22 Questions
Which pathway is activated by tissue factor during blood coagulation?
Extrinsic pathway
What is the result of clot retraction in the coagulation process?
Pulling the edges of the injured vessel together
What is the normal platelet count range in a healthy individual?
150,000/uL
What is the term for pinpoint hemorrhages on the skin?
Petechiae
What is the primary function of plasmin in the coagulation process?
Dissolution of the clot
What is the term for abnormally shaped red blood cells that occur in sickle cell disease?
Sickle cells
What is the primary cause of thrombocytopenia?
Impaired platelet production and increased destruction
What is the term for the bleeding disorder characterized by a decrease in platelet count or function?
Thrombocytopenia
What is the primary cause of iron deficiency anemia in adults?
Chronic blood loss
Which of the following is NOT a cause of anemia?
Increased erythropoiesis
What is the primary cause of iron deficiency anemia in children?
Increased iron demand due to growth
What is the name of the craving disorder associated with iron deficiency anemia?
PICA
Which of the following is a laboratory diagnostic for anemia?
Decreased MCV
What is the term for the destruction of red blood cells?
Hemolysis
What is the term for the increased production of red blood cells in response to anemia?
Erythropoiesis
What is the age range when iron requirements are highest?
3-24 months
What is the primary function of hemostasis?
To stop the flow of blood
What is the primary role of vascular smooth muscle contraction in hemostasis?
To cause vasoconstriction
What is the function of von Willebrand factor in hemostasis?
To bind to platelet receptors and cause adhesion to collagen fibers
What is the result of platelet adhesion to collagen fibers?
Platelet activation and release of ADP and TXA2
What is the role of TXA2 in hemostasis?
To promote platelet aggregation
What is the sequence of events in hemostasis?
Vessel vasoconstriction, formation of the platelet plug, and then clotting
Study Notes
Hemostasis and Blood Clotting
- Hemostasis is the stoppage of blood flow, consisting of three stages
- Stage 1: Vessel vasoconstriction, where vascular smooth muscle contraction occurs and local nervous reflexes and humoral factors (TXA2) are released from platelets
- Stage 2: Formation of the platelet plug, where vWF is released from the endothelium, binds to platelet receptors, and causes adhesion of platelets to exposed collagen fibers
- Stage 3: Development of a blood clot as a result of the coagulation process, involving two coagulation pathways: intrinsic and extrinsic
- Clot retraction pulls the edges of the injured vessel together
- Clot dissolution/lysis allows blood flow to be reestablished and tissue healing to take place
Bleeding Disorders: Platelet Disorders
- Disorders result from a decrease in the number of platelets due to decreased production, increased destruction, or impaired function
- Spontaneous bleeding often involves small vessels of mucous membranes and skin (mouth, nose, GI tract, uterine cavity)
- Cutaneous bleeding includes pinpoint hemorrhages (petechiae) and bruising (purpura)
- Petechiae indicates platelet deficiency, not dysfunction
- Thrombocytopenia is characterized by reduced platelets (< 150,000/μL), commonly caused by folic acid and vitamin B12 deficiencies
- Sickle cell disease is characterized by abnormally shaped RBCs that increase red cell adhesiveness and adherence to vessel walls, leading to hemolysis, occlusion, and ischemia
Anemia: Anemias of Deficient Red Cell Production
- Iron deficiency anemia (IDA) can be caused by four factors: loss of RBCs from bleeding, destruction of RBCs, defective RBC production, or inadequate RBC production
- IDA in adults is commonly caused by chronic blood loss, GI bleeds, or iron deficiency during childbearing age
- IDA in children is commonly caused by increased iron demand due to growth and low iron levels at birth
- Anemia manifestations include fatigue, irritability, PICA, dyspnea, tachycardia, angina, and palpitations
- Diagnosis of anemia involves decreased MCHC and MCV
Nonneoplastic Disorders of White Blood Cells: Infectious Mononucleosis
- Clinical course, most common complications, and laboratory diagnostics are key aspects of infectious mononucleosis
Learn about the three stages of hemostasis, including vessel vasoconstriction, platelet plug formation, and blood clot development. Understand the role of vWF, platelets, and collagen fibers in the process.
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