Answers to Review Questions - Chapter 49
1. What are the functions of red blood cells (erythrocytes)? Of white blood cells (leukocytes)? Of platelets (thrombocytes)?
Red blood cells are involved in gas transport (oxygen, carbon dioxide). White blood cells play a role in the body's immune defenses. Platelets are involved in blood clotting.
2. What are the three types of granular leukocytes? Describe the characteristics and one significant function of each.
Neutrophils have granules that appear neutral when stained. They are the principal phagocytic cells in the blood.
Eosinophils have granules that stain bright red. They function in detoxifying foreign proteins and other substances - involved in allergic reactions and parasitic infections. (any one of those functions…)
Basophils have deep blue granules when stained. They play a role in allergic reactions - release histamine in injured tissues and in allergic responses. Also can produce heparin to prevent blood from clotting. (any one of those functions…)
3. What are the two types of agranular leukocytes? Describe the characteristics and one significant function of each.
Lymphocytes do not have granules - have round nuclei. Produce antibodies, destroy foreign cells. (any one of those functions…)
Monocytes are the largest WBC - leaves the circulation to become a macrophage. Major function is phagocytosis of foreign cells/materials.
4. What prevents backflow of blood through the atrioventricular valves?
The leaflets of the valves are anchored to the floor of the ventricles via string-like structures called chordae tendineae.
5. What prevents backflow of blood through the semilunar valves?
The cup-shaped cusps of the semilunar valves collect with blood as it begins to be pulled back toward the ventricle - this causes the cusps to snap tightly together.
6. What is the sequence of inhaled airflow through the respiratory structures in a mammal?
Inhaled air flows from the nostrils into the nasal cavities and then through the pharynx, larynx, trachea, bronchi, bronchioles, and finally into the alveoli.
7. Describe the role of hemoglobin in oxygen and carbon dioxide transport.
Hemoglobin combines with oxygen and greatly increase the capacity of blood to transport it. Oxygen binds to the iron in hemoglobin, forming oxyhemogloblin, and it is in this form that oxygen is transported in the blood. Carbon dioxide in the blood can also be carried by hemoglobin - about 23% of CO2 is carried bound to the non-heme (non-iron) portions of hemoglobin molecules (bound to the amino acid side chains).