lesson 17 transcript + study guide

Question 1

lymphatic vessels

Answer 1

Thin-walled vessels with valves that return lymph (fluid) to the bloodstream

Question 2

lymphatic vessels transport

Answer 2

Lymph, which is excess fluid from tissues

Question 3

lymphatic nodules

Answer 3

Unencapsulated clusters of lymphatic tissue found under epithelial membranes

Question 4

lymphatic nodules function

Answer 4

Trap pathogens and activate local immune responses

Question 5

primary lymphatic organs

Answer 5

Bone marrow (B-cell maturation) and thymus (T-cell maturation).

Question 6

secondary lymphatic organs

Answer 6

Lymph nodes, spleen, and MALT—sites where lymphocytes encounter antigens

Question 7

What is innate immunity

Answer 7

A nonspecific, fast-acting immune defense that responds to all pathogens the same way.

Question 8

What are the 5 signs of inflammation

Answer 8

Redness, heat, swelling, pain, and loss of function.

Question 9

What is the purpose of inflammation?

Answer 9

To bring immune cells to the infection site and help heal damaged tissue.

Question 10

What is a fever?

Answer 10

A systemic increase in body temperature caused by cytokines like interleukin-1.

Question 11

How does a fever help fight infection?

Answer 11

It enhances phagocyte activity and decreases iron levels to slow bacterial growth

Question 12

What are phagocytes?

Answer 12

White blood cells like macrophages and neutrophils that engulf and digest pathogens

Question 13

What is adaptive immunity

Answer 13

A specific immune response that recognizes and remembers pathogens

Question 14

antigen

Answer 14

A foreign substance that triggers an immune response.

Question 15

antibody

Answer 15

A protein made by B cells that binds to and marks antigens for destruction.

Question 16

lymphocytes

Answer 16

White blood cells (B-cells and T-cells) central to adaptive immunity.

Question 17

What is humoral immunity

Answer 17

Antibody-mediated immunity involving B-cells and antibodies in the blood.

Question 18

What is cell-mediated immunity?

Answer 18

T-cell-based immunity where cytotoxic T-cells kill infected or abnormal cells

Question 19

nonspecific (innate) resistance to disease

Answer 19

inflammation
fever
phagocytes

Question 20

specific (adaptive) immunity

Answer 20

antigen
antibodies
lymphocytes
humoral (antibody-mediated) immunity
cellular (cell-mediated) immunity

Question 21

What is the function of skin in immunity?

Answer 21

Acts as a physical barrier to prevent pathogen entry.

Question 22

What is the role of mucus membranes in the immune system?

Answer 22

Trap pathogens before they can enter the body.

Question 23

How does saliva contribute to innate immunity?

Answer 23

Contains enzymes that destroy pathogens.

Question 24

What is the purpose of the flushing action of tears and urine?

Answer 24

Mechanically remove pathogens from body surfaces.

Question 25

What does stomach acid do in the immune system

Answer 25

Destroys pathogens with its low pH.

Question 26

innate (outer barriers to pathogen entry)

Answer 26

skin mucus membranes saliva flushing action of urine/tears stomach acid

Question 27

What is the role of macrophages?

Answer 27

Phagocytes that destroy pathogens by engulfing them; can consume many.

Question 28

neutrophils

Answer 28

Rapid-response phagocytes that engulf and destroy pathogens.(phagocyte)

Question 29

What is the function of natural killer (NK) cells?

Answer 29

Kill virally infected or tumor cells by inducing apoptosis. (lymphocyte)

Question 30

monocytes

Answer 30

Precursor cells that migrate to infection sites and become macrophages.(macrophage precursor)

Question 31

dendritic cells

Answer 31

Present antigens to T-cells; link innate and adaptive immunity. (lymphocyte)

Question 32

What is the MAC (Membrane Attack Complex)?

Answer 32

Complement protein complex that forms pores in pathogen membranes to kill them.(complement)

Question 33

innate (blood born)

Answer 33

macrophage neutrophil natural killer cells monocyte dendritic cell MAC

Question 34

adaptive (cellular immunity)

Answer 34

cytotoxic t cells helper t cells memory t cells MHC I (on every body cell)

Question 35

cytotoxic T cells

Answer 35

Destroy infected cells by recognizing antigens on MHC I proteins. (lymphocyte)

Question 36

What is the role of helper T cells (Th)?

Answer 36

Coordinate both B and T cells by releasing cytokines; activated via MHC II.(lymphocyte)

Question 37

memory T cell

Answer 37

Persist after infection to mount faster responses to future invasions.(lymphocyte)

Question 38

Where is MHC I found and what is its function?

Answer 38

Found on all nucleated cells; presents antigens to cytotoxic T cells. (cell membrane marker)

Question 39

adaptive (humoral immunity)

Answer 39

plasma b cells memory b cells MHC II (only on APCs) IgM IgD IgG IgA IgE

Question 40

Plasma B cells

Answer 40

Secrete antibodies into the blood to neutralize pathogens. (lymphocyte)

Question 41

Where is MHC II found and what does it do?

Answer 41

Found on antigen-presenting cells (APCs); presents antigens to helper T cells. (cell membrane marker)

Question 42

Memory B cells

Answer 42

Remain after infection to rapidly respond to future exposures (lymphocyte)

Question 43

IgM

Answer 43

First antibodies made; form pentamers to clump pathogens. (Antibodies)

Question 44

IgD

Answer 44

Act as antigen receptors on the surface of B cells. (Antibodies)

Question 45

IgG

Answer 45

Neutralize pathogens, promote phagocytosis, activate complement; most abundant in blood. (Antibodies)

Question 46

IgA

Answer 46

In body secretions like saliva, tears, and breast milk. (Antibodies)

Question 47

IgE

Answer 47

Bind to mast cells and basophils to trigger allergic reactions. (Antibodies)