A macrophage in SEM. The cell is characterized by many spiny filopodial
processes. Numerous blebs are present.

Macrophages with long extending pseudopodial processes on a latex bead.

A monocyte – a precursor cell of macrophage. The cell contains a
variable number of lysosomes in its cytoplasm.

A macrophage. The nucleus is pushed to one side. The cytoplasm contains
large phagosomes.

Plasma cells. The oval nucleus bears coarse chromatin clumps at its
periphery. Identify the dilated cisternae of rER. A small Golgi
apparatus(g) is near to the nucleus.

Collagen fibrils in different planes of section.

Collagen fibrils in longitudinal section. Note the cross striations on
each of the fibrils. Name two cell types that synthesize collagen.

A fibrocyte(fibroblast). Identify its organelles: nucleus rER and Golgi
apparatus.

A fibrocyte(fibroblast). The spindle-shaped cell has an oval nucleus.

Numerous collagen fibrils are closely associated with the cell.

Mast
cell

Mast cell. The cytoplasm is loaded with numerous membrane bound dense
granules. At the surface, a few filopodial processes are present. Name
two chemical substances produced by mast cells.

Examine the capsule(surface covering of the organ. How do you describe
its texture? Dense or loose? Extending from the capsule into the node
are some fibrous projections(trabeculae) bearing the same texture.
Ignore the rest of the tissue.

Examine the cord at low power and note that there are three vessels in
cross-section.(Ignore their detail structure). Study the connective
tissue in between the vessels. It is characterized by the presence of
large amounts of ground substance which gives it a jellylike
quality(Wharton’s jelly). The cells are widely scattered. The cytoplasm
of the cells cannot always be distinguished from the intercellular
fibrous material and precipitated mucoid mateerial.

Adipocytes(fat cells) are separated into lobules by septa composed of
dense connective tissue. In the septa may be found nerve bundles and
blood vessels. Can you recognize the fibrocytes in the septa?

Select an area which is better stained. Elastic fibres are stained
black. In the background are some lightly stained nuclei of the
connective tissue cells. Collagen fibres are stained pink.

Gordon and Sweet method for reticular fibres. Massive darkly stained
reticular fibres are seen between liver cells.

Gordon and Sweet netgrid fir reticular fibres. The stroma of the spleen
consists of a delicate irregular network of reticular fibres(black).
Entangled in the network(dense dots) are lymphoid and reticular
cells.(Move your fine adjustment to focus at different depths to
appreciate this). The trabeculae extending from the capsule show bundles
of collagen fibres(dark brown).

Return your objective to X10 and move your field down to the
subcutaneous layer containing a variable amount of fat(adipose) tissue
and sweat glands. The adipocytes(fat cells) appear empty-looking as
their contents had been washed out during slide preparation. Under X40,
note that the nuclei of the cells are pushed to the periphery of the
cells. Other structures in the dermis include the sweat glands and
Pacinian corpuscles.

A nerve cell containing clumps of inclusions (black deposits).

Nerve cell

Cilia

Endocrine cell

A neuroglia (astrocyte). The cytoplasm contains bundles of microfilaments (Mf). Other organelles present are marked N, for nucleus and Ax, for myelinated axons.

Neuroglia

Portion of a hepatocyte. Identify mitochondria (1), smooth endoplasmic reticulum (2), rER (3), and Golgi apparatus (4). Give one specific function of each of the organelles identified.

Answer

Hepatocyte

An electron micrograph showing a well-developed Golgi complex.

Golgi complex

Portion of a hepatocyte showing extensive smooth endoplasmic reticulum (sER) with associated glycogen granules (dark particles).
Within the mitochondria are numerous identifiable cristae.

Hepatocyte

A portion of a nerve cell containing massive polyribosomes and numerous cisternae of rough endoplasmic reticulum (rER).

What is their main function? Answer

The abundance of rER gives a basophilia to its cytoplasm in light microscopy.

Nerve cell

Lysosomes in a Kupffer cell. N indicates the nucleus of the cell.

Name two enzymes that may be present in lysosomes.

Answer

Kupffer cell