Central Nervous System Flashcards
intelligence is associated with what feature of the cerebral cortex?
area of infolds
what does rostral mean?
towards the nose
what does caudal mean?
towards the tip of the spinal cord
layers of the brain from bottom to top
- medulla oblongata
- pons and cerebellum
- mid brain
- Diencephalon (hypothalamus and thalamus)
- cerebrum
what are foramen?
holes in bones where nerves pass out:
• vertebral foramen where the spinal cord occupies
• intervertebral foramen where the mixed spinal nerves exit
• foramen magnum where the spinal cord exits the base of the skull
describe the vertebral column
C1-7 T1-12 L1-5 S1-5 fused Coccygeal 1-4 fused
how many nerves and how many vertebral segments?
31 pairs of nerves- C8, T12, L5, S5, Cocc1
33 vertebral segments
where does the spinal cord end?
around L1, nerves after T12 emerge lower than their spinal cord level.
where is a lumbar puncture usually undertaken?
L3-4 or L4-5, the spinal cord in not present here, however there is a continuation of the dura mater forming the lumbar cistern wheres cerebrospinal fluid is present. this minimises damage.
what are the ventral and dorsal horns?
where grey matter parts of the sensory (dorsal) and motor (ventral) synapse with the CNS. this leads to a dorsal root (afferent) and ventral root (efferent).
what are ascending and descending tracts of the spinal column?
allow communication between periphery and brain in the white matter of spinal cord.
spinal cord functions:
- Connects PNS and ANS with brain
* reflexes
where do the cranial nerves emerge from?
brain stem
how is the brain classified?
- embryologically eg rhombencephalon (hindbrain) mesencephalon (midbrain) prosencephalon (forebrain)
- functionally eg brainstem, cerebellum, cerebrum
function of the diencephalon/
- Hypothalamus: integration hub, homeostatic function, autonomic function
- Thalamus: integrates sensory info and routes it to cortex, emotional status, consciousness.
what are ganglia?
collection of cell bodies in the PNS
what are nuclei?
collection of cell bodies in the CNS
what is in the cerebral hemisphere
- cortex
* basal ganglia
what are the components of the basal ganglia?
- globus pallidus
- nucleus accumbens
- caudate nucleus
- putamen
- amygdala
what is the corpus striatum?
putamen + caudate
what is the lentiform nucleus?
Putamen + globus pallidus
function of the basal ganglia?
control movement, facilitating voluntary movement, inhibiting unwanted or inappropriate movement
FINE TUNING OF MOVEMENT
which system is the amygdala part of?
limbic system
what is the cerebral cortex?
2-4mm thick section of the cerebrum, lobes separated by fissures.
what are the cerebral cortex lobes?
- frontal
- occipital
- temporal
- parietal
within these lobes there are certain areas
which areas are present in the frontal lobe?
- prefrontal cortex (behaviour, mood, personality, think)
- broca area (motor program for speech)
- motor association area (where plan is generated)
- primary motor cortex (contralateral impulses sent to effector muscles)
which areas are present in the parietal lobe?
- primary somesthetic cortex
(primary somatosensory cortex, pain temperature touch) - somesthetic association area
(interprets information by comparing it with previous, cognition) - primary gustatory cortex (taste signals received)
which areas are present in the occipital lobe?
- primary visual cortex (received visual signals)
- visual association area (recognise familiar things)
which areas are present in the temporal lobe?
- primary auditory cortex (receives auditory signals)
- auditory association area (recognises and interprets)
- Wernicke’s Area (recognition of spoken language)
features of the cortex?
laminar, has 6 cell layers
somatotopic, each part of the brain maps on to a certain area of the brain
function of the limbic system?
emotion, memory, motivation, instinctive behaviour
what is the cerebellum?
attached to the brainstem by 3 peduncles
two hemispheres with folium (folds) separated by vermis
outer grey matter layer, with infolds
inner white matter layer
function of cerebellum?
- associated with vestibular system for balance
- posture
- learned movement
- manual skills
- fine movement
- trajectory
all in close association with spinal cord, thalamus, motor cortex.
types of white matter in the brain
- commissural fibres, connecting two hemispheres of the brain (corpus callosum)
- association fibres, connections within hemispheres
- projection fibres, vertical eg connecting spinal cord to cortex via internal capsule between lentiform nucleus and then fan out to the curter in the corona radiata.
bones of the cranium
- frontal
- ethmoid
- sphenoid
- occipital
- temporal
- parietal
contains many foramen for blood vessels and nerves.
layers of the meninges which encase the whole CNS
- periosteal and meningeal dura mater
- arachnoid mater which holes blood vessels in place
(subarachnoid space)- filled with CSF
- pia mater which follows gyri and sulci
describe the ventricular system (filled with CSF)
lateral ventricles with anterior, posterior and inferior horns. This is connected to the third ventricle via the intraventricular foramina. the third ventricle is connected to the fourth ventricle via the aqueduct. the fourth ventricle is continuous with the central canal of spinal cord.
what produces CSF?
ependymal cells in the choroid plexus in the ventricles produce 500ml per day to fill 150ml of ventricular space
composition of CSF?
similar to plasma but lower: glucose protein calcium and potassium pH
but Higher:
chloride
magnesium
function of CSF?
cushioning
nutrition
removing waste
contains immune cells
what is hydrocephalus and how is it caused?
blockage of CSF duct means CSF fluid builds up in ventricles which affects areas of the brain negatively.
can be caused by meningitis, acquired or genetic
epidural and subdural haematomas?
epidural is between dura and skull (lentiform)
subdural is between arachnoid and dura (crescent)
