Neurons Flashcards
What is an afferent neuron?
Moving away from a central organ or point
-messages from receptors to brain
What is a sensory neuron?
- messages from receptors to brain or spinal cord
- afferent, unipolar or bipolar
What is an efferent neuron?
- moving towards a central point
- messages from brain to organs
What is a motor neuron?
-messages from brain or spinal cord to organs
What is an interneuron?
- relays message from sensory neuron to motor neuron in the spinal cord
- make up the brain and spinal cord
What is a dendrite?
-point of bringing in information from other neurons
Ribosome
Connects proteins in neurons
Endoplasmic reticulum
Generates proteins
Mitochondria
Powerhouse of the cell
Golgi
Package proteins like a postal service
Synaptic vesicles
Balls in axon that contain neurotransmitters
Microtubules
Transport packaged neurotransmitters down axon
Myelin
Protects axon and promotes transmission down the axon
Terminal buttons
Collect neurotransmitters in vesicles while they await release. Bus stop of neurotransmitters.
What disease is associated with neuronal death?
Alzheimers
What are the characteristics of Alzheimer’s?
- Cerebral atrophy
- external surface: widened sulci and narrowed gyri, mostly over frontal and parietal regions
- poor new learning, changed personality, language deficits
What neuronal damage causes dementia?
- neurofibrillary tangles
- amyloid plaques
What is an amyloid plaque? What does it cause?
- What is it? cellular trash found in areas with many synapses
- contains amino acid peptide protein code beta-amyloid
- What does it cause? affected synapses degenerate
Where are amyloid plaques found
-in places with many synapses in hippocampus, frontal and temporal regions
Neurofibrillary tangles
- twisted ropes in swollen cell body
- tau proteins that accumulate, creating tangles throughout brain including layers iii and iv of cortex
Neuropathology also changes associated with dementia
- formation of lewy bodies
- Lewy body dementia
- core of granular material with main body composed of ring like filaments and degenerating organelles
- nonspecific indicator of cell pathology
Resting membrane potential
-70mV POLARISED
What disease is associated with neuronal death? Describe how it presents in the brain
Alzheimer’s. Widened sulci, narrowed gyri, shrunken like an old sponge, diagnosis associated with poor learning, changed personality, language deficits
What substances/proteins are associated with Alzheimer’s?
Neurofibrillary tangles, amyloid plaques & lewy bodies
What are lewy bodies?
Granular material/various proteins, inside neuron cell bodies, associated with Dementia and Parkinsons
What is saltatory conduction?
Passive conduction (instant and decremental) along each myelin segment to next Node of Ranvier, new action potential generated at each node, conduction like this is better than conduction in unmyelinated axons
What are the 2 main classifications of neurotransmitters?
Small and Large
What are the main types of small neurotransmitters?
Amino Acids
Monoamines
Acetylcholine
Soluble Gases & endocannabinoids
What are some examples of amino acid neurotransmitters?
Glutamate,
Gaba
Aspartate & Glycine
What is the function of glutamate?
Most prevalent excitatory NT in the CNS
What is the function of GABA and how is it made?
Synthesized from glutamate
Most common inhibitory NT in CNS
What are the two types of monoamine NTs?
Catecholamines and indolamines
What are the types of catecholamines?
Dopamine, Norepinephrine, Epinephrine
What are the types of indolamines?
Seratonin, Melatonin
How do you turn dopamine into epinephrine?
Tyrosine>L-DOPA>Dopamine>Noradrenaline>Epinephrine
How do you create serotonin?
Tryptophan>Serotonin
How do you create acetylcholine? What is its role?
Acetate+Choline=acetylcholine Activating parasympathetic nervous system at neuromuscular junction
What are two ways that drugs alter neurotransmitter activity?
While still in the neuron or at the synapse junction
Define agonists and antagonists
Agonists facilitate NT activity, antagonists decrease NT activity
What are three examples of agonists?
Cocaine, benzos, physostigmine,
What are two examples of antagonists?
Atropine and Curare
What is a disorder of the acetylcholine receptors?
Myasthenia Gravis - autoimmune disorder that destroys ACh receptors, treated with drug that decreases the amount of ACh antagonist
What is a unipolar neuron?
Neuron with 1 pole: 1 route of AP, sensory neuron that transfers information from receptors to higher order neurons e.g. Retinal Ganglion Cell
What is a bipolar neuron?
Neuron with 2 poles: 2 routes of AP, connects adjacent cells, usually in sensory system
What is a multipolar neuron?
Neuron with multiple poles: multiple routes of AP, transfers info between cells in a single structure; can collect info from many cells e.g. Interneuron
