recognize cells not displaying proper MHC I molecules
B-cells and T-cells
Phagocytosis - - CORRECT ANSWERS-invaders can be recognized by general
features or Pathogen-Associated Molecular Patterns - PAMPS
Toll-like Receptors (TLRs) are one class of Pattern Recognition Receptors - recognize
general types of molecules:
Peptidoglycan, lipopolysaccharide, double-stranded RNA
, TLRs are on the surface of phagocytic cells - there are intracellular PRRs and soluble
PRRs (collectins)
Inflammation - - CORRECT ANSWERS-an orchestrated series of cellular responses -
first responders produce cytokines to attract more cells
Capillaries become leaky and fluid moves into the tissues (edema)
Specific movement of WBCs into tissue is via a process called diapedesis
Fever is produced as a reaction to pyrogens and is generally beneficial
Virus infected cells produce - CORRECT ANSWERS-interferons - which signal cells to
self-destruct to prevent the spread of the infection
third line of defense (specific) - CORRECT ANSWERS-Stimulated by foreign molecules
defined as antigens - most commonly proteins and polysaccharides - also termed
immunogens
These can be intracellular (T-cell response) or extracellular (B-cell response)
T and B cells that might react with self-antigens are removed (clonally deleted)
Antigens on the surface of cells are also termed markers (a subclass of antigens)
The specific site (molecules) on the antigen that the antibodies or T-cells recognize -
CORRECT ANSWERS-the epitope
-Characterized by having molecular level specificity and creating a memory of the
response
B-cells respond by producing - CORRECT ANSWERS-antibodies
T-cells perform cell-mediated cytotoxicity, T-helper cells necessary for both responses
After being made in the bone marrow and processed in bone marrow (B-cells) or
thymus (T-cells).
They hang out mostly in secondary lymphatic tissue (spleen and lymph nodes, MALT)
Interact with antigen presenting cells (macrophage, dendrocytes, B-cells) to become
activated
Activation - CORRECT ANSWERS-involves processing of the antigens for display on
MHC class I or II cell surface molecules
-MHC I molecules are displayed on every nucleated cell in the body, MHC II on only
certain immune system cells
Extracellular antigens (picked up by phagocytosis) are processed and displayed on
MHC II molecules
Antigens produced inside the cell (ER-Golgi) are displayed on MHC I molecules
The activation of a response to most antigens requires MHC display and TH cell help
Interaction with MHC molecules also requires interaction with either CD4 (for help) or
CD8 (for cytotoxicity)
Once activated by antigenic peptides (on MHC) and TH cells the B or T cells clonally
expand (small percentage become memory cells)
Display of self-peptides on MHC I molecules is the basis for cellular recognition of "self"
and hence graft (transplant) rejection
