PBL 3 Flashcards
What is blood?
A suspension of cells in a solute of water, water-soluble proteins and electrolytes.
What is plasma?
Anticoagulated blood from which the cellular components (RBCs,WBCs and platelets) have been removed by centrifugation.
It contains the coagulation proteins
What is serum?
The liquid in blood that has been collected without an anticoagulant.
The coagulation proteins have clotted and formed a precipitate along with the cellular components of the blood
What is plasma?
The liquid component of blood. It is made up of about 90% water with the rest being ions, proteins, nutrients and dissolved gases
What is the function of Plasma?
Responsible for maintaining blood pH and osmotic balance. Lipids, such as cholesterol, are also carried in plasma but must travel with escort proteins as they are not water soluble.
What are RBCs?
Red Blood Cells, also known as erythrocytes are specialised cells. They don’t have a nucleus or mitochondria and have a biconcave structure
What is the function of RBCs?
To travel throughout the body and deliver oxygen/CO2 to tissues
What are platetlets?
Aslo known as thrombocytes, platelets are cell fragments which are produced when large cells called megakaryocytes break into pieces, each ones making 2000-3000 platelets as it breaks apart
What is the structure of platelets?
Platelets are roughly disc shaped about 2-4 micrometers in diameter. Their cytoplasm contains granules with substances such as fibrinogen
What is the function of platelets?
They have a large role in blood clotting
What are WBCs?
White Blood Cells, also known as leukocytes are larger than RBCs and contain a normal nucleus and and mitochondria
What is the function of WBCs?
WBCs are primarily involved in immune responses
What is endomitotic synchronous replication?
Megakaryocytes grow and grow until eventually fragments come off.
What happens after damage to a blood vessel?
Immediate vasocontriction to slow blood flow
What is extanguination?
The action of draining a person, animal, or organ completely of blood
What happens after breakage of the endothelial cell barrier?
Recruitment of platelets from the circulation to form a plug
What is platelet adhesion?
When platelets interact with other cells. This is caused by collagen exposure
What is platelet aggregation?
When platelets interact with each other, forming clots
What does platelet adhesion lead to?
The activation of platelets
What does platelet activation follow?
stimulation by agonists such as ADP and thromboxane A2 interacting with surface repceptors or by direct interaction with the subendothelial matrix.
What change occurs in platelets (change in shape etc.)
platelets convert from a compact disc to an irregular sphere shape, their surface receptors become activated, and granules in the cytoplasm secrete their contents
How is the loose plug formed?
Other circulating platelets adhere to the initial layer of platelets
What is coagulation?
The mechanism that directly leads to the conversion of the soluble plasma protein fibrinogen to the insoluble rigid polymer fibrin
What is the clotting (or coagulation) cascade?
The mechanism by which fibrinogen is converted into fibrin
What are most activated coagulation factors?
Proteolytic enzymes which in the presence of cofactors cleave other factors in an ordered sequence
How is the intrinsic pathway activated?
Exposed collagen and other negatively charged components of the subendothelium