بسم الله الرحمن الرحيم
INTRODUCTION TO HISTOLOGY
HISTOLOGY (MICROSCOPIC ANATOMY) Definition.
Light Microscope (L/M) 1- Illumination. 2- Magnification. 3- Resolution. N.B. Resolving power ( It is the least distance between 2 particles at which they will appear separated). R.P. for L/M is 250 nm
Light microscope
STAINING FOR L/M Staining with Hematoxylin and Eosin (H&E) or (Hx&E): Basophilic structures. Acidophilic structures.
(B) Electron microscopy: 1-Transmission E/M: Resolving power 0.2 nm. * Electron-dense structure **Electron-lucent structure 2-Scanning E/M: Resolving power 10 nm.
Transmission Electron Microscope
Scanning Electron microscope
THE CELL
THE CELL NUCLEUS (INTERPHASE NUCLEUS)
Shape of nuclei
Dark Nucleus (Deeply-stained nucleus)
Vesicular (open face) Nucleus
L/M: Appearance (Type): - Light nucleus (vesicular) (open face) - Dark nucleus (deeply-stained) Number: 1, 2, or more. Position: Central, eccentric, peripheral, basal. CELL NUCLEUS (Interphase Nucleus)
Cell Nucleus L/M (cont.): Size: Small, medium, large ( Nucleus/cell ratio) Shape: e.g. Rounded, oval, rod-shaped.
Nucleus (E/M diagram) RER Hc
Nucleus (Electron Micrograph) PRACTICAL
Nuclear pores PRACTICAL
Cell Nucleus (Interphase nucleus) E/M: (1) Nuclear envelope Inner nuclear membrane. Outer " ". Nuclear pores. Nuclear pore complex. Perinuclear cisterna. Nuclear lamina. N.B. Rough Endoplasmic reticula (Relation with,).
(2) Chromatin: ( Classification ): According to Metabolic activity: a- Euchromatin(Extended chromatin) b- Heterochromatin( Condensed chrom. ) According to Position: a- Peripheral chromatin. b- Nucleolus-associated chromatin. c- Chromatin islands.
Nucleolus (E/M)
(3) Nucleolus: L/M: 1-5 basophilic bodies E/M: 1- Pale-staining fibrillar center. 2- Pars fibrosa: containing rRNA (nRNA) being transcribed.
Nucleolus (cont.): 3- Pars granulosa: maturing ribosomal subunits are assembled. 4- Nucleolar matrix. N.B. Nucleolus is a non-membranous structure. Function of nucleolus: rRNA synthesis.
NUCLEOPLASM 1- Nuclear matrix. 2- Ribonucleoprotein. 3- Interchromatin granules. 4- Perichromatin granules.
CYTOPLASM (1)Organelles. (2)Inclusions. (3)Cytosol.
Cytoplasmic organelles 1- Cell Membrane. 2- Ribosomes. 3- Endoplasmic Reticulum. 4- Golgi Apparatus. 5- Endosomes 6- Lysosomes. 7- Peroxisomes. 8- Mitochondria. 9- Cytoskeleton. 10-Centrioles. 11-Cilia & flagella. 12-Filaments (thin f., intermediate f., thick f.).
Cytoskeleton 1- Thin Filaments (actin filaments). 2- Intermediate Filaments. 3- Microtubules.
Specializations of cell membranes (1)Microvilli. (2)Cilia. (3)Intercellular junctions.
Cytoplasmic Inclusions 1- Glycogen. 2- Lipids. 3- Pigments: e.g. lipofuscin pigments, melanin. 4- Crystals. 5- (Secretory granules).
CELL MEMBRANE (PLASMALEMMA)
Cell Membrane (Plasmalemma)
CELL MEMBRANE & GLYCOCALYX
GLYCOCALYX (CELL COAT)
MICROVILLI
MITOCHONDRIA
PRACTICAL
ENDOPLASMIC RETICULUM
ROUGH ENDOPLASMIC RETICULUM
RER & SECRETORY GRANULES
GOLGI APPARATUS
LYSOSOMES
CILIA
CILIA & CENTRIOLES
CENTRIOLES
MICROTUBULES & ACTIN FILAMENTS
DISTRIBUTION OF MICROTUBULES IN INTERPHASE CELLS 1- Cytoplasmic microtubules. 2- Cilia. 3- Flagella. 4- Centrioles.
Glycogen granules in hepatocyte
INTERCELLULAR JUNCTIONS
(1)Occludent junction. (2)Adherent junction. (3)Gap junction (Nexus).
OCCLUDENT JUNCTION (TIGHGT JUNCTION)
DESMOSOMES (Macula adherent junctions)
GAP JUNCTION (NEXUS)
JUNCTIONAL COMPLEX