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Laboratory Two. Histology. 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
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Laboratory Two Histology
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
Four Primary Tissue Types • Epithelial - lines & covers surfaces • Connective - protects, supports, & binds • Muscular - contracts & produces movement • Nervous – generates & conducts nerve impulses
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
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
Simple Squamous Epithelial Tissue Tissue: simple squamous E. T. Cell: squamous epithelial cell ID: flattened cells, mosaic shape Location: alveoli of lungs Function: diffusion
Simple Cuboidal Epithelial Tissue Tissue: simple cuboidal E.T. Cell: cuboidal epithelial cell ID: round centrally located nucleous Location: salivary glands Function: secretion
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)
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)
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)
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)
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
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
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
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
Cartilage Connective Tissue Tissue: Hyaline cartilage C. T. Cell: Chondrocytes ID: Cells withclear 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 withclear periphery embedded in a semi-fluid matrix,nucleous (dark dots) Location: Capping the end of bones Function: support, protection, cushion Chondrocytes inside lacunae (magnified) Chondrocytes inside lacunae (magnified)
Osseous Connective Tissue Tissue: Osseous C. T. Cell: Osteocytes ID: Cells arranged circularly around the center,nucleous (dark dots) Location: skeleton Function: support, protection Osteocytes inside lacunae (magnified)
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
Blood Connective Tissue Tissue: Blood C. T. Cell: RBC & WBC ID: RBC – look likelife 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
C.T. Assignment • View each assigned C.T. • Complete Tables 2.3 & 2.4, p34 & 35
3. Muscle Tissue(Contracts producing movement) Fig. 2.17, p26 & the model in lab: Three muscle cells/fibers
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
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
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.