Neuro Flashcards
Central nervous system consists of…
Brain, Brainstem, Spinal cord
specialised cells that support neurons in the brain
Neuroglia
components of the brainstem
midbrain
pons
medulla
5 specialised functions of the cerebral hemispheres
thought voluntary movement perception language reasoning
3 specialised functions of the brainstem
heart rate
breathing
blood pressure
3 specialised functions of the cerebellum
movement
balance
posture
at what vertebrae does spinal cord end?
L1/L2
how many spinal nerves?
+how many of each section e.g. cervical
31
8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal
what 2 factors determine the conduction velocity of an axon?
diameter
extent of myelination
name the 3 groups of neurotransmiters
excitatory
inhibitory
modulatory
2 functions of astrocytes (neuroglia)
regulate blood-brain barrier
influence local neurotransmitter and electrolyte conc.
name most numerous glia cell in CNS
oligodendrocytes
function of oligodendrocytes
produce myelin sheath in CNS
function of ependymal cells
line ventricular system - barrier between CSF and brain
involved in CSF production
function of microglia
macrophages
what are the meninges and what is their function?
3 membranes that line skull and vertebral canal
enclose brain and spinal cord
Name the 3 meninges
dura mater
arachnoid
pia mater
describe the blood vessels of the CNS
non-fenestrated
with tight junctions
endothelial cells have thick cytoplasm
endothelial cell basement membrane intimately associated with astrocyte foot processes
describe slow twitch fibres (type 1)
and their function
oxidative
fatigue resistant
postural support, distance running
describe fast twitch fibres (type 2)
fatigue rapidly but generate large peak of muscle tension
have lactate biproduct
in a sarcomere, which are the thin light bands?
actin filaments
in a sarcomere, which are the thick dark bands?
myosin fibres
in sliding filament theory, myosin heads bind to…
actin
what provides the energy for the conformational change in the myosin head?
hydrolysis of ATP
the sliding of filaments to shorten the sarcomere is initiated by what?
increase in cytosolic Ca2+
general function of a kinase enzyme
sticks P onto things
function of dystrophin
gives stability to muscle cell membrane
function of oligodendrocytes
produce myelin sheath in CNS
function of schwann cells
produces myelin sheath in PERIPHERAL NS
nodes of ranvier between myelin sheaths allow what?
saltatory conduction
name the 3 divisions of the brain (fore-, mid- and hindbrain)
prosencephalon, mesencephalon, rhombencephalon
name the divisions of the prosencephalon (forebrain)
telencephalon
diencephalon
why is MRI the best imaging technique for the brain?
good contrast between white/ grey matter and CSF in ventricles/sulci
following fertilisation, the embryo develops into a tri-laminar disc of what 3 layers?
ectoderm
mesoderm
endoderm
which layer of the tri-laminar disc thickens in the midline to form the neural crest?
ectoderm
midline groove in neural crest (neural groove) deepens and eventually detaches from the overlying ectoderm to form the …
neural tube
what cells run dorsolaterally along the neural groove?
presumptive neural crest cells
what develops from the telencephalon of the prosencephalon?
cerebral hemispheres
what develops from the diencephalon of the prosencephalon?
thalamus
hypothalamus
what develops from the mesencephalon?
colliculi
name the 2 divisions of the rhombencephalon
metencephalon
myelencephalon
what develops from the metencephalon of the rhombencephalon?
cerebellum
pons
what develops from the myelencephalon of the rhombencephalon?
medulla oblongata
what is the total volume of CSF?
120ml
in what space does CSF circulate?
subarachnoid
name the ventricles
2 lateral ventricles
3rd ventricle
4th ventricle
what connects ventricles and subarachnoid spaces?
cisterns
what does CSF contain?
protein, urea, glucose, salts
where is CSF produced?
choroid plexus
what is the choroid plexus?
network of blood vessels in each ventricle of the brain
CSF is absorbed via…
arachnoid granulations (villi)
commisure definition
tract connecting one hemisphere to the other
reticular definition
‘netlike’
when grey and white matter mix
e.g. reticular formation of the brainstem
function of the temporal lobe
understanding spoken word/ sounds
memory
emotion
function of parietal lobe
body part awareness
receives and interprets sensations (pain, touch, pressure, size)
function of occipital lobe
understanding visual images and the meaning of the written word
thalamus function
relay centre directing inputs to cortical area
hypothalamus function
autonomic NS
links endocrine system to brain
homeostasis
cerebellum attached to brainstem by
3 peduncles
superior, middle, inferior
divisions of the autonomic NS
sympathetic
parasympathetic
enteric
divisions of peripheral NS
somatic (voluntary)
autonomic (involuntary)
name the 2 divisons of parasympathetic outflow
- cranial outflow (innervates organs of head, neck, thorax, abdomen)
- sacral outflow (supplies remaining abdominal + pelvic organs)
definition of a single motor unit
single motor neuron and the muscle fibres it connects
motor command originates in what cells of the motor cortex?
pyramidal cells
function of limbic system
controls emotions and drives (sex, hunger)
cerebellum = 10% of total brain weight.
What % of the brain’s total number of neurons does it contain?
over 50%
motor commands originate in which 2 areas?
- upper motor nuclei of brainstem
2. primary motor cortex
motor commands descend along the reticulospinal tracts to the…
lower motor neurons
lower motor neurons originate in the…
spinal cord
motor command/options are selected by the…
basal ganglia nuclei
what provides precise control, fine adjustment and coordination of a motor activity?
cerebellum
what does the outer layer of the eye comprise of?
cornea
sclera
what does the middle layer (uvea) of the eye comprise of?
iris
ciliary body
choroid
what does the inner layer of the eye comprise of?
retina
components of the ciliary body
glandular epithelium
smooth muscle
function of the glandular epithelium of the ciliary body
production of aqueous humour containing cornea and lens nutrients
maintains intra-ocular pressure
function of the smooth muscle of the ciliary body
controls accommodation (adjustment of the lens to form clear images from different distances)
function of cones
colour
central vision
visual acuity (distinguishing shapes and details)
function of rods
monochromatic
peripheral vision
dark adaptation
blood supply of the eye
retinal and ciliary branches of the opthalmic artery - (branch of the internal carotid artery)
the outer ear consists of…
auricle
external auditory canal
middle ear consists of…
eardrum
hammer, anvil, stirrup (ossicular chain)
inner ear consists of…
vestibular system (3 semicircular canals - balance) cochlea (hearing part)
the 2 outer chambers of the cochlea contain what fluid?
perilymph
the 3rd and innermost chamber of the cochlea (cochlear duct) contains what fluid?
endolymph
the cochlear duct contains what membrane?
basilar membrane
what sensory organ lies on the basilar membrane?
Organ of Corti
the organ of corti consists of what?
cilia (hair cells) arranged in rows, each connected to a nerve fibre which relays impulses to 8th cranial nerve
apical (most curved) area of the cochlea transfer what frequency of impulses?
lower frequency
name 1st cranial nerve and where it exits the skull
OLFACTORY
ethmoidal foramen
name 2nd cranial nerve and where it exits the skull
OPTIC
optic canal
name 3rd cranial nerve and where it exits the skull
OCCULOMOTOR
superior orbital fissure
name 4th cranial nerve and where it exits the skull
TROCHLEA
superior orbital fissure
name 5th cranial nerve and where it exits the skull
TRIGEMINAL
superior orbital fissure (opthalmic)
foramen ovale (mandibular)
foramen rotundum (maxillary)
name 6th cranial nerve and where it exits the skull
ABDUCENS
superior orbital fissure
name 7th cranial nerve and where it exits the skull
FACIAL
internal acoustic meatus
name 8th cranial nerve and where it exits the skull
VESTIBULOCOCHLEAR
internal acoustic meatus
name 9th cranial nerve and where it exits the skull
GLOSSOPHARYNGEAL
jugular foramen
name 10th cranial nerve and where it exits the skull
VAGUS
jugular foramen
name 11th cranial nerve and where it exits the skull
ACCESSORY
jugular foramen
name 12th cranial nerve and where it exits the skull
HYPOGLOSSAL
hypoglossal canal
olfactory nerve function
sense of smell
optic nerve function
visual information (sensory)
oculomotor nerve function
eye movement
pupil constriction
eyelid
trochlear nerve function
superior oblique eye muscle
abducens nerve function
lateral rectus eye muscle
branches of the facial nerve
temporal zygomatic buccal marginal mandibular cervical
vestibulocochlear nerve function
balance
hearing
what is the pharyngeal plexus?
network of nerve fibres innervating most of the palate, larynx and pharynx
trigeminal nerve function
skin, skeletal muscles of face, nose and mouth (sensory)
muscle of mastication (motor)
facial nerve function
anterior 2/3 of tongue (sensory)
facial muscles, swallowing, nose, palate, lacrimal and salivary glands (motor)
glossopharyngeal nerve function
middle ear, posterior 1/3 of tongue (afferent)
parotid salivary gland, skeletal muscle of swallowing (efferent)
vagus nerve function
skeletal muscle of pharynx/larynx
smooth muscle/glands of thorax & abdomen
accessory nerve function
neck skeletal muscle
hypoglossal nerve function
tongue skeletal muscle
where do alpha motor neurons originate?
spinal cord
what lobe is broca’s area in?
frontal lobe
what lobe is wernicke’s area in?
temporal and parietal lobes
where is the primary motor cortex located?
pre-central gyrus
frontal lobe
where is the primary somatosensory cortex located?
post-central gyrus
parietal lobe
where is the visual cortex located?
occipital lobe (at the back of the brain)
what are gamma motor neurones?
type of lower motor neurone
take part in muscle contraction
where are the cell bodies of gamma motor neurones and alpha motor neurones located?
anterior horn of the spinal cord
where do gamma motor neurones receive input from?
pons in the brainstem
which have smaller axons, alpha or gamma motor neurones?
gamma
which directly adjust lengthening/shortening of muscle fibres, gamma or alpha motor neurones?
alpha
which has a role in keeping muscle spindles taut, gamma or alpha motor neurones?
gamma
voluntary motor control actions can be divided into…
goal directed
habit
definition of a spinal reflex
involuntary/instinctive response to stimulus
unconditioned response
