BIO 2301 HUMAN PHYSIOLOGY -
EXAM #3 QUESTIONS WITH
COMPLETE ANSWERS
Platelet plug formation steps of development - ANSWER-Damage to blood vessel ->
collagen from deeper layers of the blood vessel is exposed -> platelets adhere to
those sticky collagen fibers -> platelets release ADP and Thromboxane A2 and the
damaged endothelial cells release von Willebrand's factor -> more platelets come to
the area -> formation of a platelet plug that plugs up the hole
Limiting plug growth - ANSWER-- Nearby undamaged endothelial cells inhibit
platelet adherence by release Prostacyclin (PGl2) and nitric oxide (NO)
- This makes sure the plug does expand onto the undamaged entothelium
What are the two pathways along which a clot is formed? - ANSWER-Intrinsic
pathway and extrinsic pathways
What do both factors involve? - ANSWER-Calcium and clotting factors/proteins
Where are clotting factors made? - ANSWER-They are made by the liver and
circulate in the plasma in inactive form
What coenzyme helps the liver make clotting factors? - ANSWER-Vitamin K
What happens when a person has liver failure? - ANSWER-They are not able to
make those clotting factors and they will bleed excessively
What can act to prevent that liver from making clotting factors? What is an antidote?
- ANSWER-- Rat poison (warfarin) and Coumadin (a blood thinner) prevent the liver
- Antidote for warfarin toxicity is vitamin K
What anticoagulants function to prevent clotting and how? - ANSWER-- EDTA and
citrate function to prevent clottign by chelating calcium - they bind up the calcium in
the blood so it is not present to cause clotting
The intrinsic pathway of clotting - ANSWER-- Forms a clot in 3-6 minutes
- Is initiated only when there is damage to the lining of the blood vessel wall
- Uses the clotting proteins XII, XI, IX, VIII, X, Thrombin, and Fibrin
The extrinsic pathway of clotting - ANSWER-- Forms a clot in 15 seconds
- Is initiated when there is damage to the blood vessel and tissue around it
- Uses clotting factors VII, X, Thrombin, Firbin, and Tissue Thromboplastin
What is fibrin - ANSWER-The clot itself
What is thrombin? - ANSWER-The enzyme right before the clot - if you have
thrombin, you can form a clot
, Clot development involves... - ANSWER-the polymerization of the fibrin to form a
meshwork which traps blood cells within the clot
Clot retraction occurs and causes... - ANSWER-the cut edges of the vessel to be
brought closer together, giving you a smaller hole to repair
Rh System - ANSWER-- Involves a different antigen on the RBC membranes, the Rh
antigen
- If someone has the antigen, they are Rh positive and they will not make the
antibodies against Rh
- If someone does not have the antigen, they are Rh negative and they will make
antibodies against Rh
Erythroblastosis fetalis - ANSWER-- A problem when you have an Rh negative
mother pregnant with Rh positive baby
- During pregnancy, there is no mixing of mother's and baby's blood, however at the
time of placental separation, some of the baby's blood can enter the mother's
bloodstream
- The mother recognizes the RH antigens as foreign and fights against those RBCs
by making antibodies against RH
- The next time a woman gets pregnant with an Rh positive baby, her antibodies will
enter that baby's bloodstream and destroy the baby's RBCs - if that baby lives to be
born, it will be very anemic and need a complete blood transfusion at birth
How do you prevent erythroblastosis fetalis? - ANSWER-RHoGAM injections given
to Rh negative mothers during pregnancy?
What is hemostasis? - ANSWER-The stoppage of bleeding and consists of three
processes: vasospasm, platelet plug formation, and blood clotting
Vasospasm - ANSWER-- Mechanism: the damaged blood vessel spasms down -
caused by a reflex of the blood vessel and serotonin that is released by the damaged
blood vessel
- Significance: decreases blood loss from that vessel - you get more vasospasm with
increased damage to the vessel
What do platelets release and what does it stimulate - ANSWER-- Release PDGF
(platelet derived growth factor)
- Stimulates the healing of the blood vessel wall
What happens once healing has occurred? - ANSWER-- TPA (Tissue Plasminogen
Activator) is released from the healed endothelial cells and activates plasminogen
- Faxtor IIa and Thrombin also activate plasminogen
- Plasminogen becomes plasmin when it is active and the plasmin will digest the clot
Plaminogen is ___________ into the clot when the clot is made and the clot has a
_________ way of getting rid of itself - ANSWER-- incorpoated
- built in
EXAM #3 QUESTIONS WITH
COMPLETE ANSWERS
Platelet plug formation steps of development - ANSWER-Damage to blood vessel ->
collagen from deeper layers of the blood vessel is exposed -> platelets adhere to
those sticky collagen fibers -> platelets release ADP and Thromboxane A2 and the
damaged endothelial cells release von Willebrand's factor -> more platelets come to
the area -> formation of a platelet plug that plugs up the hole
Limiting plug growth - ANSWER-- Nearby undamaged endothelial cells inhibit
platelet adherence by release Prostacyclin (PGl2) and nitric oxide (NO)
- This makes sure the plug does expand onto the undamaged entothelium
What are the two pathways along which a clot is formed? - ANSWER-Intrinsic
pathway and extrinsic pathways
What do both factors involve? - ANSWER-Calcium and clotting factors/proteins
Where are clotting factors made? - ANSWER-They are made by the liver and
circulate in the plasma in inactive form
What coenzyme helps the liver make clotting factors? - ANSWER-Vitamin K
What happens when a person has liver failure? - ANSWER-They are not able to
make those clotting factors and they will bleed excessively
What can act to prevent that liver from making clotting factors? What is an antidote?
- ANSWER-- Rat poison (warfarin) and Coumadin (a blood thinner) prevent the liver
- Antidote for warfarin toxicity is vitamin K
What anticoagulants function to prevent clotting and how? - ANSWER-- EDTA and
citrate function to prevent clottign by chelating calcium - they bind up the calcium in
the blood so it is not present to cause clotting
The intrinsic pathway of clotting - ANSWER-- Forms a clot in 3-6 minutes
- Is initiated only when there is damage to the lining of the blood vessel wall
- Uses the clotting proteins XII, XI, IX, VIII, X, Thrombin, and Fibrin
The extrinsic pathway of clotting - ANSWER-- Forms a clot in 15 seconds
- Is initiated when there is damage to the blood vessel and tissue around it
- Uses clotting factors VII, X, Thrombin, Firbin, and Tissue Thromboplastin
What is fibrin - ANSWER-The clot itself
What is thrombin? - ANSWER-The enzyme right before the clot - if you have
thrombin, you can form a clot
, Clot development involves... - ANSWER-the polymerization of the fibrin to form a
meshwork which traps blood cells within the clot
Clot retraction occurs and causes... - ANSWER-the cut edges of the vessel to be
brought closer together, giving you a smaller hole to repair
Rh System - ANSWER-- Involves a different antigen on the RBC membranes, the Rh
antigen
- If someone has the antigen, they are Rh positive and they will not make the
antibodies against Rh
- If someone does not have the antigen, they are Rh negative and they will make
antibodies against Rh
Erythroblastosis fetalis - ANSWER-- A problem when you have an Rh negative
mother pregnant with Rh positive baby
- During pregnancy, there is no mixing of mother's and baby's blood, however at the
time of placental separation, some of the baby's blood can enter the mother's
bloodstream
- The mother recognizes the RH antigens as foreign and fights against those RBCs
by making antibodies against RH
- The next time a woman gets pregnant with an Rh positive baby, her antibodies will
enter that baby's bloodstream and destroy the baby's RBCs - if that baby lives to be
born, it will be very anemic and need a complete blood transfusion at birth
How do you prevent erythroblastosis fetalis? - ANSWER-RHoGAM injections given
to Rh negative mothers during pregnancy?
What is hemostasis? - ANSWER-The stoppage of bleeding and consists of three
processes: vasospasm, platelet plug formation, and blood clotting
Vasospasm - ANSWER-- Mechanism: the damaged blood vessel spasms down -
caused by a reflex of the blood vessel and serotonin that is released by the damaged
blood vessel
- Significance: decreases blood loss from that vessel - you get more vasospasm with
increased damage to the vessel
What do platelets release and what does it stimulate - ANSWER-- Release PDGF
(platelet derived growth factor)
- Stimulates the healing of the blood vessel wall
What happens once healing has occurred? - ANSWER-- TPA (Tissue Plasminogen
Activator) is released from the healed endothelial cells and activates plasminogen
- Faxtor IIa and Thrombin also activate plasminogen
- Plasminogen becomes plasmin when it is active and the plasmin will digest the clot
Plaminogen is ___________ into the clot when the clot is made and the clot has a
_________ way of getting rid of itself - ANSWER-- incorpoated
- built in
