Blood and the cardiovascular system Flashcards
What are the clotting factors of blood?
Calcium ions, vitamin K and villa Xa
Which blood clotting factors are required for the conversion or prothrombin to thrombin?
Calcium ions and vitamin K
What are the steps to a blood clot forming?
- Damaged blood vessel (triggers release of clotting factors)
- Formation of platelet plug (vasoconstriction limits blood flow)
- Development of clot (fibrin strands adhere to plug)
To inhibit blood clotting what would you need?
You’d need to take enzyme inhibitors
Describe an artery?
Thick walls - withstand high pressure.
Smooth muscle - vasoconstriction and vasodilation.
Elastic fiber - for distention and recoil.
Describe a vein?
Thin walls.
Valves - prevent backflow of blood.
Large lumen - little blood flow resistance.
Describe a capillary?
Microscopic - form large networks large surface area.
One squamous endothelial call thick.
permeable to water and small molecules.
What does myogenic mean?
Doesn’t rely on nervous system to stimulation contraction of the heart.
What is the hearts pace maker?
Sino atrial node.
What does the sinoatrial node do?
It is the hearts pace maker.
Describe a heart beat?
- Wave of excitation stimulated atrium to contact. ( atrial systole)
- Excitation reaches atrioventricular node delaying for atrium to empty.
- Excitation goes down bundle of his spreads up purkinje fibers walls of ventrical. (ventrical systole).
When are AV valves open?
Atrial pressure>Ventricular pressure.
When are AV valves closed?
Ventricular pressure>Atrial pressure.
When are semilunar valves open?
Ventricle pressure>Arterial pressure.
When are semilunar valves closed?
Arterial pressure>Ventricular pressure.
