Transcription
Our bleeding and coagulation disorders Playlist is not done yet in the previous video. We have discussed the normal smooth endothelium and how it's Antithrombotic today. We'll talk about hemostasis How to make the bleeding stop? Look at these blood drops dropping over the t. What am I doing with my life?
This is Medicosus perfectionalis, and let's get started. Here are my previous videos in this playlist bleeding and cardio subscribe and save this playlist Hemostasis as you know is to make the blood stable by preventing bleeding which means forming a clot Hemostasis prevention of blood loss steps vasoconstriction temporary platelet plug also known as primary hemostasis the hero here is the platelet Coagulation also known as secondary hemostasis the heroes here are the coagulation factors They include from one to 13, but no number six. I will tell you why we don't talk about coagulation fibrilysis dissolves the clot and restores the normal function and the normal laminar flow of blood then regeneration and repair to repair the injured Traumatized blood vessel, please don't confuse hemostasis with homeostasis Medicosis words of wisdom again primary hemostasis is balanced on the dynamic harmonious Antagonism between the smooth endothelium that wants the blood to flow smoothly and the thrombocytes which favor Coagulation and clotting or clotting and coagulation. So here are the steps again vasoconstriction, temporary plate of plug, coagulation, which will form a stronger plug, fibrinolysis, and between them the clot contracts and the serum form and I've talked about the difference between serum and plasma in a previous video.
Now, let's talk about the first step which is vasoconstriction constrict the vessel. So here is the story first you injure yourself because you're an idiot son of a father which will lead to vasoconstriction then temporary platelet plug also has primary hemostasis and Depending on the type of the trauma if it's very small such as a pinprick or a paper cut platelet plug is sufficient. Primary hemostasis is more than enough. Thank you so much, and we're done. But if it's a larger trauma, we need the secondary hemostasis, the coagulation cascade, to convert fibrinogen into fibrin forming a meshwork trapping the red blood cell and forming a nice strong plug to stop bleeding.
Then the clot will contract. After it contracts, it will provide the serum which is the plasma minus the clot minus the coagulation factors Then fibrinolysis will occur to restore the blood flow and to start regeneration and repair. This is just amazing This is very balanced because if you didn't clot you will bleed to death if you Over clot you will have a thrombus such as a heart attack or stroke which are major causes of death Worldwide, That's why blood coagulation is a very important subject for everybody. First step, vasoconstriction. When we're talking about this coagulation, I'm talking about the normal small blood vessel.
What do you mean by small? Capillary, arterial, and venule. It has the normal smooth knife endotheeum, which is a squamous epithelial tissue. Then you are exposed to trauma. You cut yourself.
What will happen is that the endotheem is cut. The vessel wall is cut. This will cause back pressure because the endotheem is falling like this and the blood vessel wall is going like this. This will cause back pressure over the blood coming here, and this back pressure will do what? It will decrease the blood flow, which happens to be a good thing lest you should bleed to death.
Then after this, we have muscles around the blood vessel. They will contract, and when they contract, they will help constrict this blood vessel. That's how the uterus stops bleeding after childbirth. That's why one of the most common causes of postpartum hemorrhage is uterine Atony which means there was no tone in the uterus. The uterus didn't contract so the bleeding didn't stop.
I'm talking about science and facts, not just theories. Then the vasoconstriction, how the vessel constricts? Local myogenic spasm, and this is very important for this smooth muscles of the blood vessel. Local myogenic just the trauma by itself will lead to reflexive contraction just by itself. We don't have to get, like, nerves and then the nerves come to say to the muscles to contract, and then we have a synapse and then we have, like, neuromuscular junction.
No. No. It's local. It's just reflexive. You touch it, you enter it, it contracts.
It's amazing. Then we have local oticoid factors such as the thromboxane a two who secretes these oticoid factors, the tissue and the platelets. Then we have nervous reflexes due to pain and injury. This will lead to nervous reflexes and of course the nerves knows how to vasoconstrict blood vessel. Why constrict the blood vessel?
Are you an idiot to decrease blood loss? Keep in mind the degree of compression varies depending on the tissue type. For example, the eye has very soft skin especially beneath the eye. That's why any trauma will lead to distention of the skin. It cannot constrict well.
This will lead to black eye. That's why you get a black eye when someone hits you in the face because you are hanging around with useless people. In brief, vasoconstriction, you start with a trauma. The surrounding tissue exerts back pressure, which reduces blood flow, then the smooth muscles in the surrounding tissues start to contract. Then the vessels start to constrict, thanks to the local myogenic spasm, the local otakoid factors, don't forget the thromboxane a two, and the nervous reflexes by pain to decrease blood loss.
The proconstriction substances are serotonin secreted by platelet, thromboxane a two secreted by platelet, epinephrine secreted by the adrenal gland. It's a sympathetic response to your injured fight flight mechanism, and the fibrino peptide b, which comes from fibrinoin because fibrinoin wants to become fibrin and form a clot, so it acts in its self interest to form fibrino peptide b to constrict the blood vessel and decrease bleeding, which makes perfect sense only with mitigosis. For the third time, vasoconstriction due to local myogenic spasm, otakoid factors such as thromboxane a two, nervous reflexes due to pain to decrease the blood loss. The myogenic spasm is independent of any nervous or hormonal stimulation. It's myogenic genesis from the muscles it stretch induced Depolarization use a stretch it due to trauma It will release calcium and calcium is the hero of contraction calcium Contraction and it may occur in hypertension to reduce the blood flow The vessels will constrict trying to reduce blood flow doesn't mean it will be very successful, but it's just the point Proconstriction substance are the serotonin, thromboxane a two, epinephrine, and fibrin peptide b.
Keep in mind, the greater the trauma, the stronger the vasoconstriction up to the point of complete occlusion of the vessel and stopping the blood flow completely, which gives the platelet and coagulation factor enough time to form their thing, which is the thrombus. The spasm or vasoconstriction can last four hours, again, giving time to these platelets and coagulation factors to make a thrombus. Quiz time. Which trauma is worse? Is it the transverse cutting of the blood vessel or the longitudinal cutting of the blood vessel?
Let me know in the comment section below. What happens after vasoconstriction? This is the topic of the next video. That's why you need to subscribe to my channel and go to patreon.com to get all of my notes including the notes that I'm drawing right now, which are just awesome. Thanks for watching.
This is me the closest perfect Nellis be safe. Stay happy and study hard