Chapter 7: Immune System Flashcards
Lymphatic system functions:
- Lymphatic capillaries absorb excess interstitial fluid and return it to the bloodstream.
- Lacteals in small intestine absorb dietary fas and transport them to blood stream.
- Production, maintenance, and distribution of lymphocytes in body.
- Helps in defense against pathogens.
Lymphatic vessels carry a fluid called:
lymph
Lymphatic vessel begin as what in the tissues?
Lymphatic capillaries
What are the two lymphatic ducts?
Thoracic duct and right lymphatic duct.
What does the thoracic duct do?
Collects lymph from the body below the thorax, the left arm, and the left side of the head and neck and empties into the left subclavian vein.
What does the right lymphatic duct do?
returns lymph from the right arm and right side of the head and neck into the right subclavian vein.
What body parts are apart of the lymphatic system?
Tonsil, red bone marrow, thymus, spleen, thoracic duct
What is the function of the spleen in the lymphatic system?
cleanses the blood of cellular debris and bacteria. Connective tissue divides it into white pulp and red pulp. Has thin outer capsule.
Lymphatic vessels have the presence of what and what does it do?
Presence of valves and it prevents the lymph from flowing backward.
Lymphatic Organs
Primary lymphatic organs and secondary lymphatics organ
What are the primary lymphatic organs
Red bone marrow and thymus
What are the secondary lymphatic organs?
Lymph nodes, spleen and tonsils
Red Bone marrow:
site of blood cell reproduction, B cells mature here.
Thymus:
In thoracic cavity superior to the heart. Produces thymosin, a hormone that matures the T cells.
Lymph nodes:
found along the lymphatic vessels, they filter lymph. has a capsule to divide the compartments and it is filled with macrophages that engulfs pathogens. Also houses lymphocytes which fight infections and cancer cells.
What are the two branches of our immune system?
Innate and Adaptive:
Does innate have to be functional with previous exposure to a pathogen?
No
Does innate have memory of pathogens?
No
What do innate immune defenses include?
Physical and chemical barriers to entry, inflammatory response, and protective proteins.
Physical barriers to entry:
Skin and mucous membranes. Skin has keratin to make it tough. Mucous membranes have ciliated cells which sweep away mucus with entrapped pathogens.
Chemical barriers to entry:
Acidic secretions of sebaceous glands weaken and kill bacteria on skin. Sweat, saliva and tears have lysozyme- an antibacterial enzyme. Normal flora prevent pathogens from taking up residence.
Acquired immunity examples:
Vaccine, exposure to virus, another person’s antibodies.
Apoptosis:
death of cells
Adaptive defenses come into play when:
- Innate defenses have failed to prevent an infection.
- Provide some protection against cancer
- Responds to antigens (immune system recognizes as foreign)
Adaptive defense includes which type of cells?
B cells and T cells
Two pathways of adapted immunity:
Cell-mediated and antibody-mediated
What happens in cell-mediated immunity?
T cells kill cells that are presenting a specific foreign antigen.
What happens in antibody-mediated immunity?
B cells produce antibodies that bind to free antigens in body fluids.
What is antibody mediated immunity also called?
humoral immunity
What do Cytotoxic T cells do:
destroy non self antigen bearing cells.
What do helper T cells do?
secrete cytokines
Types of cytotoxic T cells:
Perforins which punch holes.
Granzymes which enter pores then cause apoptosis.
What are B cells responsible for?
Antibody mediated immunity against pathogens.
What type of selection do B cells go through?
Clonal selection.
What happens during clonal expansion?
cytokines secreted by helper T cells stimulate B cells to clone
What do most of the cloned B cells become?
Plasma cells which produce large numbers of antibodies that bind to the antigen that initiated the whole process.
What do APC’s do?
break the ingested pathogen apart in a lysosome.
What are APC’s
macrophages
What are macrophages?
type of WBC that surrounds and kills microorganisms.
What does a T cell need to recognize an antigen?
an APC.
A piece of pathogen is displayed in the groove of a:
major histocompatibility complex protein on the cell’s surface.
