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CONNECTIVE TISSUECHARACTERISTICS:

*Most abundant tissue type; Composed of ECM (GS & Protein Fibers) + Cells(Refer to pp.129-131 for specific characteristics of each)

*Highly equipped with VAN – assists in diffusion of nutrient and waste to and from epithelium (**Be familiar with exceptions**)

*General FXN: p. 128

CLASSIFICATION:I. Embryologic CT (2)

A. **Mesenchyme** CT Stem CellB. Mucous (Umbilical Cord)

II. Mature CTA. Loose CT (3) D. Bone (“Osseous/ Osteo-”) (2)

1. Areolar 1. Compact 2. Adipose 2. Spongy3. Reticular E. Liquid CT (2)

B. Dense CT (3) 1. Blood1. DRCT 2. Lymph2. DICT3. Elastic

C. Cartilage (“Chondro-”) (3)1. Hyaline2. Fibrocartilage3. Elastic

LOOSE CT (3) 1A. AREOLAR CT : consists of all fibers, all cells, semifluid ground substance

aka: “packing material”; more GS than fibers & cellsFXN: strength, elasticity, & support

2

Collagen Fibers

RBCs in capillaries:**d/t epithelium is AVASCULAR**

Ground Substance

Fibroblast:Flat cells w/ branching processes

MacrophageCells

LOOSE CT 1B. AREOLAR CT : consists of all fibers, all cells, semifluid ground substance

aka: “packing material”; more GS than fibers & cellsFXN: strength, elasticity, & support Reticular

fiber

Collagenfiber

Mast cell –releasinghistamine

Plasma cell

Fibroblasts

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LOOSE CT 2. ADIPOSE CT : Adipocytes (derived from fibroblasts); filled w/ triglyceride dropletw/ nucleus push to periphery; *highly vascular* (significance??); BAT (fxn?)

LOC: Sub Q to skin, around heart & kidneys, yellow bone marrow, aroundjoints, and posterior to eyeballsFXN: reduce heat loss, energy reserve, support & protection

Nucleus

Triglyceride

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LOOSE CT 3. RETICULAR CT : “network” branched reticular fibers and cells

LOC: Liver, spleen, lymph nodes; RBM; reticular lamina & basement membrane; around blood vessels & muscles

FXN: support, binds; provides framework = stroma; & filters

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DENSE CT (3)1. DRCT : composed of mainly collagen fibers in an orderly pattern or “paralleled”

(non-living…significance???) with many fibroblasts present.LOC: Tendons (muscle-bone), ligaments (bone-bone), aponeurosesFXN: strong attachment; withstands tensile strength along one axis Nucleus

Chains of flatfibroblasts

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DENSE CT 2. DICT :composed of mainly collagen fibers in irregular arrangement

(non-living…significance???) with few fibroblastsLOC: fascia, reticular layer of dermis, pericardium, periosteum, perichondrium, joint capsule, organ capsules (find examples), heart valvesFXN: provides tensile strength in many directions

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DENSE CT 3. ELASTIC CT: composed of mainly elastic fibers with fibroblasts

LOC: lung tissue, walls of elastic arteries (ex: AORTA), bronchiole tubes, suspensory ligaments of penis, and some ligaments between vertebrae.FXN: stretch & recoil to original shape

Refer to the “Vascular System”, Slide #12 on the JayDocwebsite. Familiarize yourself for class discussion.

Elastic fibers

Fibroblasts

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CARTILAGE CT (3)1. HYALINE: gelatinous GS, stains vibrant pink or purple, has perichondrium (*except

articular surfaces & epiphyseal “growth” plate*…significance??); weakestLOC: most abundant cartilage in body; ends of long bonds (synovial joints), costal cartilage, nose, larynx, … and fetal skeletonFXN: provides smooth surfaces for movement, flexibility, & supportSTRXR: Lacuna, chondrocytes, ECM

ECM

perichondrium

Lacuna w/ chondrocyte… note darkly stained nucleus

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CARTILAGE CT (3)2. FIBROCARTILAGE: “feather-like” appearance; NO perichondrium; strongest

LOC: IVD, meniscus, pubic symphysisFXN: support & joining structures together; strength & regidity

Nucleus of chondrocytes

Lacuna not as apparent

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CARTILAGE CT (3)3. ELASTIC CARTILAGE: Thread like network of elastic fibers (stains black & grainy), has

perichondrium, “corn on the cob”LOC: epiglottic, external ear (auricle), Eustachian tubesFXN: strength & elasticity; able to maintain shapeSTRXR: Lacuna, chondrocytes, ECM, elastic fibers

Lacuna w/ chondrocyte… note darkly stained nucleus

Elastic fibers

perichondrium

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OSSEUS “BONE” CT (2)1. COMPACT: Thread like network of elastic fibers (stains black & grainy), has perichondrium, “corn on the cob”

LOC: refer to chapter 6 FXN: support, protectionID STRXR: Osteon (Haversian system), Central canal (Haversian canal), lamella, lacuna, osteocytes, canaliculi, Volkmann’s canal, & periosteum

2. SPONGY: know difference structures, function, and location, specific to each type of bone (p. 138-139)and chapter 6

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LIQUID CT (2)1. BLOOD: Consists of blood plasma & formed elements (RBCs, WBCs, & Platelets)

LOC: within arteries & veins, chambers of the heartFXN: RBCs- O2 & CO2 ; WBCs – immunity, phagocytosis, allergic rxn; platelets - clotting (refer to p. 140 for other terms a& identification characteristics)

Refer to slides on JayDoc website: Blood Smear – slide #17 & 20