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Tissues

Tissues. Groups of cells with a common structure and function Four primary types Epithelium Connective tissue Muscle Nervous. Epithelial Tissues. Functions: protection, filtration, absorption, secretion Location: Line body cavities, cover body surfaces Glandular epithelia

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Tissues

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  1. Tissues • Groups of cells with a common structure and function • Four primary types • Epithelium • Connective tissue • Muscle • Nervous

  2. Epithelial Tissues • Functions: protection, filtration, absorption, secretion • Location: • Line body cavities, cover body surfaces • Glandular epithelia • Exocrine glands: secretion to exterior via ducts • Endocrine glands: secretion directly into blood

  3. Epithelium Characteristics • Cells fit closely together • always one free surface • lower surface bound by “basement membrane” • Avascular (have no blood supply) • Regenerate easily if well nourished

  4. Epithelial Tissues: Classification • 1. Cell shape • Squamous: flattened cells • Cuboidal: cube shaped • Columnar: column shaped

  5. Epithelial Tissues: Classification • Number of cell layers • Simple – one layer • Stratified – more than one layer

  6. Epithelial Tissues: Attachments • Basement membrane • Structural support, attachment to tissue underneath • Made of secreted proteins

  7. Attachments: Junctions Between Cells • Tight junctions: nothing passes • Adhesion junctions: some movement between cells • Gap junctions: protein channels Figure 4.2

  8. Stratified Epithelium • Stratified squamous • Cells at the free edge are flattened • protective covering where friction is common • Locations • Skin • Mouth • Esophagus Figure 3.18e

  9. Connective Tissue Functions • Binds body tissues together • Supports the body • Provides protection Composed of cells and extracellular matrix: 1. Ground substance of water, proteins and sugars 2. Fibers

  10. A. Fibrous Connective Tissue • Function: strength and flexibility • Fibers: collagen, elastic, reticular • Matrix: water, polysaccharides, proteins • Cells: fibroblasts, WBCs, fat cells

  11. A. Fibrous Connective Tissue - 4 types • Loose (areolar): surrounds many organs, lines cavities around blood vessels • Dense: tendons, ligaments, deeper layers of skin

  12. A. Fibrous Connective Tissue Elastic: surrounds stomach, bladder, maintains shape • Reticular: internal framework of soft organs (liver) and lymphatic system

  13. B. Special Connective Tissues • Blood: fluid matrix of plasma; red blood cells, white blood cells, and platelets • Adipose tissue: fat cells; function in insulation, protection, and energy storage

  14. B. Special Connective Tissue • Cartilage: no blood vessels, high collagen content • Bone: inorganic matrix with calcium salts for hardness

  15. Muscle Tissue: • Skeletal muscle • moves body parts • voluntary, multi-nucleated • Cardiac muscle • only in the heart • involuntary, single nuclei • Smooth muscle • surrounds hollow structures • involuntary, single nuclei

  16. Nervous Tissue: Transmit Impulses • Neuron: specialized nervous system cell • Structure: cell body, dendrites, axon • Glial cells: support cells to neurons

  17. Tissue Repair • Regeneration • Replacement of destroyed tissue by the same kind of cells • Fibrosis • Repair by dense fibrous connective tissue (scar tissue) • Determination of method • Type of tissue damaged • Severity of the injury

  18. The Language of Anatomy: Body Planes Figure 1.6

  19. Anatomical Position or Direction Figure 4.9

  20. Tissue Membranes: Line Body Cavities • Body surfaces, cavities are covered by tissue membranes • Composed of tissues (epithelium and connective)* 4 types

  21. 1. Serous Membranes - reduce friction between organs • Lines interior body cavities • Serous layers separated by serous fluid Figure 4.1c

  22. Body Cavities Figure 4.8

  23. 2. Mucous Membranes - lubricate surfaces, capture debris • Epithelium (various types) plus loose connective tissue • Lines all body cavities that open to body’sexterior • absorption or secretion Figure 4.1b

  24. 3. Synovial Membrane - lubricates joints • Connective tissue only • Lines fibrous capsules surrounding joints Figure 4.2

  25. 4. Cutaneous Membrane - skin Protective boundary • Epidermis • Keratinized stratified squamous epithelium • Dermis • dense connective tissue Figure 4.1a

  26. Review - Tissue Membranes: • Serous membrane: lines internal cavities • Mucous membrane: lines external cavities • Synovial membrane: lubricate joints • Cutaneous membrane: skin

  27. Organs and Organ Systems Perform Complex Functions • Organ systems • Groups of organs that perform a common function. • Digestive system: mouth, throat, stomach, intestines, liver • Lymphatic system: lymph nodes, tonsils, spleen

  28. Homeostasis • Maintenance constant internal conditions • Mechanisms • Negative feedback: deviations from normal detected and counteracted • Components: controlled variable, sensor, control center, effector

  29. Integumentary System Forms the external bodycovering • Protects deeper tissue frominjury • Synthesizes vitamin D • Location of cutaneousnerve receptors • Aids in heat regulation • Aids in excretion of urea and uric acid Figure 1.2a

  30. Skin: Integumentary System Figure 4.10

  31. Appendages of the Skin • Sweat glands • Widely distributed in skin • Eccrine • Open via duct to pore on skin surface • Over entire body • Apocrine • Ducts empty into hair follicles • Axillary, pubic area

  32. Associated Hair Structures • Hair follicle • Dermal and epidermal sheath surround hair root • Arrector pilli • Smooth muscle • Sebaceous gland (oil) • Sweat gland Figure 4.7a

  33. Appendages of the Skin • Hair • Produced by hair bulb • Consists of hard keratinized epithelial cells • Melanocytes provide pigment for hair color Figure 4.7c

  34. Nail Structures • Free edge • Body • Root of nail • Cuticle -proximal nail fold that projects onto the nail body Figure 4.9

  35. Melanin • Pigment (melanin) produced by melanocytes • Color is yellow to brown to black • Melanocytes are mostly in the stratum basale • Amount of melanin produced depends upon genetics and exposure to sunlight

  36. Skin Cancer Types • Basal cell carcinoma • Least malignant • Most common type • Arises from stratum basale • Squamous cell carcinoma • Arises from stratum spinosum • Metastasizes to lymph nodes • Early removal allows a good chance of cure

  37. Skin Cancer Types • Malignant melanoma • Most deadly of skin cancers (50% mortality) • Cancer of melanocytes • Metastasizes rapidly to lymph and blood vessels • Detection uses ABCD rule

  38. ABCD Rule • A = Asymmetry • Two sides of pigmented mole do not match • B = Border irregularity • Borders of mole are not smooth • C = Color • Different colors in pigmented area • D = Diameter • Spot is larger then 6 mm in diameter

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