Introduction to Histology PDF

Introduction to medicine {L3} ‫م‬ SHAWABKEH ‫ب‬ ‫ش‬‫ل‬...

Introduction to medicine {L3} ‫م‬ SHAWABKEH ‫ب‬ ‫ش‬‫ل‬ ‫د وا كة‬‫ا‬ ‫م‬‫ح‬ Introduction to Histology ❖ Histology Study of cells and tissues with the aid of a magnifying instrument (the microscope). ❖ Gross anatomy : Structure that can be examined by naked eye without using microscope ❖ Cytology : study of cell structure ❖ Anatomy : the study of structure and the relationships among these structures ❖ Physiology : is the study of normal function within living creatures. ❖ Biochemistry : both life science and a chemical science Structural Levels of Organization The human body can be seen to be organized at 6 levels. These levels range from the simplest and smallest to the most complex and largest Tissue Components The major tissue components in all body : >cell >extracellular matrex >ECM produced by cell >ECM will Influence and control the cell > percent of cell more than percent of ECM except Connective tissue ECM more than cell PREPARATION OF TISSUES FOR STUDY Most common:  preparation of tissue slices or sections → studied with light microscope.  Thin slices → allow light to pass through them. 1) Cutting Cutting the sample Thickness should NOT exceed 0.5cm (for Light microscopy) & 1-2-mm (for Electron microscopy); Because the Fixative may not penetrate whole tissue. 2) Fixation Treat pieces of tissues as soon as possible after removal from the body. Treatment → immersion in fixatives. Fixative : solution of stabilizing or cross linking compounds. Common fixatives: 1- Formalin (37% formaldehyde) → LM 2- Formaldehyde and glutaraldehyde → EM ( we don’t use fixatives for Enzymatic Studies & During Surgical Procedures, instead We use Freeze Fracture (Immerse tissue in Liquid Nitrogen -70-80) because fixatives 1- disrupt enzymes, 2- and need few days to be ready.)  3) Dehydration Removal of water by immersing tissue block in gradual concentration Excretion of water from fixed tissue. Transfer through graded ethanol solutions from 70% to 100%. 4) Clearing Replacement of ethanol by organic solvent miscible with alcohol and embedding medium (paraffin wax). Toluene is miscible with alcohol and paraffin. 5) Infiltration Cleared tissue is placed in melted paraffin (Wax). The clearing solvent evaporates. The tissue is filled with liquid paraffin. 6) Embedding The paraffin-infiltrated tissue is placed in a small mold with melted paraffin and allowed to harden. 7) Trimming The hardened block of tissue with embedding medium placed in a mircotome. Steel blade→ thin slices→ for staining….. 8) Staining Tissues → colorless. Cell components with a net negative charge (anionic) stain with basic dyes (Basophilic). Cell components with a net positive charge (cationic) stain with acidic dyes (acidophilic). ✓ H&E Staining Basic dyes: -Hematoxylin. Stain basophilic components DNA (nucleus), RNA, and glycosaminoglycans Acidic dyes: -Eosin. Stain the acidophilic components of tissues cytoplasm (mitochondria), and collagen. Histology = Microscopic Anatomy. Microscopes : 1. Light microscope (Lower magnification). 2. Electron microscope (Higher magnification).  1) Light Microscopy Depend on interaction between light and tissue components. common colorful method Cell membrane can not be viewed  Types: Conventional (bright – field) Fluorescence ( Fluorescence is where an object will emit light in higher wavelength after absorbing light , the structure will bright on black background ‘use UV light “) Phase contrast (stain living structure no use of fixation and stain ) Polarizing (stain living structure no use of fixation and stain ) Total Magnification = Magnification of objective X magnification of ocular (X10) Oil immersion lens Resolving power = 0.2 μm - Bright-Field Microscopy - Fluorescence Microscopy - Phase-Contrast Microscopy - Polarizing Microscopy 2) Electron Microscopy Beam of electrons interact with structures. Short wavelength = magnify more resolution =, 3nm. magnification 400,000 (black and white) TEM (can see inside of cell) SEM (can see topography and surface of cell) Basic Types of Tissues There is 4 type of tissue Tissue type Function Epithelial Cover body surface and lines internal organs Connective Support and protection Nervous Sends and receives information about stimuli Muscle Movement  o Epithelial Tissue Cellular sheets that line the cavities of organs and cover the body surface. Lining of mucosa , stomach , cardiac Covering, lining, and protecting surfaces (eg, epidermis). Absorption (eg, the intestinal lining). Secretion (eg,glands). Why epithelial do all this ? Because epithelial cells line all external and internal surfaces of the body and All substances that enter or leave tissues and organs must cross an epithelium. Classification of Epithelium 1) Number of layers (simple Vs. stratified). 2) Morphology of surface layer (squamous, cuboidal, columnar). simple stratified Squamous to prevent water Flat nucleus loss and dehydration and Non keratinized keratinized protection Cuboidal Rounded or spherical nucleus Columnar Oval and elongated nucleus Extra type : one layer but the nucleus not at the same level) in RS in ureter ,bladder (transform its shape ) glands: o endocrine gland : release hormones into thebloodstream and include the pituitary and thyroid gland. o exocrine gland : Exocrine glands release substances, such as sebum, sweat, and digestive enzymes, through a duct to an organ or the surface of the body. o Connective Tissue Maintain the form of organs. Support & connect tissues & cells together in organs. CT = Cells + ECM (By volume : ECM >>> Cells) Major constituent →ECM (Unlike other types!). ECM = protein fibers + ground substance. Ground substance = GAGs + Proteoglycans + Glycoproteins. main component Fibers of Connective Tissue Elongated structures. Fibroblasts→ secrete→ proteins→ polymerize. Three main types: 1) Collagen fibers (strong – most common- thicker ) 2) Elastic fibers(external ear and tip of the nose, hyaline cartilage )( thinner) 3) Reticular fibers( in liver , spleen , LN) Distributed unequally among different types of CT. white “ energy storge “ Different combinations and densities of : Adipose brown “heat production “ -Cells. -Fibers. -Extracellular molecules. (elastic cartilage of ear , hyaline articulate surface in joint to reduce Cartilage friction , fibrocartilage intervertebral ‫ﻣﮭم ﺟداا‬ disc) (compact no spaces and spongy Specialized contain spaces and cavities ) red Bone bone marrow syn blood cell then become yellow and contain fats. Connective Tissue specialized liquid CT “ scattred cell Blood with ECM = PLASMA (platelet ,erythrocyte, eosinophil, neutrophil, basophil , lymphocyte ,monocyte) Regular (parallel ) Dense more fiber Irregular (different direction ) Proper Loose (areolar) Less fiber  o Muscle Tissue Main property → contractility. Abundant synthesis of the myofibrillar proteins actin and myosin. Type of muscle tissue. Regeneration of Muscle Tissue Limited regeneration Capable of a more active regenerative response. After injury, muscle cells undergo mitosis and replace the damaged tissue. (high generative capability ) Very little regenerative capacity beyond early childhood. Defects or damage replaced by proliferating fibroblasts and growth of connective tissue, forming myocardial scars (fibrosis). Skeletal muscle Cardiac muscle Smooth muscle Organization of muscle: muscle fiber : covered by endomysium bundle of fiber (fascicle): group of muscle fiber muscle : group of fascicle sounded by epimysium Muscle Fibers contain : Sarcomere: repetitive functional subunit of the contractile apparatus. Space between two Z line and it’s the smallest unit can contract. Cardiac muscle contain : intercalated disc. Fibers of a given skeletal muscle are grouped physiologically into three types and Most muscles contain a mixture of the three types. Red muscle :contract slow , use aerobic respiration White muscle (fast glycolytic ) : contract fast , use anaerobic (oxidative phosphorylation ) contain more mitochondria respiration (ocular ball muscle) EX.Muscle of neck.  o Nerve Tissue Type of nerve tissue: 1) Neurons (nerve cells) - Numerous long processes. - Initiate & propagate action potentials (excitable, irritable) 2) Glial cells - Short processes. - Support and protect neurons. Neurons Parts The functional unit in both the CNS and PNS. 1- The cell body (p erikaryon) : contains the nucleus and most of the cell’s organelles. 2- The dendrites: - numerous elongated processes extending from the perikaryon. - receive stimuli. 3- The axon: - a single long process ending at synapses specialized to generate. - conduct nerve impulses to other cells. Neurons Types - Anatomically 1- Multipolar neurons : - One axon and two or more dendrites. - Most common. 2- Bipolar neurons: One dendrite and one axon (sense organ EX cranial nerve VII hearing and balance) 3- Unipolar (pseudounipolar) neurons: - single process that bifurcates close to the perikaryon. - found in CNS dorsal root ganglia Spinal cord : Synaptic Communication Synapses : sites where nerve impulses are transmitted from one neuron to another or from neurons and other effector cells (axodendritic synapse most common ). Oligodendrocyte : wrap segments of several axon Astrocyte : formation of (myelination axons in CNS) BBB (Blood Brain Barrier ) ALSHAWABKEH Shwan cell : multiple Schwann cell is only capable of Ependymal cell : to line myelinating a Microglial cell: immune cavities and brain ‫ب‬ champer and secreting single axon in PNS defense cell release destructive chemical...‫تم و حمدالله‬ of CSF  5. which of the following component that stain by the basic / acidic dyes: Introduction to Histology a) nucleus/ collagen b) cytoplasm/ collagen 1. The para in-infiltrated tissue is placed in a small mold with melted para in and allowed to harden , is done by: c) nucleus/ glycosomioglycan a) Fixation d) tissue/ collagen b) Mounting c) Embedding 6. In Embedding, we use: d) Both A & C a) water b) Xylene 2.all of the following are type of tissue except : c) Para in a) epithelial tissue d) Alcohol b) connective tissue c) cartilage tissue 7. The step after clearing: d) nervous tissue a) Staining b) Dehydration 3. In clearing, we use: c) infiltration a) Formaldehyde d) Embedding b) Alcohol c) Water 8. The step after fixation is: d) Toluene a) Clearing 4. total magnifcation of light microscope : b) Embedding ALSHAWABKEH a) 1000-1500 c) Dehydration b) 1500-2000 d) Staining c) 120,000 d) 400,000 9. The resolution of Light & the Electron Microscopes respectively are: 13. which of the following have high generative capability: a) 0.2 µm/3 nm a) Skeletal muscle b) 3nm/0.2 µm b) smooth muscle c) 0.2nm/3 µm c) cardiac muscle d) 3 µm/0.2nm d) two answer is correct 10.which of the following neroun type that has cranial nerve VII hearing and balance : 14. the function of white / brown adipose tissue: a) multipolar neuron a) heat production / energy storage b) unipolar neuron b) energy storage / heat production c) bipolar neuron c) ca storage d) two answer is correct d) k storage 11. which of the following formation of blood brain barrier: 15. Removal of alcohol is: a) oligodendrocyte a) Clearing b) shwan cell b) Fixation c) microglial c) Dehydration d) Astrocyte d) Embedding 12. which of the following is consider under white and red muscle: 16. which of the following tissue in ureter blader : a) both of them id contract fast a) pseuostratified b) both of them is contract slow ALSHAWABKEH b) squamous c) contract fast / use anaerobic respiration c) urothelium d) contract fast / use aerobic respiration d) columnar 17. which of the following oval and elongated nucleus 22. immune defense cell release destructive chemical a) columnar a) astrocyte b) cuboidal b) microgllial c) squamous c) shwan cell d) transitional d) oligodendrocyte 18.which of the following has one layer but the nucleus not at the same level 23. wrap segment of several axon and its muelination axons in CNS a) psedostratified a) astrocyte b) cuboidal b) microgllial c) squamous c) shwan cell d) transitional d) oligodendrocyte 19. which of the following tissue prevent water loss and dehydration and protection 24. only capable of myelinating a single axon in PNS / line cavity and brain champer and secreting of CSF a) cuboidal a) astrocyte/ microgllial b) non kertinized stratified squamous ALSHAWABKEH b) microglial / astrocyte c) keratinized stratified squamous c) shwan cell / Ependymal cell d) transitional d) oligodendrocyte / Ependymal cell 20. what is the cytology? a) study of structure b) study of cell 1C 2C 3D 4A 5A 6C 7C 8C c) study of anatomy 9A 10C 11D 12D d) study of tissue 13B 14B 15A 16C 17A 18A 19C 20 B 21 A 22B 23D 24C 21. anatomy is the study of structure and the relationship among these structure: a) true b) false