Circulation Flashcards
Describe the structure of a blood vessel
- Lumen is the part where blood flow through
- The lumen contains platelets, red blood cells, white blood cells and plasma
- The lumen is forms by endothelial cells
- The endothelial cells sit of a Basel laminae
- The Basel laminae sits on a layer of smooth muscle
- The smooth muscle sits of a layer of interstitial collagen fibres
What is the plasma ?
The plasma contains water and many proteins and other molecules. It is blood minus the cells and the platelets.
What is serum ?
Blood without cells, platelets and clotting factors.
Where are many of the clotting factors produced?
In the liver
What is the clotting cascade used for?
It is used to cause the formation of a blood clot, by carrying out an amplification.
Describe the clotting cascade
Damage occurs which through a series of reactions causes prothrombin to be converted to thrombin. Thrombin then converted fibrinogen to fibrin. Fibrin then forms a mash of strands which is the base of the blood clot.
Key/New words from circulation
Prothrombin Thrombin Fibrinogen Fibrin Plasminogen Plasmin Thrombolysis Haemostasis atheroma Hypovolaemia Cardiogenetic
Describe the process in the blood vessels that leads to a clotting cascade
Damage occurs to the vessel causing the leaking of blood form the vessel. The serum comes into the contact with the interstitial collagen fibres allowing the clotting factors in the blood to be activated.
Tissue factor is also released from the smooth muscles which bind to clotting factors and initiate the clotting cascade.
What type of clotting factor are many of the clotting factors?
Serine protease which have a serine amino acid. These factors cleave other clotting factors to active them.
When serine protease cleave other clotting factors what parts of produced?
A clotting factor is cleaved into a redundant fragment and an activated clotting factor.
What are platelets?
fragments of megakaryocytes which bud off after the megakaryocyte nuclear division (they are huge cells)
What is coagulation?
The solidification of blood
What are the two types of coagulation ?
Thrombus - Occurs in flowing blood and is pale in colour. It contains a network of platelets and fibrin. Platelets have molecules which allows them to cling to the interstitial fibres, Factor VIII also helps this process.
Clot - Occurs in stagnant blood i.e. if blood leaks from a vessel a clot will form. It is a network of fibrin and red blood cells.
Describe the process of haemostasis
- Injury occurs which causes blood to leak from a vessel
- The clotting system is activated
- The stagnant blood clots
- Vasoconstriction occurs to help prevent further blood loss
- Thrombus forms in the flowing blood and stops more blood getting through the puncture.
- New vessels from into the area forming granulation tissue
- Blood vessels originate the area and allow it to stay alive
- Plasminogen is converted to plasmin and dissolves the thrombus in a process called thrombolysis
- Healing occurs leaving a scar
How does smoking effect blood flow?
It makes platelets more sticky and so they are more likely to from a clot.
Higher chance of atheroma (build up of lipid in the coronary arteries) the build up of lipid can cause a change in the blood flow and can sometimes move into the blood causing a thrombus to form.
