Connective Tissue
Nervous
Muscle

Classification of connective tissues

Connective Tissue
 Connective tissue proper
 Fluid connective tissue
 Supportive connecting tissue

Connective tissues
Connective tissue proper
 Loose connective tissue
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Areolar
Adipose
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 Reticular
Dense connective tissue
 Dense regular
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Dense irregular
Elastic tissue
Fluid CT
 Blood
Supporting CTs
 Cartilage
 Hyaline cartilage
 Elastic cartilage
 Fibrocartilage
• Bone

Areolar tissue
 A loose CTP

Areolar

Areolar: what to look for
 Fibroblasts
 Collagen fibers
 Elastic fibers
 Mast 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 cytoplasm
 Slim nuclei pushed off the side
 Found? You know where

Reticular tissue
 The third type of loose CTP

Reticular tissue

Reticular: what to look for
 Reticular fibers (network)
 Found? Internal framework in many sort organs (liver, spleen) supporting the parenchyma

Dense CTP
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Dense regular – strength in one direction
Dense irregular – strength in all directions
 Elastic tissue - pliable

Dense regular

Dense regular: what to look for
 Thick parallel bundles of collagen
 Small fibroblasts in between bundles
 Found? Tendons, ligaments, deep fascia.

Dense irregular

More dense irregular

Dense 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 bundles
 Fibroblasts
 Found? Between vertebrae, in blood vessel walls (underneath endothelium)

Fluid CT
 Blood

Blood: what to look for
 RBCs
 White blood cells (darker): monocytes, lymphocytes, granulocytes
 Platelets

Supportive CT
 Cartilage – gelatinous, padding


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Hyaline cartilage
Elastic cartilage
Fibrocartilage

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.

Hyaline cart.: what to look for
 Chondrocytes and lacunae
 No visible fibers
 Where? Most joints, nasal septum

Elastic cartilage

Elastic Cartilage

Elastic cart: what to look for
 Many elastic fibers in matrix
 Chondrocytes in lacunae
 May be stacked up

Fibrocartilage

Fibrocartilage: what to look for
 Irregular, wispy collagen fibers
 Chondrocytes
 Found? Intervertabral discs of spine, pads in knee joint

Supportive CT: Bone

 Detail 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 for
 Osteon (whole circular structure)
 Concentric lamellae (of matrix)
 Central canal (at center of lamellae)
 Osteoblasts
 Osteocytes in lacunae
 Canaliculi
Found? Bones!

Nervous tissue
 Neuron smear
 Large, pyramidal cell bodies
 Long 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)

Muscle Tissue: Skeletal
 Long, cylindrical, multinucleate cells with obvious striations
 Found 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 striations
 Found in the walls of hollow organs

Muscle Tissue: Smooth
Figure 4.11c

Exercises
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Look at all slides
Draw an example of each tissue on paper provided
11 connective tissues:
 6 CTP (3 loose, 3 dense)
 1 Fluid CT (blood)
 4 Supportive CT (3 cartilage, 1 bone)
Neurons
3 Muscle tissues
 Skeletal
 Striated
 Smooth

Turn in on Thurs 10/25
 7 drawings from 6a-1 Epithelia
 15 Drawings from 6a-2 Connective+
 Review sheet for lab 6a