Anatomy and neurotransmitters Flashcards
Parts of brainstem sup to inf
Midbrain
Pons
Medulla
Function of midbrain
Eye movements
Primitive output for hearing and vision
Function of pons
Links 2 halves of cerebellum
Coordination of eating, hearing and balance
Function of medulla
Links brainstem to spinal cord
Regulates autonomic and automatic functions
Main sulci of brain
Central - divides frontal and parietal
Lateral - divides temporal and frontal/parietal
Parieto-occipital
Functions of cerebellum
Precise voluntary movement
Coordination
Minor cognitive function
What is anterior and posterior to central sulcus
Anterior - precentral gyrus - primary motor cortex
Posterior - postcentral gyrus - primary sensory cortex
Differences between CNS and PNS
PNS axons can regenerate
Myelination by Schwann cells in PNS and by oligodendrocytes in CNS
Immune response mediated by microglia in CNS which is dampened to decrease swelling
Tumours usually benign in PNS but can be either in CNS
Where does the temporal pole lie
Middle cranial fossa
What is the corpus collosum
Bridges 2 hemispheres of cerebrum
Order of meninges from deep to superficial
Pia mater
Arachnoid mater
Meningeal dura mater
Periosteal dura mater (inner and outer skill)
Where is the subarachnoid space
Between pia and arachnoid mater
Functions of subarachnoid space
Contains CSF which makes brain weightless, protects the brain mechanically and provides glucose for brain
Where is the subdural space
Between arachnoid and meningeal dura mater
Where does the MMA lie
Between the skull and inner periosteal dura mater
Crosses the pterion
Where are the dura venous sinuses
Between the meningeal and periosteal dura mater layers
Difference between T1 and T2 MRI scans
T1: dark CSF
T2: light CSF
What contrast is used for brain MRI and how does it reveal tumours
Gadolinium
Shows disturbances in BBB and tumours are highly vascular with a poor BBB
What constitutes the BBB
Capillary endothelium
BM
End foot processes of astrocytes
What class of cells are microglia
APCs
Functions of astrocytes (5)
Structural support Glucose lactate shuffle - astrocytes store glycogen to make lactate which crosses BBB to enter glycolysis Remove glutamate Remove K+ in ECF Form BBB
Classes of neurotransmitters and some examples of each
Excitatory amino acid - glutamate
Inhibitory amino acid - GABA, glycine
Biogenic amines - ACh, NA, dopamine, serotonin, histamine
Peptides - neuropeptide Y, somatostatin
Classes of glutamate receptor
Ionoptropic - AMPA, NMDA
GPCR
General consequence of ionotropic glutamate receptor activation
Excitatory post synaptic potential where depolarisation causes more APs
Consequence of GPCR glutamate receptor activation
Decreased levels of cAMP
How do AMPA and NMDA receptors work together
AMPA receptor activation by glutamate binding causes neuronal depolarisation. NMDA receptors are only activated when glutamate binds in depolarised neurones. This allows Ca influx which up regulates AMPA receptors.
Why is glutamate toxic to neurones
Too much Ca influx via NMDA receptors
General consequence of GABA and glycine binding to their receptors
Cl- influx leading to Inhibitory post synaptic potential where hyperpolarisation causes less APs
Which drugs utilise GABA
Benzodiazepines
What receptors does ACh act on in the brain and what effect does this have on neurones
Nicotinic and muscurinic
Excitation
Where do cholinergic pathways in brain run from and to
Originate in nucleus basalis, forebrain and brainstem
Project to cortex and hippocampus
Functions of cholinergic pathways in brain
Arousal
Learning
Memory
Motor control
Pathophysiology of Alzheimer’s disease
Degeneration of cholinergic neurones in the nucleus basalis
What are the dopaminergic pathways in the brain
Mesocortical
Mesolimbic
Nigrostriatal
Tubuloinfundibular
Where does the nigrostriatal pathway run from and to
Substancia nigra to the corpus striatum
Pathophysiology of Parkinson’s disease
Loss of dopaminergic neurones in the nigrostriatal pathway
What receptors does NA act on in the brain
Alpha and beta adrenoreceptors
Where do noradrenergic and serotonergic pathways run from and to
Originate from locus ceruleus, pons and medulla
Project to cortex, hypothalamus, amygdala, cerebellum
