Lymphatic And Immune System 2 Flashcards
What is immunity?
Resistance to disease, specifically infectious disease
What is an immune response?
The coordinated reaction of the immune system and molecules to infectious microbes
What is the immune system?
The collection of cells, tissues and molecules that mediate resistance to infections
What is innate immunity?
Resistance that exists prior to exposure to the microbe(antigen)
Describe innate immunity
It is no specific and includes host defenses such as:
- Barriers to infectious agents (e.g. skin and mucous membranes)
- Certain cells (e.g. natural killer cells)
- Certain proteins (e.g. the complement cascade and interferons)
Involves processes such as phagocytosis and inflammation
Differentiate between innate immunity and acquired immunity
- innate immunity does not improve after exposure to the organism, acquired immunity
- innate immunity possess no memory but acquired immunity is characterized by long term memory
What are the first lines of defense in innate immunity?
- Skin
- Mucous membranes and secretions
- Normal flora
What is the second line of defense in innate immunity?
- Innate immune cells
- Inflammation
- Complement
- Antimicrobial substances
Describe skin
Many layers of closely packed, keratinized cells
How does the skin act as a first line of defense?
The outer epithelial layer of the skin- the epidermis- provides a formidable physical barrier to the entrance of microbes
How can pathogens penetrate the skin?
Pathogens can penetrate the epidermis and invade against tissues or circulate in the blood if there is a broken area in the skin (cuts, punctures, burns etc.)
Where are mucous membranes located ?
Line the body cavities like the GI, respiratory and reproductive tracts
How are mucous adapted to protect in innate immunity?
The epithelium of the mucus membrane secretes mucus which lubricate and trap many microbes and foreign substances
How are the mucous membranes for the upper respiratory tract better adapted for innate immunity?
Mucous membranes if upper respiratory tract contains cilia that propels inhaled dust and microbes that have become trapped in mucous toward the throat
How is gastric juice adapted for innate immunity?
It is a mixture of hydrochloride acid, enzymes and mucous that destroys many bacteria and most bacterial toxins
How does lacrimal apparatus respond to irritants?
Lacrimal apparatus of the eyes produce and drains away tears which contain lysosome , an enzyme capable of breaking down the cell walls of certain bacteria
In what substances in the body is lysozyme present?
Saliva, tears, perspiration, nasal secretions and tissue fluids
Describe the second line of defense
When pathogens penetrate the physical and chemical barriers of the skin and mucous membranes, this is what they encounter:
- Internal antimicrobial substances
- Phagocytes
- Natural Killer Cells
- Inflammation
- Fever
List the internal antimicrobial substances
(I cry in Amps)
- Interferons(IFNS)
- Complement system
- Iron-binding proteins
- Antimicrobial proteins (AMPs)
How do interferons assist in the second line of defense?
An important defense against viral infections by preventing their replication
How does the complement system aid the second line of defense in innate immunity?
Enhancing the immune reaction by causing bursting of microbes, promoting phagocytosis and contributing to inflammation
How does iron-binding protein aid in the secondary line of defense in innate immunity?
Inhibit growth of certain bacteria by reducing the the amount of available iron
How do antimicrobial proteins aid in the second line of defense in innate immunity?
Short peptides that have a broad spectrum of antimicrobial activity including killing a wide variety of microbes and attracting dendritic cells and mast cells, which participate in immune responses
Where are AMPs produced?
AMPs produced by sweat glands,neutrophils, macrophages, epithelial and platelets
How much of the lymphocytes in the blood are Natural Killer Cells ?
About 5-10%
Where are Natural Killer Cells present?
In blood, spleen, lymph nodes and red bone marrow
What type of cell do Natural Killer Cells attack?
Any body cell that display abnormal or unusual plasma membrane proteins
How Batural Killer Cells work?
Natural killer cells bind to target cells such as an infected human cell, Natural killer cells release granules containing toxic substances into the target cells
What are the 2 types of macrophages?
- Fixed macrophages
2. Wandering macrophages
What are phagocytes?
Specialized cells that perform phagocytosis (ingestion of microbes or other particles such as cellular debris)
What are the 2 types of phagocytes?
Neutrophils and macrophages
Give examples of fixed macrophages and their locations
Histocytes- macrophages in connective tissue
Kupffer cells- in the liver
Alveolar cells- macrophages in the lungs
Microglial cells in the nervous system
What wandering or non-fixed macrophages?
Develop during periods of infections from circulating monocytes and become phagocytic
What are fixed macrophages?
Constantly stand guard in specific tissues
Outline the events of phagocytosis
- Chemotaxis leads the phagocyte to the microbe
- Microbe ADHERES to the surface of the phagocyte
- Phagocyte ingests the microbe
- Digestion if the microbe
- Microbe is killed
What is inflammation?
Nonspecific, defensive response of the body to tissue damage
What are possible causes of inflammation?
Pathogens, abrasions, chemical irritations, distortion or disturbance of cells and extreme temperatures
What are the signs and symptoms of inflammation?
- Redness
- Pain
- Heat
- Swelling
- Inflammation can also cause a loss of function in the injured area
What are the 3 stages of inflammation?
- Vasodilation and increased permeability of blood vessels
- Emigration of phagocytes from the blood into interstitial fluid
- Tissue repair
What are the benefits of a fever?
Intensified effects of interferons
Inhibits bacterial growth
Speeds up tissue repair
Why does a fever occur?
Abnormmaly high body temperature occurs because hypothalamic thermostat is reset
What event prompts a fever to occur?
Occurs during infection and inflammation
-bacterial toxins trigger release of fever-causing cytokines such as interlukin-1 from macrophages
What is adaptive(specific) immunity?
The ability of the body to defend itself against specific invading agents such as bacteria, toxins, viruses and foreign tissues
What white blood cells are involved in Adaptive (specific) immunity?
B and T lymphocytes
What are antigens?
Substances that are recognized as foreign and provoke an immune response
What are the properties of adaptive immunity?
- SPECIFITY for particular antigens
2. Memory for previously encountered antigens resulting in more rapid and vigorous response in the future
What are the 2 types of adaptive immunity?
- Cell-mediated immunity
2. Antibody immunity
What is cell mediated immunity(a form of adaptive immunity)
Cytotoxic T cells directly attack invading antigens
What is cell-mediated immunity effective against?
- Intracellular pathogens which may include viruses, fungi or bacteria that are inside cells
- Some cancer cells
- Foreign tissue transplants
Explain what is antibody mediated immunity
B cell transform into plasma cells, which synthesize and secrete proteins called antibodies which bind to and inactivate specific antigens
What is antibody immunity effective against?
Effective against extracellular pathogens which include any viruses, bacteria or fungi that are in body fluids outside cells
What is another name for antibody mediated immunity? Why?
Humoral immunity- body fluids(lymph, blood etc.) are also called humors
What is the function of helper T cells?
Helper T cells aid the i,mine responses if both cell-mediated and antibody-mediated immunity
How do B cells respond to antigens?
- Respond by becoming plasma cells and making antibodies
- Some B cells become memory B cells which produce stronger response with next exposure to antigen
How do T cells respond to adaptive immunity?
- Respond with a cell mediated response
- binds to antigens on cells and attack them directly
- Secrete lymphokines that increase T cell production and directly kill cells with antigens
Contrast functions of humoral immunity, cell-mediated immunity and helper T lymphocyte
Humoral immunity- Block infections and eliminate extracellular microbes
Cell mediated immunity- Kill infected cells and eliminate reservoirs of infection
Helper T cell- Eliminated phagocytosed microbes
Contrast the effector mechanism between Hekper T cell action, humoral immunity and cell mediated immunity
Cell mediated- Killed infected cell
Helper at cell action - activated macrophage
Antibody mediated- secreted antibody
Contrast the responding lymphocyte in humoral immunity, cell-mediated immunity and riboflavin immunity
Antibody mediated immunity- B lymphocytes
Cell mediated- Cytotoxic T cell
Helper T lymphocyte
What is immunocompetentence?
The ability to carry out adaptive immune responses(opposite of immunodeficiency)
From where do B and T lymphocytes mature?
B and T lymphocytes develop in primary lymphatic organs (red bone marrow and the thymus)from pluripotent stem cells
- B cells mature in bone marrow
- T cells migrate to and mature in the thymus
Differentiate between the types of T cells
- Cytotoxic T cells( CD8 T cells) - protect body against viruses and cancer cells
- Helper T cells (CD4- T cells)- increase antibody formation, memory cells dormatiin, B cell formation and phagocytosis
Outline the B lymphocyte lineage of maturity
Common lymphoid precursor in generative lymphoid organs (in this case the bone marrow) allow the for formation of immature B lymphocytes
Immature B lymphocytes are sent to blood lymph where there is recirculating between lymph nodes and spleen for recirculation of mature B lymphocytes
Outline T lymphocyte lineage of maturity
After T lymphocytes mature in the thymus mature naive T lymphocyte are sent to the blood lymph
T lymphocytes recirculate bloodlymph, spleen, mucous all and cutaneous lymphoid tissues as mature T lymphocytes
What is self-recognition?
The ability to recognize your own proteins
What is self-tolerance ?
The lack of reactivity to peptide fragments from your own proteins
What is AIDS?
Acquired Immunodeficiency System- a condition in which a person experiences an assortment of infections due to the progressive destruction of immune system cells by the human immune deficiency virus (HIV)
What does AIDS represent?
It represents the end stage infections of HIV
What are autoimmune diseases?
When the immune system fails to display self-tolerance and attacks a person’s own tissues
Who are the most susceptible to autoimmune diseases ?
- autoimmune diseases usually occur in early adulthood
- females suffer autoimmune diseases twice as often as males
List examples of autoimmune diseases
- grave disease
- Myasthenia gravis
- Type 1 diabetes Mellitus
- Rheumatoid Arthritis (RA)
- Systemic lupus erythematosus (SLE)
