MEKANISME HEMOSTASIS Essays - , Term Papers

MEKANISME HEMOSTASIS Urutan mekanisme hemostasis dan koagulasi dapat dijelaskan sebagai berikut: 1. Segera setelah pembuluh darah terpotong atau pecah, rangsangan dari pembuluh darah yang rusak itu menyebabkan dinding pembuluh berkontraksi sehingga dengan segera aliran darah dari pembuluh darah yang pecah akan berkurang (terjadi vasokontriksi). 2. Setelah itu, akan diikuti oleh adhesi trombosit, yaitu penempelan trombosit pada kolagen. ADP (adenosin difosfat) kemudian dilepaskan oleh trombosit kemudian ditambah dengan tromboksan A2 menyebabkan terjadinya agregasi (penempelan trombosit satu sama lain). Proses aktivasi trombosit ini terus terjadi sampai terbentuk sumbat trombosit, disebut juga hemostasis primer. 3. Setelah itu dimulailah kaskade koagulasi (lihat gambar.1) yaitu hemostasis sekunder, diakhiri dengan pembentukan fibrin. Produksi fibrin dimulai dengan perubahan faktor X menjadi faktor Xa. Faktor X diaktifkan melalui dua jalur, yaitu jalur ekstrinsik dan jalur intrinsik. Jalur ekstrinsik dipicu oleh tissue factor/tromboplastin. Kompleks lipoprotein tromboplastin selanjutnya bergabung dengan faktor VII bersamaan dengan hadirnya ion kalsium yang nantinya akan mengaktifkan faktor X. Jalur intrinsik diawali oleh keluarnya plasma atau kolagen melalui pembuluh darah yang rusak dan mengenai kulit. Paparan kolagen yang rusak akan mengubah faktor XII menjadi faktor XII yang teraktivasi. Selanjutnya faktor XIIa akan bekerja secara enzimatik dan mengaktifkan faktor XI. Faktor XIa akan mengubah faktor IX menjadi faktor IXa. 4. faktor IXa akan bekerja sama dengan lipoprotein trombosit, faktor VIII, serta ion kalsium untuk mengaktifkan faktor X menjadi faktor Xa. 5. faktor Xa yang dihasilkan dua jalur berbeda itu akan memasuki jalur bersama. Faktor Xa akan berikatan dengan fosfolipid trombosit, ion kalsium, dan juga faktor V sehingga membentuk aktivator protrombin. 6. Selanjutnya senyawa itu akan mengubah protrombin menjadi trombin. Trombin selanjutnya akan mengubah fibrinogen menjadi fibrin (longgar), dan akhirnya dengan bantuan fakor VIIa dan ion kalsium, fibrin tersebut menjadi kuat. Fibrin inilah yang akan menjerat sumbat trombosit sehingga menjadi kuat. 7. Selanjutnya apabila sudah tidak dibutuhkan lagi, bekuan darah akan dilisiskan melalui proses fibrinolitik. Proses ini dimulai dengan adanya proaktivator plasminogen yang kemudian dikatalis menjadi aktivator plasminogen dengan adanya enzim streptokinase, kinase jaringan, serta faktor XIIa. Selanjutnya plasminogen akan diubah menjadi plasmin dengan bantuan enzim seperti urokinase. Plasmin inilah yang akan mendegradasi fibrinogen/fibrin menjadi fibrin degradation product [pic] Gangguan hemostasis (perdarahan abnormal) dapat disebabkan oleh beberapa hal di bawah ini: 1. Kelainan vaskuler Kelainan vaskuler adalah sekelompok kelompok keadaan heterogen, yang ditandaiu oleh mudah memar dan perdarahan spontan dari poembuluh darah kecil. Kelainan yang mendasari terletak pada pembuluh darah itu sendiri atau dalam jaringan ikat perivaskular. Pada keadaan dseperti ini, uji penyaring standart member hasil normal. Masa perdarahan normal, uji hemostasis lain juga normal. Kelainan vaskular ini terdapat dua jenis yakni herediter yang berupa Telangiektasia hemoragik herediter, serta kelainan jaringan ikat. Jenis yang lain adalah Defek vaskular didapat . 2. Trombositopenia Trombositopenia didefinisikan sebagai jumlah trombosit kurang dari 100.000/mm3. Biasanya ditandai dengan purpura kulit spontan, perdarahan mukosa, dan perdarahan berkepanjangan setelah trauma. Beberapa penyebab trombositopenia antara lain: (1)Kegagalan produksi trombosit .Ini merupakan penyebab tersering trombositopenia yang biasanya juga merupakan bagian dari kegagalan sumsum tulang generalisata Penekanan megakarisit selektif dapat disebabkan oleh toksisitas obat atau infeksi virus. (2)Peningkatan destruksi trombosit, Hal ini dibagi menjadi beberapa jenis yakni: a.Trombositopenia imun,termasuk di dalamnya ITP, karena infeksi, purpura pascatranfusi, Trombositopenia imun karena diinduksi obat, b.Purpura trombositopenia trombotik c.Koagulasi intravaskular diseminata, (3)Distribusi trombosit abnormal, (4)Kehilangan akibat dilusi, yakni berupa transfuse masif darah simpan pada pasien dengan perdarahan. 3. Gangguan koagulasi Bisa karena herediter maupun didapat, yang umumnya menggangu faktor-faktor koagulasi. a.Herediter : hemofilia A dan hemofilia B b.Didapat : defisiensi vitamin K dan penyakit hati 4.Gangguan fungsi trombosit Dibagi menjadi dua jenis, yakni: a.Didapat 1) karena obat anti trombosit seperti aspirin, 2).hiperglobulinemia, 3).kelainan mieloproliferatif dan mielodisplastik , serta 4)Uremia. b.Kelainan herediter 1) Trombastenia, 2)Sinsrom Bernard soulier, 3) Penyakit penyimpanan KELAINAN KOAGULASI . Hemofili A . Hemofili B . Kekurangan vit K (II,VII, IX, XI) Ganggan fungsi hati . DIC Adanya tissue factor (endotoxin, kerusakan jaringan dll) TF aktivasi koagulasi diikuti aktifasi fibrinolitik bergantian. Trombositopeni, APTT, PPT, TT memanjang, fibrinogen turun, FDP squestrasi PEMERIKSAAN LAB HEMOFILIA . Clotting time memanjang . APTT memanjang . Kadar Faktor VII menurun pada hemophilia A dan faktor IX menurun pada hemophilia B DIAGNOSIS DARI HASIL LAB PADA HEMOFILIA . Clotting time memanjang, Bleeding time normal . APTT memanjang, PPT normal

Pride And Pejudice Essays - Pride And Prejudice, Bennet Family

Pride And Pejudice Essays - Pride And Prejudice, Bennet Family Pride And Pejudice Family Ties In Jane Austen's novel, Pride and Prejudice, she created a realistic family image, by introducing some of the imperfections that many families encounter. The Bennet family, consisting of five daughters, a marriage obsessed mother, and an unhappily married father, contain many of these difficulties. Throughout the love, joy, heartache and pain, which evolved from the series of events the Bennet family encountered, one character in particular, Miss Elizabeth Bennet, viewed her family from another perspective. Elizabeth Bennet, though a very loving and respectable woman, had developed a rather poor opinion of her family: Had Elizabeth's opinion been all drawn from her own family, she could not have formed a very pleasing picture of conjugal felicity or domestic comfort(Pg. 209). As the second daughter of her family, Elizabeth had to deal with the many discomforts of being a daughter of five. Though Elizabeth loved her sisters dearly, she found it difficult not to see the differences between them, and in turn, each of their actions contributed to her perspective of her family. One sister in particular, Miss Lydia Bennet, caused Elizabeth the greatest concern. Lydia was a self-willed and careless(Pg.189) individual that cared only about men and marriage. As one of the youngest sisters, Lydia felt neglected from the opportunities her eldest sisters received. In turn, Lydia became the flirt of the family, causing embarrassment not only to herself, but as well to her family. When Lydia eloped t o London, Elizabeth feared that the source of her behavior was derived from the negative behavior of her parents. Not only did Elizabeth fear for Lydia's sake, she feared as well for her other sister, Catherine, who was under the direct influence of Lydia: Catherine, weak-spirited, irritable, and completely under Lydia's guidance(Pg.189). While supported by their mother's indulgence(Pg.189), the two ignorant, idle, and vain(Pg189) sisters, was a subject that Jane and Elizabeth often united to check the imprudence of Catherine and Lydia.(Pg.189). Besides the poorly thought out actions of Catherine and Lydia, Elizabeth had no problems with her other sister Mary, who mainly kept to herself, and Jane, the eldest sister, whom she shared a very close friendship with. Besides the faults of some of Elizabeth's sisters, one of the biggest faults of their family was the relationship between her father, Mr. Bennet, and her mother, Mrs. Bennet: she had never felt so strongly as now, the disadvantages which must attend the children of so unsuitable a marriage(Pg.210). Though Elizabeth loved her father dearly, she was unable to be blind to the impropriety of her father's behaviour as a husband(Pg.209). Though made up of an odd mixture of quick parts, sarcastic humour, reserve, and caprice(Pg.3), he was a man of few words and was clearly unable to make his wife understand his character(Pg.3). In the decade of the Bennets, marriage was clearly seen through beauty and fortune. It became evident, after resentment had settled in, that Mr. Bennet had married for other reasons besides love: Her father captivated by youth and beauty/ had married a woman whose weak understandings and illiberal mind, had very early in their marriage put an end to all real affectio n for her(Pg.209). Mr. Bennet's poor decision making had indeed hurt Elizabeth and impacted her opinion of her family, but by respecting his abilities(Pg.209), and being grateful for his affectionate treatment of herself(Pg.209), Elizabeth knew that her father was a man of good intentions. Besides the impression Mr. Bennet's faults had on Elizabeth, her mother's faults as well, contributed much to Elizabeth's poor opinion. Mrs. Bennet had not made marriage between her and Mr. Bennet any easier as her ignorance and folly had contributed to his amusement(Pg.3). She was a woman of mean understanding, little information, and uncertain temper(Pg.3). Elizabeth found it difficult to deal with her mother's improper judgement and nervous behaviour. Mrs. Bennet often over exaggerated small incidents and was very demanding in her ways. As a mother of five daughters, it was acceptable for her to be concerned for her daughters' future. But Mrs. Bennet 's entire business of her life was to get her daughters married(Pg.3). Elizabeth loved her mother and was appreciative of her mother's concerns, but Elizabeth was also not blind to her mother's

The Cold War and U.S. Diplomacy Essay Example | Topics and Well Written Essays - 750 words - 6

The Cold War and U.S. Diplomacy - Essay Example This essay discusses that President Truman appointed General Marshal to administer the entire process and make sure the necessary steps are taken. In the wake of such build up, General Marshals were sent to Europe in early June 1947 to assess the actual ground situation and present report to Congress about the exact amount of funding needed.In the entire scheme of Marshal Plan an amount of 17 billion dollars was to be allocated to the different countries of Europe (Chandra, 27). This scheme lasted between 1947 to 1952. The overall analysis of the scheme reveals that this was one of the most effective and successful steps undertaken at that time and allowed for the containment of the Soviet Union. While the outer origin of the funding was economic and political assistance largely, the funding allowed to help these two countries getting enrolled into the league of the defense and security system that was introduced. The NATO entity that was established in 1949, Turkey and Greece both m ade into it in 1952 (Bà ¶là ¼kbasi, 799) and were enrolled as a result of the Truman Doctrine. This can be termed as the direct success of Truman Doctrine which paid dividends on the military front as well. Historians have termed it one of the first positive and successful moves placed by the United States of America in those days which not only enabled containment but also allowed for establishing United States of America’s influence in the region. This influence enabled U.S.A maintaining an edge over its arch-rival for the next four decades.