Neuroscience

Neuroeffector junction

Neuron communicates with muscle fiber or gland

Neuromuscular junction

Neuron communicates with skeletal muscle fibers

Association neurons

Neuron interconnections in brain and spinal cord e.g. interneurons

Astrocytes

Main type of neuroglia that provides structural support, metabolic functions, regulate passage of molecules between bloodstream and CNS

Oligodendrocytes

Wrap axons in myelin sheath to increase speed of conduction in CNS

Schwann cells

Wrap axons in myelin sheath to increase speed of conduction in PNS

Microglia

Helps regulate brain development, maintenance of neuronal networks, injury repair, waste clearance

Tract

Bundle of axons, common origin and termination in CNS

Nerve

Bundle of axons (PNS)

Nucleus

Collection of neuronal cell bodies in CNS

Ganglion

Collection of neuronal cell bodies in PNS

Cerebral cortex

2-4mm grey matter, has gyri and sulci - convolutions, cortical folding

Basal ganglia

Collection of structures including caudate nucleus, lentiform nucleus - putamen, globus pallidus (externa and interna)

Striatum

Contains caudate nucleus, putamen and sometimes Globus Pallidus

Lentiform Nucleus

Putamen and Globus Pallidus

Association fibres

Green, within hemisphere

Projection Fibres

Blue, afferent - sensory, efferent - motor impulses, most travel through corona radiata

Commissural Fibers

Pink, connects corresponding cortical areas in both hemispheres e.g. corpus callosum

Decussation

The crossing of sensory and motor fibers at midline so that hemispheres process actions and sensations contralaterally

Base (of brainstem)

Part of brainstem that has mainly descending axons

Tegmentum

Part of brainstem that contains nuclei for CN III - XII, Reticular formation and ascending sensory tracts. Between base and cerebellum

Spinal cord

Has H shaped core of grey matter, with outside being white matter

Ventral horn with ventral roots

In the spinal cord where motor axons to periphery

Dorsal horn with dorsal roots

Sensory axons bringing info to spinal cord

Dura mater

Tough membrane attached to inside of skull

Arachnoid mater

Membrane between dura and pia that is cobweb like

Pia mater

Delicate membrane that follows surface of brain

Subarachnoid space

Space between arachnoid and pia mater filled with CSF

Frons

Forehead as a skull landmark

Occiput

Posterior skull landmark

Vertex

Superior/highest point of skull

Temporae

Temple skull landmark

Calvaria

Skullcap

Cran

Skull “bowl” that has 3 sections - anterior, medial, and posterior

Lacrimal bones

Contains duct for tears

Inferior nasal concha

Vomer

Palatine bone

• Transverse palatine suture

• Horizontal process

• Pyramidal Process

• Posterior nasal spine

Posterior third of hard palate

Mental symphysis

Mandible landmark

Mental protuberance

Mental Tubercles

Mandible landmarks

Mylohyoid line

Aorta

Main artery, carries blood from left ventricle to all parts of body except lungs

Internal and External carotid arteries

Common carotid artery branches into…

Middle Cerebral Artery (MCA)

Anterior Cerebral Artery (ACA)

Internal carotid artery branches into…

Middle cerebral artery (MCA)

Supplies blood to lateral surface of frontal, parietal and temporal lobes

Anterior cerebral artery (ACA)

Supplies blood to medial surface of frontal and parietal lobes, corpus callosum, basal ganglia

Basilar artery

Vertebral arteries merge to form this artery at lower border of pons

Posterior Cerebral Artery (PCA)

The basilar artery splits to form these 2 arteries that supply inferior and medial temporal lobes, and lateral and medial occipital lobes, midbrain

Circle of Willis

Arteries are linked by communicating vessels - anterior communicating artery, posterior communicating artery - at base of brain

Ischemia

Type of CVA > 80%, blocked artery resulting in part of brain losing blood supply

Thrombosis

Type of ischemia, involving the narrowing of an artery due to gradual accumulation of debris, usually in areas of turbulence, many occurring during sleep/inactivity as lower BP allows vessels to narrow or close

Embolism

Type of ischemia, fragment of material (broken off blood clot, tissue from tumor, plaque) gets lodged - sudden, often during period of activity

Hemorrhage

Type of CVA ~ 10-15% caused by rupture or leakage of cerebral blood vessels - cerebral bleeding - deprives downstream vessels, puts pressure on surrounding brain

Intracerebral hemorrhage

Type of hemorrhage, bleeding within brain tissues

Epidural/extradural hemorrhage

Type of hemorrhage, often results from meningeal artery - outside dura

Subdural hemorrhage

Type of hemorrhage, between dura and arachnoid

Subarachnoid hemorrhage

Type of hemorrhage, caused by disorders of vascular formation such as aneurysm, or arteriovenous malformation

Ectoderm

Top layer of trilaminar embryonic disk, which thickens and forms neural plate, gives rise to nervous system

Mesoderm

Middle layer of trilaminar embryonic disk, becomes cardiovascular, musculoskeletal, urinary and reproductive systems

Bottom layer of trilaminar embryonic disk, becomes respiratory and gastrointestinal systems

Neuropores

Open ends of neural tube

Choroid Plexus

Where CSF is produced

Metencephalon

Pons and cerebellum

Diencephalon

Part of brain that includes thalamus and hypothalamus

Mesencephalon

Midbrain

Myelencephalon

Medulla

Telencephalon

Cerebral hemispheres

Environmental teratogens

Substances that cause developmental defects - drugs, chemicals, infections

Anencephaly

Type of abnormal embryonic development - defective fusion of neural tube - cranial end remains open and forebrain doesn’t develop

Spina bifida

Type of abnormal embryonic development - defective fusion of neural tube - caudal end remains open, malformation of lower spinal cord

Hydrocephalus

Type of abnormal embryonic development - enlargement of ventricles due to CSF accumulation, raised intracranial pressure

Olfactory Area

Inferior temporal and insula

Gustatory area

Anterior insula and frontal operculum

Unimodal

Primarily receives input from a single sensory area

Heteromodal

Recieves input from multiple sensory of multimodal areas

Premotor area

Planning of voluntary movement, integration and interpretation of motor information, contains motor maps for movement of larger muscle groups

Supplementary motor area

Anterior to M1 & Superior to premotor area (medial surface) - maps for postural stabilization, initiation of speech

Broca’s Area (BA 44 & 45)

Dominant hemisphere (usually left)
Pars Triangularis and Pars Opercularis of inferior frontal gyrus
Programs speech movements and phoneme sequencing

Prefrontal Area

Executive functions - planning, problem solving, directing and maintaining attention, decision making. Working memory - retain info long enough to plan and execute behavioural response to a stimulus, personality

Somatosensory Association Cortex (BA 5)

Adjacent to S1 - interpretation of sensory info - lesion can result in astereognosia

Astereognosia

Inability to recognize objects by touch

Posterior parietal cortex (BA 7)

Somatosensory & visual integration, visuospatial perception and attention - representation & manipulation of objects, perception of movement
Lesions → neglect syndrome, apraxia (don’t understand things out of context)

Inferior parietal cortex (BA 39, 40)

Multimodal association cortex - visual, auditory, somatosensory info
Role in receptive language in dominant hemisphere - phonology, reading, spelling
Role in spatial & symbolic representation of abstract concepts

Superior Longitudinal Fasciculus/Arcuate fasciculus

Important tracts connecting inferior parietal cortex to Inferior frontal gyrus and Superior temporal gyrus

Visual Association cortex (BA 18, 19)

Surrounds V1 on medial surface, extending onto lateral surface, interpretation of what we see

Dorsal Stream (of Visual Association cortex)

Where - location and movement of objects

Ventral stream (of Visual association cortex)

What - form and colour of objects

Auditory association cortex

Distinguis sounds as speech, music or noise

Occipitotemporal gyrus/ fusiform gyrus

Inferior surface of temporal lobe - synthesizes and elaborates complex aspects of info - link visual object/word/face to meaning (recognize objects - names of objects)

Visual agnosia

Lesion in fusiform gyrus - can see and describe object, but don’t know what it is, may be able to recognize it using touch or smell

Prosopagnosia

Visual agnosia for faces

Basal ganglia

Regulating cortically initiated motor activity
Suppressing movements extraneous to precise and targeted motor activity
Adjusting automatic motor movements - arm swinging, facial expressions
Learned reflex control
Emotions, personality, cognition

Athetosis

Constant slow twisting movement in muscles - mostly in upper limb & Speech muscles

CN I - Olfactory

Conducts information from nasal chemoreceptors to olfactory bulb via olfactory nerves. Information travels from olfacotry bulb to olfactory tract

CN II - Optic

Light strikes retina, rods and cones convert light energy into a neural signal, excitatory or inhibitory synapses onto bipolar cells

Synapse onto ganglion cells - axons of ganglion cells are the nerve

Homonymous hemianopia

Contralateral field loss in both eyes - lesion in optic tract or optic radiations

CN III - Oculomotor

Elevates upper eyelid

Moves eyeball up, down and medially

Motor component of pupillary reflex, consensual reflex, accomodation reflex

CN - III Oculomotor Nerve Lesions

Ptosis - inability to elevate eyelids

Lateral Strabismus - eyeball deviates outwards

CN IV - Trochlear

Innervates superior oblique muscle
Keeps eyes horizontally level (stops rotation during contraction)

CN IV - Trochlear Lesions

Vertical medial strabismus - difficulty moving eyeball down and laterally

May report difficulty walking down stairs