Patho17(hemodynamics file16+17) Flashcards
(42 cards)
What is hemorrhage?
Extravasation of blood from vessels
What are the causes of hemorrhage?
Damage to blood vessels or defective clot formation, trauma, atherosclerosis, inflammatory or neoplastic erosion of a vessel wall, hemorrhagic diatheses
Define hemorrhagic diatheses.
Diverse causes, including inherited or acquired defects in vessel walls, platelets, or coagulation factors
What can hemorrhage result in? It can be location
External bleeding or accumulation of blood within a tissue as a hematoma
The hematoma ranges in importance/significance?
from trivial (e.g., a bruise) to fatal (e.g., a massive retroperitoneal hematoma resulting from rupture of a dissecting aortic aneurysm).
Names of large bleeds into body cavities in plural cavity, pericardial cavity, peritoneal cavity, joints
hemothorax, hemopericardium, hemoperitoneum, or hemarthrosis.
What can extensive hemorrhages occasionally result in?
Jaundice from massive breakdown of red cells and hemoglobin/mainly in newborns
Describe each picture related to hemorrhage
Hematoma strong/large bleed in joint cavity/hematoma fetal in brain / hematoma trivial
What is the clinical significance of a hemorrhage depend on with explain ?
the volume of blood lost and the rate of bleeding /site of hemorrhage
* Rapid loss of up to 20% of the blood volume, or slow losses of even larger amounts, may have little impact in healthy adults; greater losses, however, can cause hemorrhagic (hypovolemic) shock.
The site of hemorrhage also is important; bleeding that would be trivial in the subcutaneous tissues can cause death if located in the brain.
What is the consequence of chronic or recurrent external blood loss? And in which condition it happens?
iron deficiency anemia as a consequence of a loss of iron in hemoglobin./ due to peptic ulcer, menstrual bleeding
What are petechiae?
Minute hemorrhages (1 to 2 mm) into skin, mucous membranes, or serosal surfaces
What are some causes of petechiae?
Low platelet counts (thrombocytopenia), defective platelet function, loss of vascular wall support (as in vitamin C deficiency)
Define purpura.
Slightly larger (3 to 5 mm) hemorrhages, same disorders that cause petechiae, trauma, vascular inflammation (vasculitis), increased vascular fragility
What are ecchymoses?
Larger (1 to 2 cm) subcutaneous hematomas /causes mainly trauma and platelet not involved just coagulation cascade
What causes the characteristic color changes of a bruise ( ecchymoses)?
Extravasated red cells are phagocytosed and degraded by macrophages;
Enzymatic conversion of hemoglobin (red-blue color) to bilirubin (blue-green color) and eventually hemosiderin (golden-brown)
What is the definition of normal hemostasis?
a series of regulated processes that culminate in the formation of a blood clot that limits bleeding from an injured vessel.
What is the pathologic counterpart of hemostasis?
thrombosis, the formation of a blood clot within non-traumatized, intact vessels.
What occurs immediately after an injury to reduce blood flow?
Arteriolar vasoconstriction
What mediates arteriolar vasoconstriction?
reflex neurogenic mechanisms and augmented by the local secretion of factors such as endothelin.
What are the main components of normal hemostasis ?
platelets, clotting factors, and endothelium.
What is the transient response in normal hemostasis?
Arteriolar vasoconstriction
What is the main mediator cause vasoconstriction?
endothelin (potent endothelium-derived vasoconstrictor)
What is primary hemostasis?
Formation of the platelet plug
What happenes during the primary hemostasis(steps)?
- Platelet adhesion: interactions with subendotheial VWF, which acts as a bridge between the platelet surface receptor glycoprotein Ib (Gplb) and exposed collagen.
- platelet activation:(Thrombin activates platelets through a special type of G-protein-coupled receptor referred to as a protease-activated receptor (PAR) and by collagen and ADP.Shape change (from small rounded discs to flat plates with spiky protrusions “sea urchins” that markedly increased surface area, and the release of secretory granules.
*Recruit additional platelets»»(aggregation)to form a primary hemostatic plug.
