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The Basketweaver: Dense Irregular Connective Tissue

BIO 171  ◆  HUMAN ANATOMY & PHYSIOLOGY I  ◆  FINGER LAKES COMMUNITY COLLEGE

The Tissue Field Guide

THE IN-BETWEENERS  ◆  ISSUE #05  ◆  SERIES I: THE DENSE DIVISION

Tattoo-flash turtle, The Basketweaver, whose shell plates are each filled with pink collagen bundles running in a different direction; arrows bounce off the shell.

The Basketweaver

Dense irregular connective tissue  ·  she / her

“Whichever way you come at me, I’m already there.”

POWER: Resists a pull from every direction at once.

WEAKNESS: Never the best at any single direction.

FIBERS: Collagen, the exact same ingredient as Captain Lengthwise.

SECRET IDENTITY: The layer right under a paper cut.

Dense irregular connective tissue is the tough, multidirectional-strength tissue under your skin. Think of her as a gelatinous body stocking under the hard candy shell of your epidermis.

Has Opinions About Everything, From Every Angle

Where she lives, what she does, and the one thing she can’t do

Where she lives

  • The dermis of the skin, her flagship location
  • Tough fibrous capsules around organs like the kidney, spleen, and lymph nodes
  • Around organs that change shape a lot, like the digestive organs

Her powers

  • Strength against forces coming from every direction
  • Keeps skin intact as it stretches and pulls every time you move

Her weakness

She spreads her collagen in every direction, so she is never as strong as Captain Lengthwise in any one direction.

Same fiber, different arrangement. The arrangement is the whole difference.

Every weakness is the structure.

Same Collagen as Lengthwise. Totally Different Vibe.

Felted collagen and a patrol of immune cells

The crew: cells

Fibroblasts dominate, making collagen and maintaining the matrix; look for their purple nuclei scattered through the pink. Macrophages and mast cells patrol for pathogens and debris.

The fibers

Collagen (type I) in a random, interwoven mesh. Some elastic fibers add recoil.

The matrix

Slide prep dehydrates the tissue and the watery matrix washes out. Like dry skin, it cracks, which is why you see white space between the pink collagen.

Her Room Is Messy. It’s a System.

Real slides. Find her in every one.

ID HINT: Pink bundles crossing in every direction: a felted mat with no uniform pattern.

Exhibit A

A microscopic image shows dense irregular connective tissue. Curvy, pink collagen bundles are interwoven throughout a mostly white background. Darker stained fibroblasts are scattered among the collagen.
Small intestine, H&E, 40X (slide 029-1).

Exhibit B

Photomicrograph of dense irregular plantar skin at high magnification. The dominant visual element is dense, eosinophilic (pink) collagen fibers arranged in irregular orientation throughout the field of view. Small areas of lighter staining or white space are interspersed between fiber bundles. A small portion of skin tissue is visible that shows skin cells and vessels. Illustrates histologic features of tissue strength and support.
Thick skin, sole of the foot, H&E, 40X (slide 106).

Exhibit C

Thin skin, H&E, 40X (slide 104-2).

Micrographs: University of Michigan Histology, licensed under CC BY-NC-SA 3.0.

Microscopic view of dense irregular connective tissue from thin skin, stained in pink. The image shows irregularly arranged collagen fibers, appearing as wavy bundles of pink. Visible cells, including fibroblasts, are scattered throughout the tissue. A round gland structure, stained purple, is located on the left side.

Stalk Their Actual Profile

Drive the microscope yourself

Virtual slide: thick skin

The purple tab on the right opens a panel with information and links.

Open the slide full screen

Prove You Were Actually Paying Attention

Prove you can spot her

Mission 1: Discover the features of dense irregular

Mission 2: The Dense Three quick check

Videos Nobody Asked You to Watch (Watch Them)

People Keep Calling Her by the Wrong Name

Students confuse her with these two. Here’s how to tell.

The Packing Peanut

Tattoo-flash jellyfish, The Packing Peanut: a bell laced with fine dark elastic threads, pink collagen tentacles, and a mesh of reticular fibers inside, drawn in H&E pinks and purples; one tentacle loops around an anchor.

Areolar. Fibers also run every which way, but the Peanut is loose, with lots of open space. The Basketweaver is packed tight.

High-magnification photomicrograph of stained areolar connective tissue, originating from the scalp. Visual elements include polygonal shaped epithelial cells at the top; interwoven collagen fibers appear as wavy, pinkish-red strands; elastic fibers are thinner and darker. Cells with dark stained nuclei are interspersed throughout. The overall composition has a pinkish-red/white hue, indicative of Hematoxylin and Eosin (H&E) staining. The image is tightly cropped to showcase the cellular structure.
Areolar connective tissue, scalp sample. Microscopic view showing cells and fibers in a pinkish-red and white matrix.

Captain Lengthwise

Tattoo-flash strongman, Captain Lengthwise, lifting a barbell overhead; his body is filled with pink H&E tendon tissue of parallel wavy collagen bundles with rows of flat nuclei, and an arrow is stuck in his heel.

Dense regular. Same collagen, same packing, but all his fibers run parallel. Hers cross in every direction.

Photomicrograph of dense irregular connective tissue of plantar skin, intensely stained with hematoxylin and eosin (H&E). Thick bundles of eosinophilic collagen fibers are arranged in a non-parallel, interwoven pattern, dominating the field. Scattered elongated nuclei are seen within the collagen matrix, representing fibroblasts. The H&E staining highlights the protein-rich collagen as pink and the cell nuclei as darker shades.
Microscopic view of dense irregular connective tissue, part of the plantar skin. Pink collagen fibers with other cells.
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BIO 171  ·  HUMAN ANATOMY & PHYSIOLOGY I  ·  FINGER LAKES COMMUNITY COLLEGE

Plates and body maps drawn for this course. Micrographs from the BIO 171 slide collection.

Virtual slides courtesy of Histology Guide  ·  bettybroadbent.com

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