Vitamin K and Blood Clotting Flashcards
(30 cards)
What is the primary role of vitamin K in blood clotting?
Vitamin K is essential for the carboxylation of certain glutamate residues in proteins to form gamma-carboxyglutamate, which is necessary for blood clotting.
Which clotting factors require vitamin K for their synthesis?
Factors II (prothrombin), VII, IX, and X.
How does vitamin K facilitate the activation of clotting factors?
Vitamin K acts as a cofactor for the enzyme gamma-glutamyl carboxylase, which carboxylates glutamate residues on clotting factors.
What is the dietary form of vitamin K called?
Phylloquinone (vitamin K1).
Which form of vitamin K is synthesized by gut bacteria?
Menaquinone (vitamin K2).
Name the enzyme that vitamin K acts as a cofactor for in the clotting process.
Gamma-glutamyl carboxylase.
What is the function of gamma-carboxyglutamate residues in clotting factors?
Gamma-carboxyglutamate residues allow clotting factors to bind calcium, which is essential for their activation.
How does warfarin interfere with vitamin K activity?
Warfarin inhibits vitamin K epoxide reductase, preventing the recycling of vitamin K.
What is the consequence of vitamin K deficiency on clotting?
Increased bleeding and bruising due to impaired clotting factor synthesis.
Which population groups are at higher risk of vitamin K deficiency?
Newborns, people with malabsorption disorders, and those on long-term antibiotics.
Name a common test used to assess vitamin K status.
Prothrombin time (PT) test.
How is vitamin K absorbed in the body?
Vitamin K is absorbed in the small intestine along with dietary fats.
Which organ is primarily responsible for storing vitamin K?
The liver.
What role does vitamin K play in the activation of protein C and protein S?
Vitamin K is required for the gamma-carboxylation and activation of protein C and protein S, which are anticoagulants.
How does chronic antibiotic use affect vitamin K levels?
It can reduce gut bacteria that synthesize vitamin K2, leading to lower levels.
What is the relationship between vitamin K and osteocalcin?
Vitamin K is necessary for the carboxylation of osteocalcin, a protein involved in bone metabolism.
Which fat-soluble vitamin works closely with vitamin K in bone metabolism?
Vitamin D.
What are the two main forms of vitamin K found in supplements?
Phylloquinone (K1) and menaquinone (K2).
Name a medical condition that might require vitamin K supplementation.
Hemorrhagic disease of the newborn.
How does liver disease affect vitamin K metabolism?
Liver disease can impair the storage and metabolism of vitamin K, leading to deficiency.
What is the role of vitamin K in the synthesis of prothrombin?
Vitamin K is required for the carboxylation of prothrombin, converting it into its active form.
Which type of diet might lead to reduced vitamin K intake?
Diets low in leafy green vegetables.
What is the recommended daily allowance (RDA) of vitamin K for adults?
90-120 micrograms per day for adults.
How does vitamin K contribute to the regulation of calcium in the body?
Vitamin K-dependent proteins help regulate calcium deposition in bones and prevent arterial calcification.
