Cardiovasular System Platelets Flashcards
Platelets is also called?
thrombocytes
What is the normal platelet count?
140,000 to 440,000
Platelets are ____ true cells but are ______ that are remnants of ________ cells called____
- not
- cellular fragments
- bone marrow
- megakaryocytes
immature cells that give rise to PLTs; differentiate from hemocytoblasts in red bone marrow
megakaryocytes
a hormone/hemopoietic growth factor produced by the liver that increases the rate of PLT production by stimulating the differentiation of myeloid stem cells to megakaryocytes
thrombopoietin
What is the shape of platelets?
irregularly disc-shaped
2-4 um
have many vesicles but no nucleus
short life span (5-9 days)
What is the main function of platelets?
blood clotting
the medical term for an abnormally low PLT count w/c indicates anrisk for bleeding
thrombocytopenia
is a sequence of responses that stops bleeding
hemostasis
stimulated in response to rupture or damage to blood vessels
hemostasis
refers to the loss of a large amount
of blood from the blood vessels
hemorrhage
In vascular spasm,
blood vessel damaged in traumatized tissue→PLTs in the area of the rupture release ______→smooth muscle in blood vessel wall _______ → vasoconstriction & _____→ blood flow to ruptured vessel
- serotonin
- contracts
- spasm
this process occurs immediately once blood vessel is damaged
Vascular spasm
this process occurs within seconds from damage to the blood vessel
Platelet Plug Formation
In platelet plug formation, platelets contact and stick to the damaged blood vessels. what process is this?
platelet adhesion
In platelet plug formation, platelets are activated and release _______ and ______. What is this process called?
Thromboxane A2 and ADP
the process is called platelet release reaction
In the third step of platelet plug formation, ADO and thromboxane A2 makes other platelets in the area _____that makes platelets adhere to the originally activated platelets.
what is the platelet gathering called?
- sticky
- platelet aggregation
Platelet aggregation then promotes the formation of _______
platelet plug
it is also called blood coagulation
blood clotting
a network of insoluble protein fibers called fibrin in w/c the formed elements of blood are trapped
clot
is a series of chemical reactions that culminates in formation of fibrin threads
blood clotting
blood clotting involves several substances known as _____
clotting factors
blood clotting lead to formation of?
fibrin threads
is thus a complex cascade of _____ in which each clotting factor activates many molecules of the next one in a fixed sequence
enzymatic reaction
The clot begins to develop within _____ if the trauma is severe
And about _____ if the trauma is ______
15-20 seconds
1-2 minutes if minor
Clotting factors include _____ ions, ______, ______ and ______
- Ca++ ions
- plasma proteins
- inactive enzymes
- chemicals released by PLTs
Many of the clotting factors require _____ for their synthesis ( factors X, IX, VII and II)
vitamin K
produced by the bacteria inhabiting the large intestine & stored in the liver
vitamin k
How many clotting factors are there?
13
are “brakes” which prevent abnormal blood clotting
Hemostatic control mechanism
dissolution of a clot
fibrinolysis
an inactive plasma enzyme incorporated into the clot when a clot is formed
plasminogen
active enzyme that dissolves clots by digesting fibrin threads & inactivating fibrinogen & thrombin
plasmin or fibrinolysin
substance released by injured tissues that activate plasminogen to plasmin
Tissue plasminogen activator t-PA
the simple squamous epithelium w/c forms the inner lining of blood vessels
endothelium
the smoothness of the endothelium prevents the activation of the _____
intrinsic coagulation pathway
When the smoothness of the endothelium is lost, it activates ______ and ______
factor XII or Hageman factor
platelets
a substance w/c delays, suppresses or prevents blood clotting usually by disrupting a chemical reaction in the clotting cascade
anticoagulant
a natural anticoagulant produced by the liver w/c blocks the action of several clotting factors including factor XII, X & II
antithrombin
antithrombin blocks the action of several clotting factors
what are these?
factor XII or Hageman Factor
factor X or Stuart-Prower factor
and factor II or prothrombin
a natural anticoagulant produced by the basophils; combines w/ antithrombin & increases its effectiveness in blocking thrombin
heparin
medical term for clot
thrombus
refers to the transfer of blood or blood components from one individual to another
transfusion
an unsuccessful transfusion may be caused by interactions bet. _____ and ___
agglutinogens and agglutinins
are antigens found in the surfaces of RBCs w/c are genetically determined
agglutinogens
are antibodies found in blood
plasma
agglutinins
the clumping of RBCs w/c occurs when the antibodies in plasma bind to the antigens on the surface of the RBCs
Agglutination
Agglutination can trigger ______ of RBCs, initiate clotting & disrupt blood supply to vital organs
hemolysis
refers to categorizing blood into groups based on the presence or absence of surface antigens on their RBCs
blood grouping
What are the two blood major group?
ABO and Rh
is based on the presence (or absence) of two major protein antigens on RBC membranes - antigen A & antigen B.
ABO blood group
List the blood types and their corresponding antigens
Type A- antigen A
Type B- antigen B
Type AB- both A and B antigen
Type O- have neither antigen A or B
When there is a similar antigen, what happens?
agglutination
the screening of one’s blood for the presence of antibodies to determine ABO blood type
ABO blood typing
In ABO blood typing, the blood is mixed with different ____, which are solutions that contain antibodies
antisera
In ABO blood typing, the antisera is mixed with the RBC , if the blood coagulates with blood A, what is its blood type?
type A
helps ensure that donated blood will not bring about a hemolytic transfusion reaction in the recipient.
crossmatching
What occurs if the antibodies on the recipient’s plasma reacts with the antigens on the donor’s RBCs and thus the donor’s blood is incompatible w/ the recipient’s?
agglutination
Known as universal donor
Type O
known as universal recipient
Type AB
Rh blood group is named after?
rhesus monkey
Rh blood group is also called
D antigen
Human erythrocytes are classified as Rh positive or Rh negative depending solely on the presence or absence of the
D antigen
If Rh positive?
D antigen is present
Rh incompatibility is responsible for______ (HDN) or ________ which occurs in an Rh(-) mother which leads to death of second born Rh(+) child
hemolytic disease of the newborn
erythroblastosis fetalis
Hemolytic Disease of the newborn occurs during first or second pregnancy?