FINAL REVIEW Flashcards
3 Repugnant ideas (early 1700s)
1) Spirits running through hollow nerve fibres to brain and muscles
2) Fermentation from nerve ends and blood, activating muscle
3) Vibrations, light vibrated nerves -> sensation to brain
How did experimentation prove the repugnant ideas wrong?
1) Fluid moves slow = not as fast as NS
2) Ligation of nerves = no accumulation of fluid
3) Activating limb muscles = no increase in V
4) Nerves cut underwater = no ferment
What is Sherrington most famous for?
Reflex conduction is unidirectional and the reflex responses which he was studying were much slower than was explicable by the speed of nerve conduction (there was a delay somewhere – this was the communication b/n sensory and motor neurons)
Neural crest cell derivatives
PNS ganglia ENS ganglis Melanocytes Cartilage and bone (face, jaw) Adrenal Medulla Cells
Where are cortical interneurons produced?
In the basal forebrain (MGE - Medial ganglionic eminence)
In stimulated emission depletion (STED) methods, how is super resolution achieved?
Super resolution is achieved by narrowing the point spread function of the diffraction disc (Airy disc) by using a laser to precisely deactivate the outmost portion of the disc
In stochastic optical reconstruction (STORM) the random switching of fluorescence of individual molecules allows
Stochastically switched on, imaged and localized, and then switched off. Many cycles of this allows the centre of these discs to be calculated and the image is constructed from millions of locations.
Magnetoencephalography:
Measures the normal (tiny) magnetic fields (billion times smaller than Earth’s magnetic field) associated with brain activity.
The most sensitive magnetic detectors (semi quantum interference devices - SQUIDS) need to be cooled to the temperature of liquid helium to detect these tiny fields. It is expensive and needs to be kept cold, hence not readily available
- Good temporal, poor spatial resolution
- Not invasive
As MEG provides no structural information, the MEG data are combined with MRI or CT maps.
As you progress deeper into sleep, what is the EEG like? What kind of rhythm?
Brain behaves more coherently, delta rhythms *Loss of consciousness also shows more coherence
When you are awake and at the beginning of sleep (Stage 1 non REM sleep) EEG is quiet or noisy? High or low amplitude and frequency? What kind of rhythms?
Noisy, low amplitude, high frequency – alpha and beta rhythms
Which cranial nerves do not connect to brainstem?
CN1 and2 - Olfactory and optic nerve
EEG measures
Current produced in cortical dendrites by synaptic inputs
What does CN5 aka ___ nerve innervate
Trigeminal. Skin of face and skull
3 features of cortical represenation
1) Topographic
2) Scaled
3) Plastic (can cut off hand and cortical representation will rearrange itself)
The somatosensory cortex, on the postcentral gyrus, consists of Brodmann areas _______
1, 2, 3ab
What happens to 11-cis retinal when light hits
*11- cis retinal (has a kink) is sitting in middle of Vitamin A -> light hits -> change in conformation to All-trans retinal
Which lateral inhibition cells are involved in motion?
Amacrine cells
Ganglion cells are especially tuned for edges
-If you look slight off-center at a star, you’ll see more stars, hence more rods off centre (8 degrees)
Ganglion cells are especially tuned for edges
-If you look slight off-center at a star, you’ll see more stars, hence more rods off centre (8 degrees)
How many layers in LGN and what cell types are they?
Six
1,2 = Magnocellular layers (1 layer is for right eye, 1 for left)
3-6 = Parvocellular layers (2 for left, 2 for right)
*There is no communication between both eyes in the LGN, they are in separate layers
Where is the primary visual cortex aka Broadmanns area 17 located?
Occipital lobe around the calcarine fissure.
How many layers in primary visual cortex? Which layer does LGN input go to?
6 (Layer 1 is surface of brain – layer 6 is inside of brain). 4c
Segregation of info from different types of LGN cells
M type GC/LGN input to Layer 4C alpha
P-type GC/LGN input to Layer 4C beta
Mixing of info from each eyes occurs in layers
3 and 4B
Ventral stream
V1, V2, V4
- From calcrine fissue, starts from V1 and travels via V2 and V3 down to inferior parts of temporal lobe
- Important for perception of shape and colour, object recognition
How is impedence mismatch overcome in the ear?
The middle ear bones transfer vibrations efficiently from the tympanic membrane (air) to the oval window (liquid) by amplifying pressure. The Eustation tube allows equalisation of pressure across the tympanic membrane.
Number of taste buds
2000-5000 taste buds
Role of Granule Cells in olfactory bulb
Granule cell neurons (similar to amacrine cells in visual system) act as tuning interneurons that leads to output.
Projection neurons (1 class called mitral cell) are second order olfactory neurons that have branching dendritic trees that form glomeruli with terminals of olfactory receptor cells. Individual glomeruli encode only one odour
Projection neurons (1 class called mitral cell) are second order olfactory neurons that have branching dendritic trees that form glomeruli with terminals of olfactory receptor cells.
Primary peristalsis, all functions from stomach to anus - is this a somatic of visceral neuron function?
Visceral
*Peristalsis in the oesophagus and sphincters are somatic
Secondary peristalsis is part of CNS or ENS?
ENS
Coeliac
Gluten-intolerant as villi fall off of small intestine and mucosa becomes smooth, decreasing SA:V by 100 fold - nutrients absorbed decreased
In which parts do these actions occur
a) digestion
b) absorption
c) propulsion
a) Digestion (duodenum, jejunum)
b) Absorption (nutrient: duodenum, jejunum; water: ileum, colon)
c) Propulsion (whole length)
Superior colliculus
Aka optic tectum, role in directing eye movements