Functional Anatomy and Neurotransmitters Flashcards
What regions can the brain be divided in
Brain stem
cerebellum
forebrain
ventricles filled with cerebrospinal fluid (cavities)
Function of brain stem:
*relay centre- processing
*Reticular formation- neurones receives sensory info and understands it. Filters unnecessary info.,
consciousness,
and arousal
*balance and posture reflexes
*medulla oblongata- involuntary function- coughing, breathing, digestion
*midbrain- contains substantia nigra (parkinsons)
Function of cerebellum:
coordinated voluntary movement.
Integrates info.
Eg position of body, precise movement, procedural memory
balance
Eye movement
Diencephalon structure and function:
Thalamus
*relay centre, sensory input, motor control
Hypothalamus
*Homeostatic control centre, regulates autonomic system and endocrine system, sec. of hormones by pituitary, part of limbic system (emotions), sleep and wake cycle role
The limbic system:
Basic emotions
Fight or flight, laughing, survival, punishment pathways
Olfaction (smell)
Hippocampus - memory
The cerebrum
made of cerebral cortex and basal nuclei (grey matter)
What does the basal nuclei do
neuronal cell bodies
*striatum
*globus pallidus
*substantia nigra
*subthalamic nuclei
Control of movement
Inhibition of muscle tone (contraction)
Purposeful vs. unwanted movement
posture and support
Explain structure of cerebral cortex
2 hemispheres
shell of grey matter (cell bodies) covered by mass of white matter (myelination of axons)
Highly convoluted
controls opposite side of body
What is the somatosensory cortex
analyses inputs from mechanoreceptors, thermoreceptors and nociceptors
In parietal lube of cerebral cortex
Each area takes into from receptors from specific part of body
area of cortex proportional to info received
Plasticity with this- use dependency
What is the motor cortex
Responsible for voluntary movements
in frontal lobe
contralateral side
Use-dependency for cortical space
Motor control- how
motor cortex sends signals to alpha-motor neurones
has input from supplementary motor areas
Cortical areas involved in language
Brocas area- articulation of speech (muscles for speaking)
Wernickes area- involves comprehension and planning of language
Glial cells
astrocytes
microglia
oligodendrocytes
ependymal cells
What are astrocytes and their roles
star shaped
most abundant cells in CNS- more than neurones
dynamic role- communicate with each other and neurones
structural support- keep neurones in position
BBBarier
Repair (scar tissue)
Maintenance of extracellular environment (NTs and K+)
Modulation of synapse function (formation, maintenance, modification of NT release)
What are microglia and their function
Immune cells of CNS
release cytokines and scavenge
Resting or activated
resting- homeostatic
activated- motile and proinflammatory
role in neurodegenerative disease
What are oligodendrocytes and their function
Forms myelin sheath around neuronal axons
white matter
What are ependymal cells and their function
epithelia cells- lines cavities fluid filled cavities of CNS (ventricles)
Secrete cerebrospinal fluid
Cilliated
Part of BBB
GLUTAMATE STUFF
What is GABA
Main inhibitory NT in brain
Regulates neuronal transmission
Usually the neurones are short interneurones
How is GABA made and metabolised
Formed from glutamate by GAD
Its metabolised by GABA-T(transaminase)
Only neurones that express GAD are GABAenergic
How is GABA stored, released and reuptaken
synthesised in GABAergic nerves from glutamate
Packaged in vesicles by vesicular transporter
Can be recycled by GABA transporters (GAT) on presynaptic terminal
GABA can also be taken up by astrocytes
What drugs affect GABA transport and metabolism
Tiagabine- Reuptake inhibitor by targeting GABA transporter
Vigabatrine- Inhibitor by targeting GABA transaminase
What types of receptors does GABA act on for its inhibitory effects
2 types
GABAa- ionotropic- cys loop family
GABAb- metabotropic- class C GPCRs
What is GABAa structure and function
Post-synatic
Allow FAST movement
Ligand gated anion selective ion channel- for Cl- ions
Cl- influx causes hyperpolarisation and decreased excitability - therefore neurone is harder to meet action potential
Made of multiple subunits and is pentameric - 2 A, 2 B and 1 Y
4 transmembrane domains
N-termanus extracellular
C termanus extracellular
Loop intracellular between TM3 AND 4
TM2 is the lining of pore
