Fondamenti di anatomia e istologia

Transcription

1 Ingegneria delle tecnologie per la salute Fondamenti di anatomia e istologia aa

2 Anatomia umana Edizione italiana a cura di Fabrizio Michetti MCKINLEY - O'LOUGHLIN Data di pubblicazione: maggio 2014 Prezzo: 49,50 ISBN: Codice Piccin: Libro in italiano

3 Atlante di anatomia Edizione italiana a cura di Elena Donetti KAMINA Data di pubblicazione: settembre 2014 Prezzo: 45,00 ISBN: Codice Piccin: Libro in italiano

4 Colorare l'anatomia Edizione italiana a cura di Raffaele De Caro e Sergio Galli KAPIT - ELTON Data di pubblicazione: marzo 2016 Prezzo: 20,00 ISBN: Codice Piccin: Libro in italiano

5 Lezione 3. Cenni di embriologia ed istologia generale. -atlas-of-histology-with-functional-correlations-11thed.pdf

6 THE TISSUE LEVEL OF ORGANIZATION After studying this chapter, you will be able to: Identify the main tissue types and discuss their roles in the human body Identify the four types of tissue membranes and the characteristics of each that make them functional Explain the functions of various epithelial tissues and how their forms enable their functions Explain the functions of various connective tissues and how their forms enable their functions Describe the characteristics of muscle tissue and how these enable function Discuss the characteristics of nervous tissue and how these enable information processing and control of muscular and glandular activities our body: at least 200 distinct cell types. same internal structures but vary enormously in shape and function. occur in organized layers: tissue starts as a single cell at fertilization and it gives rise to trillions of cells, each built from the same blueprint, but organizing into tissues and becoming irreversibly committed to a developmental pathway.

7 Types of Tissues Tissue = a group of cells found together in the body, that share a common and morphological features and are arranged in an orderly pattern that achieves the tissue s functions. many types of cells, but organized into 4 broad categories of tissues: 1. epithelial 2. connective 3. muscle 4. nervous with a specific functions that contribute to the overall health and maintenance of the body. Histology = microscopic study of tissue appearance, organization, and function.

8 Tissue Preparation Light Microscopy Histology is a visual, as well as a very colorful, science that is studied with the aid of a light microscope. The prepared specimens for examination are thinly sliced, placed on a glass slide, stained with a variety of stains, and examined with a light microscope via a light beam that passes through the tissues that are fixed on the slide. Antonie van Leeuwenhoek ( ) is credited with bringing the microscope to the attention of biologists

9 Tissue Preparation Light Microscopy FIXATION = prompt immersion of the specimen with different chemical solutions, to preserve a section of tissue or organ for histologic examination essential in order to permanently preserve structural and molecular composition of specimen. to further accelerate penetration and proper fixation process, tissue specimen is first cut into small pieces and then immersed into fixative. hardens specimen for sectioning, causes cross-linkage of macromolecules within the cells, reduces cellular degeneration, preserves integrity of cells and tissues, and increases their affinity to take up different stains. most commonly used fixative for light microcopy is neutral-buffered FORMALDEHYDE. Aldehyde fixatives form crosslinks between proteins.

10 Tissue Preparation Light Microscopy

11 Tissue Preparation Light Microscopy POSTFIXATION After fixation, water must first be removed by passing it through a series of ascending ALCOHOL (ethanol) concentrations, usually from 70 to 100% then specimen must be cleared of alcohol by passing it through several changes of such clearing agents as XYLENE Once the specimen is impregnated with the clearing agent xylene, it is then placed in a warm mold containing melted PARAFFIN. Once removed from the heat source, the paraffin in the mold cools, solidifies, and encases the specimen. paraffin block then trimmed to the size of the specimen and mounted in an instrument called a MICROTOME [precisely advances the paraffin block so that the sections are cut at specific and predetermined increments with a steel knife] = sections are normally cut at 3-10 μm thickness. thin paraffin sections are then collected and floated in a warm water bath and placed onto a glass slide that has been covered with a thin layer of albumen, which serves as an adhesive medium for the specimen.

12 Staining of Sections paraffin sections on the glass slide are colorless needs to be stained. paraffin must first be dissolved from the specimen with solvents, such as xylene, and the sections rehydrated with a series of decreasing alcohol concentrations. hydrated sections can then be stained with a variety of watersoluble stains, which selectively stain various components of the specimen Most of the stains used for histologic slide preparations act like acidic or basic compounds: structures that stain most readily with basic stains are called BASOPHILIC, and those that stain with acidic stains are called ACIDOPHILIC [most common stains are hematoxylin and eosin stains]

13 Staining of Sections

14 Staining of Sections

15 Staining of Sections

16 Staining of Sections

17 Staining of Sections

18 Staining of Sections

19 Staining of Sections

20 Staining of Sections

21 Staining of Sections

22 Transmission and Scanning Electron Microscopy

23 Interpretation of Histologic Sections the most challenging and difficult aspects of histology: interpretation of what the two-dimensional histology sections represent in three dimensions. Histologic sections = thin, flat slices of fixed and stained tissues or organs mounted on flat glass slides. sections normally composed of cellular, fibrous, and tubular structures cut in different planes variety of shapes, sizes, and layers may be visible, depending on the plane of section. Fibrous structures are solid and are found in connective, nervous, and muscle tissues. Tubular structures are hollow and represent various types of blood vessels, lymph vessels, glandular ducts, and glands of the body.

24 Planes of Section of a Round, Solid Object

25 Planes of Section Through a Hollow Structure or a Tube

26 Planes of Section Through a Hollow Structure or a Tube

27 Cell microscopic anatomy (TEM)

28 Ciliated and nonciliated cells

29 Junctional complex

30 Basal region

31 Basal region in ions transporting cell

32 Cilia and microvilli

33 Nuclear envelope and pores

34 Mitochondria

35 RER

36 SER

37 Golgi apparatus

38 Lysosomes

39 Mitosis

40 The 4 Types of Tissues 1. Epithelial tissue (epithelium) = sheets of cells that cover exterior surfaces of the body, internal cavities and passageways, and forms certain glands. 2. Connective tissue = binds cells and organs together (functions: protection, support, and integration of all parts of the body) 3. Muscle tissue = excitable, responding to stimulation and contracting to provide movement, and occurs as 3 major types: skeletal (voluntary) muscle, smooth muscle, and cardiac muscle in the heart. 4. Nervous tissue = also excitable, allowing the propagation of electrochemical signals in the form of nerve impulses.

41 The 4 Types of Tissues

42 Organs are made of many different tissues of the 4 fundamental types sections through 4 different organs: Intestines, Skin, Lung, & Trachea. (each organ is made of multiple tissues and that their are variations on how the tissues are designed)

43 Embryonic Origin of Tissues totipotent three major cell lineages established within the embryo

44 Embryonic Origin of Tissues 3 lineages of embryonic cells forms 3 distinct germ layers identified by its relative position: 1. ectoderm (ecto-= outer ), 2. mesoderm (meso- = middle ), 3. endoderm (endo- = inner ).

45 Embryonic Origin of Tissues!!! epithelial tissue originates in all three layers, whereas nervous tissue derives primarily from the ectoderm and muscle tissue from mesoderm.

46 Tissue Membranes Tissue membrane = thin layer or sheet of cells that covers the outside of the body (for example, skin), the organs (for example, pericardium), internal passageways that lead to the exterior of the body (for example, abdominal mesenteries), and the lining of the moveable joint cavities. 2 basic types 1. connective tissue 2. epithelial membranes

47 Tissue Membranes 1. Connective Tissue Membranes = formed solely from connective tissue, encapsulate organs, and line our movable joints (synovial membrane) 2. Epithelial Membranes = composed of epithelium attached to a layer of connective tissue i. mucous membrane (mucosae) = line the body cavities and hollow passageways that open to the external environment, and include the digestive, respiratory, excretory, and reproductive tracts. Mucous, produced by the epithelial exocrine glands, covers the epithelial layer. The underlying connective tissue, called the lamina propria, supports the epithelial layer. ii. serous membrane = composed of mesodermally derived epithelium called the mesothelium that is supported by connective tissue, line coelomic cavities (do not open to outside). iii. cutaneous membrane (skin) = stratified squamous epithelial membrane resting on top of connective tissue.

48 The 4 Types of Tissues

49 The 4 Types of Tissues: epithelial

50 Epithelial Tissue = essentially large sheets of cells covering all the surfaces of the body exposed to the outside world + lining the outside of organs + much of the glandular tissue of the body; share structural/ functional features: highly cellular, with little or no extracellular matrix between cells cell junction = specialized intercellular connection between cell polarity = differences in structure and function between the exposed or apical facing surface of the cell and the basal surface basal lamina = (a mixture of glycoproteins and collagen) provides an attachment site for the epithelium, separating it from underlying connective tissue and attaches to a reticular lamina, which is secreted by the underlying connective tissue, forming a basement membrane that hold it all together. nearly completely avascular. capable of rapidly replacing damaged and dead cells.

51 Epithelial Tissue basement membrane

52 Epithelial Tissue basement membrane

53 Epithelial Tissue Generalized Functions of Epithelial Tissue provide the body s first line of protection from physical, chemical, and biological wear and tear, controlling permeability and allowing selective transfer of materials across a physical barrier are sometimes capable of secretion and release mucous and specific chemical compounds onto their apical surfaces. The Epithelial Cell typically characterized by the polarized distribution of organelles and membranebound proteins between their basal and apical surfaces: certain organelles are segregated to the basal sides, whereas other organelles and extensions, such as cilia (microscopic extensions of the apical cell membrane that are supported by microtubules), when present, are on the apical surface and beat in unison and move fluids as well as trapped particles.

54 Epithelial Tissue Cell to Cell Junctions Cells of epithelia are closely connected and are not separated by extracellular material. 3 basic types of connections allow varying degrees of interaction between the cells: 1. tight junctions, 2. anchoring junctions, 3. gap junctions

55 Epithelial Tissue Classification of Epithelial Tissues classified according to the shape of the cells and number of the cell layers formed. Transitional describes a form of specialized stratified epithelium in which the shape of the cells can vary.

56 Epithelial Tissue Classification of Epithelial Tissues classified according to the shape of the cells and number of the cell layers formed. Transitional describes a form of specialized stratified epithelium in which the shape of the cells can vary.

57 Epithelial Tissue goblet cell Both simple and pseudostratified columnar epithelia are heterogeneous epithelia because they include additional types of cells interspersed among the epithelial cells. For example, a goblet cell is a mucous-secreting unicellular gland interspersed between the columnar epithelial cells of mucous membranes

58 Epithelial Tissue different categories epithelial tissue cells of cell

59 Epithelial Tissue different categories of epithelial cell tissue cells

60 Epithelial Tissue Glandular Epithelium gland = a structure made up of one or more cells modified to synthesize and secrete chemical substances; most glands consist of groups of epithelial cells. 1. Endocrine Glands a ductless gland that releases secretions (hormones) directly into surrounding tissues and fluids (endo- = inside ), that are part of regulatory system 2. Exocrine Glands gland whose secretions leave through a duct that opens directly, or indirectly, to the external environment (exo- = outside ). through a tubular duct that leads to the epithelial surface

61 Epithelial Tissue Exocrin Glandular Structure Exocrine glands classified: unicellular = scattered single cells (goblet cells) multicellular (classified structure) by

62 Epithelial Tissue Exocrin Glandular Methods and Types of Secretion Exocrine glands classified mode of secretion nature of the substances released serous gland watery, bloodplasma-like secretions mucous gland watery to viscous products rich in the glycoprotein mucin. mixed glands both serous and mucous glands and release both types of secretions.

63 Epithelial Tissue Sebaceous Glands secrete oils that lubricate and protect the skin and are holocrine glands (are destroyed after releasing their contents, new glandular cells form to replace the cells that are lost).

64 Epithelial Tissue Type of Tissue Function Location removing dust and particles from lines the respiratory Pseudostratified columnar airways, has cilia passageways

65 Epithelial Tissue imple Columnar Absorption lines the uterus and most organs of the digestive tract

66 Epithelial Tissue Simple Cuboidal Secretion and Absorption glands, kidney tubules, ovaries

67 Epithelial Tissue Simple Squamous Diffusion and Filtration lungs, walls of capillaries and vessels

68 Epithelial Tissue Stratified Squamous Protects underlying cells skin(keratinized) and the throat, vagina, mouth (soft)

69 Epithelial Tissue Stratified Cuboidal Protection lines ducts of the mammary glands, sweat glands, pancreas

70 Epithelial Tissue Stratified Columnar Protection, secretion male urethra and vas deferens, parts of the pharynx

71 Epithelial Tissue Transitional (unstretched) Specialized to become distended urinary tract