Histological Techniques correctly answered rated A+ 2023/2024

Histological Techniques the very first step in histology - correct answers each sample must be identified with a unique number . thin sections of the tissues are cut for microscopic examination. summary of histology process ( 5 points) - correct answers 1)Fixation 2)Tissue processing . OR decalcification 3) Microtomy 4)Staining 5) Mounting Definition of Histology - correct answers The microscopic study of the Form and Structure of various tissue types that make up living organisms . This is done by histological techniques. Fixation Definition - correct answers Stabilization of important constituents of tissues without altering the character , so they will not be DDD in further procedures. Alternative of Fixation , incl what it demonstates and the benfit - correct answers Frozen - demonstates Lipids , that be could lost in fixation it is quick. Aim/ Effects of fixation ( 4 points) - correct answers 1) to preserve cells identical to existing life 2) prevent autolysis - the break up of living tissue , from the lack of O2 , therefore fixation stops enzyme activity 3) prevent putrefaction - the break up of tissue by bacteria , therefore fixation stops microbe action 4) easier handling ; easier cutting , stops soluble substances diffusing , helps the staining process. How Fixation works ( 3 points) - correct answers 1) form cross links between proteins to form a Gel 2) reducing solubility of proteins/lipids by ppt and coagulation( Geling) 3) Soluble proteins link to structural proteins therefore will be insouble , and stucture is mechanically strengthened . Type of Fixative used , what is it used in and what dose it need with it and why . ( 3 points) - correct answers 1) Formalin 2) is used in 10% saline 3) Needs a buffer due to formic acid The common type of fixative causes .... and what dose it do ( 3 points) - correct answers 1) Artefact Pigments 2) heme pigments , brown / black 3) causes chemical and volume changes A good fixative should be ( 4 points) - correct answers 1) Stable 2) Cheap 3) Safe 4) Penetrates well Factors of Fixation , Quality - correct answers 1) concentration 2) Agitation and Vacuum 3) Duration Speed of Fixation , as A factor ... depends on ( 3 points) - correct answers 1) Type of Tissue 2) TYpe of Fixative 3) Size/ Thickness of Tissue Limintations of Fixation ( 3 points) - correct answers 1) Slow procedure 2) Hard tissue 3) Thickness of tissue Disadvantages of Fixtation ( 3 points) - correct answers 1) Formic acid 2) very Hazordus 3)loss of lipids Fixatives can be classfied as .... and exaplain each one ( 5 points) - correct answers 1) Microatomical - preseves the anatomy of the tissue, are compound fixatives. 2) Histochemical - chemical composition of the cells/ tissues 3) Cytological - preserves intracellular structure of the cells. ( formation , structure , function ) 4) Composition: - Simple : e.g formalin - Compound: alcoholic formalin - the disadvantage of one is reduced by the other. 5) Affect - coagulant/anticoagulant -tolerant/antitolerant Tissue Processing Aim/ definintion - correct answers Embed tissues in a solid medium , which must suppport the tissues and give it rigidity for thin section, BUT not to hard is can damage the knife , in microtomy. Pre-requisites of tissue processing ( 5 points) - correct answers 1) samples must be fixed 2) a suitable size 3)not squeezed in cassette 4)the minute tissue is secures in form pads 5) fragile tissue is stuck to filter paper 3 main steps in tissue processing ( 3 points) - correct answers 1) dehydration 2) clearing 3)impregnation