Neurobiology Flashcards
what makes up the CNS?
brain and spinal cord
what makes up the peripheral nervous system?
somatic (sensory info and signals from CNS to muscles) and autonomic (regulates internal environment)
whats the difference between parasympathetic and sympathetic nervous system?
para - generally calming
sympathetic - generally arousing
what makes up the forebrain?
basal ganglia, cerebral hemisphere, diencephalon
what makes up the midbrain and hindbrain?
brain stem which is made up of midbrain, pons, medulla oblongata
hindbrain makes it all up and also includes the spinal cord and cerebellum
what makes up a neuron?
cell body/soma, dendrites, axon, axon hillcock, axon terminal
function of cell body and axon?
cell body - integrates input and converts to output
axon - conducts output signal and terminal transmits the output
what are microglia?
small mesodermally derived, defensive function - immune cells of the CNS - can become macrophages
what are astroglia?
star shaped, symmetrical, nutritive and support function
support neurons by physically separating cells
- regulating K conc
- remove neurotransmitters after they’ve been realised by neurons
- release growth factors
what’s the potential of the inside of the cell?
-50 - 70mV (inside more negative than outside)
whats the action potential graph like?
steady then curves up to overshoot (+40mV)
dips to the undershoot (-70mV)
raises again to resting potential (-65mV)
what’s the action potential?
sodium/potassium pump action - it propagates down the axon
why can’t the action potential go backwards?
due to the absolute refractory period - recovery time
why is mylein important?
insulates to prevent leakage of ions - help action potentials travel faster
what’s synaptic transmission?
action potentials depolarise the axon terminal causing the fusion of vesicles to the plasma membrane and release of neurotransmitters
what are the two types of receptors?
ionotropic - ligand gated
metabotropic - g-protein receptors
how do excitatory transmitters work?
activate receptors that allow sodium influx driving towards action potential
how do inhibitory transmitters work?
activate receptors that allow chlorine influx which drives away from action potential threshold
how does our brain make sense of the world?
detect physical stimulus to transduce it into a change in membrane potential to convert it into action potentials in sensory cell to transmit signal to sensory regions of brain to perception or conscious experience
how does the eye work?
light focused by retina - where transduction of the light occurs
photoreceptors pass info on to ganglion cells which then have the axons that come together to make up the optic nerve
detection of light by rods and cones
where does the information from your right eye go?
to the left hemisphere
whats in the somatosensory system?
skin receptors free nerve endings - temp and pain hair follices - touch moving hair meissners corpuscles - light touch merkels discs - pressure ruffinis endings - pressure pacinian corpuscles - vibration
why can we tell if there are two things touching our skin?
receptor density and number of sensory neurons touched
where does sensory info come in?
dorsal root ganglion cell
parts that make up the spinal cord?
cervical cord, thorasic cord, lumbar cord, sacral cord
how is sensory info transmitted?
info travels up dorsal column into medulla, here the dorsal column nuclei recieve the info and pass it onto the brain, axons cross over to the other side and travel through the brain stem to the thalamus and another synapse here which will send it to the cortex
where do we get most of our sensory info?
fingers, lips
types of muscles?
smooth, cardiac, striated
what helps us move?
motor neurons, unevenly distributed - more in legs
how does reflex work?
simple motor action, evoked by a sensory stimulus
types of reflex?
stretch - movement
autogenic inhibition reflex - prevents over stretch
flexor - withdrawl in response to harmful stimuli
crossed extensor - distributes load evenly
how does stretch reflex work?
action potentials flow through axon from muscle spindle into spinal cord to the motor neuron where glutamate is used to stimulate the sensory neuron and this causes the muscle to retract
which neurones are involved with pain reflex?
flexor, excitatory neurons and motor neurons
what is locomotion controlled by?
neural networks, central pattern generations
what does the motor cortex do?
complex and precise movements - lateral pathway is fine movements
what does the basal ganglia do?
voluntary movements
what does the cerebellum do?
coordination of movements, error detection
copy of commands sent to cerebellum, as is sensory feedback, the two then compared and if feedback differs from expected the error can be rectified
what do the four lobes do?
temporal - auditory perception
pariteal - somatic sensation
occipital - visual perception
frontal - motor control
ways to study brain functions?
EEG, PET scan, fMRI
what do split brain patients do?
if two objects, draw one but say the other
what are the symptoms of parkinsons?
tremours, akineasia (difficulty initiating movement), bradykinesia (slow movements), shuffling gait
what causes parkinsons and how is it treated?
loss of dopaminergic neurons of the substantia nigra
deep brain stimulation, pharmacological 2-DOPA
what is alzheimers and what are the symptoms?
neurofibrillary tangles and amyloid plaques
disrupted brain function and shrinkage of brain tissue
memory loss, language difficulties, progressive dementia
what is motor neuron disease and how is it managed?
progressive loss of motor neurons, death within 3/4 years
no effective treatment
managed through glutamate mediated excitotoxity, protein aggregates and mitochondria dysfunction
