ALL PHOTOS ARE IDENTIFIED IN THE LOWER RIGHT
CORNER WITH THE MAGNIFICATION POWER THAT
THE PHOTO WAS TAKEN WITH.
• SCAN - THIS IS A VERY LOW POWER IMAGE
THAT WE USE WHEN A SAMPLE IS SO BIG THAT
YOU CAN’T GET THE WHOLE SAMPLE INTO THE
FIELD OF VIEW AT LOW POWER. YOU WON’T SEE
THIS IN YOUR MICROSCOPE.
• LOW – THIS IS THE 40X MICROSCOPE LENS
• MED – THIS IS THE 100X MICROSCOPE LENS
• HIGH – THIS IS THE 400X MICROSCOPE LENS
• SUPERHIGH – THIS IS USING THE 400X LENS, AND
THEN USING THE ZOOM ON THE CAMARA. YOU
WON’T SEE THIS SUPERHIGH POWER IN THE
MICROSCOPE.
EVERYTHING THAT YOU ARE RESPONSIBLE
FOR ON THE HISTOLOGY IS LABELED AT
LEAST ONCE IN THIS PPT.
THERE ARE ALSO EXPLANATIONS OF WHAT
MAKES SOMETHING DISTINCTIVE, SUCH
THAT YOU CAN IDENTIFY IT.
SIMPLE SQUAMOUS EPI
ARTERY
EPITHELIAL TISSUES
ARE EITHER
GLANDULAR OR
LINING. HERE WE’RE
LOOKING AT THE
LINING AND WE’LL USE
THE ARTERY
VEIN
LOW
LINING!
MED
SEE HOW THE TEXTURE OF THE LINING IS
DIFFERENT THAN THE UNDERLYING STUFF
(MUSCLE). THAT IS THE SINGLE LAYER OF
FLAT (SQUAMOUS) CELLS.
HIGH
SIMPLE CUBOIDAL EPI
medulla
This is a whole kidney, which is divided
into layers. The middle layer is called the
medulla, and is where we’ll find our
simple cuboidal epithelium
SCAN
SEE THAT THERE ARE DIFFERENT
TEXTURES IN THIS SLIDE? THE
NATURE OF THE KIDNEY IS THAT
THESE TUBULES ALL SWEEP DOWN
TOWARDS THE SAME PLACE TO EXIT
THE KIDNEY. SO A SECTION THRU
THE KIDNEY IS GOING TO CATCH
SOME OF THE TUBULES IN CROSS
SECTION AND SOME IN
LONGITUDINAL SECTION. WE’LL SEE
HIGH POWER OF BOTH AREAS
LOW
THIS IS MEDIUM POWER OF THE LEFT PORTION
OF THE PREVIOUS PHOTO – THE
LONGITUDINAL SECTIONS…
MED
Simple cuboidal epi lining - a
cross section of a tubule
HIGH
Simple cuboidal epi lining a
longitudinal section of a tubule
HIGH
WHY DO THESE CELLS APPARENTLY HAVE NO
NUCLEI?
Simple cuboidal epi lining a
longitudinal section of a tubule
HIGH
SIMPLE COLUMNAR EPI
THE STOMACH HAS BOTH
LINING EPITHELIUM AND
GLANDY EPITHELIUM. THE
VERY EDGE IS THE LINING
AND ALL THE PURPLE
STUFF UNDER IT ARE THE
GASTRIC GLANDS
LOW
WE’RE LOOKING
HERE
MED
SEE HOW THE LINING CELLS ARE TALL AND HAVE
NUCLEI AT THE BASE, AND HOW THE NUCLEI ARE LINED
UP IN A NICE ROW?
HIGH
STRATIFIED SQUAMOUS EPI
– NON-KERATINIZED
Note the dark staining at the bottom of
the tissue, reflecting the packed nuclei.
LOW
As the cells are pushed away from the basal
layer, they get flatter, and the nuclei get spread
out too.
MED
HIGH
flattening
In this slide the flattening isn’t as obvious, but
we can still see the the density of the nuclei
decrease as the cells are pushed to the surface
HIGH
STRATIFIED SQUAMOUS EPI
– KERATINIZED
THIS IS ALL
ADIPOSE
TISSUE
Look here
for the epi
LOW
The basal layer of the st. sq epi
curves around as the epidermis
invaginates into the dermis. There
are clearly layers here – we’ll get to
them later. For now just note the
concentrated, darkly staining nuclei
at the base, thinning out a bit as they
get pushed off the basal layer. Also
note the thick superficial layer of
pure keratin.
MED
BORDER BETWEEN
THE EPI AND THE
UNDERLYING TISSUE
HIGH
SIMPLE COLUMNAR EPI.
W/ MICROVILLI
LINING THE
LUMEN…
BLOOD VESSELS
JEJUNUM
LOW
A SNIPPET OF THE PANCREAS
MED
THIS IS A SINGLE LAYER, SO
LOOK AT HOW THE NUCLEI ARE
LINED UP, AND LOOK AT THE
EDGE OF THE CELLS, THAT
DARKEaNED LINE ARE THE
PACKED MICROVILLI (TOO
SMALL TO BE SEEN ONE BY ONE,
BUT SO DENSE THEY
COLLECTIVELUY STAIN DARKER
HIGH
PSUEDOSTRATIFIED,
CILIATED
COLUMNAR EPI.
NEXT TO THE
LUMEN
LOW
MED
WE CAN SEE THE
CILIA
THIS IS A BLOB OF
LYMPHATIC TISSUE WBCS
THESE ARE COLUMNAR CELLS, BUT
THE NUCLEI AREN’T IN A NICE ROW –
THEY’RE IN A JUMBLED MESS
THIS IS MUSCUS GUNK ON THE SURFACE OF THE CILIA
HIGH
TRANSITIONAL EPI.
Bladder slides are tough to make, the layer
under the epithelial layer separates as the
section is made, resulting in all those
spaces, which are ‘artifacts’
MED
Transitional epi is designed to be able to stretch
and collapse as the bladder slowly fills and then
quickly collapses. The nuclei are jumbled, but are
clearly NOT columnar.
HIGH
LOOSE CT
WHEREAS EPI CONSISTS OF
TIGHTLY PACKED CELLS
WITH ALMOST NO MATERIAL
BETWEEN THEM, CT IS
MOSTLY ‘INSTITIAL’ STUFF
(FIBERS AND SUCH), AND THE
CELLS ARE WIDELY
SCATTERED. EVERYWHERE
YOU SEE A NUCLEUS IS A
CELL
LOW
MED
Look at how scattered the nuclei (and
therefore the cells) are. Most of the mass of
CT is extracellular material, made by the
fibroblasts. All the pinkish and thin black
strands are the fibers that give the tissue
(along with the nature of the ground
substance) its character
This is loose ct, disorganized with the fibers
not nearly as compacted as Dense CT
HIGH
DENSE IRREGULAR CT
Back to the skin to see DICT. It’s here,
below the epithelial layer, but above the
fatty layer
LOW
There are a bunch of accessory
structures here. Ignore them for
now. Look at the disorganized
stuff that is the ‘stuff ‘ of this
layer
MED
Ignore all the extra stuff in the layer – there
are blood vessles and glands here – and look
at the thick pinkish collagen fibers. They’re
not regularly arranged and there are way
more of them than in LCT
HIGH
REGULAR DENSE CT
EVEN AT LOW POWER WE CAN
SEE HOW THERE IS AN
ORGANIZATION, REFLECTING
THE FIBERS BEING PARALLEL TO
EACH OTHER AND GIVING THE
TISSUE POINT-TO-POINT
STRENGTH AS OPPOSED TO
DISTRIBUTED STRENGTH
LOW
MED
HIGH
HYALINE CARTILAGE
Back to the trachea for hyaline
cartilage
LOW
MED
Note the
chondrocytes in
their lacunae, and
the perichondrium
HIGH
ELASTIC CARTILAGE
This is an animal ear. We can see
the epidermis, then a layer of
muscle, then the cartilage layer
LOW
Elastic cartilage has much less
interstitial area than any other CT, but
what it has stains dark with elastic
fibers
MED
Chondrocyte in its lacunae
Perichondrium
HIGH
FIBROUS CARTILAGE
Part of an intervertebral disk, so the
cartilage is mostly collagen with very
little elastin; it’s also layered for
additional strength
LOW
The chondrocytes are
stacked between the layers.
MED
HIGH
COMPACT BONE
WE USE A DIFFERENT STAIN FOR
BONE, THAT MAKE MINERALS
LOOK GOLDISH. AND WHEN THE
SLIDE IS MADE, THE STAIN (WHICH
STARTS BLACKISH) DOESN’T WASH
AWAY FROM SPACES, LEAVING
THEM BLACK. SO ALL THE BLACK
AREAS ARE ACTUALLY EMPTY.
LOW
THIS IS A HAVERSIAN SYSTEM, WITH A
CANAL IN THE MIDDLE,, SURROUNDED BY 3
OR 4 HAVERSIAN LAMELLAE
THESE LAMELLAE, WHICH DON’T
BELONG TO ANY SYSTEM, ARE
INTERSTITIAL LAMELLAE
VOLKMAN’S CANAL
MED
INTERSTITIAL
LAMELLAE
ALL THE
SMALL BLACK
SPOTS ARE
LACUNAE
WITH
OSTEOCYTES
ALL THE LITTLE LINES
SPOKING OUT ARE
CANALICULI
HAVERSIAN CANAL
HIGH
SKIN
HYPODERMIS
WITH
ADIPOSE
TISSUE
TRUE SWEAT GLAND WITH
PIECES OF ITS DUCT
HEADINIGI TOWARDS THE
SURFACE
DERMIS
WITH DICT
EPIDERMIS
WITH
STRATIFIED
SQUAMOUS
EPI
PACINIAN
CORPUSULE
THIS IS A FINGERTIP WHICH HAS A THICK
KERATIN LAYER
LOW
THIS IS THE SCALP, WITH A THINNER KERATIN
LAYER AND LOTS OF HAIR FOLLICLES
SHAFT
ROOT SURROUNDED
BY FOLLICLE
TRUE
SWEAT
GLANDS
SEBACEOUS
GLANDS
LOW
ST CORNEUM
ST GRANULOSUM
ST SPINOSUM
PAPILLARY
LAYER OF
DERMIS
ST BASALE – THE ONE
LAYER AT THE BASE OF
THE EPIDERMIS
RETICULAR LAYER OF DERMIS
DERMAL
PAPILLA
MED
PACINIAN
CORPUSULE
HIGH
THE STRATUM CORNEUM IS MUCH
THINNER AND LESS STURDY ON
THE SCALP, SO IT SEPARATES INTO
ARTIFACTS WHEN THE SLIDE IS
MADE
ALL WE CAN REALLY POINT
TO HERE IS THE ST BASALE,
ST SPINOSUM AND ST
CORNEUM
DERMIS WITH DICT
HIGH
SEBACEOUS GLAND
HIGH
ARRECTOR PILI
SUPERHIGH
MEISSNER’S CORPUSULE
WITHIN DERMAL PAPILLA
SUPERHIGH