Neuroscience Midterm- from notes/ activities

What is neuroscience?

field of science that studies the central and peripheral nervous system as well as interacting components that determine behavioral and cognitive functions

trephination

boring holes into the skull, thought if you drilled holes, evil would leave (abnormal psych)

heart considered more impt than the brain in prehistoric times

ancient greece

brain used for sensing the environment

hippocrates- brain was also seat of intelligence

aristotle- brain was a radiator to cool down body

roman empire

Galen-

* embraced hippocratic view
* dissections
* cerebrum- soft, receive sensations
* cerebellum- hard- command muscles
* ventricles- hollow and fluid filled with humors

galen

* embraced hippocratic view
* dissections
* cerebrum- soft, receive sensations
* cerebellum- hard- command muscles
* ventricles- hollow and fluid filled with humors

renaissance to 19th cent

andreas vesalius

* added detail to structure of brain
* brain was machine like - fluid forced form ventricles through nerves caused movement

descartes

* people have soul

17-18th cent

two types of brain tissue: gray and white

end of 18th cent

* nervous system completely dissected and gross anatomy described
* recognized 2 divisions: central and peripheral systems
* bumps (gyri) and grooves (shallow) and fissures (deep) in the surface of every brain

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what we know at end

* brain injuries dirupt sensations
* brain communicates via nerves
* brain has diff identifiable parts

19th cent

ben franklin

luigi galvani and emil du bois reymond exp- muscles twitch when nerves electrically stimulated→ nerves conduct electricity

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charles bell and francois magendie

* bell cut each nerve root to test hypothesis that roots carry info in diff direction
* ventral- muscle paralysis
* dorsal- carry sensory info
* each nerve is a mixture of many wires, some bringing info and some sending info
* experimental ablation method- systematically destroying parts of brain to determine function

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franz gall

* bumps on surface of skull reflect bumps on surface of brain (phrenology)

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flourens

* ^^ disagrees

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paul broca

* had pt that could understand language but could not speak
* death of man→ broca examined brain and found lesion in left frontal lobe → this and other similar cases led him to conclude that this region of the human cerebrum specifically responsible for the production of speech

charles darwin

* behavior can evolve→ natural selection

theodor schwann

* cell theory- all tissues composed of microscopic units called cells

luigi galvani and emil du bois reymond exp

\- muscles twitch when nerves electrically stimulated→ nerves conduct electricity

charles bell and francois magendie

* bell cut each nerve root to test hypothesis that roots carry info in diff direction
* ventral- muscle paralysis
* dorsal- carry sensory info
* each nerve is a mixture of many wires, some bringing info and some sending info
* experimental ablation method- systematically destroying parts of brain to determine function

franz gall

* bumps on surface of skull reflect bumps on surface of brain (phrenology)

flourens

disagreed with franz gall’s idea of phrenology

paul broca

* had pt that could understand language but could not speak
* death of man→ broca examined brain and found lesion in left frontal lobe → this and other similar cases led him to conclude that this region of the human cerebrum specifically responsible for the production of speech

different levels of neuroscience

molecular

cellular

systems

behavioral

cognitive

nissel stain

able to see nissel bodies: clump of material surrounding nucleus of neuron

golgi stain

soak brain in silver chromate

able to see cell nucleus and neurites

revolutionary for nueroscience

soma

nucleus, RER, SER, golgi, mitochondria

neurites

axon- only in neurons

* axon hillock
* axon collaterals- branches from axon
* axon terminal- part in contact with other nuerons

dendrites- covered with synapses

* dendritic spines

glia

Astrocytes

* fill spaces btwn neurons and regulate chemical of extracellular space

myelinating glia

* axon insulation
* oligodendroglial CNS
* Schwann cells PNS
* diseases MS (CNS) or GBS (PNS)

non neuronal cells

ependymal cells

* line fluid filled ventricles and play a role in cell migration

microglial

* remove debris from dead or degenerating neurons and glia

vasculature

* arteries, veins, capillaries

Na/K pump

3 Na outside membrane, 2 K inside

\-70 is resting mem potential

changes electrochemical gradient

action potential

* stimulus needed
* \

1. Resting: at -70mv inside
* when stimulated to -55mV (threshold), sends electrical impulse down axon
* mechanically gated Na channels open before threshold reached
* \

2. once threshold reached: voltage gated sodium channels open and Na rushes in → depolarization to 40 mV
* \

3. voltage gated potassium channels let K flow out → repolarization to -75 (repolarization stage)
* \

4. repolarization stage goes too far (hyper polarization) neuron cannot do anything until it reaches -70 mV again, sodium potassium pump must do this (called refractory period)

threshold of action potential

\-55 mV

if not reached, there is no action potential

what can be varied is the frequency of pulses, or number of pulses

voltage

the measure of potential energy generated by separated charges

membrane potential

voltage gated ion channels

open and close in response to changes in membrane potential

ligand gated channels

only open when specific neurotransmitter latches onto it

mechanically gated channels

open in response to the physical stretching of the membrane

elevation in what ion causes neurotransmitters to be released?

calcium

The brain

frontal lobe

motor cortex

sensory cortex

parietal lobe

occipital lobe

temporal lobe- above ear

cerebellum- below temporal lobe

broca and werniche area both on left side

cerebellum

movement and control center

electrical synapses occur at…

gap junctions

neuromuscular synaptic transmission

occur btwn axons of motor neurons in spinal cord and skeletal muscle

fast and reliable

largest synapse in the body

gustation

taste

olfaction

smell

5 taste qualities

sweet, salty, umami, sour, bitter