PSIO202 Exam 2 Lecture 15-16

Question 1

What are the functions of the lymphatic system?

Answer 1

returns excess ISF to the circulation, immune response/protect body from infection, and transport dietary fats and vitamins

Question 2

What are the two ducts in the lymphatic system, and what do they drain?

Answer 2

thoracic duct - drains left side up upper body and all of lower body
right lymphatic duct - drains right side of upper body

Question 3

What are the key features of lymphatic capillaries?

Answer 3

close ended, one way valves, larger than blood capillaries, and have lymph nodes at regular intervals

Question 4

Lymphatic tissues create a dense 3D meshwork of…

Answer 4

reticular connective tissue

Question 5

What occupies the spaces in the meshwork of lymphatic tissue?

Answer 5

lymphocytes and phagocytes

Question 6

What are the primary/generative lymphatic tissues?

Answer 6

red bone marrow and the thymus

Question 7

What are the secondary lymphatic tissues?

Answer 7

lymph nodes, spleen, mucosal associated lymphoid tissue (peyer’s patches, appendix, tonsils), and cutaneous associated lymphoid tissue

Question 8

What cells are produced from lymphoid stem cells?

Answer 8

T lymphoblasts, B lymphoblasts, and NK lymphoblasts

Question 9

What leukocytes are produced from myeloid stem cells?

Answer 9

eosinophilic myeloblasts, basophilic myeloblasts, and CFU-GM which creates myeloblasts and monoblasts

Question 10

What cells come from myeloblasts?

Answer 10

neutrophils

Question 11

What cells come from monoblasts?

Answer 11

monocytes and macrophages

Question 12

What are leukocytosis and leukopenia? What are the causes of each?

Answer 12

leukocytosis - high WBC count secondary to infection, strenuous exercise, anesthesia, or surgery

leukopenia - low WBC count secondary to radiation, septic shock, or chemotherapy

Question 13

What are cytokines? How are they produced, and why? What are two types?

Answer 13

local hormones of bone marrow
produced by marrow cells to stimulate proliferation of other marrow cells
colony-stimulating factors (CSF) and interleukins

Question 14

Do WBC’s have a nucleus? Do they have hemoglobin?

Answer 14

they all have a nucleus, not no hemoglobin

Question 15

What are the granulocytes and agranulocyte leukocytes?

Answer 15

granular: neutrophils, eosinophils, and basophils
agranular: monocytes and lymphocytes

Question 16

What is the percentage of WBC that are circulating in the blood at any given time?

Answer 16

2%

Question 17

How many RBC vs WBC in the blood?

Answer 17

1 WBC for every 700 RBC

Question 18

Since very few WBC are in the blood, where are the rest?

Answer 18

lymphatic fluid, lymphatic tissue of the skin, lungs, lymph nodes, and spleen

Question 19

What do neutrophils do?

Answer 19

fast response to bacteria
-release defensin, creates holes in bacterial cell walls
-release lysozymes, which destroy bacteria
-release strong oxidants, which destroy bacteria

Question 20

What do eosinophils do?

Answer 20

leave the capillaries to enter tissue fluid
-release histaminase, which breaks down histamine and calms the response of basophils
-attack parasitic worms
-phagocytose antibody-antigen complexes

Question 21

What do basophils do?

Answer 21

• inflammatory and allergic reactions
• leave capillaries and enter connective tissue as mast cells
• release heparin, histamine, and serotonin: heighten inflammatory response, increase blood flow, and create allergic reactions

Question 22

What do B cells do?

Answer 22

antibody-mediated immunity,
stay in lymphatic tissue,
destroy bacteria and their toxins,
turn into plasma cells which produce antibodies that enter the lymphatic fluid

Question 23

What do T cells do?

Answer 23

cell mediated immunity,
go out into tissues,
attack viruses, fungi, transplanted organs, cancer cells, and some bacteria

Question 24

What do natural killer cells do?

Answer 24

directly attack and destroy many kinds of microbes and some tumor cells

Question 25

Where are B and T cells matured?

Answer 25

B cells - bone marrow T cells - thymus

Question 26

Where do most lymphocytes reside?

Answer 26

spleen and lymph nodes

Question 27

Where do B and T cells act? (in lymphatic tissue, blood, etc.) Something ends up in the blood in each case - what?

Answer 27

B cells remain in the lymphatic tissue and release antibodies in to the blood T cells leave the lymphatic tissue and enter the blood to migrate to distant sites

Question 28

What do monocytes do?

Answer 28

arrive in large numbers at sites of infection (slower, but more of them) become wandering macrophages once they leave the capillaries destroy microbes and clean up dead tissue following an infection

Question 29

When do monocytes become macrophages?

Answer 29

when they leave the capillaries

Question 30

What does a differential WBC count do?

Answer 30

detect changes in numbers of circulating WBC (percent of each type)

Question 31

What are normal WBC counts?

Answer 31

N- 60-70% L- 20-25% M- 3-8% E- 2-4% B- <1%

Question 32

What causes a change in the count for each leukocyte type?

Answer 32

N- bacterial infection L- viral infection M- fungal/viral infection E- parasite or allergy B- hypothyroid or allergy

Question 33

Describe the process of emigration

Answer 33

WBCs roll along the endothelium. integrins on WBC stick to the selectins on the endothelial cells chemokines stimulate the affinity of integrins for selectins

Question 34

What are the steps of phagocytosis?

Answer 34

chemotaxis, adherence, and destruction

Question 35

What occurs in the chemotaxis step of phagocytosis?

Answer 35

chemokines that are released from the pathogen/infected cell attract phagocytic cells

Question 36

What occurs in the adherence step of phagocytosis?

Answer 36

- phagocytes fuse to the pathogen's membrane - pseudopodia wrap around it, ingesting the pathogen to form a phagosome (the pathogen inside the WBC)

Question 37

What occurs in the destruction step of phagocytosis?

Answer 37

- phagosome fuses with a lysosome to create a phago-lysosome - lysosomal enzymes destroy the membrane of the pathogen - fragments of the dead pathogens are encapsulated in a residual body or removed from the cell by exocytosis

Question 38

What types of leukocytes primarily perform phagocytosis?

Answer 38

neutrophils and monocytes

Question 39

What are the two main types of immunity?

Answer 39

innate (non specific) and aquired (adaptive, or specific)

Question 40

What are the innate defenses?

Answer 40

physical barriers, fever, inflammatory response, and antimicrobial substances/cells that can kill (interferons, phagocytes, complement proteins, and natural killer cells)

Question 41

What are the physical barriers of innate immunity?

Answer 41

skin, mucus membranes, hair, acid, and tears

Question 42

How do tears contribute to innate immunity?

Answer 42

they contain lysozymes

Question 43

What aspects of the skin make it a good physical barrier for innate immunity?

Answer 43

sebaceous glands, sudoriferous glands, and lysozymes

Question 44

What causes an increase in body temperature (fever)?

Answer 44

pyrogens, which are secreted by phagocytes when exposed to bacteria and other foreign substances

Question 45

In what ways can a moderate fever be beneficial?

Answer 45

liver and spleen sequester iron and zinc, trigger production of interferons, bacterial enzymes stop functioning, and increased metabolic rate helps inflammatory response

Question 46

What are four signs of inflammation?

Answer 46

redness, heat, swelling, and pain

Question 47

What does inflammatory response do for innate immunity?

Answer 47

prevent spread of damaging agents, promote disposal of debris and pathogens, set the stage for repair

Question 48

What are the phases of phagocytic mobilization of inflammatory response?

Answer 48

1. leukocytosis- cytokines released by injured cells trigger neutrophils to be released 2. margination- neutrophils cling to the walls of capillaries in the injured area 3. diapedesis- neutrophils squeeze through the capillary walls and begin phagocytosis 4. chemotaxis- chemokines attract neutrophils to the site

Question 49

How do antimicrobial substances enhance innate defenses (generally)?

Answer 49

attacking microorganisms directly, and hindering microorganisms ability to reproduce

Question 50

What are interferons produced by?

Answer 50

natural killer cells, macrophages, T lymphocytes, and virus infected body cells

Question 51

What do interferons do?

Answer 51

they warn adjacent cells and alter cellular activities

Question 52

Why are interferons non-specific?

Answer 52

they act on a large number of viruses, not a specific virus

Question 53

How do interferons work?

Answer 53

infected cell produces interferons, those interferons bond to a nearby cell's interferon receptor, turns on the gene for antiviral protection which blocks viral reproduction.

Question 54

What is a complement system?

Answer 54

11 specific proteins that complement the action of antibodies

Question 55

What do complement proteins do?

Answer 55

They attach to antobody-antigen complexes, providing a second line of defense against an invasion by pathogens

Question 56

What is the end result of a complement protein?

Answer 56

formation of a membrane attack complex (MAC) that attracts phagocytes, stimulates phagocytosis and inflammation

Question 57

What is opsonizing?

Answer 57

coating with C3b that can create strong bonds with the pseudopodia

Question 58

Describe the process of the complement system.

Answer 58

circulating proteins are activated by antigens they self assemble to become a membrane attack complex MAC forms a pore where ISF can pour in and rupture the microbe (cytolysis) C3a and C5a degranulate the mast cell, releasing histamine and causing the capillaries to become more leaky. Increased permeability allows more phagocytes to exit the blood vessel and engulf the microbes. microbes are also opsonized by C3b so pseudopodia can more strongly attach.

Question 59

What percent of the lymphocytes are natural killer cells?

Answer 59

5-10%

Question 60

How do natural killer cells function?

Answer 60

Kill tumor cells and some viruses via cytolysis. They secrete perforin and granzymes which perforates the cell membrane and activate an apoptotic pathway within the target cell.