Lab 1

Lab 1

ANIMAL TISSUES

1Levels of OrganizationAnimals are multicellular heterotrophs whose cells lack cell walls.Most animals exhibit a hierarchical level of organization:Cells are organized into tissuesTissues combine to form organsOrgans comprise organ systems2What is a tissue?Group of similar cells that perform a specialized function.Examples include:Bone tissueBlood tissueMuscle tissue34 basic types of animal tissue:EpithelialConnectiveMuscleNervous4Epithelial Tissue

Apical (free) surface covers body surface or lines interior of organsBasal surface adheres to the basement membraneCharacteristics:Cells fit closely together forming continuous sheets5Epithelial TissueSupported by connective tissueAvascular, but innervatedHave remarkable powers of regenerationVariety of functions depending on type (protection, absorption, filtration, excretion, secretion)6Epithelial TissueClassification based on # of cell layers and shape of cells on apical surface.# of Cell Layers:Simple one layer of cellsStratified two or more layersPseudostratified simple, but appears stratified7Epithelial TissueCell shape on apical surface:Squamous flattened & scale-likeCuboidal box-likeColumnar tall & column-like8Connective TissueCharacteristics:Most are well vascularizedConsists of widely-spaced cells and fibers embedded in a non-living extracellular matrixVariety of functions depending on type (support, binding other tissues, transport, defense, storage)

9Muscle TissueCharacteristics:Well vascularizedPacked with actin & myosin filamentsFunction to contract producing most types of body movements10Nervous TissueCharacteristics:Composed of two types of cells:Neurons specialized to generate and transmit impulses; amitoticNeuroglia (glial cells) protect, support & insulate neuronsMain component of the nervous system (brain, spinal cord & nerves)11This weeks lab is devoted to histology (the study of tissues).12Exercise A: Epithelial Tissues

surface view

Simple squamous epitheliumLocation alveoli of lungs, lining of heart & blood vesselsFunction allows diffusion of materialslateral view13Exercise A: Epithelial Tissuescross sectionSimple cuboidal epitheliumLocation kidney tubules & ducts; ovary surfaceFunction secretion & absorptionlongitudinal section

simple cuboidal epitheliumbasement membrane14Exercise A: Epithelial TissuesSimple columnar epitheliumLocation lines digestive tract from stomach to the rectumFunction absorption & secretion

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Exercise A: Epithelial TissuesPseudostratified columnar epitheliumLocation lining of trachea & upper respiratory tractFunction secretion & propulsion of mucusciliaciliated cellgoblet cellbasement membraneconnective tissuebasal cell16

Exercise A: Epithelial TissuesStratified squamous epitheliumLocationkeratinized type: epidermis of skinnon-keratinized type: linings of esophagus, mouth & vaginaFunction protection connective tissuestratified squamous epitheliumNon-keratinizedKeratinized17

Exercise B: Connective TissuesLoose (areolar) connective tissueLocation widely distributed under epitheliaFunction cushions organs Elastic fiberFibroblast nucleusCollagen fiberGel-like matrix18Exercise B: Connective TissuesAdiposeLocation under skin; around kidneys & eyeballs; in breastsFunction supports & protects organs; insulates against heat loss; provides reserve fuel

19Exercise B: Connective TissuesDense (fibrous) connective tissueLocation tendons & ligamentsFunction attaches muscle to bone (tendons) & bone to bone (ligaments)

20Exercise B: Connective TissuesHyaline cartilageLocation covers ends of long bones; nose, trachea & larynxFunction support & reinforcement

Chondrocytes sitting in lacunae (cavities)Matrix packed with collagen fibers21

Exercise B: Connective TissuesBoneLocation bonesFunction support & protection; calcium storage; provides levers for muscles to act on; site of blood cell productionOsteocyte sitting a in lacuna (cavity)Canaliculi

OsteonCentral canal22

Exercise B: Connective TissuesBloodLocation contained within blood vesselsFunction transport of gases (O2 & CO2), nutrients & metabolic wastesPlasma (liquid matrix)Red blood cellsPlateletWhite blood cells:neutrophilmonocytelymphocyte 23

Exercise C: Muscle TissuesSkeletal muscleLong, cylindrical, multinucleate cells with obvious striationsLocation attached to bones or occasionally to skinFunction voluntary movementStriationsNuclei24

Exercise C: Muscle TissuesCardiac muscleBranched, uninucleate cells with striationsLocation walls of the heartFunction contract involuntarily to propel bloodStriationsIntercalated discBranched cell 25

Exercise C: Muscle TissuesSmooth muscleTapered, uninucleate, non-striated cellsLocation walls of hollow organsFunction contract involuntarily to propel materials along internal passagewaysNucleiLongitudinal layerCircular layer

Individual muscle cell26

Exercise D: Nervous TissueNeuronscell body contains nucleuscytoplasmic processes:dendrites transmit impulses to cell bodyaxon transmits impulses from cell bodyNeurogliaNeuron cell bodyNeuronal processes(axons & dendrites) Neuron nucleus27