Exam 1: Ch.3 Immune System Flashcards
What is our body’s three mechanisms of protection?
- Surface Protection
- Acute Inflammation
- Immune Response
What type of protection is keratin on the skin, mucus in respiratory and digestive systems, and an acidic env. in the vagina all examples of?
surface protection
What type of immunity is surface protection considered?
innate immunity
What type of protection is a non-specific process that involves neutrophils, macrophages, and eosinophils moving into an area?
Acute inflammation
What type of immunity is acute inflammation?
innate immunity
Immune response is an example of _____ immunity. ( or ____ immunity)
acquired immunity; or adaptive immunity
What are the two many types of Acquired Immunity (adaptive immunity)?
- Humoral Immunity
2. Cell Mediated Immunity
Which type of Adaptive immunity is usually a response to invading bacteria?
Humoral immunity
Which type of Adaptive immunity is usually a response to viruses, fungi, or foreign cells?
Cell Mediated Immunity
What is Humoral immunity usually mediated by?
What is Cell Mediated immunity usually mediated by?
B cells and plasma cells, with T cells
T cells
What will Humoral immunity involve the production of?
antibodies
T/F. Cell mediated immunity depends on B cells participation.
False– it DOES NOT require B-cell participation
What kind of response does Cell mediated immunity create?
a cytotoxic response
What are the three functions of the immune system?
- Storage of lymphocytes
- Increase numbers of lymphocytes
- Provide a favorable env. for establishing immunity
What are the two general components of the immune system?
- Diffuse lymphatics
2. Lymphatic organs
Diffuse lymphatics has a ______ capsule and functions in _____ type(s) of immunity.
no or incomplete capsule
fxns in Humoral immunity
Lymphatic organs have a ___ and function in ________ type(s) of immunity.
has a capsule
Humoral AND cell-mediated immunities
_____ Lymphoid organs provide an env. where lymphocytes become immunocompetent.
Primary
_____ Lymphoid organs provide an env. where lymphocytes can contact foreign antigens and interact with each other.
Secondary
What are examples of Primary lymphoid organs?
thymus and bone marrow
What are examples of Secondary lymphoid organs?
spleen and lymph nodes and diffuse lymphatics
What are the two categories of Diffuse Lymphatics?
- MALT (Mucosal-Associated Lymphatic Tissue)
2. Tonsils (2 types)
What are the two “subcategories” of MALT (Mucosal-Ass. Lymphatic Tissue)?
- GALT (Gut-Associated Lymphatic Tissue)
2. BALT (Bronchial-Ass. Lymphatic Tissue)
Where is MALT found?
GI, respiratory, and urogenital tracts
In MALT, if there is a lymph nodules, what can we assume?
B cells dividing –> B memory cells + plasma cells —> IgG or IgA
Secretory IgA. What are they?
secreted onto free epithelial surfaces and are an important first line of defense against infection
T/F. Secretory IgA’s are Antigen specific.
True
Where are examples of where Secretory IgA’s can be found?
- tears
- saliva
- gut lumen
- nasal cavity
- vaginal surface
What three things are IgA’s able to do?
- neutralize viruses
- neutralize bacterial toxins
- decrease microbial adhesion to host cells
What type of lymphatic tissue is found in individual lymph nodules or Peyer’s patches in the ileum?
GALT (Gut-Ass. Lymphatic Tissue)
–in GI tract
What type of lymphatic tissue commonly forms when air tubes bifurcate and are lymph nodules w/in the respiratory system?
BALT (Bronchial-Associated Lymphatic Tissue)
What are the two types of Tonsils?
- With Epithelial Folds = Pleated Tonsils
2. With Tonsilar Crypts
What type of tonsils are Pharyngeal Tonsils?
Epithelial Folds (Pleated Tonsils)
What type of tonsils are Palatine Tonsils(Faucial Tonsils)?
Tonsilar Crypts
What type of tonsils are Lingual Tonsils?
Tonsilar Crypts
Where are pharyngeal tonsils located and what is their surface epithelium?
1 in roof of nasopharynx
respiratory epithelium
What are pharyngeal tonsils called when they are inflamed? When this occurs when can be blocked?
adenoids
eustachian tubes and may cause ear infs.
What are palatine tonsils also known as?
Faucial tonsils
Where are Palatine (Faucial) Tonsils located? What type of surface epithelium do they have?
boundary of oral cavity and oropharynx
stratified squamous
(partial capsule likely)
What are two advantages of Palatine tonsils? What is one disadvantage?
Advantages:
- more surface area for detecting foreign antigens
- more area for lymph nodule formation of CT
Disadvantage:
1. Deep depressions–> bacteria can thrive –> inflam. –> tonsillitis
Where are Lingual Tonsils located? What type of surface epithelium?
dorsal posterior 1/3 of the tongue in oral cavity
stratified squamous (same as Palatine tonsils)
What is the tonsillar ring around the openings to the digestive and respiratory systems called?
Waldeyer’s Ring
Lymph nodes are small oval organs that are strung along the length of lymphatic vessels. Where are they common in? Are they a primary or secondary lymph organ?
neck, axilla, and groin regions
secondary lymph organ
What are the two major functions of lymph nodes?
- Filtration of lymph using phagocytosis
2. Establish humoral and cell mediated immunities (= both types of adaptive immunity)
What does the structure of a lymph node all include?
- Capsule
- Afferent Lymphatics
- Efferent Lymphatics
- Hilum
- System of Sinuses
- Regions of a Lymph Node
What is the capsule of a lymph node? (describe tissue)
dense irregular CT of moderate thickness
What does the capusule of a lymph node contain that is dense irregular CT that divides regions into compartments?
Trabeculae (or called Septa)
Afferent lymphatics are ______ vessels and ____ valves.
Efferent lymphatics are _____ vessels and ____ valves.
Afferent–> in-coming and has valves
Efferent –> out-going and has valves
What structure of a lymph node is the recessed area where efferent lymph exits and blood will enter and exit called?
hilum
What are the four sinuses involved in the system of sinuses of a lymph node?
- Subcapsular Sinus (Marginal Sinus)
- Cortical Sinus
- Deep Cortical Sinus
- Medullary Sinus
What sinus is the first to receive afferent lymph?
subcapsular sinus (= Marginal Sinus)
What lymph node sinus passes through the cortex?
Cortical sinus
What lymph node sinus passes through the deep cortex/ paracortex region?
Deep cortical sinus
What lymph node sinus passes through the medulla region?
Medullary sinus
What are the three regions of the lymph node from outermost to innermost?
- Cortex
- Paracortex
- Medulla
Cells within all regions and sinuses of the lymph node are supported by a system of what?
reticular fibers, which are produced by reticular cells
What cells are found in the cortex region of the lymph node?
- macrophages
- reticular cells
- some T cells and plasma cells
- follicular dendritic cells (FDCs)
What is the primary cell type found in the cortex of a lymph node?
B lymphocytes (B cells)
What activity takes place in the cortex of a lymph node?
phagocytosis and humoral immunity (primary IgG)
What region of the lymph node contains lymph nodules?
cortex
What are the two types of Lymph nodules?
- Primary Lymphoid Nodule
2. Secondary Lymphoid Nodule
Which lymphoid nodule forms in response to a foreign antigen?
Secondary
Which lymphoid nodule does not contain germinal centers?
Primary
Which lymphoid nodule contains germinal centers?
Secondary
Which lymphoid nodule are you more likely to find naive B cells and many B memory cells?
Primary
Which lymphoid nodule will you find active B cell division?
Secondary
Which lymphoid nodule will you find FDCs (Follicular dendritic cells)?
Secondary
What region of the lymph node is known as the Thymus Dependent Zone?
Paracortex (= Deep Cortex)
What are the cell types found in the paracortex region of a lymph node?
- macrophages
- reticular cells
- some B cells
- dendritic cells (DCs)
What is the primary cell type found in the paracortex region of a lymph node?
T lymphocytes (T cells)
Activity in the paracortex of a lymph node consists of what three things?
- long term storage site for T cells; can enlarge with T-cell stimulation
- phagocytosis
- cell mediated immunity
What region of a lymph node will you find HEV’s? What are HEV’s?
= High Endothelial Venules
found in paracortex
What type of cells are HEV’s lined with?
(High Endothelial Venules)
cuboid cells
What is the function of HEV’s?
promote passage of B and T cells into the lymph node from the blood
What is considered an important cross-over point b/w the blood and lymph fluids in the lymph node?
HEV’s (High Endothelial Venules) in the paracortex
What will cause the paracortex to thin?
HIV
why?– b/c the retrovirus is taking out the T-helper cells
What cells are found in the medulla of a lymph node?
- macrophages
- reticular cells
- B cells
- DCs (dendritic cells)
- fewer T cells
What is the primary cell type found in the medulla of a lymph node?
Plasma cells
What activity does the medulla of a lymph node have?
phagocytosis and some cell-mediated immunity
much Humoral immunity b/c of antibody secretion
What part of the lymph node will we find the medullary sinuses and medullary cords?
Medulla region
What are the areas of lower cell density in medulla region of a lymph node?
medullary sinuses
What are the areas with high cell density b/w the sinuses in the medulla of a lymph node?
medullary cords
The thymus is a ____ lymph organ that extends over the great heart vessels.
primary
When does involution of the thymus begin? Where does it start and end?
begins after puberty
- 1st in septa
- 2nd in cortex
- 3rd in medulla
At what age is there little functioning thymus left?
25 years of age
What is the important function of the thymus?
Establishment of immunocompetent T lymphocytes
What does the important function of the thymus– Establishment of immunocompetent T lymphocytes mean for the body?
- can distinguish self from non-self antigens
2. to develop self tolerance
What is a T lymphoblasts in the thymus called?
thymocyte
What are two structural characteristics of the thymus?
- thin delicate capsule of dense irregular CT
2. Lobules with a peripheral cortex and a central medulla
What are the 4 types of Thymic supportive tissue?
- Capsule
- Septa
- Adipose
- Microstroma = thymic epithelial cells (TEC’s)
What is another name for the Thymic Epithelial Cells (TEC’s)?
Epithelioreticular Cells (TEC’s)
How many differnt types of TEC’s are there?
TEC’s = Thymic Epithelial Cells
6 types
What are 5 functions of the TEC’s (thymic epithelial cells)?
- offer support using cytoplasmic proceses
- Secrete thymic hormones and cytokines
- form thymic corpuscles (Hassal’s bodies)
- important component of blood-thymic barrier
- function as APC for maturing T cells
T/F. TEC’s (thymic epithelial cells) produce reticular fibers.
FALSEEEEEE
What is the function of the secreted thymic hormones and cytokines?
influence T cell maturation, division, and activities
Where are thymic corpuscles (Hassall’s bodies) located in the thymus? What type of TEC’s form these?
medullla
TEC Type VI
What is the function of thymic corpuscles formed by the thymus?
secrete cytokines to influence local dendritic cells and the development of some T cells
T/F. The size and number of thymic corpuscles increase with age.
True
What does the blood-thymic barrier consist of?
- continuous capillaries with a thick basal lamina (note: also pericytes outside of the basal lamina)
- perivascular compartment
What does the perivascular compartment of the blood-thymic barrier consists of?
CT with many macrophages to destroy foreign molecules
What type of TEC type does the blood-thymic barrier have complete covering of with a basal lamina?
TEC Type I
What is the function of the blood-thymic barrier?
to prevent T cells from physically contacting foreign antigens
What is the blood-thymic barrier only around? Why?
cortical capillaries–> to allow self-molecules through but block blood/lymph macromolecules
What are the functioning regions (parenchyma) of the thymus?
- Cortex (high cell density)
2. Medulla (lower cell density)
What types of cells are found in the Cortex of the thymus?
- large numbers of T cells
- large numbers of macrophages
- TEC Types I, II, III
TEC types I, II, III are found in what functioning area of the thymus?
Cortex
TEC types IV, V, VI are found in what functioning area of the thymus?
Medulla
What types of cells does the medulla of the thymus contain?
- fewer but larger T cells
- macrophages
- APC: dendritic cells
- TEC Types IV, V, VI
Where are T lymphocytes produced? Where do they mature?
bone marrow
thymus
As T lymphocytes enter the Thymus for the first time, what do we call them?
as immunoINcompetent T cells (thymocytes)
Where do T lymphocytes leave the bloodstream and enter the thymus?
at corticomedullary line
Once T cells enter the thymus they migrate to periphery of the cortex and then what?
T cells divide and are tested thru the Positive Selection process
What happens to T cells that fail the Positive Selection process?
~98% fail and will undergo apoptosis
What happens to the T cells that survive the Positive Selection process in the thymus?
migrate back towards the medulla
Once T cells migrate back toward the medulla they will continue maturation in the medulla through what type of process?
Negative Selection Process –> cytoxic T and T helper cells
How do mature immunocompetent T cells leave the thymus?
in post-capillary venules or efferent lymph
Where does these mature immunocompettent T cells go once they leave the thymus?
secondary lymphoid organs like lymph nodes and spleen
What is lacking the the thymus?
- afferent lymph vessels
- reticular fibers–therefore no..
- reticular cells
What are the 5 functions of the spleen?
- immunity
- blood filtration using macrophages
- long term T cell storage
- Stores some WBCs and platelets, and large numbers of monocytes
- hemopoietic organ in fetus
What does the spleen serve as for the fetus?
hemopoietic organ
The spleen has a convex surface and a concave area called what?
hilum
What are 6 structures of the spleen?
- hilum
- Capsule
- Trabeculae
- Lymphatic vessels (efferents only)
- support by reticular fibers
- Parenchyma
Describe the capsule of the spleen.
Thick dense irregular fibroelastic CT
are some smooth muscle cells and/or myofibroblasts
Describe the Trabeculae of the spleen.
- dense irregulat CT;
- thick, numerous, tortuous;
- carries blood vessels (i.e. trabecular arteries)
T/F. The spleen contains both afferent and efferent lymphatic vessels.
False– the spleen only contains efferent vessels
Are there reticular fibers in the spleen?
yes, they support the cells, and they are produced by reticular cells
What are the two areas of the splenic parenchyma?
- White pulp
2. Red pulp
T/F. Most of the spleen is Red pulp.
True
What part of the splenic parenchyma consists of areas of concentrated WBCs, primarily lymphocytes?
White pulp (~5-20% of the spleen)
What is the general function of the White pulp of the spleen?
immunity
In the spleen, hat part contains Splenic Nodules?
the White pulp
Where is the white pulp located in the spleen?
next to the capsule and septa
Who more commonly has Splenic Nodules? What cell type is primarily here? And what type of immunity?
children; primarily B cell structure; and humoral immunity
What are PALS? Where are they found in the spleen?
= Periarteriolar Lymphoid Sheaths
in the White pulp
Can you describe what the PALS of the white pulp of the spleen include? (cells, what surround, immunity type)
- long term storage site for T cells
- primarily a T cell structure
- surround Central Arterioles
- cell-mediated immunity
In the spleen, where are T cells primarily?
in the PALS of the white pulp
“lets get some PALS together for some Tea”
What do we call the areas that are not white pulp or CT in the spleen?
Red pulp (most of the spleen is red pulp)
What are the two functions of the Red pulp of the spleen?
- Rapid blood filtration
2. allows contact with blood-bourne foreign antigens
The structure of the Red pulp consists of what two main things?
- circulation of closed and open capillaries
2. Splenic cords
Describe the circulation of the Red pulp of the spleen.
Combination of:
1. Closed – capillaries connect to fenstrated venous sinuses made of Stave Cells
- Open – capillaries end abruptly; all blood enters red pulp to be filtered
What is unique about the closed capillaries in the Red pulp of the spleen?
only some blood is filtered here
Where in the red pulp does all blood enter it to be filtered?
open capillaries
What are Stave cells?
make up the fenstrated venous sinuses in the Red Pulp
are unusually elongated endothelial cells
What do the Splenic cords components include?
(in Red pulp)
- loose network of reticular fibers
- reticular cells
- MANY macrophages
- Blood = WBCs, RBCs, platelets, monocytes
- APC’s = mostly dendritic cells and macrophages
- Plasma cells (b/c they don’t circulate in blood)
What APC’s are found in the Splenic cords of the red pulp?
mostly dendritic cells and macrophages
What does the blood in the Splenic cords of the splenic red pulp consists of?
WBCs, RBCs, platelets, moncytes
When someone has a Splenectomy, what are three effects that occur?
- Blood changes and there is an increase in bumber of platelts and abnromal RBC’s
- Infection– increase risk of bacterial septicemia
- Liver take up blood filtration
What takes up blood filtration when someone has a splenectomy? How soon does this occur?
Liver (some in bone marrow too)
- starts in ~2hrs with some filtration and fully fxning in ~24hrs
- macrophages numbers increase greatly
Children than must have a splenectomy are at a greater risk of bacterial septicemia when they are inf. with what ?
Strep pneumo
What causes infectious mononucleosis?
Epstein-Barr virus (EBV) in mucus and saliva
Where will the EBV first replicate? Where can it spread to?
nasopharyngeal epithelium–> can spread to salivary glands, lymph nodes, and oropharyngeal lymphoid tissues—>
then spread to liver, spleen, B cells, and blood
What occurs if B cells are infected by EBV as they circulate through the oropharynx?
initiate a cytotoxic T cell response —–> decrease B cell numbers
What are the primary source of the new EBV?
epithelial cells
