Laboratory Two Histology 9/19/2018

Histology Study of structure and function of tissue: Groups of cells that are structurally and functionally the same A combination of living and no-living material Go over each microscope Illustrate and write anatomical details Touch only the fine focus knob Pointer helps you locate the assigned structure 9/19/2018

Four Primary Tissue Types Epithelial - lines & covers surfaces Connective - protects, supports, & binds Muscular - contracts & produces movement Nervous – generates & conducts nerve impulses 9/19/2018

1. Epithelial Tissue (E.T.) Lines, covers surfaces both inside & out Consists of many cells, tightly packed together Usually arranged in layers (except glands, p22, fig 2.3) Simple (1 layer) or stratified (2 or more layers) Attached to deeper tissue by basement membrane A free surface is found opposite basement membrane In stratified E.T., a layer of mitotically active cells are found in direct contact with basement membrane called basal cell layer You need to be able to find free surface and BM in microslides Basement membrane is a complex structure produced by the basal surface of the epithelium and the underlying connective tissue. Basement membrane consists of laminins, collagens (predominantly collagen IV), proteoglycans, calcium binding proteins such as fibulin, and various other structural or adhesive proteins. The major non-collagenous components are the heterotrimeric laminin glycoproteins 9/19/2018

Specific Types of Epithelial Tissues are Characterized by: Number of layers: Simple (1 layer) - secretion, absorption, filtration Stratified (>2 layers) – wear & tear Cell shape (p22, Fig2.2) 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 One layer means one side you have free surface and one side is attached to another tissue. 9/19/2018

Simple Squamous Epithelial Tissue Tissue: simple squamous E. T. Cell: squamous epithelial cell ID: flattened cells, mosaic shape Location: alveoli of lungs Function: diffusion Show cell membrane, nucleous, MB, basal cell layer, free surface, CT for each ET Alveoli: microscopic sacs in lungs which exchange gas by diffusion Do you think this will be a good tissue for wear & tear? 9/19/2018

Simple Cuboidal Epithelial Tissue Tissue: simple cuboidal E.T. Cell: cuboidal epithelial cell ID: round centrally located nucleous Location: salivary glands Function: secretion 9/19/2018

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) 9/19/2018

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) 9/19/2018

Pseudostratified Ciliated Columnar E. T. 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 Higher magnification (showing cilia and goblet cell) 9/19/2018

Transitional Epithelial Tissue Tissue: T. E.T. ID: stratified columnar when stretched Location: urinary bladder (distended) Function: accommodates fluctuation in the volume of fluid, protects against caustic effect of urine Relaxed urinary bladder (Stratified cuboidal cells when relaxed) 9/19/2018

E.T. Assignment View each assigned E.T. through microscopes or as micrographs Complete Tables 2.1 & 2.2, p31 & 33 Illustrate the specific tissue Label the assigned structures on your illustration Record & learn one location and one function for each tissue 9/19/2018

2. 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 Free fatty acids enter adipocytes and reassemble as triglycerides 9/19/2018

Areolar Connective Tissue Tissue: Areolar C. T. Cell: Fibroblast (most common) ID: Irregularly & loosely arranged protein fibers, dots are nucleous of fibroblasts Location: Under the skin Function: Attachment, support Macrophages are large cells with obvious cytoplasm rarely seen! 9/19/2018

Adipose Connective Tissue Tissue: Adipose C. T. Cell: Adipocyte ID: Large clear cells with nuclei pushed to the sides Location: Breasts, hips Function: Energy storage, cushioning, insulation 9/19/2018

Cartilage Connective Tissue 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 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 Lacuna is the gap in the matrix after the cell dies We will study one of the three cartilage CT: Hyaline, Fibrocartilage, and elastic cartilage Chondrocytes inside lacunae (magnified) Chondrocytes inside lacunae (magnified) 9/19/2018

Osseous Connective Tissue Tissue: Osseous C. T. Cell: Osteocytes ID: Cells arranged circularly around the center, nucleous (dark dots) Location: skeleton Function: support, protection Cells arranged circularly around the center where the blood vessels are, they are trapped inside the bony matrix after laying it Go over the osseous connective tissue model in the lab, show lacunae Osteocytes inside lacunae (magnified) 9/19/2018

Dense Regular Connective Tissue Tissue: Dense regular 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 9/19/2018

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 9/19/2018

C.T. Assignment View each assigned C.T. Complete Tables 2.3 & 2.4, p34 & 35 9/19/2018

3. Muscle Tissue (Contracts producing movement) Fig. 2.17, p26 & the model in lab: Three muscle cells/fibers 9/19/2018

4. Nervous Tissue (Generates & conducts nerve impulses, responds to stimuli) Fig. 2.18, p27 & the model in the lab: Nerve cell or neuron ID: Large cell body with a few short branches and one long branch 9/19/2018

Integumentary System (Skin) This organ system consists of: Epidermis: Stratified squamous E.T. Dermis: Sebaceous & sweat glands Arrector pilli muscle Meissner (light touch) & pacinian (pressure) corpuscles (sense receptors) Hypodermis (not part of skin): Adipose C. T. Learn locations of all four primary tissue types, and the assigned layers and structures on the skin model Consider your own body and apply common sense to complete Table 2.5, p36 9/19/2018

Table 2.6, p. 37 ( Epithelial Membrane) A thin layer that covers a structure or lines a cavity. Consists of E.T. and C.T. Mucous membranes (line cavities that open to the outside) Serous membranes (line cavities that do not open to the exterior) Other membranes: cutaneous membrane (stratified squamous ET and dense CT) synovial membrane (lines inside of joint cavities) periosteum (surrounds bone) Read relevant material in your textbook Look up membrane, secretion, location and body cavities. Other membranes: cutaneous membrane (SSET and dense CT) and synovial membrane (lines inside of joint cavities), periosteum (surrounds bone) 9/19/2018