40 Questions
What hormone regulates red blood cell production?
Erythropoietin
What is the lifespan of erythrocytes?
About 120 days
What is the primary stimulus for increased erythropoiesis?
Hypoxia
What causes the bright red color of arterial blood?
High levels of oxyhaemoglobin
What type of cells have an important function in defense and immunity?
Leukocytes (white blood cells)
What do rising white cell numbers in the bloodstream usually indicate?
A physiological problem, e.g. infection, trauma or malignancy
What is the specialized role of eosinophils?
Elimination of parasites, such as worms
What are the toxic chemicals stored in eosinophils' granules used for?
Elimination of parasites
What is the main constituent of plasma?
Water
What is the main function of albumins in plasma?
Maintain normal plasma osmotic pressure
What is the main function of globulins in plasma?
Antibodies (immunoglobulins)
What is the most abundant clotting factor in blood?
Fibrinogen
Where are most blood cells synthesized?
Red bone marrow
What is the main function of erythrocytes?
Transport of gas, mainly oxygen
What is the average lifespan of erythrocytes in the circulation?
About 120 days
Where is haemopoiesis confined in adults?
Flat bones, irregular bones, and the ends of long bones
What are the components transported by blood?
oxygen, nutrients, hormones, heat, antibodies, cells of the immune system, clotting factors, wastes
What is the composition of blood in terms of plasma and cell fraction?
plasma constitutes 55% of the volume of blood, and the cell fraction 45%
How can blood cells and plasma be separated?
by centrifugation (spinning) or by simple gravity when blood is allowed to stand
What proportion of body weight does blood make up in a 70 kg man?
about 7%
How does the total blood volume in adults differ between males and females?
about 80 mL/kg body weight in males and 70 mL/kg in females
What role does continual blood flow play in maintaining a constant environment for body cells?
It maintains a fairly constant environment for body cells by keeping blood volume and the concentration of blood constituents within narrow limits.
How is heat produced from metabolically active organs distributed around the body?
Heat produced from metabolically active organs is distributed around the body by the bloodstream, maintaining core body temperature.
What method can be used to separate blood cells and plasma?
Centrifugation (spinning) or simple gravity when blood is allowed to stand
What is the main function of eosinophils in allergic inflammation?
Promoting tissue inflammation by releasing toxic chemicals
What substances are packed in the cytoplasmic granules of basophils?
Heparin (an anticoagulant), histamine (an inflammatory agent), and other substances that promote inflammation
What is the main difference between mast cells and basophils?
Mast cells are fixed in the tissues, while basophils are not
What is the main function of macrophages in the body?
Actively phagocytic and synthesizing/releasing an array of biologically active chemicals, including cytokines
Where do most lymphocytes develop from?
Pluripotent stem cells in red bone marrow and precursors in lymphoid tissue
What promotes blood clotting and causes haemostasis?
Substances contained in the granules of platelets
What is the lifespan of platelets in the circulation?
Between 8 and 11 days
What is the first step in the final common pathway of blood clotting?
Formation of prothrombin activator
What is the role of thromboplastin in blood clotting?
Thromboplastin initiates coagulation by activating the extrinsic pathway.
Which factors does Vitamin K help synthesize in the blood clotting process?
Vitamin K helps synthesize factors II, VII, IX, and X.
What is the first stage in the breakdown of a blood clot?
Fibrinolysis, which involves the breakdown of fibrin.
How does the intrinsic pathway of blood clotting get triggered?
The intrinsic pathway is triggered when blood comes into contact with damaged blood vessel lining (endothelium).
What is the role of plasmin in the breakdown of a blood clot?
Plasmin breaks down fibrin, progressively removing the clot to allow tissue repair to proceed.
What are the control and braking mechanisms in blood clotting?
Control and braking mechanisms include the smoothness of normal blood vessel lining, deactivation of activated clotting factors by anticoagulants, and clearance of activated clotting factors by the liver.
What is the function of heparin and antithrombin III in blood clotting?
Heparin and antithrombin III deactivate activated clotting factors.
How does the extrinsic pathway of blood clotting get activated?
The extrinsic pathway is activated rapidly (within seconds) following tissue damage, when thromboplastin or tissue factor is released from damaged tissue.
This quiz covers the process of erythrocyte development from stem cells, known as erythropoiesis. It includes the transformation of immature cells into reticulocytes and their maturation into erythrocytes within the bloodstream, during which they lose their nucleus.
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