tissue level of organization
DESCRIPTION
Tissue level of organization. Fall 2012 . vocab development. holos – entire hyalos – glass inter – between krinein – to separate lacus – lake meros – part neuro – nerve os – bone . a – without apo – front cardium – heart chondros – cartilage dendron – tree desmos – ligament - PowerPoint PPT PresentationTRANSCRIPT
TISSUE LE
VEL OF
ORGANIZATION
F A L L 20 1 2
• a – without• apo – front• cardium – heart• chondros –
cartilage• dendron – tree• desmos –
ligament• glia – glue• histos – tissue
• holos – entire• hyalos – glass• inter – between• krinein – to
separate• lacus – lake• meros – part• neuro – nerve• os – bone
VOCAB DEVELOPMENT
• peri – around• phagein – to eat• pleura – rib• pseudes – false• sistere – to set• soma – body• squama – plate
or scale• vas – vessel
VOCAB DEVELOPMENT
FOUR TISSUE TYPES • cells combine to form tissues• tissues are groups of specialized cells and cell
products that perform a limited number of functions • histology is the study of tissues • 4 basic types of tissues• epithelial• connective• muscle• neural
EPITHELIAL TISSUE• includes epithelia and glands• epithelia are layers of cells that cover internal or external surfaces • glands are composed of secreting cells derived from epithelia
EPITHELIAL TISSUE• Important Characteristics•cells that are bound closely together •a surface exposed to the environment or to some internal chamber or passageway•attachment to underlying connective tissue by a basement membrane•absence of blood vessels•continual replacement or regeneration of epithelial cells that are damaged or lost at the exposed surface
EPITHELIAL TISSUE • Functions of Epithelial Tissue• Provide physical protection•Control permeability• Provide sensation• Produce specialized secretions •Gland cells •Glandular epithelium• Exocrine- secretions are discharged to the surface of the epithelium• Endocrine- secretions are released into the surrounding tissue fluid and blood • These secretions are usually called hormones.
INTERCELLULAR CONNECTIONS • Undamaged epithelia form effective barriers.• The plasma membranes are held together by CAMs
and by a thin layer of intercellular cement. The CAMs bind to:
Cytoskeletal filaments Each other Extracellular materials
The CAMs form specialized attachment sites called cell junctions 3 types of junctions
Tight junctions Gap junctions Desmosomes
BASEMENT MEMBRANE • Lies between the epithelium and underlying
connective tissues • No cells, it is made up of a network of proteins • Provides strength and resists distortion
EPITHELIAL RENEWAL & REPAIR • Maintains its structures by the continuous
division of stem cells • Stem cells are unspecialized cells • Found in the deepest layer of the epithelium, near
the basement membrane
CLASSIFICATION OF EPITHELIA • Classified according to:• Number of cell layers• Shape of exposed cells
CLASSIFICATION OF EPITHELIA • Cell layers• Simple epithelium• Single layer of cells covering the basement
membrane • Thin• Found in protected areas inside the body • Line internal compartments & passageways • Common where absorption & secretion takes
place
CLASSIFICATION OF EPITHELIUM• Cell layers• Stratified Epithelium • Several layers thick above the basement membrane • Found in areas subject to mechanical or chemical
stresses
CLASSIFICATION OF EPITHELIUM• Cell shapes• Squamous • Cells are thin & flat• Nucleus occupies the thickest portion of each cell
• Cuboidal • Appear square in 2 dimensions• Appear hexagonal in 3 dimensions • Nucleus is near the center of each cell
CLASSIFICATION OF EPITHELIUM • Cell shapes• Columnar • Hexagonal, but taller & more slender than cuboidal • Nucleus is found near basement membrane
CLASSIFICATION OF EPITHELIA • Simple Squamous Epithelia• Found in protected regions where absorption takes
place or a slippery surface • Ex: exchange surfaces of lungs, lining of ventral body
cavities, lining of blood vessels• Simple Cuboidal Epithelia • Provides limited protection & occurs where absorption
& secretion take place • Secret enzymes & buffers in the pancreas & salivary
glands
CLASSIFICATION OF EPITHELIA • Simple Columnar Epithelia • Provide some protection & may occur in areas of
absorption or secretion• Ex: lines the stomach, the intestinal tract, and many
excretory ducts • Stratified Squamous Epithelia• Found where mechanical stresses are severe• Ex: surface of the skin, lining of the mouth, tongue,
esophagus
CLASSIFICATION OF EPITHELIA• Stratified Cuboidal Epithelia • Relatively rare• Ex: along the ducts of sweat glands and the ducts of
the mammary glands • Stratified Columnar Epithelia• Relatively rare• Ex: portions of the pharynx, epiglottis, urethra
CLASSIFICATION OF EPITHELIA • Psuedostratified Epithelia • Called this because it looks stratified but it is not • Found in portions of the respiratory tract
• Transitional Epithelia• Stratified epithelium that tolerates repeated
stretching • Lines the urinary bladder
GLANDULAR EPITHELIA • Exocrine secretions are produced by exocrine
glands and are discharged through a duct to the outside.
• Endocrine secretions are produced by ductless glands and are released into blood or tissue fluids
GLANDULAR EPITHELIA • Mechanisms of Secretion • Merocrine secretion• Most common form of secretion• Leaves the cell intact and able to function • Product is released from secretory vesicles by
exocytosis • Ex: mucus
GLANDULAR EPITHELIA • Mechanisms of Secretion• Apocrine secretion• Involves the loss of cytoplasm and the secretory
product• Leaves the cell intact and able to function
GLANDULAR EPITHELIA • Mechanisms of Secretion• Holocrine secretions • Entire cell becomes packed with secretions and
bursts and dies • Ex: sebaceous glands
GLANDULAR EPITHELIA • Types of secretions • Serous • Watery solution contains enzymes (saliva)
• Mucous• Thick, slippery mucus (snot)
• Mixed • Contains more than one type of secretion
CONNECTIVE TISSUES • 3 basic components• Specialized cells• Protein fibers• Ground substance• Fluid
• Matrix- extracellular protein fibers & ground substance that surround the cells of connective tissue
CONNECTIVE TISSUES • Never exposed to the outside• Highly vascularized • Contain receptors that provide pain, pressure,
temperature, & other sensations
CONNECTIVE TISSUES • Functions • Support & Protection• Transportation of materials• Storage of energy reserves • Defense of the body
CONNECTIVE TISSUES • Three major types • Connective tissue proper• Fluid connective tissues • Blood • lymph
• Supporting connective tissues • Cartilage • Bone
CONNECTIVE TISSUE PROPER • Cells found in connective tissue proper• Fibroblasts • Fibrocytes• Macrophages• Fat cells (adipocytes) • Mast cells
CONNECTIVE TISSUE PROPER• 3 types of connective tissue fibers • Collagen fibers• Most common fibers in connective tissue proper
• Elastic fibers • Return to their original shape after stretching
• Reticular fibers• Least common • Form the framework of various organs
CONNECTIVE TISSUE PROPER • Types of connective tissue proper• Classified into types based on their relative
proportions or cells, fibers, & ground substance • Loose• Dense
CONNECTIVE TISSUE PROPER • Loose Connective Tissues • Locations• Beneath the dermis of the skin • Digestive tract• Respiratory and urinary tracts • Between muscles• Around blood vessels, nerves, & joints
CONNECTIVE TISSUE PROPER • Loose connective tissue functions. • Cushions organs• Provides support, but allows independent movement• Phagocytic cells defend against pathogens
CONNECTIVE TISSUE PROPER• Loose Connective Tissue• Adipose tissue (composed mainly of triglycerides) • Locations:• Underneath the deep skin (sides, buttocks,
breasts)• Padding around eyes and kidneys
• Functions: • Provides padding & cushions shocks • Insulates• Stores energy reserves
CONNECTIVE TISSUE PROPER• Dense Connective Tissue• Locations: • Between skeletal muscles & skeleton• Tendons- connect muscle to bone
• Between bones • Ligaments – connect bone to bone
• Covering skeletal muscles• Capsules of internal organs
CONNECTIVE TISSUE PROPER• Dense connective tissue • Functions:• Provides firm attachment• Conducts pull of muscles• Reduces friction between muscles• Stabilizes relative position of bones• Helps prevent over expansion of organs (bladder)
FLUID CONNECTIVE TISSUES • 2 types• Blood• Plasma- watery matrix• Red blood cells• Account for half the volume of blood• Transport oxygen through the blood
• White blood cells- immune response • Platelets- clotting
• Lymph • Forms as interstitial fluid enter lymphatic vessels • Circulated throughout the entire body• Supports your immune system
SUPPORTING CONNECTIVE TISSUES • 2 types • Cartilage • Bone
SUPPORTING CONNECTIVE TISSUES • Cartilage• Heals poorly because it is avascular• 3 types of cartilage• Hyaline cartilage• Elastic cartilage• Fibrous cartilage
SUPPORTING CONNECTIVE TISSUES• Elastic Cartilage • Locations: • Auricle of external ear• Epiglottis • Auditory tube• Part of larynx
• Functions:• Provides support• tolerates distortion without damage and returns to
original shape
SUPPORTING CONNECTIVE TISSUES • Hyaline Cartilage• Locations: • Between tips of ribs & bones of the sternum • Cover bone surfaces at synovial joints• Supporting larynx, trachea, & bronchii• Forms part of the nasal septum
• Functions:• Provides stiff but somewhat flexible support• Reduces friction between bony surfaces
SUPPORTING CONNECTIVE TISSUES• Fibrous Cartilage• Locations:• Pads within knee joint• Between the pubic bones of the pelvis &
intervertebral discs• Functions:• Resists compression• Prevents bone on bone contact • Limits relative movement
SUPPORTING CONNECTIVE TISSUES • Bone• Osteocytes- cells that make up bones (hard outer part
of the bone)• Periosteum- covering around the bone
MEMBRANES • Membranes are physical barriers• 4 types • Mucous• Serous• Cutaneous• Synovial
MEMBRANES • Mucous Membranes • Line cavities• Communicate with the exterior
MEMBRANES • Serous Membranes • Line sealed, internal sub divisions of the ventral cavity • 3 serous membranes • Pleura- line the pleural cavities and covers the lungs• Peritoneum- line the abdominal cavity & covers the surface of the
enclosed organs • Pericardium- lines the pericardial cavity & covers the heart
• Parietal & visceral portions • Parietal portion- lines the inner surface of the cavity• Visceral portion- covers the outer surface of organs within the
body cavity• Primary function: Minimize friction between the parietal and
visceral surfaces when an organ moves or changes shape
MEMBRANES • Cutaneous Membrane• Covers the surface of the body (skin) • Thick • Waterproof• Usually dry • Consists of: stratified squamous epithelium &
underlying dense connective tissues
MEMBRANES • Synovial Membranes• Consist primarily of loose connective tissue & an
incomplete layer of epithelial tissue• Found in joints that are allowed to move free • Lubricates joints
MUSCLE TISSUE• Specialized from contraction• 3 types:• Skeletal• Cardiac• Smooth
MUSCLE TISSUE • Skeletal Muscle Tissue• Cells- long, cylindrical, striated, multinucleate • Locations: • Combined with connective tissues & neural tissue in
skeletal muscles• Functions:• Moves or stabilized the position of the skeleton• Guards entrances and exits to the digestive,
respiratory, and urinary tracts• Generates heat• Protects internal organs
MUSCLE TISSUE• Cardiac Muscle Tissue• Cells: short, branched, and striated; usually have a
single nucleus• Location:• Heart
• Functions:• Circulates blood• Maintains blood pressure
MUSCLE TISSUE • Smooth Muscle Tissue • Cells: short, spindle shaped, and non striated; single
central nucleus • Location: • Walls of blood vessels• Digestive, respiratory, urinary, & reproductive organs
• Functions:• Moves food, urine, and reproductive tract secretions• Controls diameter of respiratory passageways• Regulates diameter of blood vessels
NEURAL TISSUE • Specialized for the conduction of electrical
impulses from one region of the body to another. • Most is found in the brain and spinal cord • 2 basic types of cells• Neurons• 3 main parts • Cellbody• Dendrites• Axon
• neuroglia