…pass the tissues please… Histology …pass the tissues please…

I. Intro to Histology Tissue definition: A group of similar cells working towards one unifying goal Tissues components Similar cells Extracellular Matrix - water, NaCl, ions, calcium, fibers, nutrients, etc..

I. Intro to Histology The 4 types of tissues Epithelial         * covers body surfaces         * lines hollow organs         * lines body cavities and ducts         * forms glands and secretions Connective         * protection and support         * binding together (like glue)         * energy storage Muscle * movement and force (including peristalsis) Nervous * coordinates body activities

I. Critical Thinking Question? What tissue type does blood belong to? A. Epithelial B. Connective C. Muscle D. Nerve E. Blood isn’t a tissue

II. Epithelial Anatomy Location Covers external surfaces Lines internal surfaces such as cheeks, blood vessels, organs etc… Glands

II. Epithelial Anatomy Basic Anatomy Cells bound tightly together Classified by shape of cells and number of layers Avascular Contain Stem cells Has an exposed surface (Apical membrane) Has a surface bound to connective tisuuse (basal membrane) Apical Surface Basal (basement) Connective tissue

III. Epithelia Physiology Function Provides protection internally and externally Controls permeability Provides for touch/stimuli Produces secretions: exocrine – released onto surfaces digestive enzymes, sweat endocrine – releases into tissue fluid and blood Hormones (chemical messengers) from pancreas, thyroid, pituitary, etc

II. Epithelial Anatomy Basic Anatomy Apical Surface may contain specialized structures Cilia for movement Microvilli for increased absorption (Brush Borders)

II. Epithelial Anatomy The Brush Border

II. Epithelial Anatomy Basic Anatomy Basal Membrane: “Basement” Provides strength to epithelium Creates barriers to prevent molecules from entering connective tissue

II. Epithelial Anatomy Classification Systems By Layers Shape Simple: single Stratified: multiple Pseudostratified: appears multiple, but really simple Shape Squamous: Flat Cubodial: cube-like Columnar: column-like Transitional: changes Example. Simple cubodial = 1 cell thick of cube shaped cells

IV. Epithelial Tissues: Simple Squamous Anatomy Lining of body cavities, organs, blood vessels, alveoli lung surface Serous Membranes Physiology Diffusion Secretions

IV. Epithelial Tissues: Simple Squamous

IV. Epithelial Tissues: Simple Squamous

IV Epithelial Tissues: Simple Cuboidal Anatomy Digestive tract, Kidney tubules, glands Physiology Absorption and Secretions

IV Epithelial Tissues: Simple Cuboidal

IV Epithelial Tissues: Simple Columnar Anatomy Lining of digestive tract Modified by presence of cilia Contains “Goblet cells” Physiology Help move surface material Absorption

IV Epithelial Tissues: Simple Columnar

IV Epithelial Tissues: Simple Cuboidal Simple Columnar

IV Epithelial Tissues: Simple Columnar

IV Epithelial Tissues: Stratified Squamous Anatomy Outer most layer- squamous cells Inner- cuboidal or columnar Lining of mouth, esophagus, skin Can be keratinized Physiology Protection Secretion Moistens membranes

IV Epithelial Tissues: Stratified Squamous Stratified Squamous – non keratinized

IV Epithelial Tissues: Stratified Squamous Keratinized Stratified Squamous Keratin: Waxy protective coverings Waterproofs

IV Epithelial Tissues: Pseudostratified Columnar Anatomy One layer All attach to the basal membrane Appears stratified Upper respiratory tract Physiology Move material

IV Epithelial Tissues: Pseudostratified Columnar

V. Connective Tissue Abundant extracellular material Matrix (dominant part) or ground substance Fiber, cells in liquid, gel, or solid matrix Never exposed to “outside environment” If exposed, causes a response for “damage control” (ie. Bleeding) Functions Bind and/or support other tissue Energy storage Defense of the body

V. Connective Tissue Classification is based on the composition of matrix… 1. Connective Tissue Proper – loose and dense. subcutaneous, fat, tendons and ligaments 2. Fluid connective tissue 3. Supporting connective tissue

V. Connective Tissue Connective Tissue Tissue Proper Fluid Supporting Blood Lymph Loose Dense Cartilage Bone Dense Regular Dense Irregular

VI. Connective Tissue Proper - Either loose or dense - Examples: subcutaneous, fat, tendons and ligaments Tissue Proper is composed of … Fibroblasts – homeostasis of tissue Macrophages – engulf waste Fat cells – permanent residents Mast cells – near blood vessels, release chemicals to elicit injury response

VI. Connective Tissue Proper 3 Fibers Collagen - long and straight, most common fibers, strong but flexible Elastic – branched and wavy, contains elastin, are elastic Reticular – less common, thin, branching, interwoven framework of fibers

VI. Connective Tissue Proper Loose or areolar Fewer fibers but all kinds Cushioning and support Deep to skin, between muscles, around vessels Dense Fibrous abundant, organized collagen fibers Tendons and ligaments Dense Regular or Dense irregular

VI. Connective Tissue Proper Dense Regular collagen runs parallel, packed tightly, aligned with forces Tendons and ligaments Provides attachements Dense Irregular with collagen to provide support and strength Gives skin its strength

VII. Adipose Adipose Connective Tissue Loose connective Store large droplets of fat Large “marshmellow” looking cells Nuclei squished to one side

VIII. Fluid Connective Tissue Blood Plasma: Liquid matrix RBC’s WBC’s Lymphatic System Lymph: fluid portion Part of your immune system

IX. Supporting Connective Cartilage Connective Tissue Rubbery consistency (matrix) Avascular

IX. Supporting Connective Types of Cartilage Hyaline – most common Joints, rib cage, respiratory tract Elastic Mostly elastic fibers, Very flexible Outer ear, nose, epiglottis Fibrocartilage Mostly collagen fibers, durable, strong, tough Backbone (resist compression, absorb shock…)

IX. Supporting Connective Bone Osteocytes: bone cells Hardest connective tissue Spongy bone Ends of long bones Compact Shafts of long bones Tightly organized

Bone Connective Tissue

X: Muscle Functions: Three types 1. Skeletal 2. Smooth 3. Cardiac Cells have ability to contract Locomotion Support Other body movement

X: Muscle: Skeletal Voluntary movement Long and cylindrical (up to 25 cm) Transverse striation multi-nucleated

X: Muscle: Smooth Involuntary movement Long, spindle shape Single nucleus Internal organs

X: Muscle: Cardiac Striations Involuntary One nucleus Intercalated disks Heart muscle

XI: Nervous Cells very high ability to Two types of cells Respond to stimuli Transmit impulses Two types of cells Neurons – conduct nerve impulses Neuroglia – provide physical support, maintain chemical composition of tissue fluids, nutrients…

XI: Nervous Cell Body(3) Dendrites (5) Axon(1) Very LONG cells Can’t be replaced Very LONG cells Create the human “electrical system”