Anatomy & Physiology, ch. 4 Tissues Anatomy & Physiology, ch. 4

Question of the Day What are the levels of organization found in the human body? 2

Levels of Organization Atoms, Molecules, Macromolecules, Organelles Cells Tissues Organs Organ Systems Organisms 3

Tissue Groups of cells with specialized structure/function 4 major types Epithelial, Connective, Muscular, Nervous 4

Epithelial Epithelia and Glands Important characteristics free surface exposed to environment or some internal chamber/passageway basement membrane attaches it to connective tissue Avascular 5

Function of Epithelia Physical protection Controls Permeability Provides Sensations Produces specialized Secretions glandular epithelium (exocrine and endocrine) 6

Cell Junctions between Epithelia Gap Junction connection via channel proteins cardiac muscle and smooth muscle tissue Tight Junction interlocking proteins on the outer lipid layer of membranes prevents loss of water and solutes between cells Desmosome protein filaments and intercellular cement 7

General Structure Contain microvilli or cilia on exposed surface specialize in active and passive transport increases surface area Basement membrane connects epithelium to connective tissue Stem cells responsible for cellular division and replacement/renewal of epithelia 8

Classification of Epithelia Cell Layers simple ephithelium Thin, areas of secretion or absorption line chambers/passageways stratified ephithelium Thicker, areas of mechanical/chemical stresses Cell Shape Squamous Cuboidal Columnar 9

Simple Epithelial Simple Squamous lining of body cavities, blood vessels, heart, surface of lungs, kidney tubules Simple Cubodial Secrets enzymes and buffers in pancreas/salivary glands, lines kidney tububles Simple Columnar Stomach, digestive tract, excretory ducts 10

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Pseudostratified Epithelia Appears to be many layers Nuclei at different levels Respiratory tract Ciliated pseudostratified epithelia line the nasal cavity, trachea, bronchi and portions of male reproductive system 12

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Transitional Epithelium Forms a barrier between waste Increase tension/pressure causes a change in cell shape Lines Ureters and Urinary Bladder 14

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Stratified Epithelial Squamous Epidermis, mouth, throat, vagina, anal canal Cubodial Sweat, salivary, mammary glands, pancreas, (lumen) Columnar Superfical layer is columnar; basal are cubodial Pharynx, male reproductive 16

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Glandular Epithelia Produce and secrete substances into ducts or bloodstream Exocrine Into a duct Apocrine-lose parts of cell during secretion Merocrine- water, protein-rich secretion via exocytosis Holocrine- entire cell lyses during secretion Secretions Serous:watery solution containing enzymes Mucous: thick, mucous Mixed: more than 1 type of gland cell, 2 different exocrine secretions or 1 exo/endocrine secretions Endocrine Into bloodstream/tissue 18

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Connective Tissue Never exposed to the environment outside the body Basic Structure Specialized cells Protein fibers Ground Substance 20

Functions of Connective Support and Protection Transport Materials Stores Energy Immunity 21

Classification of Connective Based on physical properties of ground substance Connective Tissue Proper many types of cells and fibers Fluid Connective Tissue distinctive cells in watery ground substance Supporting Connective Tissue Matrix is dense and closely packed fibers Cartilage and bone 22

Connective Tissue Proper Adipocytes Mast cells Near blood vessels (heparin & histamine) Macrophages Scavenger/defense cells Fibroblasts Most common and most numerous Star shaped and release 3 types of fibers Collagen Elastic Reticular 23

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Fibroblast Fibers Collagenous Elastic Reticular Thick collagen fibers that are flexible but slightly elastic; great textile strength Thin elastin fibers that stretch easily and resume shape thin collagen fibers that are branched and form delicate supporting networks Ligaments Tendons Vocal cords various organs 25

Loose Connective Tissue Least specialized Binds skin to underlying tissues, fills spaces between muscle, under most layers of epithelium aka. Areolar Tissues 26

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Adipose Tissues Formed when fat is deposited into cytoplasm of cells Cushions joints and some organs, takes up space, insulator, energy storage Between muscles, beneath skin, around organs and joints 28

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Dense Connective Tissue Closely packed collagen and elastin fibers Poor blood supply Extremely strong tissue Binds body parts, tendons, ligaments, scalera of eye 30

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Blood & Lymph Transports nutrients and other materials Maintains homeostasis Forms in the red bone marrow Comprised of red blood cells, white blood cells, platelets, and blood plasma 32

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Cartilage Ridge form of connective tissue Matrix is comprised of collagenous fibers Chondrocytes are located within the matrix in the lacunae Perichondrium surrounds cells and provides nutrients Tissue repair is extremely slow Provides support/protection, framework, structural models for bones 3 types 34

Cartilage Types Hyaline Elastic Fibrocartilage Fine collagen fibers; most common Dense elastin fibers; flexibility Tough collagen fibers End of bones, respiratory passage, nose Ears, larynx Spine, knee, pelvic girdle 35

Bone Ridgedness due to CaCO3 and Ca3PO4 Matrix has many collagenous fibers Osteocyte is in the lacunae forming a lamellae which when added to matrix forms the osteon Healing happens faster than cartilage Protection/support/framework 36

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Muscle Tissue Has the ability to contract 3 types Skeletal Smooth Cardiac 38

Muscle Tissue Types Skeletal Smooth Cardiac Voluntary; contains striations; stimulated by nerve impulse Involuntary; lacks striations Involuntary; striated; jointed cells via intercalated disc Attached to bone Walls of hallow organs Heart only 39

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Nervous Tissue Coordinates, regulates, and integrates body functions Comprised of Neurons Neurological cells help to support neurons 41

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