Page 6 - Headlines Histology2024_Neat

• The engulfed material is surrounded first by cytoplasmic extensions called
pseudopodia.

• When the particles become completely surrounded, the plasma membrane
fuses and the membrane surrounding the engulfed particles forms a vesicle,
known as a phagosome or endocytotic vesicle, which detaches from the
cell membrane to float freely within the cytoplasm.

• Once the phagosome enters the cytoplasm it fuses with the lysosomes and
their contents are subjected to enzymatic digestion.

Exocytosis
• Exocytosis (Exo = out) is the process by which some membranous vesicles

located within the cytoplasm fuse with the plasma membrane and release
their contents outside the cell. It occurs in many secretory processes.
Functions of the cell coat (Glycocalyx)
• Mechanical and chemical protection the cell membrane.
• Aids in the induction of immunological (antigen-antibody) response.
• Site for binding of hormones.
• Shares in the formation of intercellular adhesions.
• Contributes to the formation of the basement membrane.
• Cell recognition.
Other functions of the cell membrane include
• Transmission of nerve impulses in muscle and nerve cells.
• Myelin sheath formation (Schwann cell around peripheral nerves).
• Share in the formation of microvilli, cilia, flagella and cell junctions.

Mitochondria

• Mitochondria are membranous organelles involved primarily in cell
respiration and energy production.

• With LM, they appear as granules, rod-like or thread-like.
• Their size rage from 5-10 ?m length and 0.5-1 ?m in diameter.

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