Flashcards in 32. Specialized Tissues, Stem Cells And Tissue Renewal Deck (23):
What is the role of the sensory cells that are present in the sensory epithelia?
1. Act as transducer
2. Convert environmental signal to electrical form, for CNS interpretation
Are the sensory epithelial cells highly conserved throughout evolution?
What are the sensory cells in the nose?
1. Olfactory sensory neurons
What are the sensory cells present in the ear?
Auditory hair cells
What are the sensory cells present in the eyes?
What is located on the apical end of the sensory cells?
Structure that will detect the external stimulus and convert it to change the membrane potential
What is located at the basal end of the sensory cells?
Synapses with neurons to specific brain regions
What are bipolar neurons with a dendrite facing the extracellular environment, and where does the axon travel?
1. Olfactory neurons
2. Axon travels along olfactory nerve to the olfactory bulb
What type of neuron is the olfactory neuron and how does it run to the brain?
1. Bipolar neuron, with dendrites facing the extracellular environment
2. Axons run with the olfactory nerve to the olfactory bulb
What are the olfactory neuron supporting cells?
1. Cells present between neurons that anchor and separate neurons from one another.
What are the cells that are in contact with the basal lamina referred to as?
Where are odorant receptor proteins found in olfactory receptors?
Found on free surfaces of cilia
What type of receptor are the odorant receptors that are located on free cilia surfaces?
G protein coupled receptors
How do olfactory neurons generate an action potential when that specific odorant receptor is bound with an odor?
1. GPCR are activated to form cAMP
2. cAMP opens ion channels allowing sodium/calcium influx into cell
3. Forming action potential
What do the olfactory neuron action potentials act on?
1. Act on glomeruli located on olfactory bulbs on each side of brain
What is the average turn over for an olfactory neuron?
What is the rare case of adult neurogenesis, specifically in the CNS?
1. Regeneration of olfactory axons, receptors, and bulb attachment
Why is olfaction considered to be linked with neurodegenerative disorders?
1. Aging individuals display reduced activity in olfaction
What is an initial clinical finding in cases of idiopathic Parkinson's disease?
1. Reduced sense of smell
What parts of the brain have been shown to contain stem cells?
1. Ventricles of forebrain. These migrate to olfactory bulb
2. Hippocampus. Memory and learning region
What are neurospheres (clusters of neural stem cells) able to differentiate into?
2. Glial cells
How are some non-mammalian animals able to regenerate amputated limbs?
1. Cells de-differentiate to embryonic cells
2. Embryonic cells proliferate to form limb bud.
3. Cells then re-differentiate to tissue specific