Test 2 Flashcards
Rostral
Towards beak (anterior)
Caudal
Towards tail (posterior)
Dorsal
top surface
Ventral
Bottom surface
Lateral
Toward side
Medial
Toward midline
Ipsilateral
same side
contralateral
opposite side
transverse plane
perpendicular to ground and neuroaxis
sagittal
parallel to neuroaxis
horizontal
parallel to ground
cortex
collection of neurons that form a thin sheet
nucleus
distinguishable mass of neurons, usually deep within the brain
Locus
small, well defined group of neurons
Ganglion
collection of neurons in the PNS (1 in the CNS)
Commissure
collection of axons that connect two sides of the brain
Nerve
bundle of axons in PNS (1 in CNS)
Suture
fibrous joint of skull bones
Bregma
intersection of coronal suture and sagittal suture
Meninges
Three layers of tissue (dura matter, arachnoid membrane, and pia matter) encasing the brain, pain receptors located here not in brain
Meningitis
inflammation of meninges
Subarachnoid space
filled with CSF
Cerebrospinal fluid
Yellowish fluid containing salts and nutrients that bathes the CNS
Choroid plexus
produces CSF
Ventricular system
A series of hollow, interconnected chambers filled with CSF (1+2–>3–>aqueduct–>4–>subarachnoid space–>vascular system
Corodoplexus
Controls pressure in brain
Hydrocephalus
Accumulation of CSF in the ventricles due to blockage
Verebral arteries
Arteries whose branches enter skull and become the posters (caudal) cerebral arteries
Internal Carotid Arteries
Branches enter skull and become the anterior and middle cerebral arteries
Spheriopalatine ganglioneuroalgia
Transient headache cause by rapid presentation of cold foods to palate which induces dilation of internal carotid artery and eventually pain in the meningies (brain freeze)
Blood Brain Barrier
mechanism inhibiting most chemicals and pathogens from entertain brain. capillary endothelial cells more tightly packed within CNS
Midbrain
Medulla oblongata, pons, and cerebellum
Medulla oblongata
role in cardiovascular function (heartbeat and blood pressure), gateway to brain (separates brain and spinal chord), and area postrema (vomit from too much toxins)
Pons
Role in sleep and arousal, locus coeruleus (blue spot), noradrenergic system (norepinephrine)
Cerebellum
Receives incoming sensory and outgoing motor information, coordinates signals (allows movement to flow)
Midbrain
Reticular activating system, superior colliculus
Reticular activation system
Role in arousal, sleep, muscle tone, and movement. Damage = coma
Superior colliculus
Involved in visual reflexes and foveation
Forebrain
limbic system, thalamus, hypothalamus, corpus colosseum, basal ganglia, cerebral cortex
Limbic system
Brain areas associates with emotion (amygdala) and memory (hippocampus)
Thalamus
Relay station for neural signals (sensory signals), massa intermedia (thalamic commissure, only 2/3 of human brains have this, more common in females and schizos)
Hypothalamus
Controls autonomic nervous system
Suprachiasmatic nucleus: circadian rhythms of sleep and temperature (dorsal to optic chasm)
Corpus Callosum
Large bundle of axons that connects both cerebral hemispheres, thicker in woman, longer in psychopaths, is severe epilepsy then split brain operation
Basal Ganglia
Brain areas involved in control of movement (group of structures) - caudate nucleus, putamen, globes pallidus
Cerebral cortex
Layer of unmyelinated neurons (gray matter) convolusions, where size and convolutions vary greatly among species (handout) fissure, sulcus, gyrus
Stroke
Sudden appearance of a neurological deficit due to disruption in cerebral blood supply (cerebrovascular accident)
Ischemic stroke
death of brain tissue (cerebral infarction) resulting from an inadequate supply of blood and oxygen due to blockage of artery
Atherosclerosis
Condition characterized by build up of plaque-lipid material covered with fibrous tissue embedded in artery wall
Thrombotic stroke
Type of ischemic stroke; blood flow reduction due to atherosclerosis in a cerebral blood vessel that eventually occludes it
Embolic stroke
Type of ischemic stroke; reduction of blood flow when an embolus travels to cerebral artery and forms a plug
Hemorrhagic stroke
Loss of blood flow when a cerebral blood vessel ruptures
Edema
Accumulation of fluid
Cerebral aneurysm
Dilation or swelling of cerebral blood vessel due to weakness in vessel wall (congenital vascular malformation or hypertension)
Circle of Willis
Several arteries come together
Umbra
Area of tissue death from CVA
Punumbra
Region surrounding immediate damage (cells survive at least temporarily after stroke)
Tissue plasminogen activator (tPA)
Intravenous drug that breaks up a clot allowing blood flow to return to deprived area of the brain
Neuroplasticity
Altering or modification of neurons, their networks, or their function due to experience or trauma
Synkinesis
Involuntary movement accompanying a voluntary one due to the misfiring of nerves following a trauma
Collateral sprouting
newly formed branch by an uninjured axon to replace synapses vacated by an injured neuron
Kennard Principle
maxim suggesting that the earlier in life damage occurs, the better recovery
Localization of function
Principle that specific functions are mediated by circumscribed brain locations
Experimental ablation
Destroy (lesion) area of the brain and observe possible changes in behavior and location
Aspiration
Remove tissue via pipette connected to vacuum pump
Radiofrequency lesion
Produced by heat generated from circuit passing through an electrode (kills everything in the area)
Excitotoxicity lesion
Produced by intracerebral injection of an excitatory amino acid (ed Kainic acid); kills neurons, not axons. “stroke”
Reversible lesion
temporary disruption produced by injecting a local anesthetic
Sham lesions
placebo procedure tat duplicates all steps of producing a brain legion except for the one that actually causes the brain damage
Stereotaxic surgery
Brain surgery using a stereotaxic apparatus to position an electrode or cannula in a specified position of the brain
Stereotaxis atlas
Collection of drawings of brain sections for a particular animal with measurements that provide coordinates relative to bregma
Stereotaxis apparatus
device that permits a surgeon to position an electron or cannula into a specific part of the brain
Histological techniques
procedures used to examine anatomy of tissue
Neuronal labeling
Histological method in which dye is injected into the brain, unsolved by neurons and transported within cell
Anterograde
label neural connections from cell bodies to terminal endings
Retrograde
label neural connections from terminal endings into cell bodies
Psychosurgery
Neurosurgery performed to alter brain structure or function
Cingulotomy
RF lesioning of the cingulum bundle passing through cingulate gyrus to relieve chronic pain and OCD
Extraocular muscles
six muscles that mediate movement of eye (and a seventh moves eyelid)
Micronystagmus
Eyes constantly moving, but if paralyzed, can’t see
Strabismus
Disordered misalignment of eyes - lazy eye
Sclera
Tough outmost coat of the eyeball compromised of densely packed fibers; white of eye
Conjunctiva
transparent membrane that keeps visible sclera moist
Cornea
Transparent dome shaped window covering front of the eyeball that focuses light to posterior eyeball; 66% eye’s optical power
Astigmatism
Not properly focusing since cornea is deformed
Iris
pigmented muscular membrane that fillets and controls to regulate amount of light entering through pupil; eye color; controlled by ANS
Lens
elliptical optical element that in conjunction with cornea focuses light toward back of the eyeball (retina) (33% of optical power)
Emetropia
ideal focus of image at back of eyeball
Myopia
image focused in from of the retina (focuses too soon, then blurs)
Hyperopia
Image focused behind retina
Cataract
opacity of the lens that reduces visual acuity 20/200 or worse; brunescence (browning) naturally occurs with age
Vitreous humor
Clear viscous fluid occupying central cavity of eyeball; maintains intraocular pressure (IOP)
Retina
photosensitive tissue lining the posterior eyeball consisting of interconnected nerve cells (including photoreceptors)
Fovea
depression at center of retina
Convergence
Many neurons synapse onto a single neuron, about 126 million photoreceptors feed into 1 million ganglion cells
Rods
Responsible for night vision (100 million total), about 120 rods:1 ganglion; high convergence means greater sensitivity due to summation of responses; they burn out in high light
Cons
Light vision (20 million total); about 6 cones:1 ganglion; low convergence means greater discrimination (acuity) due to point-to-point responses
Light
Form of electromagnetic radiation-energy produced by vibrations of electrically charged material
wavelength (nm) visible spectrum in humans 400-700 nm
Photoreceptors
neurons (in the retina) that absorb and transfuse light energy into a neural signal; cones in the center and rods periphery
Inner segment
Nucleus and organelles
Outer segment
thin disks (rods) or folds (cones) of membrane
Photopigment
Molecule embedded in a membrane disc or fold that absorbs light; 4 total = 3 cones + 1 rod
Dichromacy
two cones - color blind
Opsin
Long chain of amino acids
Retinal
Altered form of vitamin A
Phototransduction
Conversion of electromagnetic radiation (light) into a neural signal; ion channels open in dark - membrane potential slightly negative; ion channels close when light - membrane potential hyperpolarized
Optic nerve
bundle of about 1 million ganglion cell axons that conveys visual signal to regions of the brain
Optic chiasm
region where fibers serving nasal retinae crossover, contralateral processing, optic tract
superchiasmatic nucleus (SCN)
hypothalamic cell group that mediates several visceral functions entrained to the day-night cycle (sleep and body temp) (regulates pineal gland activity)
Edinger-Westphal Nucleus
midbrain cell group mediating pupillary reflexes; regulate light levels
Superior colliculus
Midbrain structure coordinating eye and head movements; visual reflexes; attention
Lateral geniculate nucleus (LGN)
thalamic structure where about 90% of ganglion axons project en route to visual cortex; optic radiations
Perimetry
measurement of visual field integrity and limits via lights projected at various locations in a homogenous field; lesions along visual pathways yield specific patterns of visual field loss
Scotoma
small area of blindness in visual field
Hemianopia
Blindness in half of visual field
Quadrantopia
blindness in one quadrant of visual field
Primary visual cortex
cortex along calcimine fissure that receives visual input from retina via LGN
retinotopic map
arrangement in which spatial distribution of cells corresponds to the retinal cell distribution
Coritcal magnification
over representation of retinal space by cortical space
feature detectors
neurons that respond selectively to a specific feature of the stimulus
simple cells
cells in primary visual cortex that respond most vigorously to lines of a particular orientation; biased for vertical or horizontal
Complex cells
cells in primary visual cortex that respond most vigorously to moving stimuli
Visual agnosia
Rare neurological condition in which an individual cannot perceive or recognize some aspect of a visual scene
Apperceptive visual agnosia
failure to perceive objects (forms) despite normal visual acuity
Simultagnosia
Inability to perceive more than a single object at a time
Prosopagnosia
failure to recognize particular faces (but parts of face usually identifiable)
Face cells
feature detectors in fusiform face area (FFA) that responds to faces anywhere in visual field
Face inversion effect
loss of normal proficiency at face perception when faces are inverted
Cerebral achromatopsia
inability to discriminate different colors
akinetopia
inability to determine velocity or direction of movement
binding problem
problem of how neural activity in separated areas of the brain is combined to create a coherent perception
kinetosis
transient debilitating condition characterized by dizziness vertigo and nausea
Vestibular system
three organs (sacral, utricle, and semicircular canal) adjacent to the inner ear that mediate posture, balance, and sense of orientation
Otolith organs
two membranous, fluid filled sacs (organs) that register gravity plus vertical (saccule) or horizontal (utricle) movement
Otoliths
dense, calcium carbonate particle suspended in endolymph (inner ear fluid)
macula
patch of receptive tissue
saccule
hair cells on wall
utricle
hair cells on floor
Semicircular canals
three fluid filled, toroidal tubes that tie above the inner ear at right angles to each other and register rotary motion of head
pitch (yes) yaw (no) roll (?)
Ampulla
Spherical enlargement at base of canal containing vestibular sensory organs
Cupula
tongue shaped gelatinous mass in ampula containing tufts of hair from vestibular organs
Vestibular nerve
Part of vestibulocochlear nerve that conveys vestibular signal to the brain
Oculomotor nucleus
group of midbrain cells that mediate eye movements relative to head position and movement (edinger-westphal nucleus)
vestibulo-obular reflex
reflective eye movement initiated when the head or body moves to stabilize position of eyes relative to a target
Oculocephalic reflex
VOR to maintain forward gaze during neck rotation
Caloric reflex test
VOR test for nystagmus (involuntary eye movement) induced by irrigating the auditory canal with cold or warm water
COWS - cold opposite, warm same
Sensory conflict theory
periods of unusual passive motion causes disruption of the usual close correspondence between the visual system and vestibular system concerning spatial orientation
Vomiting center
Cell groups in the dorsal-lateral medulla that vomiting reflex (cerebellum show mismatch between vision and vestibular sense –> chemoreceptor trigger zone –> vomiting center)
