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Tissue = A collection of cells that perform related functions, and are similar in structure Histology = The study of tissues The Four Primary Tissue Types.

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Presentation on theme: "Tissue = A collection of cells that perform related functions, and are similar in structure Histology = The study of tissues The Four Primary Tissue Types."— Presentation transcript:

1 Tissue = A collection of cells that perform related functions, and are similar in structure Histology = The study of tissues The Four Primary Tissue Types Epithelial Connective Muscular Nervous

2 Epithelial Tissue 1.Epithelium / -a = cell layer (barrier) –Protection: covering or lininginside and out –Permeability control: selective secretion and absorption –Sensation: touch receptors etc. and neuroepithelium of special senses 2.Glands = secretory structure –Specialized secretions

3 BM apical basal Structural Characteristics of Epithelia Cellularity Cell to cell contacts Polarity Support by connective tissue Avascular (esp. skin) Regeneration/repair

4 Polarity of Epithelial Cells

5 Classification of Epithelia The function of the epithelium determines which type. Typically classified according to 1. Number of cell layers Simple vs. Stratified 2. Shape of cell Squamous, cuboidal, columnar

6 Simple Squamous Epithelium Location: Lining of ventral body cavities, e.g. peritoneum Lining of blood vessels (endothelium) Alveoli

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8 Function of Simple Squamous E. Friction reduction (cavity lining) Blood vessel permeability control (capillaries) Gas absorption and secretion (lung) Not very protectiveonly one cell thick

9 Simple Cuboidal Epithelium Function:Function: Secretion Absorption Location:Location: Lining of ducts Glands (salivary, pancreas, thyroid) Kidney tubules

10 Thyroid Follicle

11 Simple Columnar Epithelium Function:Function: Secretion Absorption Location:Location: GI tract Many excretory ducts

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13 Pseudostratified Ciliated Columnar Epithelium Function: Mucociliary Blanket Function: Mucociliary Blanket Mixture of cell types nuclei located at various distances from surface. Yet: all cells contact BM Mixture of cell types nuclei located at various distances from surface. Yet: all cells contact BM Location: Location: Respiratory tract except for lungs

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16 Stratified Squamous Epithelium Function Protection against abrasion, pathogens, chemicals, heat/cold… Keratinized vs. non-keratinized Location ? Where we need protection!Location ? Where we need protection! Skin surface Entrances/exits of body, e.g. mouth, vagina

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19 Sweat gland Stratified cuboidal and columnar: quite rare, found in glands and ducts

20 Transitional Epithelium Function ?Function ? Extreme expansion & recoil Layered appearance due to overcrowding. All cells contact BM.Layered appearance due to overcrowding. All cells contact BM. Location ?Location ? Bladder, ureters, renal pelvis

21 stretched

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23 Glandular Epithelia ExocrineExocrine Glands have ducts Secretion to the outside of the body Simple or compound Endocrine Endocrine Glands have no ducts Hormones (into the bloodstream) Types of Glandular Secretions:

24 Location in the Body

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26 Connective Tissue: Supports, protects, binds tissues Structural characteristics: Specialized cells Extracellular protein fibers (collagen) Ground substance (fluid-like) extracellular matrix

27 Functions of C.T. Structural framework for body (p77) Transport of fluids and dissolved materials Support and protection for organs Energy storage (fat) Defense

28 Classification of C.T. C.T. proper (viscous matrix with fibrous, insoluble proteins) Areolar (loose), reticular, dense, adipose Supporting C.T. (gelatinous or solid matrix) Cartilage, bone Fluid C.T. (watery matrix with dissolved proteins) Blood, lymph

29 Classification of Connective Tissue

30 Connective Tissue Proper - viscous matrix -Includes loose, reticular, dense C.T. Think about dermis Types of Fibers: Collagen Elastic Reticular Defense: Macrophages Plasma Cells Mast Cells Other WBC

31 Fluid C. T. Blood (Ch 17) Lymph (Ch 20)

32 Supporting C.T. Cartilage –Hyaline, cells in lacunae Articular cartilage, symphysis pubis –Elastic Ear, larynx –Fibrocartilage Intervertebral discs Bone (Chapter 5) –Mineral matrix

33 Study individual types of c.t. in lab

34 Membranes = Combination of Epithelia & C.T. Mucous membranes, –Lining of cavities that communicate with exterior Serous membranes, –Lining of sealed, internal cavities Cutaneous membranes, –Skin

35 Know special names of serous membranes depending on location Also know difference between parietal and visceral Membranes, contd

36 Mucous vs. Serous Membrane

37 Cutaneous & Synovial Membranes

38 C.T. Framework of Body Also: Hypodermis or subcutaneous layer

39 Muscle Tissue Muscle Tissue Three types: Skeletal Cardiac Smooth (not striated)

40 Skeletal Muscle Voluntary Heavily striated Multinucleate periphery of the cell

41 Cardiac Muscle Heart (Only) Involuntary Striated Intercalated disks Heavily branched Single central nucleus

42 Smooth Muscle Involuntary Esp. digestive system No striations Very slow Single central nucleus

43 Nervous Tissue (ch 12) Neurons –Transmit electrical impulses Neuroglia –Supportive cells of the nervous system

44 Ne Neural Tissue

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