What functions does blood perform in transport, defense, and coagulation?
It transports oxygen, nutrients, carbon dioxide, and metabolic waste, and supports immune defense and coagulation.
What body temperature does blood help regulate?
Around 37°C.
What pH range does blood buffer?
7.35–7.45.
What proportions of blood are cells and plasma?
Blood is 40–45% cells and 55–60% plasma.
What does hematocrit measure, and what are its average values in men and women?
It measures the blood-cell volume fraction; averages are 46% in men and 42% in women.
What are the approximate proportions of water, proteins, and other substances in plasma?
About 90% water, 8% proteins, and 2% other substances.
Which substances are included among plasma’s other components?
Ions, glucose, vitamins, hormones, enzymes, urea, uric acid, and creatinine.
What roles do plasma proteins perform in blood?
They maintain colloid osmotic pressure, transport substances, buffer pH, support coagulation and defense, and serve as a protein reserve.
Where does hematopoiesis occur in healthy people, and what drives precursor-cell production?
It occurs mainly in bone marrow under the influence of growth factors.
Which blood cells arise from a lymphoid stem cell?
T cells, B cells, and natural killer cells.
Which blood cells arise from a myeloid stem cell?
Granulocytes, monocytes, erythrocytes, and platelets.
What shape and approximate diameter characterize erythrocytes?
They are biconcave cells about 7.5 μm in diameter.
What does hemoglobin consist of?
Four polypeptide chains and iron-containing heme groups.
What triggers erythropoietin release from the kidney?
Oxygen deficiency.
What is the approximate total leukocyte count per microliter?
About 5,000 per μl.
What percentage of leukocytes are neutrophils?
50–70%.
How long can neutrophils circulate at most?
10 hours.
What do monocytes become after entering tissues?
Macrophages.
What is the approximate size range of monocytes?
12–20 μm.
Which lymphocytes form specific antibodies?
B lymphocytes.
How do platelets form, and where do they originate?
They form by cytoplasm shedding from megakaryocytes in bone marrow.
Where are platelets broken down, and after how long?
In the spleen and liver after one to two days.
What is the approximate number of platelets?
About 200,000.
What sequence forms a white thrombus during primary hemostasis?
Vessel constriction, platelet adhesion, and platelet aggregation.
What initiates the coagulation cascade in secondary hemostasis?
Mutual activation of coagulation factors.
What does the coagulation cascade cleave fibrinogen into?
Fibrin.
What forms a red thrombus during secondary hemostasis?
A firm fibrin mesh containing platelets and erythrocytes.
At what temperature and for how long are erythrocyte concentrates stored?
At 4°C for 42 days.
What condition are erythrocyte concentrates used to treat?
Anemia.
At what temperature and for how long are platelet concentrates stored?
At 20–24°C for five days.
What condition are platelet concentrates used to treat?
Bleeding tendencies caused by thrombocytopenia.
At what temperature and for how long is fresh frozen plasma stored?
At −30 to −40°C for two years.
What does fresh frozen plasma replace?
Proteins and coagulation factors.
What are ABO antigens on erythrocytes?
Surface structure variants that may be recognized as foreign in another person's blood.
What do antibodies do against antigens?
They can defend against them.
Which antibodies react with ABO erythrocyte surface structures?
IgM antibodies.
What can ABO reactions between erythrocyte structures and IgM antibodies cause?
Agglutination, or cell clumping.
Which antigen distinguishes rhesus-positive from rhesus-negative erythrocytes?
Rhesus-positive erythrocytes have the D antigen; rhesus-negative erythrocytes lack it.
When can a rhesus-negative person develop anti-D antibodies?
After direct contact with D-positive blood.
How can a rhesus-negative mother form anti-D antibodies after childbirth?
Contact with a rhesus-positive child's erythrocytes may cause her to form IgG anti-D antibodies.
What three functions does the lymphatic system perform?
Drainage, immune defense, and fat transport.
Which organs are primary lymphatic organs?
Bone marrow and thymus.
Which organs are secondary lymphatic organs?
The spleen, lymph nodes, and MALT.
How does lymph travel from lymph capillaries toward the thoracic duct?
Through lymph vessels and nodes, large lymphatic vessels, and the cisterna chyli.
Which lymphocyte type predominates in lymph node cortex follicles?
B cells.
Which lymphocyte type predominates in the lymph node region between cortex and medulla?
T cells.
Where is the thymus, and what maturation process does it support?
It lies in the anterior mediastinum above the pericardium and supports T-lymphocyte maturation and selection.
What do the thymic cortex and medulla contain?
The cortex contains T cells and precursors, while the medulla contains few lymphocytes.
Which thymocytes continue developing during positive selection?
Those recognizing self MHC with low affinity.
What happens to thymocytes that strongly bind self-antigen–MHC complexes?
They undergo apoptosis through negative selection in the medulla.
What usually happens to strongly autoreactive B cells in bone marrow?
They undergo apoptosis through clonal deletion.
What permits B cells to continue maturing during bone-marrow selection?
Weak B-cell receptor binding to self-antigens presented by stromal cells.
What cells does bone marrow form from a pluripotent stem cell?
All immunocompetent cells.
Which structures and components are found in bacterial cells?
Cell membranes, cell walls, flagella, 70S ribosomes, nucleoids, plasmids, and cytosol.
Which factors contribute to bacterial pathogenicity?
Capsules, pili, enzymes, and toxins.
Which three criteria are used to classify bacteria?
Form, staining, and oxygen relationship.
What are the three bacterial forms?
Cocci, rods, and spirals.
Which staining categories distinguish bacteria?
Gram-positive and Gram-negative.
How are bacteria classified by oxygen relationship?
As aerobic or anaerobic.
Which cell expels its nucleus during erythropoiesis?
The normoblast.
How is iron released from heme transported back to bone marrow?
By transferrin.
What is the main defense role of eosinophils?
They defend against parasites, especially worms.
What do basophil granules contain that contributes to immediate allergic reactions?
Histamine.
What do endothelial-cell von Willebrand factor and platelet aggregation support?
Platelet adhesion at the vessel wall, followed by aggregation.
How does anti-D prophylaxis prevent maternal antibody formation?
Passively administered IgG anti-D hemolyzes fetal erythrocytes entering the mother’s circulation.
What proportion of fluid filtered from blood capillaries becomes lymph?
About 10%.
Where is the spleen located?
In the left upper abdomen beneath the diaphragm.
Why do primary lymphatic organs test developing lymphocytes against self-antigens?
To remove or restrain autoreactive cells and establish immune tolerance.
Answer 33 questions on Blood and Lymphatic System.
1. A person's blood helps maintain a stable internal environment; which set of functions best describes how it does so?
2. A laboratory measures the volume fraction of blood cells in a blood sample; what is this measurement called?
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