Module 13: Blood and Blood Vessels Flashcards
Granulocytes
Neutrophils
Eosinophils
Basophils
Agranulocytes
Lymphocytes
Monocytes
Neutrophils
Engulf foreign material
Eosinophils
Combat allergies
Basophils
Assist blood clotting
Lymphocytes
Produce antibodies
Monocytes
Engulf large particles
Platelets (thrombocytes)
Fragments of large bone marrow cells called megakaryocytes
Sticky and clump together forming plugs that close torn blood vessels
Lifespan is about 7 days
Clot formation processes
Vasoconstriction
Platelet plug formation
Coagulation
Platelet plug formation
Platelets are attracted by the collagen in the exposed connective tissue
Platelets adhere to the connective tissue and to each other (platelet plug)
Coagulation
If an injury is more severe and a more stable clot is required
Coagulation factors are activated
In the presence of calcium ions, prothrombin is converted to thrombin
Thrombin then converts fibrinogen into fibrin
Fibrin threads then form a mesh that adheres to the damaged tissue and traps blood cells and platelets to form the clot
Fibrinolysis
After healing has taken place, the clot is dissolved by specific enzymes that digest fibrin strands and inactivating some of the coagulation factors
Vitamin K
Stimulates liver cells to increase the synthesis of prothrombin and other clotting factors
Polycythemia
Abnormally high percentage of RBCs
Thrombopoetin
Hormone produced by the liver
Stimulates platelet formation
Transferrin
Fe3+ transporter
Arteries
Transport blood AWAY from the heart
Walls are thicker than the walls of veins
Three layers (tunics)
Arterioles
Small arteries
Regulate blood flow from arteries to capillaries
Three layers (tunics)
Veins
Transport blood TOWARDS the heart
Three layers (tunics)
Because of low blood pressure in veins located inferior to the heart, veins have valves to prevent backflow of blood
Venules
Small veins Gather blood from capillaries and deliver it to veins Three layers (tunics) except where they are located close to the capillaries; this is where they have only two layers
Capillaries
Microscopic and the smallest of blood vessels
Sites for exchange of gases, nutrients, and wastes products
throughout the body
No layers – only one cell thick (epithelial)
Arterial capillaries contain oxygenated blood
Venous capillaries contain deoxygenated blood
Hemophilia
Inability to clot blood
Three types of capillaries
Continuous
Fenestrated
Sinusoid
Portal vein
Transports blood from one capillary network to another