Lymphatic System

Question 1

What is the lymphatic system?

Answer 1

• network of vessels with associated glands and nodes that extends throughout the body, enabling circulation
• No pump

Question 2

What is lymph? What is it made of?

Answer 2

• fluid of lymphatic system

- made of interstitial fluid

Question 3

Why is the lymphatic system not an enclosed system?

Answer 3

• Allows interstitial fluid in or out, that’s why

Question 4

What is the structure of lymph?

Answer 4

• colourless or pale yellow and similar in composition to blood plasma

Question 5

What is the function of the lymph?

Answer 5

-helps maintain fluid balance between interstitial fluid and blood

Question 6

Where does lymph form, and where does it go?

Answer 6

• forms in closed-ended tubes called lymphatic capillaries in capillary beds
• liquid is eventually emptied into veins near heart

Question 7

What do lacteals in villi do?

Answer 7

Carry digested fats to lymph vessels

Question 8

What are lymphocytes and where do they mature?

Answer 8

• they are a type of white blood cell

- they mature in lymph nodes

Question 9

What are lymph nodes?

Answer 9

• glands of the lymphatic system

- Also contain macrophages

Question 10

The spleen is a secondary lymphatic organ. Explain in detail how it plays a role in the lymphatic system.

Answer 10

• 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

Question 11

What is the body’s first line of defence?

Answer 11

• Barriers to keep pathogens out

Question 12

What is the body’s second line of defence? inflammatory response?

Answer 12

• 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

Question 13

What is the body’s third line of defence? what is the immune system response?

Answer 13

• specific defences against particular pathogens

- The immune response occurs as it recognizes, attacks, destroys, and remembers the antigen

Question 14

How does the body prevent pathogen entry? (First line of defence)

Answer 14

• eyelashes, cilia of the respiratory tract, tears, stomach acid, etc.
  The Skin

Question 15

How does the skin prevent pathogen entry? (6)

Answer 15

• largest barrier
• hostile environment for many microorganisms
• dry
• lots of tough, relatively indigestible keratin (protein)
• Oil‘s containing bactericides
• Perspiration forms acidic layer

Question 16

What are the non-specific defences of the body? (2nd line of defence)

Answer 16

• 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

Question 17

What are the specific defences of the body? (third line of defence)

Answer 17

• 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

Question 18

What are antibodies?

Answer 18

• proteins that recognize foreign substances and act to neutralize or destroy them

Question 19

Where do B lymphocytes mature in?

Answer 19

In the bone marrow

Question 20

Where do T lymphocytes mature in?

Answer 20

They are produced in bone marrow but mature in thymus gland near heart

Question 21

How does life before birth affect specific defences? I think specific defences

Answer 21

• before birth, the body is cataloguing molecules that are part of itself (recognition proteins)
• this allows for pathogens to be identified

Question 22

What are antigens and how do they aid in specific defences? How about receptors?

Answer 22

• 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)

Question 23

What is the structure of antibodies and what do they do?

Answer 23

• 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)

Question 24

How do B cells work?

Answer 24

• 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

Question 25

What do T cells do?

Answer 25

• fight off invaders using cellular immunity

recruit other cells to deal with infection

Question 26

How do T cells work?

Answer 26

1. 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
2. Killer T cells bind with infected cells, puncture a hole in their cell membrane and destroy them
3. Suppressor T cells slow and suppress process of cellular immunity to avoid destroying normal tissue
4. Memory T cells do not react at first exposure, but remain in bloodstream and can act quickly if antigen is encountered again

Question 27

What are the four types of immunity?

Answer 27

• Active immunity, passive immunity, inborn immunity, maternal immunity

Question 28

What is active immunity?

Answer 28

An individual produces antibodies against an antigen

- due to exposure or induced by an immunization

Question 29

What is passive immunity?

Answer 29

• an individual is given prepared antibodies via an injection

Question 30

What is maternal immunity?

Answer 30

• passive immunity acquired by an individual as antibodies pass from the mother to the fetus through the placenta

Question 31

What is inborn immunity?

Answer 31

Immunity inherited from parents genetically and protects individual throughout his or her life (innate immunity)