12/17/20151 Laboratory Two Histology

12/17/20152 Histology Study of structure and function of tissues – Groups of cells that are structurally and functionally the same –A combination of living and non-living material Go over each microscope –Illustrate and write anatomical details –Touch only the fine focus knob –Pointer helps you locate the assigned structures

12/17/20153 Four Primary Tissue Types 1.Epithelial - lines & covers surfaces 2.Connective - protects, supports, & binds 3.Muscular - contracts & produces movement 4.Nervous – generates & conducts nerve impulses

12/17/ Epithelial Tissue (E.T.) Lines, covers surfaces both inside & out Consists of many cells, tightly packed together Usually arranged in layers (except glands) –Simple (1 layer) or stratified (2 or more layers) Secured to deeper tissue by basement membrane A free surface is found opposite basement membrane

12/17/20155 Specific Types of Epithelial Tissues are Characterized by: Number of layers: –Simple (1 layer) - secretion, absorption, filtration –Stratified (>2 layers) – wear & tear Cell shape –Squamous – flat from side, like fried egg from top (yolk: nucleous) –Cuboidal - as wide as tall as deep, nucleous in center –Columnar – tall & thin, nucleous elongated

12/17/20156 Simple Squamous Epithelial Tissue Tissue: simple squamous E. T. Cell: squamous epithelial cell ID: flattened cells, mosaic shape Location: alveoli of lungs Function: diffusion

12/17/20157 Tissue: simple cuboidal E.T. Cell: cuboidal epithelial cell ID: round centrally located nucleous Location: salivary glands Function: secretion Simple Cuboidal Epithelial Tissue

12/17/20158 Simple Columnar Epithelial Tissue Tissue: simple columnar E. T. Cell: columnar epithelial cell ID: elongated nuclei, closer to BM, one layer Location: small intestine Function: secretion of digestive enzymes, absorption of nutrients Higher magnification (showing goblet cells)

12/17/20159 Pseudostratified Ciliated Columnar E. T. Higher magnification (showing cilia and goblet cell) Tissue: P. C. C. E.T. Cell: columnar epithelial cell with their elongated nuclei appear in multi- layer (cells with different dimension are arranged in one layer) ID: ciliated Location: trachea Function: protection (cilia moves mucous along with unwanted substances in air upwards

12/17/ Stratified Squamous Epithelial Tissue Tissue: S. S. E.T. Surface cells: Squamous E. C. ID: multiple layer, squamous cells at free surface (As cells mature, they change shape) Location: esophagus Function: protection against wear & tear Lower magnification (see abrupt change in tissue type at BM)

12/17/ Transitional Epithelial Tissue Relaxed urinary bladder Tissue: T. E.T. ID: stratified with cuboidal EC Location: urinary bladder (distended) Function: accommodates fluctuation in the volume of fluid, protects against caustic effect of urine

12/17/ E.T. Assignment View each assigned E.T. through microscopes or as micrographs Complete your histology worksheet in your handout –Illustrate the specific tissue –Label the assigned structures on your illustration –Record & learn one location and one function for each tissue

12/17/ Connective Tissue (C.T.) Protects, supports, binds Consists of relatively few cells scattered in non-living matrix Matrix varies –Fluid (e.g. plasma of blood C.T.) –Semi-solid matrix of cartilage –Solid (e.g. bone) –May contain various types of protein fibers arranged in various ways and with a range of densities Cells vary too –RBCs carry oxygen and WBCs & macrophages are protective –Chondrocytes secrete the matrix in cartilage C.T. –Osteocytes secrete bony matrix in osseous C.T. –Fibroblasts secrete fibers –Adipose cells store fat

12/17/ Osseous Connective Tissue Osteocytes inside lacunae (magnified) Tissue: Osseous C. T. Cell: Osteocytes ID: Cells arranged circularly around central canal, deposit the matrix in layers call lamella, nucleous (dark dots) Location: skeleton Function: support, protection

12/17/ Hyaline Cartilage Connective Tissue Chondrocytes inside lacunae (magnified) Tissue: Hyaline cartilage C. T. Cell: Chondrocytes ID: Cells with clear periphery embedded in a semi-fluid matrix, nucleous (dark dots) Location: Capping the end of bones Function: support, protection, cushion Chondrocytes inside lacunae (magnified) Tissue: Hyaline cartilage C. T. Cell: Chondrocytes ID: Cells with clear periphery embedded in a semi-fluid matrix, nucleous (dark dots) Location: Capping the end of bones Function: support, protection, cushion

Fibrocartilage Connective Tissue Tissue: Fibrocartilage C. T. Cell: Chondrocytes ID: Cells (dark dots) embedded in a matrix with blue collagen fibers Location: Disks between the vertebrae of spinal column Function: cushion

12/17/ Dense Fibrous Connective Tissue Tissue: Dense fibrous C. T. Cell: Fibroblasts ID: Parallel collagen fibers packed tightly, nuclei of fibroblasts (dark dots) Location: tendon (muscle to bone) and ligament (bone to bone) Function: attachment

12/17/ Areolar Connective Tissue Tissue: Areolar C. T. Cell: Fibroblast (most common) ID: Irregularly & loosely arranged collagen and elastic fibers, dots are nuclei of fibroblasts Location: Under the skin Function: Attachment, support

12/17/ Tissue: Adipose C. T. Cell: Adipocyte, signet ring cells, or fat cells ID: Large clear cells with nuclei pushed to the sides by fat vacuoles Location: Breasts, hips Function: Energy storage, cushioning, insulation Adipose Connective Tissue

Reticular Connective Tissue Tissue: Reticular CT Cells: Reticular cells, blood cells ID: network of reticular fibers embedded in cells Location: spleen Function: framework to support free blood cells

12/17/ Blood Connective Tissue Tissue: Blood C. T. Cell: RBC & WBC ID: RBC – look like life saver, no nucleous, high in number WBC – different shapes, have a nucleous, low in number Location: blood vessels Function: gas & nutrients transport, protection against infection

12/17/ C.T. Assignment View each assigned C.T. Complete illustrations in your worksheet

12/17/ Muscle Tissue ( Contracts producing movement ) Muscles cells are called fibers Cells vary in their number of nuclei and shape, and whether or not they are banded

Tissue: Smooth Muscle Cell: smooth muscle cell ID: many nuclei crammed in, no striation Location: stomach Function: movement of substances Tissue: Cardiac Muscle Cell: cardiac muscle cell ID: intercalated disks, striated uninucleated Location: heart Function: heart pump Tissue: Skeletal Muscle Cell: Muscle fiber ID: Striated with multiple nuclei Location: arm Function: movement of body

12/17/ Nervous Tissue Tissue: Nervous tissue Cell: Multipolar neuron ID: Cell body with processes Location: Nervous system Function: Conduction of nerve impulses

12/17/ Integumentary System (Skin) This organ system consists of 2 layers: –Epidermis: Stratified squamous E.T. –Dermis (papillary and reticular layers): Sebaceous & sweat glands Hair folicle Arrector pilli muscle Meissner corpuscles (sense receptors for light touch) –Hypodermis (not part of skin): Adipose C. T. Pacinian corpuscles (sense receptors for pressure) Learn locations of all four primary tissue types, and the assigned layers and structures on the skin model