Immune system Flashcards
The immune system has three types of components
– Lymphoid tissues
– Various types of immune cells
– Chemical signals that coordinate responses
The immune system is able to recognize molecules as
foreign (“non-self”) and specifically attack them
Functions of immune system
Protects against pathogens – Bacteria – Viruses – Parasites Protects against foreign molecules (e.g., toxins) • Removes dead or damaged cells • Attempts to recognize and remove abnormal cells
3 types of immune system pathologies
Incorrect immune responses – Autoimmune disease (e.g., Type 1 diabetes) • Overactive immune responses – Allergies • Lack of immune response – Immunodeficiency disease (ex: AIDS)
2 lines of defense in the organism
- Physical and chemical barriers
2. Immune defenses
Examples of physical and chemical barriers
–Skin, epithelial linings, and cilia
–Acids, mucus, and lysozymes
2 types of immune defenses
Innate and Acquired/adaptive
Differences between innate and acquired immunity
–Innate immunity
• Non-specific – responds to a range of signals
• Immediate response
–Acquired/adaptive immunity
• Specific – attacks a specific pathogen or antigen
• Slower but stronger response
• Memory allows for fast responses upon re-exposure
4 examples of chemicals that act as barriers
- sebum( secreted by sebaceous glands, low pH inhibits
microbial growth - Perspiration (flushes skin of microbes, contains lysozyme
- gastric juice (low pH, presence of enzymes)
- urine: flushes preventing attachment
What is part of our innate immunity
Epithelial
Phagocytes (activate complement and NK cells)
Complement
NK cells (a type of lymphocyte)
Cells that are part of adaptive immunity
B lymphocytes that will differentiate to plasma cells that will produce antibodies upon exposure of particular antigen
T lymphocytes , cytotoxic T cell and T helper
4 steps in an immune response
- Detection and identification of the foreign
substance - Communication with other immune cells
- Recruitment of other immune cells, and
coordination of the response - Destruction or suppression of the invader
What is a lymphatic system
a vascular system that collects tissue fluid and returns it to the blood.
This lymphatic fluid (called lymph) is monitored for pathogens by immune system cells as it travels
What in lymphatic system is packed with T and B cells
Lymph nodes
What happens to lymph after certain period of time
It is going to be dumped back into the veins and thus right atrium
How much of fluid gets into the lymph system every day?
3.6L
The flow of lymph depends on
Muscle contraction, because it has no driving force
Primary lymphoid tissues
Bone marrow
Thymus
Encapsulated lymphoid tissues
Lymph nodes
Spleen
Lymphoid nodules are also called what type of lymphoid tissues
Diffuse, for example gut-associated lymphoid tissue (GALT) . they are found beneath epithelial
Where thymus gland is found
A 2-lobed organ located in thorax just
above heart
When thymus gland reaches its peak size and what happens after
adolescence, then shrinks and is replaced
by adipose
What cells are eliminated during the development in thymus
cells that would be
self-reactive in the thymus are eliminated
Thymus produces
T lymphocytes
- Peptides: thymosin, thymopoietin,
thymulin
what are lymphoid nodules
Loose connective tissue with densely packed
lymphocytes
• Not surrounded by a fibrous capsule
In germinal center of lymph nodules what can be found
Dividing lymphocytes
Lymphoid nodules size
Size can increase or decrease depending on number of
lymphocytes present
Where lymphoid nodules are found
Located beneath epithelial lining of organs that have
direct contact to the outside world (digestive,
respiratory, urinary
Distribution of Lymphoid Nodules
– Respiratory tract (tonsils)
– Along digestive and urinary tracts
Steps in viral invasion
Viral invasion of host cell
Synthesis of new viral
nucleic acids and proteins
Self-assembly of new viral
macromolecules into new
virus particles
Virus particles released
from host cell
What is interferon
A chemical that will be released from virus infected cells.
It will warn nearby cells and induce the production of antiviral protein (AVP)
Anatomy of lymph nodes
Will have multiple afferent lymph vessels coming to the germinal core, screens and then the fluid goes out through efferent vessel. Has lymph node artery and vein
B cells are around the cortex
then t cells (paracortical) and medullary cords are macrophages and plasma cells
Anatomy of spleen
Darker regions of red pulp
are closely associated with
extensive blood vessels and
open venous sinuses.- associated with RBCs
Regions of white pulp resemble the interior of lymph nodes and are composed mainly of lymphocytes Located behind the stomach
Division of WBCs
Granulocytes(neutrophiles,basophules,eosinophils)
Agranulocutes (monocytes, lymphocytes,dendritic cells)
Appendix has a lot of
Lymphoid nodules
Mast cells have similar function to ___, however
Basophils
Release histamine and heparin
Mast cells are tissue specific, when basophils are in circulation
What kind of cells are highest in population in blood and their function
Neutrophils
Ingest and
destroy
invaders
Eosinophils function
Destroy invaders, particularly antibodycoated parasites
Function of monocytes and macrophages
Ingest and destroy
invaders.
Antigen presentation
What cells are a link between innate and adaptive immunity, their other name and function
Dendritic cells Also called Langerhans cells, veiled cells Recognize pathogens and activate other immune cells by antigen presentation
Lymphocytes and plasma cells function
T, B, NK cells
Specific responses
to invaders, including
antibody production
Types of macrophages (brain,lungs,spleen,kidney, liver, epidermis)
Microglial Alveolar Macrophages in sinuses of spleen Macrophages in kidney Kupffer cell Dendritic cells Macrophages in joints
Natural cells are good at
Releasing granules that kill some virus-infected cells and abnormal looking cells
Why most pathogens do not enter the body
they are kept out by surface tissues and their secretions: • Physical barriers – Skin – Mucous membranes • Chemical barriers – Stomach acid – Lysozyme in many secreted fluids