Transcript Document
Image Review #4 muscle and neural tissue [email protected] • 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 • Bigsmall: – 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? • Bigsmall • 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