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Tissues. Chapter 5. Tissues . Groups of cells to perform specialized structural and functional roles. 4 major types of tissues: Epithelial Connective Muscle Nervous. Epithelial Tissue. EpT. Epithelial Tissue.
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Tissues Chapter 5
Tissues • Groups of cells to perform specialized structural and functional roles
4 major types of tissues: • Epithelial • Connective • Muscle • Nervous
Epithelial Tissue • Cover all body surfaces both interior and exterior, the major tissue of most organs
This tissue has two sides, one free side, and one attached by a basement membrane. • Lacks blood vessels
Functions • Secretion • Absorption • Excretion • Sensory reception • protection
Types Simple squamous Simple cuboidal Simple columnar Pseudostratified columnar Stratified squamous Transitional epithelium
1. Simple squamous • Single layer of thin flattened cells. • Cells are tightly packed • Nuclei are broad and thin • Located in areas of diffusion
2. Simple cuboidal • Single layer of cubed cells • Centrally located spherical nucleus • Located in areas of secretion
3. Simple Columnar • Single layer of elongated cells • Nuclei located in a line near the basement membrane
Located in the linings of most organs • Thick for protection • Microvilli for increased surface area • Goblet cells to produce mucus.
4. Pseudostratified Columnar • Appear layered (Are NOT!) • Nuclei are located at more than one level • Goblet cells spread throughout
Cilia to keep mucus moving • Located in tubes for transport (not vessels)
5. Stratified Squamous Epithelium • Many layers of cells making a relatively thick tissue • Cells reproduce in deep layers, older cells are pushed outward to die and be sloughed off.
Located in areas of exposure • Contains the protein keratin in areas of outward exposure
6. Transitional Epithelium • Specialized to deal with changing tension. • When an organ is contracted the cells appear layered • Lining may stretch to 1 cell thick.
Connective Tissue • The most abundant tissue type by weight. • Tissue varies in consistency from liquid semi-solid solid.
Functions • Provides support • Serves as framework • Fills spaces • Stores fat • Produces blood cells
6. Provides protection against infection 7. Helps repair tissue damage
Cell Types • Resident cells: present in stable numbers • Wandering cells: appear temporarily in injured tissues • Mast cells: large, widely distributed, release heparin and histamine.
Fiber Types • Collagenous: relatively thick, flexible but not very elastic, withstands a pulling force. (tendon) • Elastic: not as strong but very elastic (vocal) • Reticular: very thin, highly branched, form delicate supporting networks.
CT types • Loose CT (areolar): • binds skin to underlying organs • fills spaces between muscle • contains numerous blood vessels • Layered fibers separated by a gel-like substance
2. Adipose (fat): • Store fats in droplets • Found beneath the skin, between muscles, and around organs • Used for protection and insulation
3. Fibrous CT: • Poor blood supply • Densely packed tissue • Withstand strong pulling force
4. Cartilage: • Rigid CT • Chondrocytes develop in lacunae • Covered in perichondrium • Blood supplied by perichondrium
Cartilage types: • Hyaline: delicate, trachea • Elastic: flexible, ears • Fibrocartilage: shock absorbing, intervertebral discs
5. Bone: • Most rigid CT • Due to mineral salts
6. Blood: • Most fluid • Function in transport and regulation • Components: • Plasma: fluid • RBC: carry oxygen • WBC: immune function • Platelets: cellular particles
Muscle Tissue • Contractile fibers • Skeletal • Smooth • Cardiac
Nervous Tissue • Highly conductive • Brain, spinal cord, and peripheral nerves • Neurons: individual nerve cells • Neuroglial cells: support cells, connect neurons to blood vessels