Review: Epithelial Tissue

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• “There are 2 basic kinds of epithelial tissues.” What could that mean?

• You are looking at epithelial cells from the intestine. What do you expect to see?

• You are looking at epithelial cells from the trachea. What do you expect to see?

4-1 Four Types of Tissue

Tissue Type Role(s)

- Covers surfaces/passages- Forms glands

- Structural support- Fills internal spaces- Transports materials

- Contraction!

- Transmits information (electrically)

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Classification of connective tissue

1. Connective tissue proper1a. Loose: areolar, adipose, reticular 1b. Dense: dense regular, dense irregular, elastic

2. Fluid connective tissue2a. Blood: red blood cells, white blood cells, platelets2b. Lymph

3. Supporting connective tissue3a. Cartilage: hyaline, elastic, fibrocartilage3b. Bone

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Defining connective tissue by the process of elimination

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LAB MANUAL Figure 6.4 Areolar connective tissue: A prototype (model) connective tissue.

Macrophage

Fibroblast

Lymphocyte

Adipocyte

Mast cell

Capillary

• Reticular fiber

• Elastic fiber

• Collagen fiber

Cell types Extracellularmatrix

Fibers

Ground substance

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The Cells of Connective Tissue Proper

Melanocytes and macrophages, mesenchymal, mast;Adipo- / lympho- / fibrocytes and also fibroblasts.These are the cells of connective tissue proper;Sing this song the whole day long until you know them all!

Melody playback: http://www.noteflight.com/scores/view/172efe927723615fe7c94fc62ff05ab7bc5ce26a

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4-4 Connective Tissue:importance of extracellular matrix!

Tissue Type Extracellular stuff?

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Extracellular matrix =ground substance + extracellular protein fibers

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Proteins’ structures suggest their functional properties

9Which is elastin, and which is collagen?

Tie-in with Chapter 3:Where are extracellular proteins made?How do they reach their final destination?

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LAB MANUAL Figure 6.5a Connective tissues.

Embryonic connective tissue: Mesenchyme

Fibers

Groundsubstance

Mesenchymalcell

Description: * gel-like ground substance* sparse, fine fibers* star-shaped mesenchymal cells

Function:

Location: Primarily in embryo

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LAB MANUAL Figure 6.5b Connective tissues.

Connective tissue proper: loose connective tissue, areolar

Collagenfibers

Fibroblastnuclei

Elasticfibers

Laminapropria

Epithelium

Description: * gel-like matrix with all 3 fiber types* cells: many types!

Function:

Location: Widely distributed under epithelia

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LAB MANUAL Figure 6.5c Connective tissues.

Connective tissue proper: loose connective tissue, adipose

Vacuolecontainingfat droplet

Nuclei offat cells

Description: * sparse matrix * closely packed adipocytes* nucleus pushed to the side

Function:

Location: * under skin* around kidneys & eyes* abdomen* breasts

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LAB MANUAL Figure 6.5d Connective tissues.

Connective tissue proper: loose connective tissue, reticular

White blood cell(lymphocyte)

Reticularfibers

Description: * network of reticular fibers* loose ground substance* reticular cells

Function:

Location: Lymphoid organs (lymph nodes, bone marrow, spleen)

Spleen

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LAB MANUAL Figure 6.5e Connective tissues.

Connective tissue proper: dense connective tissue, dense regular

Collagenfibers

Nuclei offibroblasts

Shoulderjoint

Ligament

Tendon

Description: * primarily parallel collagen fibers* major cell type: fibroblast

Function:

Location: * Tendons* Ligaments

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Figure 6.5f Connective tissues.

Photomicrograph: Elastic connective tissue in thewall of the aorta (250).

Connective tissue proper: dense connective tissue, elastic

Elasticfibers

Heart

Aorta

Description: * Mostly elastic fibers

Function:

Location: * Walls of large arteries* Between vertebrae

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LAB MANUAL Figure 6.5g Connective tissues.

Connective tissue proper: dense connective tissue, dense irregular

Nuclei offibroblasts

Collagenfibers

Fibrousjointcapsule

Description: * primarily irregularly arranged collagen fibers * major cell type: fibroblast

Function:

Location: * capsules of organs & joints * dermis of skin

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LAB MANUAL Figure 6.5h Connective tissues.

Cartilage: hyaline

Chondrocytein lacuna

Matrix

Costalcartilages

Description: * amorphous but firm matrix* collagen fibers form an imperceptible network

Function:

Location: * ends of long bones* ribs* nose, trachea, larynx

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LAB MANUAL Figure 6.5i Connective tissues.

Cartilage: elastic

Chondrocytein lacuna

Matrix

Description: * Similar to hyaline cartilage, but more elastic fibers

Function:

Location: * external ear (auricle)* epiglottis

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LAB MANUAL Figure 6.5j Connective tissues.

Photomicrograph: Fibrocartilage of an intervertebraldisc (160). Special staining produced the blue color seen.

Cartilage: fibrocartilage

Chondrocytesin lacunae

Collagenfiber

Intervertebraldiscs

Description: * Matrix similar to but less firm than hyaline cartilage’s* Mostly thick collagen fibers

Function:

Location: * intervertebral discs* pubic bones* knee joint

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LAB MANUAL Figure 6.5k Connective tissues.

Bones (osseous tissue)

Centralcanal

Lacunae

Lamella

Description: * hard, calcified matrix with many collagen fibers* osteocytes in lacunae* abundant blood supply

Function:

Location:

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LAB MANUAL Figure 6.5l Connective tissues.

Photomicrograph: Smear of human blood (1000);two white blood cells (neutrophil and lymphocyte) areseen surrounded by red blood cells.

Blood

Plasma

Neutrophil

Red bloodcells

Lymphocyte

Description: * fluid matrix (plasma)

Function:

Location:

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4-4 Connective Tissue

• Functions of Connective Tissues?

(summary of previous slides…)

1. Connective tissue proper

2. Fluid connective tissues

3. Supporting connective tissues

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Review: Connective Tissue

• Which is stiffer?

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Review: Connective Tissue

• Which is stiffest, based on location in body?

• Hyaline cartilage

• Elastic cartilage

• Fibrocartilage

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