Flashcards in Immunity/Lymphatic System Deck (116):
Which immune reactions are present at birth?
What is the role of natural killer cells?
Recognize a substance as "not me" and attack it
What is the role of specific immune response?
To recognize and remember specific antigens; second response more rapid and rigorous
What are four of the body's first-line defenses?
Skin, mucous membranes, gastric juices, lysozymes
What does gastric juice do for immunity?
It kills bacteria
What do lysozymes do for immunity?
Break down bacteria cell walls
Where are lysozymes found?
Tears, saliva, sweat, nasal secretions
What are some examples of second-line defenses?
Complement system, transferrin, interferons, phagocytes, ect.
What is the complement system?
A series of protein molecules in a chain reaction that kills microbes and causes inflammation
What is transferrin?
Protein in blood that binds iron and prevents bacteria from accessing it
What are interferons?
Tell neighboring cells how to stop viral replication
Which cells secrete interferons?
Lymphocytes, macrophages, and fibroblasts
What is sebum?
Oil on the skin that stops bacterial and fungal growth
What are natural killer cells?
Cells that patrol the body tissues and kill enemy cells (cancer) use perforin
What are phagocytes?
Cells that ingest foreign debris/cells
What are the 4 responses of inflammation (English and Latin)?
1. Heat (Calor)
2. Swelling (Tumor)
3. Pain (Dolor)
4. Redness (Rubor)
What is local vasodilation a mechanism of?
What is the purpose of local vasodilation?
Blood vessels expand to become more leaky in one location; lets immune cells move from blood to the tissues
What are the main chemicals that cause vasodilation?
Histamines and leukotrienes
What is local edema a mechanism of?
How does local edema work?
Causes fluid to leave capillaries; local swelling; helps "wash away" byproducts of battles with bacteria
What 4 things happen when leukocytes get involved in the inflammatory process?
What is it called when WBCs in bloodstream move towards the edge of the capillary?
What is is called when WBCs squeeze out of the capillary and into tissues?
What is chemotaxis?
Chemicals that guide phagocytes to where the battle isq
What is phagocytosis?
Neutrophils and macrophages that eat bacteria and debris
What is the name for the coating of an antigen with molecules that help phagocytes eat it?
What is the name of the proteins used in opsonization?
What are chemicals that cause a fever called?
What is the complement system?
A non-specific immune defense; involves proteins that work together to form a membrane attack complex (MAC) on a cell membrane; promote chemotaxis
How does a MAC cause cytolysis?
A huge hole in the cell, fluid rushes in and bursts the cells
What is fever?
A non-specific immune defense, intensified effects of interferons, inhibit bacterial growth, speeds up enzymes
What causes a fever?
bacterial toxins that trigger release of cytokines, tell hypothalamus to reset the body's temperature
What are "self-antigens"?
Antigens that identify our own cells
What molecules tell the immune system if there is a problem inside of a cell?
The Major Histocompatibility Complex (MHC)
What is antigen presentation?
When a phagocyte phagocytizes a bacterium and puts a fragment of the ingested bacteria on the outside (skull on a spike)
What are antigen presenting cells?
Dendritic cells, macrophages, and B-cells that combine the bacterial bit with the MHC II complex to display to the helper T-cells
What are MHC I cells?
Major Histocompatibility Cells; self-antigens on all body cells that help the T-cells identify self; found on outside of cell in emergency
What are MHC II cells?
Receptors cell (usually APC) makes, bind with antigen and displays it on cell surface (pole for the skull)
What are the two types of T-cells?
Helper T-cells and Cytotoxic T-cells
What on the T-cell binds to the antigen?
T-cell receptors (TCR)
What do B-cell receptors do?
Identify foreign antigens
What protein helps helper t-cells bind with APCs?
What protein helps cytotoxic t-cells bind with infected/damaged cells?
Where does the MCH II reside?
On the macrophage that has eaten the bacteria
What is Cell-mediated immunity?
MHC I pathway
- MHC I
- cytotoxic T
- perforin (big boom)
To what does the term "immune surveillance" refer?
Cytotoxic T cells, macrophages, and NK cells roaming the halls looking for invaders
What is humoral immunity?
Antibody-mediated immunity; uses body fluids instead of locking things up inside the cell
In humoral immunity, what happens when a bacterium is detected?
Macrophage/dendritic cell eats (phagocytizes) it and digests it (with lysozymes)
In humoral immunity, once the bacteria is digested and torn into pieces, what happens?
- MHC II complex displays it outside macrophage
- Helper T cell comes
- attaches with TCR and CD4
Once the T cell is attached to the MHC II, what happens?
- T cell replicates
- creates memory cells
- replicants create fever via interleukins
What cells do T cells communicate with concerning the invader?
Where in the lymphatic tissues can B-cells be found?
Lymph nodes, spleen, Peyer's patches
What activates lymphatic B-cells?
T-cells or direct contact with bacteria
What is the name for mature B-cells?
What do plasma cells do in the body?
Release enzymes against the enemy
What kind of cells have a large amount of rough ER?
What does the rough ER?
Make antibodies which are proteins - enzymes to kill invaders
What are dendritic cells?
The main type of APC; used to engulf and process antigens and present the antigen to other cells
Where are dendritic cells found?
Skin, nose, lungs, intestines
Describe the composition of antibodies
Proteins with 2 light chains and 2 heavy chains
What are the 5 classes of antibodies?
IgA, IgB, IgD, IgE, IgM
What does the Ig in IgA stand for?
What do antigens combine with?
The antigenic determinant (head of skull) that triggered its production
What neutralizes toxins to prevent spreading?
Describe antibody agglutination
One antibody binds to 2 or more foreign cells at the same time acting like glue that makes them stick together
Is the primary response of antibodies and b-cells strong or weak, and why?
Weak, it doesn't have memory yet
What factors contribute to the strength of a secondary reaction to a foreign invader?
Thousands of memory cells proliferate into plasma cells and cytotoxic t-cell; recognition and removal is swift
What is the most common form of artificially acquired active immunity?
How do vaccines work?
Stimulate cell and antibody-mediated immune response - creates memory cells
Of what are vaccines composed?
Immunogenic (not pathogenic) antigens
What causes autoimmune disorders?
The immune system mistaking normal self antigens for foreign invading antigens
Why might the body attack the heart if it is infected by streptococcus?
It looks like heart valve antigens
In what disease does the body attack the myelin sheath of neurons?
In what disease does the body attack the skin?
In what disease does the body attack the joints?
What is an allergy reaction?
A hypersensitivity reaction
What is a Type 1 allergic reaction?
Actual allergy; anaphylaxis - death is on the table
What is a Type 2 allergic reaction?
Cytotoxic: antibodies directed against blood cells or tissue cells (ex. blood transfusion)
What is a Type 3 allergic reaction?
Immune complex: when a cluster of bacteria/viruses/etc. gets attacked, can damage kidneys
What is a Type 4 allergic reaction?
Delayed hypersensitivity reaction: 12-72 hours later
What causes a Type 4 reaction?
Intracellular bacteria also some food sensitivities
What is the difference between naturally and artificially acquired active immunity?
Naturally = production of one's own antibodies or T cells from antigen exposure
Artificially = From vaccination, weakened antigens trigger antibodies
What is the difference between naturally and artificially acquired passive immunity?
Naturally = antibodies from another person (hi, mom!)
Artificially = injection of immune serum from another person or animal with antibodies toward specific pathogens
What is the primary difference between lymphatic and circulatory capillaries?
Lymphatic carry lymph, circulatory carry blood
Are lymphatic capillaries or circulatory ones larger?
Lymphatic are larger
Describe the structure of lymphatic capillaries
One way structure permits interstitial fluid to flow into vessel but not out, has a valve
Where does the lymphatic system start?
What structural adaptations enable lymphatic capillaries to absorb extracellular fluid?
- Ends of endothelial cells overlap
- Greater pressure outside allows capillaries to fill
What is the general flow of structures in the lymphatic system?
Capillaries - vessels - trunks - ducts
What is the thoracic duct?
The left lymphatic duct
Where does the thoracic duct begin?
Dilation in the abdomen, the "cisterna chyli"
From the cisterna chyli, where does the lymph fluid move?
Toward the merging point of the left subclavian and jugular veins, then back to blood circulation
What does the right lymphatic duct drain?
Upper right side of the body
Where does the right lymphatic duct flow into?
The merging point of the right subclavian and right jugular veins
What does the thoracic duct drain?
Everything except the upper right side of the body and head
What is the gross anatomy of a lymph node?
- bean shaped
- central medulla (with t cells, b cells, plasma cells, dendritic cells, and macrophages)
What vessels bring lymph into a node?
Afferent lymphatic vessels
What vessels take lymph out of a node?
Efferent lymphatic vessels
What is the function of lymph nodes?
Monitor the lymph for microorganisms, cancer, waste and mount a response
What is the gross anatomy of the spleen?
- 5 inches
- under lower ribs on left side
- smooth, convex surface conforms to concave diaphragm
What are the two substances found in the spleen?
Red pulp and white pulp
What are the 2 parts of red pulp?
1. A blood filled venous sinus
2. Splenic tissue = splenic cords
Of what are splenic cords composed?
RBC's, macrophages, lymphocytes, and plasma cells
What is the function of splenic red pulp?
Blood filter to remove waste, like damaged RBC's, platelet reservoir
What is the role of splenic red pulp for a fetus?
Produce RBC and WBC
What composes splenic white pulp?
Lymphocytes and macrophages
What is the function of splenic white pulp?
Act like a large lymph, contains b cells, t cells, and macrophages; involved in immunological functions like production of antibodies
Where is the thymus located?
Underneath the sternum
Describe the anatomy of the thymus
Soft, bi-lobed, full size in childhood then shrinks
What is the function of the thymus?
Site of T cell maturation, secrete thymosins (maturation aid)
What matures into T cells?
What is the function of the tonsils?
Sample all substance coming in through the nose or mouth and test for toxins
What are the three types of tonsils?
Palatine, pharyngeal, lingual
What is the location and function of Peyer's patches?
- "border guards"
- Found in ileum
- aggregated clusters of lymphatic follicles or nodules
- sample ingested items before absorption