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Body Tissues. Chapter 3 – Part 2. Histology 4 Tissue Types: 1. Epithelial – (covering) 2. Connective – (support) 3. Muscle – (movement) 4. Nervous – (control). Tissue. Lining, covering, & glandular Functions: Protections, absorption, filtration, & secretion. Epithelial Tissue.
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Body Tissues Chapter 3 – Part 2
Histology • 4 Tissue Types: • 1. Epithelial – (covering) • 2. Connective – (support) • 3. Muscle – (movement) • 4. Nervous – (control) Tissue
Lining, covering, & glandular Functions: Protections, absorption, filtration, & secretion Epithelial Tissue
Special Characteristics: • Cells fit closely together to form sheets • Has a free surface (apical surface) • Lower surface – (basement membrane) • Epithelial to connective • Avascular – no direct blood supply • Diffusion • Regenerate easily Epithelial Tissue, Cont’d…
Classification of epithelium • Named according to # of layers & shape of cells at the free surface • Layers: • Simple (1 layer) • Stratified (2 or more layers) • Shape: • Squamous – flat • Cuboidal – cube shaped • Columnar – taller than wide Epithelial Tissue, Cont’d…
Epithelial Tissue, Cont’d… • Simple Epithelium: absorption, secretion, & filtration • Simple Squamous Epithelium – forms serous membranes (serosae - fluid) • Lines body cavities & organs
Epithelial Tissue, Cont’d…Simple Epithelium, cont’d… • Simple Cuboidal – glands & ducts
Epithelial Tissue, Cont’d…Simple Epithelium, cont’d… • Simple columnar epithelium – forms mucus membranes (mucosae). • Lines cavities open to exterior • Ex. Respiratory Tracts, Digestive Tracts
Epithelial Tissue, Cont’d…Simple Epithelium, cont’d… • Pseudostratified Columnar Epithelium • Lines Respiratory Tract • Ciliated
Epithelial Tissue, Cont’d… • Stratified Epithelia–layered; protects • Stratified Squamous Epithelium – most common; high abuse & friction. • Ex. Skin, mouth, esophagus
Epithelial Tissue, Cont’d…Stratified Epithelia, cont’d… • Stratified Cuboidal & Stratified Columnar: • Rare; large ducts
Epithelial Tissue, Cont’d…Stratified Epithelia, cont’d… • Transitional Epithelia:function is stretching
Epithelial Tissue, Cont’d… • Glandular Epithelia: glands; produces & secretes • 2 types: • 1. Endocrine Glands (ductless) • Directly into the blood stream • Hormones (ovaries, testes, adrenal) • 2. Exocrine Glands (ducts) • Sweat, oil • Liver
Answers: A - simple columnar epithelium. B - simple columnar epithelium with cilia. C - stratified squamous epithelium. D - simple squamous epithelium. E - transitional epithelium. F - pseudostratified epithelium. G - stratified squamous epithelium. H - choanocytes I - stratified columnar epithelium with cilia.
Functions: protection, support, & binding together Most abundant tissue type Found everywhere in the body Connective Tissue
Connective Tissue, Cont’d… • Some vascular • Some avascular (cartilage) – heals slowly • Many different types of cells • Extracellular Matrix: non-living substance outside of cell; can be liquid, semisolid or gel-like, or very hard • Examples: Fat (soft); Bone (hard) • Tissue can bear weight, withstand stretching & abrasions. Common Characteristics:
Connective Tissue, Cont’d… • Bone (osseous tissue) – vascular • Bone cells surrounded by hard matrix of calcium salts & collagen fibers • Function: protect & support other organs Types of Connective tissue:
Connective Tissue, Cont’d…Types, Cont’d… • Cartilage – avascular • Less hard/more flexible than bone • Hyaline cartilage- voice box; covers end of bone; attaches ribs to sternum; skeleton of fetus • Elastic cartilage- more elasticity. Ex: ears, nose • Fibrocartilage- highly compressible and cushion-like; between vertebrae
Connective Tissue, Cont’d…Types, Cont’d… • Dense Connective Tissue (fibrous tissue) • Mostly collagen fibers • Forms strong, rope-like structures • Ex: Tendons; Ligaments
Connective Tissue, Cont’d…Types, Cont’d… • Loose Connective Tissue- Softer & fewer fibers • Areolar Tissue • Soft, pliable tissue that protects & wraps body organs • Universal packing tissue & connective tissue glue that helps hold internal organs together • Edema- areolar tissue soaks up fluid in inflamed area; swells & becomes puffy
Connective Tissue, Cont’d…Types, Cont’d… • Adipose Tissue – “fat” • Forms subcutaneous layer below skin; insulates & protects from heat & cold. Loose Connective Tissue, Cont’d
Connective Tissue, Cont’d…Types, Cont’d… • Reticular Connective Tissue • Delicate network of fibers • Found in lymph nodes • Ex: Spleen and bone marrow.
Connective Tissue, Cont’d…Types, Cont’d… • Blood – “vascular tissue” • Blood cells surrounded by blood plasma • Protein fibers in blood • Blood clotting
Specialized to contract or shorten Muscle Cells (muscle fibers) Muscle Tissue
MuscleTissue, Cont’d… • Skeletal Muscle- (striated muscle) • Attached to skeleton; forms flesh • Voluntary • Cells are long, cylindrical, multinucleate, & striated Types of Muscle Tissue (3 types)
MuscleTissue, Cont’d…Types, Cont’d… • Cardiac Muscle- (heart only) • Has striations, uninucleate; fit tightly together; gap junctions • Involuntary
MuscleTissue, Cont’d…Types, Cont’d… • Smooth Muscle- (visceral) • No striations, single nucleus & spindle-shaped (pointed at both ends) • Found in walls of stomach, bladder, uterus & blood vessels (hollow organs) • Contracts slowly • Peristalsis – wave-like motion through small intestine • Involuntary
Cells = Neurons • Function = Irritability & Conductivity • Tissue Repair (Wound Healing) • Defense at tissue level – skin, mucous membranes, cilia, and acid in stomach glands. • Inflammation – body response to prevent further injury. IV. Nervous Tissue
Immune Response – specific to invaders • 2 Ways tissue repairs (depends on tissue type and severity of injury) • Regeneration: replacement of destroyed tissue by same kinds of cells • Fibrosis: repair by dense connective tissue (fibrous) – forms scar tissue IV. Nervous Tissue….cont’d
Process of tissue repair: • Capillaries become permeable/allows clotting fibers to seep to injury (bleed) • Blood Clot forms/then scab • Granulation tissue forms (new skin) • Epithelium regenerates/scab falls off (healed) **Scar Tissue cannot function as original cells. IV. Nervous Tissue….cont’d
Growth through cell division puberty Replacement of tissue exposed to friction lifetime Epithelial Tissue – Mitotic Connective Tissue – Mitotic (forms scar tissue) Muscle Tissue – Amitotic after puberty Nervous Tissue – Amitotic shortly after birth V. Development Aspects of Cells & Tissues
Aging – Caused by chemical and physical exposures and genetics, and stress • Neoplasm: abnormal Cell division – multiply wildly – benign or malignant (tumor) • Hyperplasia: enlarged tissue due to local irritant or condition • Ex. Anemia/Bone marrow undergoes hyperplasia to produce more red blood cells • Ex. Breast enlargement during pregnancy V. Development Aspects of Cells & Tissues…Cont’d
Atrophy: decrease in size – loss of stimulation • Ex. Muscle reduction from wearing a cast V. Development Aspects of Cells & Tissues…Cont’d