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Image Review #4
muscle and neural tissue
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• What are the three types of muscle?
• Which types are striated muscle?
• What are the three types of muscle?
– Skeletal, smooth, and cardiac
• Which types are striated muscle?
– Skeletal and cardiac
• Bigsmall:
– Fasicle made up of myofibers made up of
myofibrils which contain sarcomeres
• What is a syncytium?
• What is the epimysium?
• What is the perimysium?
• Edomysium?
• Bigsmall
• Fasicle made up of myofibers made up of
myofibrils which contain sarcomeres
• What is a syncytium?
– Multiple nuclei but continuous cytoplasm
• What is the epimysium?
– Connective tissue covering of the muscle
• What is the perimysium?
– CT surrounding each fasicle
• Edomysium?
– Surronds individual myofibers
Skeletal Muscle
• The key is to look for
striation
Smooth Muscle
• Look to see if you
can find it cut on
both planes
• Also look to see if
you can see the
characteristic whorls
(not in this picture)
smooth muscle
Smooth muscle
Dense Regular CT
Cardiac muscle
• Some things to
note about Cardiac
Muscle
– It is NOT a
syncitium so nuclei
are more centrally
located and only
one per cell
– Joined by
intercalating discs
cardiac
• skeletal
skeletal
cardiac
Parts of the Neuron
• Neuronal perikaryon—contains Nissl substance
• Dendrites—processes extending from cell body,
branched, tapering.. Contain nissl substance
• Axon hillock—wider than the axon
• Axons—constant diameter with little branching
– NO NISSL SUBSTANCE
• Synapses—occur between various parts of
neurons
Neurons cont.
• What are the possible synapses?
• Talk to me about synaptic vesicle recycling
• Neurons cont.
• What are the possible synapses?
– Axo-somatic—axon to cell body
– Axo-dendritic—synapse onto dendrite
– Axo-axonic—axon to axon
• Talk to me about synaptic vesicle recycling
– Reclaimed by endocytosis involving
CLATHRIN
Development of Neurons
• Growth cone—drives axon elongation
– Leading edge—filopodia sense environment
and grow in proper places
• Netrins—guidance molecules for neuronal
growth
– Axoplasmic transport
• Anterograde—toward terminal—kinesins
• Retrograde—toward cell body—dyeins
– If I were you I would ABSOLUTELY
KNOW THESE
Non-neuronal cells
• Astrocytes
– Proliferate and form scars after injury—gliosis
• Oligodendrocytes (Schwann cells in PNS)
– CNS myelin forming cells
Peripheral Nervous System
• What are the three main parts of the PNS?
Peripheral Nervous System
• What are the three main parts of the PNS?
– Ganglia—clusters of neuron cell bodies
w/support cells
– Nerve fibers—axons and support cells, no cell
bodies
– Nerve endings and organs of special sense
Peripheral Nerves
• Circle of wavy shit – works every time
Peripheral nerves Cont.
• Like muscle there is CT around the nerves
• Epineurium around the whole thing
• Perineurium—surrounds each bundle of
axons
• Endoneurium—surrounds each axon
Myelination
• Schwann cells
• What does myelination do?
– Increases conduction velocity
– Nodes of ranvier are where Na+ channels are
concentrated in myelinated axons
Ganglion = fried eggs
NODE OF RANVIER
LOTS OF FUN
REVIEW IMAGES
Smooth muscle
• NONE OR VERY LITTLE SPACE between cells
• Silky looking
• LESS NUCLEI then dense regular CT
– Nuclei are also ligher in smooth muscle b/c they arent
as smashed
• SMALLER FASCICLES than skeletal
– But both have peripheral nuclei
• Can go in 50 different directions
– Compare this to dense regular CT that all moves the
same direction at the same time
What is this?
DENSE REGULAR CT
• Nuclei are DARK and PLENTIFUL
• Tissue looks like its all moving together
Way fewer nuclei in the smooth muscle on the right
Where do we find lots of smooth
muscle?
• GI tract for peristalsis
• Around arteries
• So if I were you if they label stuff that is
making a tube (artery or esophagus) I would
keep smooth muscle in mind
Around artery
• What kind of fibers do we see around the
innermost part of the artery?
Around artery
• What kind of fibers do we see around the
innermost part of the artery?
ELASTIC – wavy looking
• Smooth muscle is also often found in the
same tissue cut both ways – both
longitudinally and cross section
– This is another good clue
Here you see the smooth muscle
going 3497319847 different ways
In cross section smooth muscle has VERY
LITTLE space between the cells and the
nuclei are found in the periphery like
skeletalmuscle, but the fascicles are MUCH
SMALLER
• What in the
hell is this?
• Well, you can see
the little pinocytic
vescicles around
the side –
CAVEOLAE!!
• You also see
dense bodies and
plaques in the
cytoplasm
• Not so hard
anymore, its
smooth muscle
Skeletal muscle
•
•
•
•
HUGE GIANT fascicles
Nice and red in most slides
Peripherally placed nuclei
Also look for dense regular CT tendon
around it
• If I were you I would know very well the
divisions of the skeletal muscle sarcomere
and what is found in each one
• TERMS TO
KNOW:
– M line
– Z line
• BLACK
– A band
– I band
– H zone
Also in EM
• Look for
mitochondria
between the
sarcomeres, they
think its funny to
label it here and
catch everyone
off guard
• Looks striated
• Peripheral nuclei
• Easy enough –
skeletal muscle
Hi, what am I?
Hi, what am I?
perimyseum
enodmyseum
• Endomyseum vs. perimyseum
– Perimyseum has much more CT, surrounds
many fibers vs. just ONE like endomyseum
• Same shot, cross section
• Endo around ONE FIBER, peri around
MANY and is much more CT looking
One last time
cardiac
• Intercalated disks
– Sometime you have to look for these, please do
so
•
•
•
•
Branching
Like skeletal, is striated
One central nuclei per cell
LOTS MORE SPACE between cells when
cut in cross section vs. smooth muscle
LOTS OF SPACE in X section
vs. little space in smooth
What are these intercalated disks
you speak of?
• Have DESMOSOMES
• Have GAP junctions
• Lets demonstrate:
• Lets also look for lots of
mito and maybe even a
little glycogen (but not in
this image) – these cells
need lots of energy
• Nice little
summary
neurons
Lab 10
Nerve cell body
• NO NISSL SUBSTANCE IN AXON
HILLOCK OR AXON – JUST
DENDRITES AND CELL BODY!
– Helps when you have to decide axon vs.
dendrite
Has nissl, thus, dendrite
No nissl, thus, axon
Neurons have a prominent
nucleolus
• Why? Making
neurotransmitter,
that’s why there is
lots of nissl stain
too
– Remember, nissl
is for RER 
protein making
Ganglion = fried eggs. Works
every time.
Hi, we look like fried eggs
What the….!?!?
Myelinated axons
• Must say myelinated, if you don’t then you
will die.
• In EM almost all the time, looks like a
bunch of black surrounding a cell
• On our written last year they gave us 4 pics
of a neuron being myelinated and asked us
to put them in chronological order, so you
may want to be familiar with this topic
What would
you say this is?
• Well I would say that is a schwann cell
• Why? It is surrounding a nerve fiber and
myelinating it
Another look….
Hi, I am a
nice
schwann
cell
nucleus
Peripheral nerves
• How do you know what these look like?
EVERY SINGLE TIME it is a circle of
wavy shit. If they label something and it is
circular and is filled with random wavy shit,
it is peripheral nerve.
Circles of wavy shit
Neural coverings. Know them.
• Epi around a bunch of peripheral nerves
• Each peripheral nerve (circle of wavy shit)
surrounded by a perineurium
• the axons surrounded by endoneurium
• Each individual axon may or may not be
surrounded by myelin sheath
Enjoy this picture
Epi has the most CT-like
appearance and peri around each
individual circle of wavy shit
Epi around many circles of w. s.
Peri around 1 circle of w.s.
Endo surrounds the little axons in
the c.o.w.s.
Where is epi? Where is peri?
Get it?
epi
peri
peri
peri
epi
Quiz time
Ganglion
why? Fried eggs.
Myelinated axon. Must
say myelinated. If you
don’t you will miss it.
What are these?
Peripheral nerves
why? Circle of wavy
shit.
Green arrow is pointing to…?
Well you see nissl
substance, so dendrite
Unmyelinated axon, no
black around it
COLLAGEN
do not be fooled. Looks
too perfectly round to be
glycogen, which has
irregular borders
Motor end plate
why? Neuron ending on
skeletal muscle
Karyotype
I told you not to forget
this
• Left is glycogen – black clumping looking
stuff
• Right is RER. You can see the ribosomes
and the sacs are very flattened
What cytoskeletal element do we
see here
It’s a desmosome –
looks hairy
that makes the answer
intermediate filaments
Centriole
its by the nucleus – here
b/c it does stuff in cell
division
• What stain is this
PAS – goblet cells are
magenta
SER – looks like a
bunch of blebs. We
don’t see any here but
we would also look
for….?
Round mito!
Brown fat – red b/c of
mito and many fat drops
per cell
Spongy bone spicule
Adipose tissue
And I leave you with the mullet
of the week
Don’t be that guy