Neuroscience Flashcards
Which mechanoreceptors in the skin are fast adapting?
Pacinian corpuscles
Meissner’s corpuscles
Cutaneous thermoceptors
Which mechanoreceptors in the skin are slow adapting?
Merkel’s receptors
What type of neurones are nociceptor neurones?
A-delta and C
What type of neurones detect touch, proprioception and vibration?
A-beta
What type of neurones detect proprioception?
A-alpha
What are types of macroglia?
Schwann cells
Oligodendrocytes
Ependymal cells
Astrocytes
Why is regeneration not possible in the CNS?
There is no endoneurial tube to support regeneration
Signalling in the CNS actively prevents regeneration
What are ependymal cells?
Cells that line the ventricles of the nervous system (fluid filled cavities)
Involved in production of CSF
The cells are ciliated to help circulate the CSF `
What are functions of astrocytes?
- Neural guidance during development
- Form scaffold of brain and spinal cord
- Form BBB by froming tight junctions with
periceytes - prevent CNS regeneration by forming scar tissue - damaged cells cause reactive astrogliosis, produce inhibitory molecules that inhibit growth of damaged axons
- supply neurones with glucose from blood
- modulate cerebral blood flow
What are microglia?
Macrophage cells of the CNS. They have motile processes which monitor the environment and danger signals will trigger transformation. They become activated and may become phagocytic. They are involved in injury response/repair.
How is salt taste detected?
A high amount of Na+ (from NaCl) will enter taste cells through channels by diffusion from an area of high concentration to an area of low concentration. This depolarises the cell so a signal can be sent to the brain.
How is sour taste detected?
Increased H+ which enters through TRP channels blocks K+ channels, sodium is still entering so this causes depolarisation so signal is sent to brain.
How is sweet taste detected?
GPCR
T1R2 and T1R3 subunits
Activates PLC/IP3
Calcium release causes depolarisation
How is bitter taste detected?
GPCR
Two T2R subunits
Activates PLC/IP3
Calcium release causes depolarisation
How is umami taste detected?
GPCR
T1R1 and T1R3 subunits
Activates PLC/IP3
Calcium release causes depolarisation
What are the cranial nerves involved in gustation?
VII - facial
IX - glossopharyngeal
X - vagus
What is the process of how smell is detected?
- odorant binds to receptor
- The receptor is coupled to a G protein –> intracellular cascade
- Na+ and Ca2+ channels open which causes depolarisation
- If threshold reached then AP produced
- From olfactory neurone –> olfactory bulb –> olfactory cortex
What are the 3 ossicles called?
Stapes
Malleus
Incus
What are the ossicles for?
Amplification of sound
What are the muscles of the middle ear and what are they for?
Stapedius muscle and tensor tympani muscle
The attenuation reflex - help ear to adapt to and filter out background noise
Where is the eustachian tube and what does it do?
Between the nasal cavity and pharynx
Equalises pressure
What are the semicircular canals?
Part of the vestibular system and are used for balance
What are the 3 bony canals and what are they?
scala vestibuli
scala tympani
scala media
The 3 canals coil in a snail to make the cochlear
Where are different frequencies heard and what is the ability to distinguish between frequencies called?
High frequency heard at the base of the cochlear
Low frequencies heard at the apex of the cochlear
Tonotopy
