Connective

1. Loose (areolar, adipose, reticular)2. Dense (dense irregular, white fibrous)3. Cartilage (hyaline, elastic, fibrocartilage)4. Bone5. Blood6. Mesenchyme

FunctionsA. SupportB. Connecting partsC. Storage (calcium, energy)D. Protection (skull, ribs, kidneys)E. Movement (muscle attachments)F. Blood formation and transport

1.28

CT Glue

Chondroitin sulfate

Common, long, white, wavy

Thin, wire-like, flexible

Short, branching (netting)

1.30

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Figure 4.7 Areolar connective tissue: A prototype (model) connective tissue.

Macrophage

Fibroblast

Lymphocyte

Fat cell

Mast cell

Neutrophil

Capillary

Cell types Extracellularmatrix

Fibers• Collagen fiber• Elastic fiber• Reticular fiber

Ground substance

Pg 128

Cells?Blood vessels?Nerves?

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Figure 4.13 Embryonic germ layers and the primary tissue types they produce.

MesodermEndoderm

16-day-old embryo(dorsal surface view)

EpitheliumNervous tissue(from ectoderm)

Muscle and connectivetissue (mostly frommesoderm)Ectoderm

Pg 144

Mesenchyme -ameboidStem cellsFlexible

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Figure 4.8k Connective tissues.

(k) Others: blood

Description: Red and whiteblood cells in a fluid matrix(plasma).

Function: Transport ofrespiratory gases, nutrients,wastes, and other substances.

Location: Contained withinblood vessels.

Photomicrograph: Smear of human blood (1860x); twowhite blood cells (neutrophil in upper left and lymphocytein lower right) are seen surrounded by red blood cells.

Neutrophil

Red bloodcells

Lymphocyte

Plasma

Pg 137

Liquid matrix called PlasmaWater soluble fibers

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Figure 4.8a Connective tissues.

(a) Connective tissue proper: loose connective tissue, areolar

Description: Gel-like matrix with allthree fiber types; cells: fibroblasts,macrophages, mast cells, and somewhite blood cells.

Function: Wraps and cushionsorgans; its macrophages phagocytizebacteria; plays important role ininflammation; holds and conveystissue fluid.

Location: Widely distributed underepithelia of body, e.g., forms laminapropria of mucous membranes;packages organs; surroundscapillaries.

Photomicrograph: Areolar connective tissue, asoft packaging tissue of the body (300x).

Epithelium

Laminapropria

Fibroblastnuclei

Elasticfibers

Collagenfibers

Pg 131

Jello! Filler tissue

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Figure 4.8b Connective tissues.

(b) Connective tissue proper: loose connective tissue, adipose

Description: Matrix as in areolar,but very sparse; closely packedadipocytes, or fat cells, havenucleus pushed to the side by largefat droplet.

Function: Provides reserve foodfuel; insulates against heat loss;supports and protects organs.

Location: Under skin in thehypodermis; around kidneys andeyeballs; within abdomen; in breasts.

Photomicrograph: Adipose tissue from thesubcutaneous layer under the skin (350x).

Nucleus offat cell

Vacuolecontainingfat droplet

Adiposetissue

Mammaryglands

Pg 131

Triglycerides

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Figure 4.8c Connective tissues.

(c) Connective tissue proper: loose connective tissue, reticular

Description: Network of reticularfibers in a typical loose groundsubstance; reticular cells lie on thenetwork.

Function: Fibers form a soft internalskeleton (stroma) that supports othercell types including white blood cells,mast cells, and macrophages.

Location: Lymphoid organs (lymphnodes, bone marrow, and spleen).

Photomicrograph: Dark-staining network of reticularconnective tissue fibers forming the internal skeletonof the spleen (350x).

Spleen

White bloodcell(lymphocyte)

Reticularfibers

Pg 132

Supports soft organs

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Figure 4.8e Connective tissues.

(e) Connective tissue proper: dense connective tissue, dense irregular

Description: Primarilyirregularly arranged collagenfibers; some elastic fibers;major cell type is the fibroblast.

Function: Able to withstandtension exerted in manydirections; provides structuralstrength.

Location: Fibrous capsules oforgans and of joints; dermis ofthe skin; submucosa ofdigestive tract.

Photomicrograph: Dense irregularconnective tissue from the dermis of theskin (400x).

Collagenfibers

Nuclei offibroblasts

Fibrousjointcapsule

Pg 133

Dermis, Deep fascia

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Figure 4.8d Connective tissues.

(d) Connective tissue proper: dense connective tissue, dense regular

Description: Primarily parallelcollagen fibers; a few elastic fibers;major cell type is the fibroblast.

Function: Attaches muscles tobones or to muscles; attaches bonesto bones; withstands great tensilestress when pulling force is appliedin one direction.

Location: Tendons, mostligaments, aponeuroses.

Photomicrograph: Dense regular connectivetissue from a tendon (500x).

Shoulderjoint

Ligament

Tendon

Collagenfibers

Nuclei offibroblasts

Pg 133

(White Fibrous)

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Figure 4.8f Connective tissues.

(f) Connective tissue proper: dense connective tissue, elastic

Description: Dense regularconnective tissue containing a highproportion of elastic fibers.

Function: Allows recoil of tissuefollowing stretching; maintainspulsatile flow of blood througharteries; aids passive recoil of lungsfollowing inspiration.

Location: Walls of large arteries;within certain ligaments associatedwith the vertebral column; within thewalls of the bronchial tubes.

Elastic fibers

Aorta

HeartPhotomicrograph: Elastic connective tissue inthe wall of the aorta (250x).

Pg 134

Clicker Question: Which of the following statements regarding connective tissue are true?

1. The 3 main components of connective tissue are: ground substance, fibers and proteoglycans.2. All connective tissue has a good blood supply.3. Collagen fibers provide a lot of strength within connective tissue.4. Connective tissue can have a nerve supply.

A. 1, 3, 4 B. 3, 4 C. 2, 3, 4 1, 2, 3