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
flattening HIGH
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 JEJUNUM BLOOD VESSELS A SNIPPET OF THE PANCREAS LOW
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 PACINIAN CORPUSULE TRUE SWEAT GLAND WITH PIECES OF ITS DUCT HEADINIGI TOWARDS THE SURFACE DERMIS WITH DICT EPIDERMIS WITH STRATIFIED SQUAMOUS EPI 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 ROOT SURROUNDED BY FOLLICLE SHAFT TRUE SWEAT GLANDS SEBACEOUS GLANDS LOW
ST CORNEUM ST GRANULOSUM ST SPINOSUM PAPILLARY LAYER OF DERMIS RETICULAR LAYER OF DERMIS ST BASALE THE ONE LAYER AT THE BASE OF THE EPIDERMIS 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