Pl. VI · Stratifex columnaris — stratified columnar

The plate

The specimen, drawn

Pl. VI

The tissue as you will meet it on the slide.

Habitat & range

Where it lives

Body map

Where this tissue is found.

Range

• Parts of the male urethraThe tube that carries urine from the bladder to the outside of the body.
• Some large excretory ducts
• Parts of the conjunctiva
• Transition zones between other epithelia

Collection record

• Add your slide numbers here.

Niche

What it does for a living

A junction tissue. It mostly turns up where one kind of lining becomes another, doing a little protection and a little secretionThe process of moving substances from the blood into the nephron tubule to be excreted in urine. and specialising in neither.

field collected specimen

How to know it on sight

• Two layers: short cellsThe basic structural and functional units of life. on the membrane, tall columnar cells on top.
• Uncommon enough that you should doubt yourself and check the organ first.

Specimen 1

Specimen 2

Specimen 3

People keep calling her by the wrong name

Look-alikes

Three plates. Read the line underneath each one before you decide.

Pseudostratified columnar

Tell them apart by whether every cell reaches the membrane. If it does, it is pseudostratified however many rows of nucleiClusters of neurons in the CNS responsible for processing information. you see.

Simple columnar

Tell them apart by looking underneath for the short cells.

Stratified cuboidal

Tell them apart by the height of the top row.

Examine it yourself

The virtual slide

Zoom in until you can see the surface of the cells, then find the basement membrane underneath.

Virtual slide courtesy of Histology Guide.

Field notes

Why this animal

The giant squid: real, rarely seen, mostly known from damaged specimens and second-hand accounts. Most of what students “know” about this tissue is also second-hand.