Nervous system Flashcards
(55 cards)
What are the three lobes in your primitive prototype brain?
How do they split into the 5 main mature lobes?
Prosencephalon (forebrain) mesencephalon (midbrain) rhombencephalon (hindbrain). Prosen splits into telencephalon which is your cerebral cortex, and diencephalon which is thalamus + hypothalamus. Mesencephalon stays the same as the midbrain and rhomb splits into meta (cerebellum) and myelin (medulla).
Walk me through the divisions of the nervous system, starting with CNS and PNS
CNS is made up of the brain and the spinal chord, PNS is made up of all the nerves that come off of it. Can be divided into afferent (sensory) and motor (efferent). Motor can be somatic (voluntary) or autonomic. ANS can be sympathetic (fight or flight) or parasympathetic (rest and digest)
What do we call a collection of nerve cell bodies outside of the CNS
A ganglion !
Four defined regions of every neuron and its function
Dendrites - receive messages from neighbouring neurons
Cell body - house nucleus, mitochondria etc for cell
axon- transmits messages
synaptic terminal - passes messages onto other neurons
Walk me through the events at a chemical synapse
An action potential reaches the synaptic terminal which triggers voltage gated calcium channels to open. This influx of calcium channels forces the vesicles to fuse to the membrane and release their neurotransmitter. The NT diffuses across the cleft and binds to receptors on dendrites / cell bodies, triggering a response in the neighbouring neuron. NT is either reabsorbed or recycled unless acted upon by drugs (SSRI etc)
Neuroanatomical orientation above the midbrain diencephalic junction? Below it?
Above: Dorsal (top), caudal (back), ventral (bottom), rostral (front)
Below: Dorsal (back), caudal (bottom), ventral (front), rostral (top)
List the three planes of axis and what view they give
Saggital plane down the medial line - gives right and left
coronal / frontal plane horizontally - gives front and back
transverse - gives top and bottom
What is the most common excitatory NT in the CNS? Most common inhibitory?
Glutamate and GABA
What is Myasthenia Gravis
An autoimmune disorder where a loss of neuromuscular transmission from destruction of Ach receptors prevents nerve impulses from triggering a muscular contraction. Most commonly affects eyes, face, and swallowing
NT involved in executive functions, motor control, motivation, arousal, reinforcement, and reward…..
Dopamine !
Agonist is cocaine
Antagonist is antipsychotics, reduces dopamine output
Explain the four dopaminergic pathways
- Mesolimbic - VTA to NA, schizo has too much here
- Mesocortical - VTA to cortex, schizo has to little here
- Nigrastriatal- Substantia nigra to striatum
- Tuberoinfudibular - hypothalamus to pituitary gland
What causes Parkinson’s disease
reduced dopamine output from substantia nigra onto the striatum
What NT does the sympathetic post ganglion release? Some functions?
Norepinephrine
In the brain - it increases arousal, alertness, memory retrieval, focus
Body - releases glucose from storage, increases HR, reduces blood to GI
Which cells produce myelin in CNS and PNS?
Oligo in CNS, multiple neurons at once, no nodes of ranvier
Schwann in PNS - one part of axon at once, nodes of ranvier
Name for the end of the spinal chord at L1/L2?
Name for nerve roots after this?
Conus medullaris and cauda equina
Function of the thalamus
Relay station for sensory and other inputs into the cortex (synapse here), acts as a selective filter and information processor
General functions of frontal lobe, temporal lobe, occipital lobe, and parietal lobe.
Frontal lobe - motor, production of speech (broca), problem solving, planning, emotions, judgement, impulse control i.e higher order functions
Parietal lobe - sensation
temporal- speech comprehension, auditory information, memory
occipital - visual processing
Two primary visual cortex pathways ?
Dorsal - parieto occipital - where
Ventral - occipital temporal - what
Three types of white matter pathways within the brain?
Projection fibres, association fibres, commissural fibres
Axons of projection fibres are gathered into a small bundle called the _____ and above this they spread out to form the _____
Internal capsule, corona radiata
What do commissural fibres do?
Connect alike areas in the right and left hemisphere i.e corpus collosum
What causes Guillan Barre syndrome
Autoimmune destruction of Schwann cells in the PNS. Usually after an infection or surgery, lose muscle strength in the periphery.
For blood supply to the brain, which arteries ascend anterior vs posterior ?
Anterior we have the carotid arteries coming off the aorta and subclavian (internal goes through carotid canal)
Posterior we have vertebral arteries coming off subclavian (Forman magnum)
Where is the carotid sinus and what does it do
Bulge in the internal carotid right after bifurcation at level of C3/4. Houses sensory baro recptors that project to the medulla and sense changes in blood pressure
