Lymphatic System Flashcards
What is the lymphatic system?
- network of vessels with associated glands and nodes that extends throughout the body, enabling circulation
- No pump
What is lymph? What is it made of?
- fluid of lymphatic system
- made of interstitial fluid
Why is the lymphatic system not an enclosed system?
- Allows interstitial fluid in or out, that’s why
What is the structure of lymph?
- colourless or pale yellow and similar in composition to blood plasma
What is the function of the lymph?
-helps maintain fluid balance between interstitial fluid and blood
Where does lymph form, and where does it go?
- forms in closed-ended tubes called lymphatic capillaries in capillary beds
- liquid is eventually emptied into veins near heart
What do lacteals in villi do?
Carry digested fats to lymph vessels
What are lymphocytes and where do they mature?
- they are a type of white blood cell
- they mature in lymph nodes
What are lymph nodes?
- glands of the lymphatic system
- Also contain macrophages
The spleen is a secondary lymphatic organ. Explain in detail how it plays a role in the lymphatic system.
- The spleen plays a role in filtering and cleansing
1. Lymphocytes cleans blood of foreign particles
2. Macrophages remove defective blood cells
3. Lymph nodes cleanse lymph as lymph is filtered as it moves through many sinuses of the lymph node
—> macrophages engulf pathogens and debris
What is the body’s first line of defence?
- Barriers to keep pathogens out
What is the body’s second line of defence? inflammatory response?
- General or non-specific defences against a wide variety of pathogens
- inflammatory response including swelling, redness, warmth, pain, and presence of Phagocytes to engulf pathogens
What is the body’s third line of defence? what is the immune system response?
- specific defences against particular pathogens
- The immune response occurs as it recognizes, attacks, destroys, and remembers the antigen
How does the body prevent pathogen entry? (First line of defence)
- eyelashes, cilia of the respiratory tract, tears, stomach acid, etc.
The Skin
How does the skin prevent pathogen entry? (6)
- largest barrier
- hostile environment for many microorganisms
- dry
- lots of tough, relatively indigestible keratin (protein)
- Oil‘s containing bactericides
- Perspiration forms acidic layer
What are the non-specific defences of the body? (2nd line of defence)
- cell-mediated immunity
Three types of white blood cells: - neutrophils and monocytes kill bacteria by phagocytosis
- Natural killer cells target body cells that have become cancerous or infected by viruses
What are the specific defences of the body? (third line of defence)
- antibody-mediated immunity
- each person develops a unique immune system due to exposure to different diseases —> based upon lymphocytes in the circulatory system
—> two main types: B lymphocytes (B cells) or T Cells
What are antibodies?
- proteins that recognize foreign substances and act to neutralize or destroy them
Where do B lymphocytes mature in?
In the bone marrow
Where do T lymphocytes mature in?
They are produced in bone marrow but mature in thymus gland near heart
How does life before birth affect specific defences? I think specific defences
- before birth, the body is cataloguing molecules that are part of itself (recognition proteins)
- this allows for pathogens to be identified
What are antigens and how do they aid in specific defences? How about receptors?
- molecules found on the surface of body cells and pathogens; identification system
- antigen receptors on B and T cells recognize invaders and cause response (receptors are readers, not enzymes, but fit w antigen)
What is the structure of antibodies and what do they do?
- have the same shape as antigen receptors for specific antigen
- bind with and neutralized threat with these antigens
(antigen receptors will produce antibodies, antibodies bind with antigen to clump it and mark to be destroyed)
How do B cells work?
- different B cells produce different antibodies to identify different pathogens
- once activated, a B cell divides to produce plasma cells (these cells produce antibodies) and memory B cells that remain in the blood, ready to fight any new infection by the same pathogen at a later time
What do T cells do?
- fight off invaders using cellular immunity
recruit other cells to deal with infection
How do T cells work?
- Antigens from engulfed pathogens move to surface of macrophage after being destroyed
—> helper T cells recognize antigen and give off chemical signals to stimulate more macrophages, B cells and T cells - Killer T cells bind with infected cells, puncture a hole in their cell membrane and destroy them
- Suppressor T cells slow and suppress process of cellular immunity to avoid destroying normal tissue
- Memory T cells do not react at first exposure, but remain in bloodstream and can act quickly if antigen is encountered again
What are the four types of immunity?
- Active immunity, passive immunity, inborn immunity, maternal immunity
What is active immunity?
An individual produces antibodies against an antigen
- due to exposure or induced by an immunization
What is passive immunity?
- an individual is given prepared antibodies via an injection
What is maternal immunity?
- passive immunity acquired by an individual as antibodies pass from the mother to the fetus through the placenta
What is inborn immunity?
Immunity inherited from parents genetically and protects individual throughout his or her life (innate immunity)
