Week 10 Histology Flashcards
What are the structures present in a typical neuron?
Dendrites Cell Body Axon Synapse Synaptic Bouton
What structures are present in a typical neuron cell body?
Rough Endoplasmic Reticulum/Nissl Substance Mitochondria Golgi Lysosomes Nucleus and Nucleolus
What is the purpose of the nucleolus?
Creates rRNA
Increases transcriptional activity.
What is the synaptic bouton and what does it do?
Terminal end of axon.
Where vesicle transport occurs.
What are the characteristics of a motor neuron?
Multipolar
Large neuron cell body.
Large axon
Many dendrites
Give an example of a motor neuron in the CNS.
Betz cells in the Cerebral cortex
Anterior Horn of the spinal cord
What are the characteristics of a sensory neuron?
Unipolar
1 major process with 2 branches.
One to the CNS and one to the target sensory area.
What are the characteristics of an Interneuron?
Bipolar
Local connections in the CNS.
Basket cells.
What are the functions of a neuron?
Gather sensory information.
Process information
Provide memory
Generate signals.
Name a specialised type of synapse.
Neuromuscular Junction (NMJ) Skeletal muscles synapse.
What is the target of a synapse and what is it involved in?
Dendritic Spines
Memory Storage
Name the triangular shaped neurons and where they most commonly occur?
Pyramidal cells.
Cerebral Cortex
What are the other types of specific neurons in the CNS?
Purkinje cells - multipolar - Cerebellum cortex.
Granule cells - multi-processed - Cerebellum and Hippocampus.
Glia - Support cells - Neuropil.
Describe Motor Neuron Disease, how is it caused and what are some specific types?
Progressive disease.
Causing weakness in voluntary muscles due to the death of motor neurons.
Most common is Amyotrophic Lateral Sclerosis where MN death occurs in the cortex, brainstem and spinal cord.
Bulbar Palsy where MN death occurs in brainstem.
Muscular Atrophy where MN death occurs in the LMN death.
What does the CNS consist of?
Brain, Spinal Cord and most Nerve Cell Bodies.
What NCB aren’t present in the CNS but are present in the PNS?
Peripheral NCB involved with the Dorsal Root Ganglia and NCB in the Autonomic NS involved with sympathetic control in the spinal cord and parasympathetic control in organs.
What cells are present in the CNS and what are they involved in?
Oligodendrocytes - MYELIN production.
Astrocytes - Form BBB.
Ependyma - Line the CHOROID PLEXUS and produce CSF.
Microglia - Macrophages.
Which proteins are present in CNS myelin and what do they do?
Proteolipid protein (PLP) - Links exoplasm together.
Myelin Basic protein - Links cytoplasm together.
Myelin Associated Glycoprotein - Binds the surface of oligodendrocytes together.
What pathologies are involved in this?
PLP - mutations cause degeneration of myelin - Pelizaeus-Merzbacher which causes mental disability.
Spastic Paraparesis - affects the spinal cord myelin.
The gene is on the X chromosome so it is prevalent in males.
MBP - Multiple Sclerosis
MAG - Spastic Paraplegia - affects the lower limbs.
What is multiple sclerosis and how is it caused?
CNS disease that affects the brain and spinal cord.
Autoimmune disease that affects attacks the CNS myelin.
Causes tremors, spasticity, hyperreflexia and muscle weakness.
Describe the tissue preparation process for frozen sections.
Harvest brain.
Immerse in 30% sucrose.
Trim brain for easy mounting onto frozen platform.
Slicing using a microtome.
Mount, dehydrate and Nissl Stain for microscopy.
Immunolabelling some slides.
What does immersing the tissue in 30% sucrose do?
Removes the water to decrease buoyancy and protect the tissue when it is frozen.
How is the tissue dehydrated?
Soaking in graded ethanol.
What are the pros and cons of preparing tissue using frozen sections?
Pros - Quick and tissue retains antigenicity.
Cons - Ice crystal damage can occur which decrease resolution.
