Chapter Summary
I. CIRCULATING BLOOD*
A. Erythrocytes (RBC)
RBCs are pink, biconcave discs that are 7 to 8 μm in diameter.They are filled with hemoglobin and possess no nuclei.
B. Agranulocytes
1. Lymphocytes
Histologically, lymphocytes may be small, medium, or large (this bears no relationship to T cells, B cells, or null cells). Most lymphocytes are small (8 to10 μm in diameter) and possess a dense, blue, acentrically positioned nucleus that occupies most of the cell, leaving a thin rim of light blue, peripheral cytoplasm. Azurophilic granules (lysosomes) may be evident in the cytoplasm.
2. Monocytes
Monocytes are the largest of all circulating blood cells (12 to 15 μm in diameter).There is a considerable amount of grayish-blue cytoplasm containing numerous azurophilic granules. The nucleus is acentric and kidney-shaped and possesses a coarse chromatin network with clear spaces. Lobes of the nucleus are superimposed on themselves, and their outlines appear to be distinctly demarcated.
C. Granulocytes
1. Neutrophils, the most populous of the leukocytes, are 9 to 12 μm in diameter and display a light pink cytoplasm housing many azurophilic and smaller specific granules. The specific granules do not stain well, hence, the name of these cells. The nucleus is dark blue, coarse, and multilobed, with most being two to three lobed with thin connecting strands.
2. Eosinophils are 10 to 14 μm in diameter and possess numerous refractive, spherical, large, reddish-orange specific granules. Azurophilic granules are also present. The nucleus, which is brownish-black, is bilobed, resembling sausage links united by a thin connecting strand.
3.Basophils, the least numerous of all leukocytes, are 8 to 10 μm in diameter. Frequently, their cytoplasm is so filled with dark, large, basophilic specific granules that they appear to press against the cell membrane, giving it an angular appearance. The specific granules
*All of the colors designated in this summary are based on the Wright’s or Giemsa’s modification of the Romanovsky-type stains as applied to blood smears.
usually mask the azurophilic granules, as well as the S-shaped, light blue nucleus.
D. Platelets
Platelets, occasionally called thrombocytes, are small, round (2 to 4 μm in diameter) cell fragments. As such, they possess no nuclei, are frequently clumped together, and present with a dark blue, central granular region, the granulomere, and a light blue, peripheral, clear region, the hyalomere.
II. HEMOPOIESIS*
During the maturation process, hemopoietic cells undergo clearly evident morphologic alterations. As the cells become more mature, they decrease in size. Their nuclei also become smaller, the chromatin network appears coarser, and their nucleoli (which resemble pale grayish spaces) disappear. The granulocytes first acquire azurophilic, and then specific granules and their nuclei become segmented. Cells of the erythrocytic series never display granules and eventually lose their nuclei.
A. Erythrocytic Series
1. Proerythroblast
a. Cytoplasm
Light blue to deep blue clumps in a pale grayish-blue background.
b. Nucleus
Round with a fine chromatin network; it is a rich burgundy red with 3 to 5 pale gray nucleoli.
2. Basophilic Erythroblast
a. Cytoplasm
Bluish clumps in a pale blue cytoplasm with a hint of grayish pink in the background.
b. Nucleus
Round, somewhat coarser than the previous stage; burgundy red. A nucleolus may be present.
3. Polychromatophilic Erythroblast
a. Cytoplasm
Yellowish pink with bluish tinge.
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b. Nucleus
Small and round with a condensed, coarse chromatin network; dark, reddish black. No nucleoli are present.
4. Orthochromatophilic Erythroblast
a. Cytoplasm
Pinkish with a slight tinge of blue.
b. Nucleus
Dark, condensed, round structure that may be in the process of being extruded from the cell.
5. Reticulocyte
a. Cytoplasm
Appears just like a normal, circulating RBC; if stained with supravital dyes (e.g., methylene blue), however, a bluish reticulum—composed mostly of rough endoplasmic reticulum—is evident.
b. Nucleus
Not present.
B. Granulocytic Series
The first two stages of the granulocytic series, the myeloblast and promyelocyte, possess no specific granules. These make their appearance in the myelocyte stage, when the three types of myelocytes (neutrophilic, eosinophilic, and basophilic) may be distinguished. Since they only differ from each other in their specific granules, only the neutrophilic series is described in this summary, with the understanding that myelocytes, metamyelocytes, and stab (band) cells occur in these three varieties.
1. Myeloblast
a. Cytoplasm
Small blue clumps in a light blue background. No granules. Cytoplasmic blebs extend along the periphery of the cell.
b. Nucleus
Reddish-blue, round nucleus with fine chromatin network. Two or three pale gray nucleoli are evident.
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2. Promyelocyte
a. Cytoplasm
The cytoplasm is bluish and displays numerous, small, dark, azurophilic granules.
b. Nucleus
Reddish-blue, round nucleus whose chromatin strands appear more coarse than in the previous stage. A nucleolus is usually present.
3. Neutrophilic Myelocyte
a. Cytoplasm
Pale blue cytoplasm containing dark azurophilic and smaller neutrophilic (specific) granules. A clear, paranuclear Golgi region is evident.
b. Nucleus
Round, usually somewhat flattened, acentric nucleus, with a somewhat coarse chromatin network. Nucleoli are not distinct.
4. Neutrophilic Metamyelocyte
a. Cytoplasm
Similar to the previous stage except that the cytoplasm is paler in color and the Golgi area is nestled in the indentation of the nucleus.
b. Nucleus
Kidney-shaped, acentric nucleus with a dense, dark chromatin network. Nucleoli are not present.
5. Neutrophilic Stab (Band) Cell
a. Cytoplasm
A little more blue than the cytoplasm of a mature neutrophil. Both azurophilic and neutrophilic (specific) granules are present.
b. Nucleus
The nucleus is horseshoe-shaped and dark blue, with a very coarse chromatin network. Nucleoli are not present.
6 MUSCLE
CHAPTER OUTLINE
Graphics
Graphic 6-1 Molecular Structure of Skeletal Muscle
p. 132
Graphic 6-2 Types of Muscle p. 133
Tables
Table 6-1 Comparison of Skeletal, Smooth, and
Cardiac Muscles
Table 6-2 Characteristics of Muscle Fibers
Plates
Plate 6-1 |
Skeletal Muscle p. 134 |
Fig. 1 |
Skeletal muscle l.s. |
Fig. 2 |
Skeletal muscle x.s. |
Fig. 3 |
Skeletal muscle x.s. |
Plate 6-2 |
Skeletal Muscle Electron Microscopy |
|
(EM) p. 136 |
Fig. 1 |
Skeletal muscle (EM) l.s. |
Fig. 2 |
Skeletal muscle (EM) l.s. |
Plate 6-3 |
Myoneural Junction, Light and Electron |
|
Microscopy (EM) p. 138 |
Fig. 1 |
Myoneural junction. Lateral view |
Fig. 2 |
Myoneural junction. Surface view |
Fig. 3 |
Myoneural junction (EM) |
Plate 6-4 |
Myoneural Junction, Scanning Electron |
|
Microscopy (SEM) p. 140 |
Fig. 1 |
Myoneural junction. Tongue (SEM) |
Plate 6-5 |
Muscle Spindle, Light and Electron |
|
Microscopy (EM) p. 141 |
Fig. 1 |
Muscle spindle |
Fig. 2 |
Muscle spindle (EM) |
Plate 6-6 |
Smooth Muscle p. 142 |
Fig. 1 |
Smooth muscle l.s. |
Fig. 2 |
Smooth muscle l.s. |
Fig. 3 |
Smooth muscle. Uterine myometrium x.s. |
Fig. 4a |
Smooth muscle x.s. |
Fig. 4b |
Smooth muscle. Duodenum |
Plate 6-7 |
Smooth Muscle, Electron Microscopy |
|
(EM) p. 144 |
Fig. 1 |
Smooth muscle (EM) l.s. |
Plate 6-8 |
Cardiac Muscle p. 146 |
Fig. 1 |
Cardiac muscle. Human l.s. |
Fig. 2 |
Cardiac muscle. Human l.s. |
Fig. 3 |
Cardiac muscle. Human x.s. |
Fig. 4 |
Cardiac muscle. Human x.s. |
Plate 6-9 |
Cardiac Muscle, Electron Microscopy |
|
(EM) p. 148 |
Fig. 1 |
Cardiac muscle (EM) l.s. |
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