Blood, Hemostasis and Lymphatics

Question 1

antigen

Answer 1

any substance that causes an antibody response to be generated

Question 2

antibodies

Answer 2

substances created by our immune cells and are capable of binding to foreign substances

Question 3

blood typing

Answer 3

involves mixing blood w/ different antisera

Question 4

ABO blood groups

Answer 4

based on having an A, B, both or no antigens on red blood cells

Question 5

Rh blood group

Answer 5

a group of antigens discovered on the red blood cells of rhesus monkeys that is also present to some extent in humans, presence indicated by “+”

Question 6

how do Rh antibodies develop?

Answer 6

they will only develop on Rh- blood only with exposure to the antigen

Question 7

hemolytic disease of the newborn

Answer 7

this disease occurs in the fetus if the fetus is Rh+ while the mother is Rh- (and later develops antibodies); this causes issues for 2nd pregnancy if fetus is Rh+ (particular antibodies; IgG can be transported across placenta to confer protection to fetus) — antibodies in mother would bind to blood forming within fetus and destroys the blood

Question 8

hemostasis

Answer 8

sequence of responses that stops bleeding and prevents hemorrhage from smaller blood vessels

Question 9

platelet features

Answer 9

disc shaped, 2-4 micron cell fragments, no nucleus and a short lifespan

Question 10

platelet production

Answer 10

pluripotent to myeloid stem cell, becomes megakaryoblast to megakaryocyte to platelets

Question 11

what are the functions of a platelet?

Answer 11

stop blood loss from damaged vessels by forming a platelet plug and releasing chemicals that promote clotting/vascular spasm

Question 12

what are the 3 mechanisms to reduce blood loss?

Answer 12

vascular spasm, platelet plug formation and blood clotting

Question 13

vascular spasm

Answer 13

prompt constriction of a broken vessel; most immediate protection against blood loss

Question 14

steps of platelet plug formation

Answer 14

adhesion, release reaction and aggregation

Question 15

platelet adhesion

Answer 15

platelets stick to exposed collagen underlying damaged endothelial cells in vessel wall

Question 16

platelet release reaction

Answer 16

release of serotonin (vasoconstriction), ADP (activates platelets) and thromboxane A2 (both)

Question 17

platelet aggregation

Answer 17

clumping of platelets during wound healing (platelet plug)

Question 18

blood clotting (coagulation)

Answer 18

Forms as platelets become enmeshed in fibrin threads

Question 19

a blood clot contains…

Answer 19

platelets, fibrin and RBCs

Question 20

formation of fibrin

Answer 20

cascade of reactions in which each clotting factor activates the next in a fixed sequence

Question 21

thrombus

Answer 21

clot in an unbroken vessel

Question 22

thromboembolus

Answer 22

clot travelling around in the blood stream

Question 23

positive feedback in blood clotting

Answer 23

exposed collagen attracts platelets which bind to the damaged site; platelets become activated and attract more platelets which release substances that promote clotting and form a plug; clot growth stops once the binding sites are covered

Question 24

extrinsic pathway

Answer 24

evokes clotting within a blood vessel if there is damage to the tissue outside the vessel

Question 25

intrinsic pathway

Answer 25

cascade of clotting factors leading to the formation of a clot within an injured vessel

Question 26

convergence of extrinsic and intrinsic pathways

Answer 26

(extrinsic) Ca2+ release activates factors X and V to form prothrombinase, (intrinsic) activated platelets to platelet phospholipids contribute to eventual activation of factors X and V + Ca2+ to form prothrombinase

Question 27

common pathway

Answer 27

prothrombinase converts prothrombin to thrombin with the help of Ca2+; then thrombin produces insoluble fibrin threads that become strengthened fibrin threads with factor XIII

Question 28

clot retraction & blood vessel repair

Answer 28

clot plugs ruptured area of blood vessel; platelet pull on fibrin threads causing clot retraction and edges of damaged vessel are pulled together - fibroblasts and endothelial cells repair the blood vessel

Question 29

clot lysis (fibrinolysis)

Answer 29

dissolution of the clot; as son as clotting begins, the anti-clotting factor is also activated but much slower to act

Question 30

fibrinolysis pathway

Answer 30

activated factor XII and tPA works on inactive plasminogen to turn it into active plasmin that breaks down fibrin and dissolves the clot

Question 31

antiplatelet agents

Answer 31

e. g. aspirin - prevent platelet reaction from occuring

e. g. clopridogrel - prevent platelet “party”

Question 32

anticoagulants

Answer 32

suppress/prevent blood clotting; e.g. heparin prevents formation of fibrin thread, warfarin is a vitamin K antagonist (clotting factors can’t work)

Question 33

thrombolytics

Answer 33

break existing clots; e.g. tPa and streptokinase

Question 34

what does the lymphatic system consist of?

Answer 34

lymph, lymphatic vessels, structures containing lymphatic tissue, red bone marrow

Question 35

what are the functions of the lymphatic system?

Answer 35

drain excess interstitial fluid from tissue spaces and return it to blood, transport dietary lipids & lipid-soluble vitamins from the GI tract, carry out immune responses

Question 36

where do lymphatic vessels originate?

Answer 36

start in the tissue sb/w capillary beds - “close-ended” lymph capillaries that lie adjacent to blood capillaries in the tissue spaces

Question 37

how can lymph flow be aided?

Answer 37

similar to aiding venous return, by valves, skeletal muscle pump and respiratory pump

Question 38

lymph drainage

Answer 38

returns excess fluid and plasma proteins to the circulation mainly by draining into the L or R subclavian through the right lymphatic or left thoracic duct

Question 39

cisterna chyli

Answer 39

an enlarged pouch on the thoracic duct that serves as a storage area for lymph moving toward its point of entry into the venous system

Question 40

primary lymphoid organs

Answer 40

the bone marrow and thymus; responsible immune cell production and education

Question 41

secondary lymphoid organs

Answer 41

lymph nodes/nodules and spleen; where most immune responses occur

Question 42

where are major lymph nodes located?

Answer 42

cervical, axillary and inguinal regions

Question 43

why do lymph nodes have many afferent but few efferent vessels?

Answer 43

it slows the flow of lymph as it goes through the lymph node and allows immune cells (T and B cells) the opportunity to see what is being drained from the tissue