Lecture 7 Nucleus PDF

LECTURE 7 BAS 1103 THE NUCLEUS Professor Doctor GHADA FAROUK MOHAMED 1 FACULTY OF PHYSICAL THERAPY BAS1103 ...

LECTURE 7 BAS 1103 THE NUCLEUS Professor Doctor GHADA FAROUK MOHAMED 1 FACULTY OF PHYSICAL THERAPY BAS1103  THE NUCLEUS It is a membrane bound structure that carries the DNA. FACULTY OF PHYSICAL THERAPY BAS1103  THE NUCLEUS CENTRAL ECCENTRIC PERIPHERAL BASAL APICAL FACULTY OF PHYSICAL THERAPY BAS1103  THE NUCLEUS Binucleated Multinucleated Mononucleated FACULTY OF PHYSICAL THERAPY No nucleus BAS1103  THE NUCLEUS FACULTY OF PHYSICAL THERAPY BAS1103  THE NUCLEUS Structure Nuclear envelope. Chromatin. Nucleolus. Nuclear matrix. FACULTY OF PHYSICAL THERAPY 6 BAS1103  THE NUCLEUS Nuclear Envelope With LM: it appears single basophilic membrane. FACULTY OF PHYSICAL THERAPY BAS1103  THE NUCLEUS Nuclear Envelope With EM: it is formed of two membranes Outer nuclear membrane: Continuous with rER& studded with ribosomes. Inner nuclear membrane: Has chromatin attached. The nuclear envelope is perforated by openings called the nuclear pores. FACULTY OF PHYSICAL THERAPY 8 BAS1103  THE NUCLEUS Chromatin FACULTY OF PHYSICAL THERAPY BAS1103  Types of chromatin Telomere 1) Extended: "Euchromatin": Heterochromatin o Uncoiled. o Ready to be transcribed. 2) Condensed "heterochromatin": o Coiled. Euchromatin o Can't be transcribed. FACULTY OF PHYSICAL THERAPY 10 BAS1103  THE NUCLEUS FACULTY OF PHYSICAL THERAPY 11 BAS1103  THE NUCLEUS With EM the condensed chromatin are distributed as: Peripheral chromatin: close to the inner nuclear membrane. Nucleolus associated chromatin: around the nucleolus. Chromatin islands: appear as scattered granules. FACULTY OF PHYSICAL THERAPY BAS1103 12  THE NUCLEUS Function of chromatin: Directs protein synthesis. Store genetic information. FACULTY OF PHYSICAL THERAPY BAS1103  THE NUCLEOLUS It is prominent in protein synthesizing cells. With LM: It is rounded. Basophilic due to RNA & nucleolus associated chromatin. FACULTY OF PHYSICAL THERAPY BAS1103  THE NUCLEOLUS By EM: Not limited by membrane. Appears spongy formed of two parts: Light part: filled with nuclear matrix. Dark part FACULTY OF PHYSICAL THERAPY BAS1103  THE NUCLEOLUS Function of nucleolus: Site of transcription of rRNA and its assembly into ribosomal subunits. FACULTY OF PHYSICAL THERAPY BAS1103 FACULTY OF PHYSICAL THERAPY BAS1103 References 1. Junqueira’s Basic Histology: Text and Atlas, Thirteenth Edition by Anthony Mescher (Jan, 2013) 2. diFiore’s Atlas of Histology: with Functional Correlations by Victor P. Eroschenko PhD (Jan, 2012) FACULTY OF PHYSICAL THERAPY BAS1103