Animal Histology Introduction PDF

Animal Histology -By Mohamad Shokor- For more information: 71325049  Introduction Syllabus: 1-Epithelial Tissue 18 pages- Usually we forget the details in this chapter, so we should repeat them alot 2-Non-specialized Connective 7 pages-Easi...

Animal Histology -By Mohamad Shokor- For more information: 71325049  Introduction Syllabus: 1-Epithelial Tissue 18 pages- Usually we forget the details in this chapter, so we should repeat them alot 2-Non-specialized Connective 7 pages-Easier than ch-1- but we should pay attention for understanding the ideas not only Tissue memorizing them like a parrot 3-Adipose Tissue 2 pages-The easiest chapter 4-Cartilage Tissue 6 pages-Small chapter,but pay attention for the characteristics of each type of cartilage. 5-Bone Tissue 12 pages-Understanding the ideas in this chapter is very important. 6-Blood Tissue 14 pages-Summarizing this chapter will make it easier. 7-Muscle Tissue 15 pages-Use animated videos from YouTube to understand the ideas will 16 pages-Easy to memorize with respect to chapter 5,6 and 7 especially if you studied it from 8-Nervous Tissue anatomy also, since there is some common ideas.  Introduction Histology is the study of tissues Tissues are sets of differentiated cells that are: 1. localized in one place 2. contribute to the same biological function. Tissues are made up of cells and of all the elements filling the intercellular or extracellular medium.  4 Types of Tissues 1. Loose, Dense, Reticular, and Elastic 2. Adipose Glandular 3. Cartilage 4. Bone 5. Blood Covering Epithelial Connective Skeletal Muscle Nervous PNS Cardiac Smooth CNS  ❑ The tissues differentiate during embryonic development from the three primitive embryonic germ layers: Note for the Exam: gives part of the epithelial Epidermis and Dermis tissues (the epidermis) are 2 different Things and the nervous tissue. gives rise to the covering It is at the origin of: epithelium lining the: 1. the non-specialized connective tissues 1. Intestine 2. Cartilage 2. respiratory system 3. Bone 3. urogenital tract. 4. the wall of the heart and vessels 5. smooth and striated muscles(cardiac and skeletal)  Ch-1-Epithelial Tissues Epithelial tissues are composed of cells that are: 1. Tightly packed together with very narrow intercellular spaces 2. At the limit of visibility under the light microscope. 3. Polarized cells 4. Closely juxtaposed 5. Integral with each other 6. Ensuring their cohesion by different adhesion junctions and involved in one or more common physiological functions 7. It rests on a basal membrane that separates it from a connective tissue.  2 types of Epithelia Covering epithelia (surface or lining) that cover other tissues, Glandular epithelia (with secretory function) that are specifically involved in the elaboration of a secretory product. Note: The epithelia of the body derive from the three embryological germ layers: the ectoderm, the endoderm and the mesoderm.  Covering Epithelia They are tissues formed by one or many layers of epithelial cells closely juxtaposed, with sometimes the presence of non-epithelial cells. These tissues rest on an underlying connective tissue through a basal lamina. Very Important Idea: They are innervated(there is nerves) and non- vascularized (the blood vessels of the underlying connective tissue do not cross the basal lamina), and they have a great capacity for regeneration.  Types of Covering Epithelia ❑ Epidermis: the covering epithelium of the skin ❑ Mucosal epithelium: covers open cavities that extend the inside of the body to the outside (airways, digestive tract, urinary tract, genital tract) ❑ Endothelium: covers the cardiovascular cavities(blood vessels) Closed Cavities ❑ Mesothelium: covers the serous cavities (pleural, peritoneal and pericardial)  Characteristics of Epithelial Cells: 1-Cohesion: 2-Epithelial morphology: adhesion molecules and specialized because of the strong junction systems attach the epithelial interactions that exist between cells and maintain the cohesion the epithelial cells and the basal between these cells and with the basal lamina and their juxtaposition, lamina. the epithelial cells adopt either a: ‫ ببعض‬Cells ‫يعني كيف عم علق ال‬ 1. squamous or 2. cuboidal or 3. cylindrical (columnar) shape. squamous cuboidal columnar  3-Presence of intermediate filaments of cytokeratin in their cytoplasm: Cytokeratin are a specificity of epithelial cells. They are network of protein filaments that provide structural support and help maintain the shape of cells. 4-Polarity: the polarity of epithelial cells is manifested by: ❑ Asymmetrical distribution of the components of the cytoplasm ❑ Asymmetrical distribution of the components of the plasma membrane (proteins, enzymes, receptors…). Thus, the epithelial cell has three distinct domains:  Apical Domain -this domain is in contact with the external environment -or faces the lumen of the cavities of the organism. -It is the most specialized domain because it contains most of the proteins necessary for the specific functions of the organ. It also has membrane specializations (microvilli, cilia…).  Lateral Domain -it designates the surfaces that are apposed to neighboring cells. -It contains most of the proteins required for the fundamental processes common to all cells (polarized and non-polarized). -There are anchoring and adhering junctions in this domain. Tight junctions connecting adjacent epithelial cells are closer to the apical pole.  Basal Domain -it rests on the basal lamina. -Hemi-desmosomes and focal adhesion points are observed.  Basement Membrane (or Basal Lamina) Functions: 1. participates to the polarization of epithelium 2. plays a mechanical role by ensuring the cohesion between the latter and the underlying connective tissue. 3. It plays a role in the exchange and filtration processes and in the control of cellular metabolism. Note: Basal laminae also exist around some cells (adipose cells, muscular cells…).  Exercises Partial 2019-2020 Partial 2018-2019 Highlighting and Organization Thanks For Your Attendance For more information about Histology private course: 71325049