neuro

what is a multipolar neuron?

many dendrites with a single axon

what is a bipolar neuron?

single dendrite and single axon

what is a pseudo-unipolar neuron?

single projection from soma, diving two axons (peripheral and central)

what is grey matter?

neuronal cell bodies and dendrites

what is white matter?

acons and myelin

what is a ganglia/ganglion?

collections of cell bodies outside the CNS

what are nuclei/nucleus?

collections of cell bodies within the CNS

what cells produce myelin in the CNS?

oligodendrocytes

what cells produce myelin in the PNS?

schwann cells

what is the diameter, myelination, conduction velocity, and function of Aα neuron fibres?

12-20 μm, myelinated, 70-120 m/s, proprioception/motor

what is the diameter, myelination, conduction velocity, and function of Aβ neuron fibres?

5-12 μm, myelinated, 30-70 m/s, touch

what is the diameter, myelination, conduction velocity, and function of Aγ neuron fibres?

3-6 μm, myelinated, 15-30 m/s, motor

what is the diameter, myelination, conduction velocity, and function of Aδ neuron fibres?

2-5 μm, myelinated but thin, 12-30 m/s, pain/temp/touch

what is the diameter, myelination, conduction velocity, and function of B neuron fibres?

<3, myelinated, 3-15 m/s, autonomic NS

what is the diameter, myelination, conduction velocity, and function of C neuron fibres?

0.3-1.3, not myelinated, 0.5-2.3 m/s, pain/autonomic NS

what is convergence between neurons?

multiple presynaptic neurons converge with one post-synaptic neuron

what is divergence between neurons?

single presynaptic neuron synapses with multiple post-synaptic neurons

what are the stages of prenatal development

1. pre-embryonic stage (zygote)

2. embryonic stage (embryo)

3. fetal stage (fetus)

what is the pre-embryonic stage and how long does it last?

fertilisation of ovum by sperm, days 0-14

what is the embryonic stage, and how long does it last?

zygote implanting in the uterus, day 15 - end of week 8

how long does the fetal stage?

from the 8th week till birth

what are the layers of the embryonic disk?

• endoderm: gut, liver, pancreas, and respiratory system

• mesoderm: muscle, skeleton, excretory and circulatory system

• ectoderm: sensory, organs, hair, skin, nails, and whole CNS and PNS

what is neurogenesis and when does it occur?

generation of new nerve cells, weeks 13-24 of development

what is a teratogen?

substances/conditions that disturb the development of an embryo

what is a neonate/neonatal?

first 4 weeks after birth

what are the brackets for babies terms?

• Extremely premature = 23-28 weeks

• Very pre-term = 28-32 weeks

• Moderately pre-term = 32-36 weeks

• Late pre-term =36-37 weeks

what is the function of the frontal lobe?

motor, cognition, social, executive functioning

what is the function of the parietal lobe?

sensory, somatic, proprioception, attention

what is the function of the temporal lobe>

auditory

what is the function of the occipital lobe?

visual information

what is the function of the limbic lobe?

emotion and memory

what is the function of the insula lobe?

mood, olfaction, and memory

where is the primary motor cortex?

with pre-central gyrus of the frontal lobe

where is the primary somatosensory cortex?

post-central gyrus of the parietal lobe

where is the primary auditory cortex?

temporal lobe

where is the primary visual cortex?

sits in the visual association cortex of the occipital lobe

where is the broca’s area and what does it do?

sits within the frontal lobe, plays a role in speech production

where is the wernicke’s area and what does it do?

parieto-temporal area, role in speech comprehension

what brodmann area is the primary motor cortex?

area 4

what brodmann area is the primary somatosensory cortex?

3, 1, and 2

what brodmann area is the premotor cortex?

area 6

what brodmann area is the broca’s area?

areas 44 and 45

what brodmann area is the wernicke’s area?

area 22

what are association fibres?

fibres that connect areas within one hemisphere to eachother

what are the association fibres?

• cingulum

• uncinate fasciculus

• super longitudinal fasciculus

• inferior longitudial fasciculus

what do short fibres connect?

connect adjacent gyri

what do cingulum fibres connect?

frontal, parietal, and other cortices

what do uncinate fasciculus fibres connect?

frontal and temporal cortices

what do super longitudinal fasciculus fibres connect?

cortices of all lobes

what do inferior longitudinal fasciculus fibres connect?

temporal and occipital lobes

what do commissural fibres connect?

connects corresponding regions of the hemispheres (corpus callosum is an example of a commisural fibre)

what do projection fibres connect?

• sensory and motor fibres within the cerebrum

• they connect the brain with the brainstem and spinal cord

what does the diencephalon include?

• thalamus

• epithalamus

• hypothalamus

• subthalamus

what does the thalamus do?

• integrates information from the cerebellum and the basal ganglia

• has a dozen nuclei seperated into groups that are divided by white matter

  • anterior

  • medial

  • lateral (dorsal and ventral)

what does the epithalamus do?

• connects the limbic system and other parts of the brain

• secretion of melatonin via pineal gland

• regulation of motor pathways and emotions

what is the function of the hypothalamus?

• homeostasis

• reproductive and defense behaviours

• emotional expression of pleasure, rage, and fear

• endocrine regulation of growth, metabolism, and reproductive organs

what is the function of the subthalamus?

• modulation of movement

what are the directional terms for the cerebellum and brainstem?

• rostral

• dorsal

• caudal

• ventral

what are the structures of the brainstem from a ventral and sagittal view?

• crus cerebri

• middle cerebellar peduncle

• pyramids of the medulla

what are the structures of the brainstem from a dorsal view?

• superior colliculi: vision

• inferior colliculi: auditory

• cerebellar peduncles

  • superior

  • middle

  • inferior

• floor of the 4th ventricle

• fasciculus cuneates and gracilis

what is the function of the olfactory nerve?

olfaction

what is the function of the optic nerve?

• vision

• pupillary light reflex

what is the function of the oculomotor nerve?

• efferent for movement of eyeball and elevation of upper eyelid

• parasympathetic for pupillary constriction and accommodation

what is the function of the trochlear nerve?

• movement of the eyeball for ocmplex movements (superior oblique muscle)

• movement of the eye medially and down

what are the branches and the function of the trigeminal nerve?

• opthalmic: sensory

• maxillary: sensory

• mandibular: ipsilateral muscles of mastication

what is the function of the abducens muscle?

• movement of the eyeball to abduct the eyeball (lateral rectus)

what are the afferent functions of the facial nerve?

• sensation to the anterior 2/3rd of the tongue

• posterior ear canal

what are the efferent functions of the facial nerve?

• fibres of the small middle ear muscle help the auditory protective reflex

• parasympathetic efferent fibres to the glands (tears and saliva)

what are the functions of the vestibulocochlear nerve?

• balance via

  • semicircular canals

  • utricle and saccule

• hearing via cochlear

what are the afferent functions of the glossopharyngeal nerve?

• taste for posterior 1/3 of tongue

• touch/pressure/pain for the pharynx and posterior tongue

• autonomic and afferent from the carotid body convey blood pressure and chemical signals

what are the efferent functions of the glossopharyngeal nerve?

• parasympathetic efferent fibres to parotid salivary gland

• efferent fibres to stylopharyngeus to elevate pharynx whilst swallowing

what are the afferent functions of the vagus nerve?

• larynx, pharynx, and external ear

• autonomic afferent from pharynx, larynx, thorax, and abdomen

what are the efferent functions of the vagus nerve?

• efferent to pharyngeal muscles

• parasympathetic efferent to pharynx, larynx, thorax, and abdomen

what are the functions of the accessory nerve?

• efferent to the trapezius and sternocleidomastoid muscles

what are the functions of the hypoglossal nerve

• general somatic efferent to the ipsilateral muscles of the tongue (intrinsic and majority extrinsic)

what are plexi?

enlargements in the cervical and lumbar areas

what is the filum terminale?

connective tissue extending from the cauda equina and ending in the coccyx

what is the cauda equina?

long nerve roots from L1 that extend down the lumbosacral vertebral column and innervate the legs

what is the conus medullaris?

end of the spinal cord

what are the meninges?

• dura mater: outermost layer

• arachnoid mater: between pia and spinal cord

• pia mater: adhered to spinal cord surface

what are the horns of the spinal cord?

dorsal, ventral, and lateral

what is the dorsal (posterior) horn of the spinal cord?

site of termination of many afferent neurons via root

what is the ventral horn of the spinal cord?

contains lower efferent motor neurons via root

what is the lateral horn of the spinal cord?

area that processes autonomic information at T1-L2 segments

what is the dorsal root of the spinal cord?

afferent fibres with cell bodies located in dorsal ganglia

what is the ventral root of the spinal cord?

efferent fibres with cell bodies lying within the spinal grey matter

what is the spinal nerve?

connector of the dorsal and ventral roots of the spinal cord

what is the ventral ramus?

area that supplies muscles of the back and overlying skin

what is the dorsal ramus?

area that supplies muscles of the trunk and limbs of overlying skin

what tracts of the spine are afferent?

ascending

what tracts of the spine are efferent?

descending

what groups are part of the ascending tracts?

the lateral and medial groups

what groups are part of the descending tracts?

• medial lemniscus system

• spinocerebellar tracts

• anterolateral system

what makes up the lateral group of the spine?

• lateral corticospinal tract

• rubrospinal tract

what makes up the medial group of the soine

• reticulospinal tract

• reticulospinal tract

• vestibulospinal (medial and lateral)

• medial cortispinal

what makes up the medial lemniscus system?

• fasciculus gracilis

• fasciculus cuneatus

what makes up the spinocerebellar tracts?

• posterior

• anterior

what makes up the anterolateral system?

• lateral spinothalamic tract

• anterior spinothalamic tract

how many spinal nerves are there?

31

how many spinal nerves are in each segment?

• 8 cervical

• 12 thoracic

• 5 lumbar

• 5 sacral

• 1-2 coccyx