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Lab Exercise 6a-2

Connective TissueNervousMuscle

Classification of connective tissues

Connective Tissue

Connective tissue proper Fluid connective tissue Supportive connecting tissue

Connective tissuesConnective tissue proper

Loose connective tissue AreolarAdiposeReticular

Dense connective tissueDense regularDense irregularElastic tissue

Fluid CTBlood

Supporting CTsCartilageHyaline cartilageElastic cartilageFibrocartilage

• Bone

Areolar tissue

A loose CTP

Areolar

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Areolar: what to look for

FibroblastsCollagen fibersElastic fibersMast cells and macrophages

Found? Throughout body, under dermis, divides skin from underlying tissues

Fibroblasts

Resting fibroblasts typically have so little cytoplasm that the cells appear, by light microscopy, as "naked" nuclei

Fibroblast Adipose tissue

Another lose CTP (note nucleus)

Adipose: what to look for

Lots of cytoplasmSlim nuclei pushed off the side

Found? You know where

Reticular tissue

The third type of loose CTP

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Reticular tissue Reticular: what to look for

Reticular fibers (network)

Found? Internal framework in many sort organs (liver, spleen) supporting the parenchyma

Dense CTP

Dense regular – strength in one directionDense irregular – strength in all directionsElastic tissue - pliable

Dense regular

Dense regular: what to look for

Thick parallel bundles of collagenSmall fibroblasts in between bundles

Found? Tendons, ligaments, deep fascia.

Dense irregular

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More dense irregularDense irregular: what to look for

Mesh of collagen fibers (irregular looking)Interspersed fibroblasts

Found? Dermis of skin, periosteum, perichondrium

Elastic tissue Elastic tissue: what to look for

Elastic fibers (instead of collagen fibers) in large bundlesFibroblasts

Found? Between vertebrae, in blood vessel walls (underneath endothelium)

Fluid CT

Blood

Blood: what to look for

RBCsWhite blood cells (darker): monocytes, lymphocytes, granulocytesPlatelets

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Supportive CT

Cartilage – gelatinous, paddingHyaline cartilageElastic cartilageFibrocartilage

Hyaline cartilage

Glasslike because fibers not visible

More hyaline

There are collagenous and elastic fibers lying in the cartilage matrix but they are invisible because their “refractive index” is the same as that of the matrix (like cornea)

More hyaline

Hyaline cartilage Hyaline

Hyaline cartilage (lavender matrix), with perichondrium (pink) outside it. The latter is a dense regular collagenous CT. Cartilage cells = chondrocytes, and they are lying in the lacunae.

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Hyaline cart.: what to look for

Chondrocytes and lacunaeNo visible fibersWhere? Most joints, nasal septum

Elastic cartilage

Elastic Cartilage Elastic cart: what to look for

Many elastic fibers in matrixChondrocytes in lacunaeMay be stacked up

Fibrocartilage Fibrocartilage: what to look for

Irregular, wispy collagen fibersChondrocytes

Found? Intervertabral discs of spine, pads in knee joint

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Supportive CT: BoneDetail of lacuna, showing radiating canaliculi. Tissue fluid from the capillaries and connective tissue of the Haversian canal can seep through these spaces and channels, bringing nutrients to the stellate osteocytes residing there.

Bone: what to look forOsteon (whole circular structure)Concentric lamellae (of matrix)Central canal (at center of lamellae)OsteoblastsOsteocytes in lacunaeCanaliculi

Found? Bones!

Nervous tissue

Neuron smearLarge, pyramidal cell bodiesLong processes extending out

Nervous Tissue

Figure 4.10

3 Types of Muscle Tissue

Skeletal muscle:large body muscles responsible for movement

Cardiac muscle:found only in the heart

Smooth muscle:found in walls of hollow, contracting organs (blood vessels; urinary bladder; respiratory, digestive and reproductive tracts)

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Muscle Tissue: Skeletal

Long, cylindrical, multinucleate cells with obvious striationsFound in skeletal muscles that attach to bones or skin

Muscle Tissue: Skeletal

Figure 4.11a

Muscle Tissue: Cardiac

Branching, striated, uninucleate cells interlocking at intercalated discs

Muscle Tissue: Cardiac

Figure 4.11b

Muscle Tissue: Smooth

Sheets of spindle-shaped cells with central nuclei that have no striationsFound in the walls of hollow organs

Muscle Tissue: Smooth

Figure 4.11c

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ExercisesLook at all slidesDraw an example of each tissue on paper provided11 connective tissues:

6 CTP (3 loose, 3 dense)1 Fluid CT (blood) 4 Supportive CT (3 cartilage, 1 bone)

Neurons3 Muscle tissuesSkeletalStriatedSmooth

Turn in on Thurs 10/25

7 drawings from 6a-1 Epithelia15 Drawings from 6a-2 Connective+Review sheet for lab 6a