Tissues

1. Tissues

2. Students, • Please note: This is a rough draft of a power point that has not been proofread or redrafted. I am sorry for any spelling, grammatical errors, etc. • It is basically a rough draft for key points of the tissues to go along with my lecture-lab presentation of the tissues. • It does not contain everything you need to know. • It is merely a guide. • Please use your objectives and exercises to study thoroughly for the lab quizzes.

3. Never use coarse adjustment on any power higher than 4x !

4. Epithelial tissue • Lines internal body cavities and passage ways; covers body surfaces • Usually named after the cell shape • 2 questions • How many layers of epithelial cells are present? • One-simple • More than one-stratified • What is the shape of the cells at the apical surface( the top of the cell which faces the lumen or body surface) ? • Squamous-flat like a fried egg( yolk is the nucleus)

5. Flat shape allows easy diffusion; filtration, secretion-reduces friction • cuboidal epithelium: ( cube-shaped) ( die-one) shaped like an ice cube; large round , centrally located nucleus • Columnar epithelium (column-shaped) oblong or oval shaped nucleus is generally located at the base of the cell • Exceptions • Pseudostratified columnar epithelium • Pseudo-false • “falsely stratified” • Looks like multiple layers of cells , but each cell actually touches the basement membrane • Nuclei of cells are at different layers • Note: these cells are ciliated in the trachea, nasal cavity and bronchi.

6. Transitional epithelium –what does transition mean? • Relaxed bladder-dome-shaped cells at the surface; note: nuclei are key feature-note shape and stain • Bladder, ureters, urethra, renal pelvis-things that have to change shape • Stretched-cells appear more flattened at the surface.

7. Connective Tissue • Connective tissue is for structural support of other tissues and organs. It is the most abundant type of tissue. It is composed of cells, fibers , and ground substance. • The two most common types of proteins are elastin and collagen. Collagen-strength (tendons) elastin(stretch) (aorta) • Elastin- stains black with our slides. • Collagen- stains pink or blue with our slides.

8. Loose connective Tissue • Areolar connective tissue-collagen, elastin, and fibroblasts—make collagen • Adipose connective tissue-adipocytes-fat cells-note: uninuclear cells; all the fat pushes the nucleus to the side of the cell. • Reticular connective tissue: cobwebs; network of reticular fibers which help to support many different cell types. • Spleen, lymph nodes, liver, kidney • Supportive net-like structure for many different cell types

9. Dense regular connective tissue • Fibrous connective tissue-collage fibers make-up most of dense regular connective tissue • Tendons- The Achille’s tendon (Calcaneal tendon) is the strongest tendon in the body. • Regular arrangement of collagen fibers • Slightly wavy appearance • Flattened fibroblast nuclei • Dense irregular connective tissue • Random arrangement of collagenfibers; patchwork • Dermis of the skin • Can be pulled in many different directions; pull on your skin-it pulls in many different directions • Helps resist stresses applied

10. Cartilage( no blood supply) • Key feature: Chondrocytes with in lacunae • Chondro: cartilage • Can tell the different types based on the matrix-firm gel material that contains protein fibers, etc. • Swiss cheese, Geico commercial or eyes staring at you! • Hyaline cartilageconnective tissue: smooth purple matrix • Elastic cartilageconnective tissue: black elastin fibers • Fibrocartilageconnective tissue; note:collagen fibers stain blue on these slides

11. Elastic connective Tissue • Places where you need stretch-Aorta; helps control blood Pressure; stretch and recoil of the tissue. • Bone Connective tissue • Looks like tree trunks –osteon of bone( compact bone) • Osteocytes Osteo-bone Cyte-cell Hard substance composed of calcium phosphate and collagen fibers • Blood connective tissue • Note the diversity of connective tissue; tissues as hard as bone and something with the fluidity of blood • Erythrocytes: mature red blood cells are anuclear; shape and function; transport respiratory gases • Erythro:red • Cyte:cell

12. Leukocytes • Leuko-white • Cyte-cell • Have a dark staining nucleus • 5 specific types-211 material • Involved in immune responses; defense

13. Muscle • Skeletal muscle • Striations, multinucleate; stacked logs with zebra stripes; many nuclei / cell; regular arrangement; voluntary • Cardiac muscle • Intercalated disc- specialized junction-allows passage of ions, yet keeps the cells in close contact or glued together so that contraction can occur in an orderly fashion; special gap and desmosome junction • Usually uninuclear • -interbranching pattern-Purkinje system or intrinsic conduction system; involuntary • Smooth Muscle • Involuntary; no striations; staggered, tapered cells; usually oval shaped nuclei

14. Nervous Tissue • Conduct electrical impulse; fast response • Functional unit: neuron

15. Integumentary System • Skin • Largest organ in the body • Three regions (layers) of the skin • EpidermisEpi- upon, derm-: skin • Stratified squamous epithelium • Dermis • Hypodermis(subcutaneous layer) • Hypo-under, below • Mainly adipose connective tissue • Also has a good supply of blood vessels so subcutaneous injections are given with a hypodermic needle

16. Five cell layers of the epidermis • “Can Lucy give Some blood?” • From superficial to deep • Thick Skin • Stratum CorneumDead cells ; water proofing layer; protection; slough off • Stratum lucidum What does lucid mean? • Stratum granulosumLook for black granules. • Stratum spinosumSpine-like appearance of interconnecting cells • Stratum basaleBottom layer of cells; in contact with basement membrane –one cell layer • Thin skin does not have a stratum lucidum.

17. Two regions of the dermis • Papillary region • Upper one fifth of the dermis • Consists primarily of loose connective tissue. • Note: Meissner’s corpuscles are in the papilla of the dermis. • Function in fine touch • Reticular region • Deeper four fifths of the dermis • Consists primarily of dense irregular connective tissue

18. Sensory Receptors and Sweat glands • Meissner’s corpuscles: tactile; fine touch • Pacinian corpuscle: deep pressure; “ lamellated corpuscle”; “ dried out sliced onion”; located near the surface of the hypodermis or deep in the reticular layer of the dermis Sudoriferous Glands Exocrineglands-secrete their secretions into ducts The ducts are lined by stratified cuboidal epithelium-usually only about 2 cell layers sudor:sweat eccrine: merocrine; widely distributed; secrete a watery secretion apocrine: armpits, groin, nipples; secrete both proteins and lipids; “bacteria food”; body odor

19. Hair • Sebaceous glands- often associated with hair follicles; secrete an oily secretion called sebum • Arrector pili muscle; smooth muscle; involuntary; “goose bumps” • Hair follicle; makes the hair shaft • Hair root