Central Nervous System |
the portion of the vertebrate nervous system consisting of the brain and spinal cord 429 |
Cephalization |
the concentration of nerve tissue and sensory organs at the anterior end of an organism –rostral *toward the snout 430 |
Rostral |
On the head, towards the nose 430 |
Brain |
that part of the central nervous system that includes all the higher nervous centers –pinkish gray tissue -wrinkled –male mass 1600 g. / 3.5 lbs –female mass 1450 g. / 3.2 lbs –both are equal in size 430 |
Embryonic Development of neural tube |
–embryonic ectoderm 1 neurall plate froms form surface ectoderm 2 neural plate iaginates, forming the neural groove, flanked by neural folds 3 neural fold cells migrate to form neural crest, which will form musch of the PNS and many other sturctures 4 neural groove becomes the neural turbe which will form CNS structures –3 weeks ectoderm thickens to form neural plate –4th week, neural tube formed / differentiates rapidly into the CNS –5th week, primary vesciles give rise to secondary brain vesicles –26th week,continued growth causes surfaces to crease and fold 430 |
Neural plate |
Thickened region of ectoderm formed by the third to fourth week of embryonic development, which develops into the neural tube. –ivaginates forming a groove flanked by neural folds 430 |
Neural Folds |
Raised ridges in the neural plate that surround the deepening 430neural groove. |
Neural groove |
Groove resulting from further growth and thickening of the neural plate. — 430 |
Neural tube |
a tube of ectodermal tissue in the embryo from which the brain and spinal cord develop 430 |
Ectoderm |
The outermost of the three primary germ layers in animal embryos; gives rise to the outer covering and, in some phyla, the nervous system, inner ear, and lens of the eye. 430 |
Caudal |
constituting or relating to a tail 430 |
Neural Crest |
A band of cells along the border where the neural tube pinches off from the ectoderm; the cells migrate to various parts of the embryo and form the pigment cells in the skin, bones of the skull, the teeth, the adrenal glands, and parts of the peripheral nervous system. –some neurons destined to reside in ganglia 430 |
Primary Brain Vesicles |
expansion of the neural tube into forebrain (prosencephalon), midbrain (mesencephalon) and hindbrain (rhombencephalon) 430 |
Prosencephalon |
Developing forebrain that will become the diencephalon and telencephalon. 430 |
Forebrain |
AKA; prosencephalon top of the brain which includes the thalamus, hypothalamus, and cerebral cortex; responsible for emotional regulation, complex thought, memory aspect of personality 430 |
Mesencephalon |
the middle part of the brain between the diencephalon and the pons; also called the midbrain –remains undivided 430 |
Midbrain |
AKA; mesencephalon 430 |
Rhombencephalon |
–hind brain –divides into metencephalon and myelencephalon 430 |
Hindbrain |
AKA; rhombencephalon 430 |
Secondary brain vesicles |
subdivision of the primary brain vesicles into –telencephalon, diencephalon,-forebrain — metencephalon, and myelencephalon–hindbrain –week 5 430 |
Telencephalon |
a subdivision of the brain that, along with the diencephalon, makes up the prosencephalon (forebrain); cerebral hemispheres –endbrain 430 |
Diencephalon |
This part/lobe of the brain is responsible for Body temperature regulation, pituitary hormone control, autonomic nervous system responses. Includes: –thalamus, –epithalamus, –Hypothalamus –retina of eye –interbrain 430 |
Metencephalon |
the part of the hindbrain that develops into the –pons and the –cerebellum –medulla oblongata –afterbrain 431 |
Myelencephalon |
The most posterior region of the brain; the area of the brain stem between the metencephalon and the spinal cord, one of the two divisions of the hindbrain (the other is the metencephalon). –spinal brain 431 |
Cerebral hemispheres |
the right and left halves of the cerebrum 431 |
Cerebrum |
anterior portion of the brain consisting of two hemispheres 431 |
Hypothalamus |
a neural structure lying below the thalamus; directs eating, drinking, body temperature; helps govern the endocrine system via the pituitary gland, and is linked to emotion 431 |
Thalamus |
the brain’s sensory switchboard, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla 431 |
Epithalamus |
contains the hormone-secreting pineal gland; forms the roof of the diencephalons 431 |
Pons |
a band of nerve fibers linking the medulla oblongata and the cerebellum with the midbrain 431 |
Cerebellum |
the "little brain" attached to the rear of the brainstem; it helps coordinate voluntary movement and balance 431 |
Medulla Oblongata |
lower or hindmost part of the brain 431 |
Brain Stem |
the part of the brain continuous with the spinal cord and comprising the medulla oblongata and pons and midbrain and parts of the hypothalamus 431 |
Midbrain Flexures |
result from restricted space for brain development 431 |
Cervical Flexures |
When the neural tube bends at the junction of the hindbrain and spinal cord –brain grows more rapidly than membranous skull that contains it 431 |
Convolutions |
the folds in the cerebral cortex that increase the surface area of the brain 431 |
Embryonic Scheme |
Embryonic development 431 12.2 |
Medical Scheme |
effect of space restriction on brain development 431-432 |
Cortex |
the layer of unmyelinated neurons (the gray matter) forming the cortex of the cerebrum 431 |
Ventricles, brain |
–arise from expansions of lumen cavity of embryonic neural tube –ventricular chambers filled with cerebrospinal fluid –lined by ependymal cells / type of neuroglia 431 |
Ependymal Cells |
type of neuroglial cell found in the ventricles, circulate cerebrospinal fluid 431 |
Lateral Ventricles |
–paried –deep in each cerebral hemisphere –large C shaped chambers, reflect pattern of cerebral growth –Anteriorly / lie close together / separated by thin median membrane called septum pellucidum –communicates with third ventricle in diencephalon 431 |
Brain Development, space restriction, effect of |
–5th week, formation of two major flexures causes the telecephalon and diencephalon to angle toward the brain stem –13th week, development of cerebral hemispheres, also 26th week and birth –initially cerebral surface is smooth –6th month, folding begins, convolutions become more obvious as development continues Figure 12.3 432 |
Septum Pellucidum |
A structure that lies immediately ventral to the corpus callosum, is most prominent anteriorly, and consists of two thin-walled membranes separated by a narrow cleft, forming a small cavity (cavum of septum pellucidum). –transparent wall 432 |
Third Ventricle |
a narrow ventricle in the midplane below the corpus callosum 432 |
Interventricular foramen |
the small opening (on both the right and left sides) that connects the third ventricle in the diencephalon with the lateral ventricle in the cerebral hemisphere –foramen of Monro 432 |
Forth Ventricle |
ventricle located between the brain stem and the cerebellum 432 |
Cerebral aqueduct |
a canal connecting the third and fourth ventricles 432 |
Lateral Apertures |
the side walls of the fourth ventricle that assists in connecting the ventricles to the fluid filled space surrounding the brain 433 |
Median Aperture |
One of the three openings in the roof of the fourth ventricle through which cerebrospinal fluid enters the subarachnoid space of the brain and cord. Also called the foramen of Magendie. 433 |
Subarachnoid Space |
contains cerebrospinal fluid –surrounds brain 433 |
Cerebral Hemispheres |
the right and left halves of the cerebrum –83% of brain mass –elevated ridges of tissue called gyri –shallow grooves / sulci –deeper grooves / fissures 433 |
Gyri |
elevated ridges on cortical surface of the cerebral hemisphere, which increase the surface area and provide space for additional cortical neurons 433 |
Sulci |
shallow grooves that seperate gyri 433 |
Fissures |
deep grooves in the brain –separate large regions of the brain 433 |
Longitudinal Fissure |
divides the cerebrum into right and left cerebral hemispheres 433 |
Transverse Cerebral Fissure |
separates the cerebrum and the cerebellum 433 |
Central Sulcus |
a brain fissure extending upward on the lateral surface of both hemispheres 433 |
Frontal Lobe |
that part of the cerebral cortex in either hemisphere of the brain lying directly behind the forehead 433 |
Parietal Lobe |
that part of the cerebral cortex in either hemisphere of the brain lying below the crown of the head 433 |
Precentral Gyrus |
the convolution of the frontal lobe that is bounded in back by the central sulcus and that contains the motor area , frontal lobe; primary motor cortex; controls somatic motor neurons 433 |
Postcentral gyrus |
the convolution of parietal lobe that is bounded in front by the central sulcus 433 |
Occipital Lobe |
that part of the cerebral cortex in either hemisphere of the brain lying in the back of the head 433 |
Parietooccipital Sulcus |
located on the medial surface of the hemisphere 433 |
Lateral Sulcus |
separates temporal lobe from parietal and frontal lobes 433 |
Temporal lobe |
that part of the cerebral cortex in either hemisphere of the brain lying inside the temples of the head 433 |
Insula |
cerebral lobe located deep within lateral sulcus forms part of its floor 433 |
Basal Nuclei |
masses of cerebral gray matter buried deep in the white matter- 3 brain centers: caudate nucleus, putamen, and globus pallidus- receive input from substantia nigra of the midbrain and motor areas of the cerebral cortex, and send signals back to both of these locations- involved in motor control 433 |
Cerbral Cortex |
the intricate fabric of interconnected neural cells that covers the cerebral hemispheres; the body’s ultimate control and information-processing center –gray matter –neuron cell bodies –dendrites –associated glia –blood vessels –NO fiber tracts –Billions of neurons arranged in six layers –2-4mm thick 1/8 in. –40% of brain mass –convolutions triple its surface area –K. Brodmann / 1906 numbered mosiac of 52 cortical areas called Brodmann areas 435 |
Brodmann Areas |
A classification of cortical regions based on subtle variations in the relative appearance of the six layers of neocortex. –52 areas –K. Brodmann / 1906 435 |
Cerebral Cortex, functions |
Functional areas –motor areas –sensory –association –Each hemisphere controls sensory and motor functions of opposite side 2 hemispheres no entirely equal in function / lateralization ( specialization) of cortical functions no functional area of cortex acts alone and conciuos behavior involves the entire cortex in one way or another 435 |
Motor Areas |
functional area of the cerebral cortex that controls voluntary motor functions –posterior part of frontal lobes 1 Primary motor cortex 2 Premotor cortex 3 Broca’s Area 4 Frontal Eye Field 437 |
Primary Motor Cortex |
The region of the cerebral cortex that directly controls the movements of the body; located posterior to the frontal lobes –precentral gyrus of frontal lobe of each hemisphere 435 |
Pyramidal Cells |
a neuron characterized by a pyramid-shaped cell body and elongated dentric tree; found in the cerebral cortex –in gyri –allow concious control –precise or skilled voluntary movements of skeletal muscles –project to spinal cord 435 |
Pyramidal tracts |
massive voluntary motor tracts formed by long axons of pyramidal cells whichh project to the spinal cord 435 |
Corticospinal Tracts |
arise from primary motor cortex, crosses in medulla, descends via lateral corticospinal tract to ventral gray matter (anterior horn cells). 10% of fibers do not cross. Voluntary motor control 435 |
Somatotopy |
mapping the body in CNS structures 435 |
Motor Homunculi |
upside – down caricatures representing the motor innervation of body regions 435 |
Premotor Cortex |
anterior to the precentral gyrus in the frontal lobe; controls learned motor skills of a repetitious or patterened nature; coordinates movement of several muscle groups simultaneously or sequentially; involved in planning of movements that deepend on sensory feedback –15% of pyramidal tract fivers –memory bank for skilled motor activities 437 |
Broca’s Area |
controls language expression-an aread of the frontal, usually in the left hemisphere, that directs the muscle movements involved in speech –lies anterior to inferior region of premotor area –becomes active as we prepare to speak and even think about voluntary motor activities other than speech 437 |
Motor Speech Area |
a part of the left frontal lobe responsible for coordinating the muscles used in producing speech. it is often called broca’s area, after its discoverer. is one of the exceptions to the rule that the left side controls the right side of your body. 437 |
Frontal Eye Field |
located partially in and anterior to the permotor cortex and superior to Broca’s area; controls voluntary movement of the eyes; wont control eye reflexes 437 |
Sensory Areas |
–occur in the …… –parietal –insular –temporal –occipital lobes 1 Primary somatosensory Cortex 2 Somatosensory Association Cortex 3 Visual Areas 4 Auditory Areas 5 Olfactory Cortex 6 Gustatory Cortex 7 Visceral sensory Area 8 vetibular -equilibrium Cortex 437-439 |
Primary Somatosensory Cortex |
resides in the postcentral gyrus of the parietal lobe, just posterior to the primary motor cortex; receive information from the general (somatic) sensory receptors in the skin and from proprioceptors (position sense receptors) in skeletal muscles, joints, and tendons; capable of spatial discrimination (identification of body region being stimulated) 437 |
Spatial Discrimination |
identifying the site or pattern of the stimulus (studied by the two-point discrimination test) 437 |
Somatosensory Homunculus |
the "little man" representation of the somatosensory cortex, more sensitive to physical stimuli have more space on homunculus (face, hands, lips) BODY MAP 437 |
Somatosensory Association Cortex |
lies posterior to primary somatosensory cortex and has many connections with it; function is to integrate sensory inputs (temperature, pressure, and so forth) relayed to it via the primary somatosensory cortex to produce an understanding of an object being felt; determines size, texture, and relationships of parts of objects being felt 437 |
Visual Areas |
extreme posterior aspect of occipital lobe- impulses from the eyes by way of the optic nerves and tracts, area 18 is association are for the interpretation of what we see 437 |
Primary Visual Cortex |
on the extreme posterior tip of occipital lobe, but most of it is buried in the calcarine sulcus in medial aspect of occipital lobe; recieves visual information that originates on retina of the eye 437 |
Primary Visual Striate Cortex |
what the Posterior pole of the Occipital lobe is known as because of its striped appearance 437 |
Visual Association Area |
Located next to the primary visual cortex, transforms basic sensations, such as lights, lines, colors, and textures, into complete, meaningful visual perceptions, such as persons, objects, or animals. 438 |
Auditory Areas |
superior margin of themporal lobe abutting lateral sulcus –sound energy excites hearing receptors of inner ear –impulses transmitted to primary auditory cortex –interpreted as pitch loudness and location 438 |
Auditory Association Area |
interpretation of sounds as speech, music, or noise. 438 |
Olfactory Cortex |
lies on medial aspect of the temporal lobe in a small region called piriform lobe which is dominated by hooklike uncus; part of the primitive rhinecephalon which includes all parts of cerebrum that recieves olfactory signals (olfactory tracts and bulbs that extend to the nose); region of conscious awarness of oders 438 |
Piriform Lobe |
olfactory portion of the brain that’s seperated from the rest of the cerebrum by a sulcus at the anterior part 438 |
Uncus |
Medial surface of the olfactory area deep within the temporal lobe 438 |
Rhinencephalon |
Includes all parts of the creebrum that receive olfactory signals–the orbitofrontal cortex, the uncus and associated regions located on or in the medial aspects of the temporal lobes, and the protruding olfactory tracts and bulbs that extend to the nose. –limbic system 439 |
Limbic System |
a system of functionally related neural structures in the brain that are involved in emotional behavior 439 |
Gustatory Cortex |
region involved in perception of taste stimuli; located in insula deep to temporal lobe 439 |
Visceral Sensory Area |
posterior to gustatory cortex; involved in conscious perception of visceral sensations (ex: upset stomach, full bladder) 439 |
Vestibular equilibrium cortex |
Posterior of the insula and adjacent parietal cortex that is responsible for conscious awareness of balance 439 |
Multimodal Association Areas |
receive inputs from multiple sensory areas; send outputs to multiple areas, including the premotor cortex; allow us to give meaning to information received, store it as memory, compare it to pervious experience, and decide on action to take; each individiual perception come together (hear, see, touch, feel, and smell); can be divided into 3 parts (anterior association area, posterior association area, limbic association area) 439 |
Anterior Association Area |
in frontal lobe, also called prefrontal cortex; the most complicated cortical region of all; involved with intellect, complex learning abilities, recall, and personality; contains working memory needed for judgment, reasoning, persistence, and conscience; development depends on feedback from social enviornment 439 |
Posterior Association Area |
large region encompassing parts of temporal, parietal, and occipital lobes; play role in recognizing patterns and faces, localizing us and our surroundings in space, and binding different sensory inputs into a coherent whole; involved in understanding written and spoken language 439 |
Limbic Association Area |
includes cingulate gyrus, the parahippocampal gyrus, and hippocampus; part of limbic system; provides emotional impact that makes a scene important to us; hippocampus establishes memories that allow us to remember incidents 439 |
Lateralization of Cortical Functioning |
Right or left dominance is based on which hemisphere is dominant for language. 90% of people are left dominate and most are also right-handed. Left hemisphere controls: reasoning, language, math ability, logic. Right hemisphere controls: creativity, intuition, emotion, visual. 439 |
Lateralization |
localization of function on either the right or left sides of the brain 440 |
Cerebral Dominance |
the tendency of each brain hemisphere to exert control over different functions, such as language or perception of spatial relationships –90% of people have left hemisphere dominance over language, math, logic 440 |
Cerebral White matter |
second of three basic regions of each cerebral hemisphere; responsible for communication between cerebral areas and between cerebral cortex and lower CNS centers; consists mainly of myelinated fibers bundled into large tracts 440 |
commissures |
Connections of nerve fibers which allow the two hemispheres of the brain to communicate with one another 441 |
Commissural Fibers |
Connect 2 hemispheres and allow communication between them. 441 |
Corpus Callosum |
–largest commissure –lies superior to lateral ventricles –deep within longitudinal fissure 441 |
Posterior commissures |
joining of axons from one side of spinal cord to the other. 441 |
Anterior Commissures |
allows communication between olfactory nerves and oculomotor nerves 441 |
Projection fibers |
type of fiber tract; enter cerebral cortex from lower brain or spinal cord centers or descend from cortex to lower area; motor output leaves through these fibers from cerebral cortex; tie the cortex to rest of nervous system and to body’s receptors and effectors; run vertically 441 |
Internal Capsule |
a compact band formed by projection fibers at the top of the brain stem on each side; pass between the thalamus and some of basal nuclei 441 |
corona Radiata |
–radiating crown –distinctive arrangement of projection tract fibers 441 |
Basal Nuclei |
AKA; Basal Ganglia –deep within cerebral white matter –third basic region of each himisphere –subcortical nuclei 441 |
Basal Ganglia |
–AKA; basal nuclei –deep within cerebral white matter –third basic region of each himisphere –subcortical nuclei –a set of subcortical structures that directs intentional movements 441 |
Caudate Nucleus |
learning, memory, comprehension of language, part of basal ganglia –most of mass of each grop of basal nuclei 441 |
Caudate Nucleus Putamen |
2 components of the basal ganglia that receive input from the cerebral cortex and substantia nigra, send output to the globus pallidus –& globus pallidus constitiute most of the mass of each group of vasal nuclei 441 |
Globus Pallidus |
large subcortical structure, one part of the basal ganglia –most of mass of each group of basal nuclei 441 |
Lentiform Nucleus |
a basal ganglion shaped like a lens and including the outer reddish putamen and the inner pale yellow pallidum –flanks internal capsule laterally 441 |
Corpus Striatum |
the name for lentiform and caudate nuclei because the fibers of the internal capsule that course past and through them give them a striped appearance 441 |
Subthalamic Nuclei |
Located in subthalamus, all subthalamic nuclei are interconnected with ascending +descending nerve tracts, and work together with the basal nuclei cerebellum+ cerebrum. In control of body movement –functionally associated with basal nuclei 441 |
Substantia Nigra |
a layer of deeply pigmented gray matter in the midbrain 441 |
Diencephalon |
Forming central core of forebrain and surrounded by cerebral heimspheres the ____________consists largly of three paired stuctures………… Thalamus, Hypothalamus, Epithalamus –these gray matter areas collectively enclose third ventricle 441 |
Thalamus |
large egg-shaped structures of gray matter that form the dorsal subdivision of the diencephalon –bilateral egg shaped nuclei –form superolateral walls of third ventricle –"inner room" 441 |
Interthalamic Adhesion |
AKA; intermediate mass A small, midline mass of gray matter that connects the right and left thalamic bodies –80% of diencephalon 441 |
Intermediate Mass |
Another name for interthalamic adhesion? 441 |
Ventral posterolateral Nuclei |
recieve impulses form general somatic sensory receptors –touch, pressure, pain, ect. 442 |
Lateral Geniculate Bodies |
can be found by following the optic tracts under the pyriform lobes of the brain. these are lateral bulges of the thalamus and are relay centers for vision. many of the fibers within the optic tracts terminate here. 442 |
Medial Geniculate Bodies |
relays centers for sound 442 |
Hypothalamus |
–below thalamus –caps brain stem –forms inferolateral walls of third ventricle –merging into midbrain inferiorly, hypothalamus extends from optic chisma(cross over point of the optic nerves) to posterior margin of mammillary bodies 443 |
Mammillary bodies |
paired pealike nuclei that bulge anteriorly from the hypothalamus; relay stations in the olfactory pathways 443 |
Infundibulum |
A stalk that attaches the pituitary gland to the hypothalamus. –between optic chiasma and mammillary bodies 443 |
Pituitary Gland |
the master gland of the endocrine system –base of hypothalamus 443 |
Hypothalamus, Homeostatic Roles |
1 Autonomic Control center 2 Center for emotional response 3 body temperature regulation 4 Regualtion of food intake 5 regulation of water balance and thirst 6 regualtion of sleep-wake cycles 7 control of endocrine system functioning 443-444 |
Autonomic control center |
This regulates autonomic activity by controlling those areas in the brain and spinal cord involved with activity, thereby influencing blood pressure, heart rate and force of contraction of heart, digestive tract motility, pupillary size and other visceral function. 443 |
Center for emotional response |
–hypothalamus lies at heart of limbic system (emotional part of brain) 444 |
Body temperature regulation |
w/in the hypothalamus, measures temp of blood in the brain 444 |
Regulation of food intake |
When energy inputs and outputs are balanced, the body remains constant. The hypothalamus plays a key role in regulating feeding behaviors. –response to changeing blood levels of certain nutrients or hormones 444 |
Regulation of water balance and thirst |
–hypothalamus –body fluids become too concentrated osmoreceptors are activated- –release antidiuretic hormone ADH > causes kidney to retain water –same conditions also stimulate hypothalamic neurons in thirst cneter causing thirst 444 |
Regualtion of sleep wake cycles |
–hypothalamus helps geuglate sleep through operation of suprachiasmatic nuclesu –daylight / dark cues from visual 444 |
Osmoreceptors |
detect changes in concentration of solutes in body fluids and resultant changes in osmotic activity 444 |
Suprachiasmatic Nucleus |
a cluster of neurons in the hypothalamus that receives input from the retina regarding light and dark cycles and is involved in regulating the biological clock 444 |
Control of endocrine system functioning |
–hypothalamus –helmsman of endocrine system in 2 ways ——releasing and inhibiting hormones —–supraoptic and paraventricular nuclei produce hormones ADH and oxytocin 444 |
Releasing and inhibiting hormones |
produced by the hypothalamus, this controls the release of each of the hormones released by the anterior pituitary 444 |
Supraoptic Nuclei |
One of the two pairs of hypothalamic nuclei that contain neurons whose axons terminate in the posterior pituitary; this pair is located above the optic chiasm, just posterior to the suprachiasmatic nuclei. 444 |
Paraventricular Nuclei |
One of the two pairs of hypothalamic nuclei that contain neurons whose axons terminate in the posterior pituitary; this pair is located on the dorsal surface of the hypothalamus on each side of the third ventricle. 444 |
Epithalamus |
contains the hormone-secreting pineal gland; forms the roof of the diencephalons and most dorsal portion 444 |
Pineal Gland |
a small endocrine gland in the brain 444 |
Pineal Body |
a small endocrine gland in the brain 444 |
Brian Stem, Regions |
Mid brain Pons Medulla Oblongata –each roughly an inch long / account for 2.5% of brain mass –nuclei of gray matter embedded in white matter –rigid automatic behaviors necessary for survival –between cerebrum and spinal cord –pathway for fiber tracts running between higher and lower neural centers –associated with 10 of 12 pairs of cranial nerves –innervation of head 445 |
Mid brain |
Between diencephalon and pons –ventral aspect tow bulging cerebral peduncles from vertical pillars 445 |
Cerebral Peduncles |
two bulging structures that contain descending pyramidal motor tracts –little feet of the cerebrum 445 |
Crus Cerebri |
leg of the cerebrum; on each penduncle; contains a large pyramidal motor tract descending toward the spinal cord 445 |
Superior Cerebellar Peduncles |
dorsally connects the cerebellum to the midbrain 445 |
Cerebral aqueduct |
a canal connecting the third and fourth ventricles 446 |
Periaqueductal Gray matter |
The____________surrounds the cerebral aqueduct and is part of the midbrain. It is involved in pain suppression, serves as a link between the fear-perceiving amygdala and the autonomic nervous system nerve pathways that control flight-or-fight and contains 2 nuclei giving rise to cranial nerves III and IV. 446 |
Oculomotor Nuclei |
periaqueductal gray matter also includes nuclei that control two cranial nerves the ___________ and Trochlear nuclei 446 |
Trochlear nuclei |
periaqueductal gray matter also includes nuclei that control two cranial nerves the ___________ and Trochlear nuclei 446 |
Corpora Quadrigemina |
located in the midbrain; contains reflex centers for vision and audition –raise 4 domelike portursions on dorsal midbrain surface 446 |
Superior Colliculi |
Paired gray matter structures of the dorsal midbrain that receive visual information and are involved in direction of visual gaze and visual attention to intended stimuli. 446 |
Inferior Colliculi |
midbrain structures that control sound localization 446 |
Substantia Nigra |
a layer of deeply pigmented gray matter in the midbrain 446 |
Red Nucleus |
A brainstem structure related to motor control. –deep to substantia nigra 446 |
Reticular Formation |
a complex neural network in the central core of the brainstem 447 |
Pons |
–bulging brain stem region wedged between teh midbrain and medulla oblongata –dorsally forms part of anterior wall of 4th ventricle –pons = bridge –conduction tracts –two different directions –deep projection fibers fun lingitudinally –complete pathway between higher braincenters and spinal cord a brain structure that relays information from the cerebellum to the rest of the brain 447 |
Middle Cerebellar Peduncles |
extending laterally from pons; large rope-like; contains axons from basis pontis neurons 447 |
Pontine Nuclei |
–relays for "conversations" between motor cortex and cerebellum –trigeminal –abducens –facial nerves 447 |
Trigeminal |
the main sensory nerve of the face and motor nerve for the muscles of mastication –issue from pontine nuclei 447 |
Abducens |
a small motor nerve supplying the lateral rectus muscle of the eye –issue from pontine nuclei 447 |
Facial nerves |
motor and sensory nerves and helps with facial expression and salivary glands –issue from pontine nuclei 447 |
Medulla Oblongata |
lower or hindmost part of the brain –most inferiro part of brain stem at level of foramen magnum of skull 447 |
Pyramids |
large longitudinal ridges –flanking midline on medulla ventral aspect –formed by large pyramidal (corticospinal ) tracts — decend from motor cortex 447 |
Decussation of the pyramids |
area of the medulla where descending motor tracts cross the midline and descend to the body 447 |
Inferior cerebellar peduncles |
fiber tracts connecting medulla and cerebellum –dorsally 447 |
Olives |
–lateral to pyramids –oval swellings –do resemble olives –caused by wavy folds of gray matter 447 |
Inferior Olivary Nuclei |
that fold of gray matter that cause the olive oval swellings. These nuclei relay sensory information on the state of stretch of muscles and joints to the cerebellum 447 |
Hypoglossal nerves |
manage tongue (speaking/chewing/swallowing) –emerge from groove between pyramid and olive on each sid of the brain stem 448 |
Medulla, Cranial nerves |
hypoglossal –glossopharyngeal –vagus vestibulocochlear –cochlear nuclei 448 |
Cochlear Nuclei |
Second-order relay neurons (i.e., dorsal and ventral cochlear nuclei); located at the medullopontine junction; associated with the transmission of auditory impulses. 448 |
Vestibular Nuclear Complex |
vestibular nuclei; mediate responses that maintain equilibrium 448 |
Nucleus Gracilis |
receives general sensory info from the lower half of the body –somatic sensory information ascends from spinal cord to somatosensory cortex 448 |
Nucleus Cuneatus |
receives general sensory info from the upper half of the body 448 |
Medial Lemniscus |
Major ascending sensory pathway arising from the nucleus gracilis and nucleus cuneatus, mediating conscious proprioception and tactile sensations from the limbs to the contralateral ventral posterolateral thalamic nucleus. 448 |
Visceral Motor Nuclei in Medulla |
1 Cardiovascular Center 2 Respiratory Centers 3 Various other centers , regulate vomiting, hiccupinng, swallowing, coughing, sneezing –hypothalmus exerts control over many visceral functions by relaying insturctions through medullary reticular centers which carry them out 449 |
Brain Regions, Major / Functions |
Table 449 |
Cardiovascular Center |
the region of the brain stem (medulla oblongata) that regulates the heart 449 |
Vasomotor Center |
adjusts blood vessel diameter to regulate blood pressure 449 |
Cardiac Center |
adjusts rate and force of heart beat 449 |
Cerebellum |
the "little brain" attached to the rear of the brainstem; it helps coordinate voluntary movement and balance –11% of brain mass 450 |
Cerebellar hemispheres |
2 lateral hemispheres make up cerebellum along w/vermis in midline 450 |
Vermis |
the narrow central part of the cerebellum between the two hemispheres –wormlike 450 |
Folia |
Small page-like gyri of the cerebellum 450 |
Cerebellum Fissures |
Anterior posterior flocculonodular 450 |
Dentate Nuclei |
The cerebellum has a cortex of gray matter, internal white matter and the____________, small, deeply situated paired masses of gray matter. 450 |
Purkinje Cells |
cell bodies–flat cells in sequential planes. transmits inhibitory message to cells in the nuclei of the cerebellum and vestibular nuclei of the brainstem which in turn sends information to the midbrain and the thalamus 450 |
Arbor vitae |
cerebellar white matter –resembles branching tree 450 |
Cerebellar Peduncles |
Three large pairs of tracts (inferior, middle, and superior) that connect the cerebellum to the rest of the brain stem. 450 |
Ipsilateral |
on or relating to the same side (of the body) 450 |
Superior Cerebellar Peduncles |
caary instructions from neurons in the deep cerebellar nuclei to the cerebral motor cortex via thalamic relays 450 |
Middle Cerebellar Peduncles |
carry one way communication from the pons to the cerebellum, advising the cerebellum of voluntary motor activities initiated by the motor cortex 450 |
Inferior Cerebellar Peduncles |
connect medulla and cerebellum; convey sensory information to the cerebellum from (1) muscle prorioceptors throughout the body and (2) the vestibular nuclei of the brain stem, which are concerned with equilebrium and balance 450 |
Cerebellar Processing, Functional Scheme |
1 motor areas of cerebral cortex notify cerebellum of intent to initiate voluntary muscle contractions 2 at same time, cerebellum recieves info from porprioceptors through out body > cerebellum evaluates body position and momentum > where body is and where its going 3 cerebelllar cortex calculates best way to coordinate force, direction and extent of meuxle contraction to prevent overshoot, maintain posture, and ensure smooth cordinated movements 4 via superior peduncles, cerebellum dispatches to cerebral motor cortex ‘blueprint’ for coordinating movement cerebellar fibers send information to brain stem muclei > influence motor neurons of spinal cord 450 |
Cerebellum, Cognitive Function |
450 |
Brain systems, functional |
Lilmbic system Reticular Formation 451 |
Limbic system |
a system of functionally related neural structures in the brain that are involved in emotional behavior –located on medial aspect of cerebral hemisphere and diencephalon 452 |
Rhinencephalon |
–septal nuclei –cingulate gyrus –parphippocampal gyrus –dentate gyrus –C shaped hippocampus –amygdala 452 |
Amygdala |
an almond-shaped neural structure in the anterior part of the temporal lobe of the cerebrum 452 |
Diencephalon, limbic structures |
hypothalamus anterori thalamic nuclei –fornix link systems regions together 452 |
Anterior Thalamic Nuclei |
it relays/ relay nucleus to the limbic system 452 |
Fornix |
an arched bundle of white fibers at the base of the brain by which the hippocampus of each hemisphere projects to the contralateral hippocampus and to the thalamus and mamillary bodies 452 |
Cingulate Gyrus |
a long curved structure on the medial surface of the cerebral hemispheres 452 |
Memory |
hippoamus and amygdala play role in memory 452 |
Reticular Formation |
a complex neural network in the central core of the brainstem –extends through cnetral core of medulla oblongata, pons, and midbrain –loosly clustered neurons inwhat is otherwise white matter –form 3 broad columns along length of brain stem 1 raphe nuclei 2 medial large cell group 3 lateral small cell group of nuclei 452 |
Raphe Nuclei |
a group of nuclei located in the reticular formation of the medulla, pons, and midbrain, situated along the midline; contain serotonergic neurons 452 |
Medial large cell group |
452 |
Lateral small cell group of Nuclei |
452 |
Reticular Activation System |
RAS –99% of all sensory stimuli from RAS and cerebral cortex disreguarded as uniportant –damage could reslut in permanent coma specialized nerve fibers through which the reticular formation sends impulses to the cerebral cortex; the reticular formation and reticular activation system are responsible for alertness during the day and can prevent sleeping at night 453 |
Reticulospinal Tracts |
Integrates information from the motor systems to coordinate automatic movements of locomotion and posture.Facilitates and inhibits voluntary movement, influences muscle tone 453 |
Reticular Motor Nuclei |
–vasomotor –cardiac –respiratory centers of medulla are autonomic centers that regulate visceral motor functions 453 |
Electorencephalogram |
monitoring surface electrical activity called brain waves by connecting electrodes on the scalp –EEG 453 |
Brain Waves |
patterns of neuronal electrical activity recorded; generated by synaptic activity at the surface of the cortex 453 |
Alpha Waves |
the relatively slow brain waves of a relaxed, awake state –regular and rhythmic –low amplitude, synchronous –8-13 Hz 454 |
Beta Waves |
rapid brain waves appearing when a person is awake –rhythmic 14-30 Hz 454 |
Theta Waves |
4-7 Hz –more irregular –common in children –uncommon in awake adults / may appear when concentrating 454 |
Delta Waves |
Lowest frequency, Highest Amplitude. Stage 3-4 DEEP SLEEP. Sleepwalking, bedwetting, and NIGHT TERRORS. –retuclar activatin system is damped, such as during anesthesia –awake adults, indicate brain damage 454 |
Epileptic Seizures |
usually have a sudden onset and in most instances stop spontaneously They are usually brief – seconds to minutes Seizures are frequently followed by a period of drowsiness and confusion (post-ictal) –electrical discahrges –no messages can get through — 1 in 100 454 |
Absence Seizures |
May be seen in children who are accused of inattention in class and confused with ADHD. 454 |
Petit Mal |
a seizure (or a type of epilepsy characterized by such seizures) of short duration characterized by momentary unconsciousness and local muscle spasms or twitching 454 |
Tonic clonic |
stiffening-jerking; a major motor seizure involving all muscle groups; previously termed grand mal (big bad) seizure 454 |
Grand Mal |
old name for generalized tonic-clonic seizure 454 |
Aura |
a sensation (as of a cold breeze or bright light) that precedes the onset of certain disorders such as a migraine attack or epileptic seizure 454 |
Vagus Nerve Stimulator |
localized limitation – Implanted device Stimulates left vagus nerve 30 seconds/5min 30% experiences 50% reduction Complications: shortness of breath hoarseness sore throat, coughing ear and throat pain nausea and vomiting 454 |
Consciousness |
an alert cognitive state in which you are aware of yourself and your situation 1 involves simultaneous activity of large areas of the cerebral cortex 2 superimposed onother types of neural activity 3 holistic and totally interconnected 455 |
Consciousness; defined on continuum |
1 alertness 2 drowsiness or lethargy 3 stupor 4 coma |
Syncope |
a sudden, and generally temporary, loss of consciousness and postural tone, due to inadequate flow of oxygenated blood to the brain (fainting) 455 |
Coma |
a state of deep and often prolonged unconsciousness 455 |
Brain Death |
death when respiration and other reflexes are absent 455 |
Sleep, types |
Non rapid eye movement NREM rapid eye movement REM –1st 30-45 min pass through 2 stages of NREM and into NREM satges 3 & 4 called slow wave sleep –blood pressure and heart rate also dercrese with deeper sleep –90 min after sleep NREM stage 4 has been achieved 455 |
Non-Rapid eye Movement |
a recurring sleep state during which rapid eye movements do not occur and dreaming does not occur 455 |
Rapid Eye Movement |
rapid eye movement sleep, a recurring sleep stage during which vivid dreams commonly occur. Also known as paradoxical sleep, because the muscles are relaxed (except for minor twitches) but other body systems are active. 455 |
Slow Wave Sleep |
The last two stages of sleep, characterized by slow brain waves, deep breathing, and calm heartbeat 455 |
Sleep Patterns |
REM NREM stage 1; relaxation begins; EEG shows alpha waves, arousal is easy –NREM stage 2; irregular EEG with sleep spindles; arousal is more difficult –NREM stage 3; sleep deepens; theta and delta waves appear; vital signs decline –NREM stage 4; EEG is dominated by delta waves; arousal is difficult; bed-wetting, night terrors and sleepwalking may occur 455-456 |
Circadian Rhythm |
the biological clock; regular bodily rhythms (for example, of temperature and wakefulness) that occur on a 24-hour cycle. 455 |
Sleep Importance |
–deprivation of REM becomes moody and depressed –varous personality disorders — 16 hrs for infants –7 1/2 – 8 1/2 in early adult hood –stage 4 often disappears in those over 60 |
language |
important functionof brain –practically all of the association cortex on left side is involvoed in one way or another 457 |
Aphasias |
loss of spoken or written language due to injury or disease 457 |
Wernicke’s Area |
controls language reception-a brain area involved in language comprehension and expression;usually in the left temporal lobe 457 |
Memory |
Short Term Memory STM Long Term Memory LTM, — the power of retaining and recalling past experience 457 |
Short Term Memory |
activated memory that holds a few items briefly, such as the seven digits of a phone number while dialing, before the information is stored or forgotten 457 |
Long Term Memory |
the relatively permanent and limitless storehouse of the memory system. Includes knowledge, skills, and experiences 458 |
Memory, Transfer |
1 Emotional state – Norepinephrine, neurotransmitter involved in memory released in emotionally charged event which helps with recall 2 Rehearsal – enhances memory 3 Association – tying new memory to old memory 4 Automatic Memory Figure 12.22 458 |
Memory Consolidation |
The physical and psychological changes that take place as the brain organizes and restructures information to make it a permanent part of memory. 458 |
Memory, Categories |
Declarative – fact – memories Procedural – skills – memories Motor Memory – riding bike Emotional memory – heart pounding when you hear a rattle snake nearby 458 |
Declarative memory |
The part of long-term memory where factual information is stored, such as mathematical formulas, vocabulary, and life events. 458 |
Procedural Memory |
Memory of learned skills that does not require conscious recollection 458 |
Motor Memory |
Memory that is said to exist "in the hands of a musician." That is, it is unconscious and functions by allowing each action in a series to trigger the next move. A musician, for example, who only has motor memory for a certain piece would be able to physically play that song but unable to mentally rehearse it. 458 |
Emotional Memory |
an acting technique pioneered by Stanislavsky in which the actor recalls the visual and auditory images, or physical circumstances of a real life (or imagined) event in order to relive the emotions accompanying it; also called sense memory or affective memory 458 |
Memory, Brain Structures Involved |
memory stored in regions of bran that need them so new inputs can be associated withh the old –visual memories stored in occipital cortex –memories of music in temporal cortex Sensory and motor inputs > Association Cortex > Basal Nuclei> Thallamus> Premotor Cortex –sensory and motor input flows throught association cortices and relayed via basal nuclei –Dopamine released from Substantia Nigra is necessary for this circuit fot function Picture……… 459 |
Antograde Amnesia |
Caused by damage to hippocampus, Disrupts long-term memory, Can’t form any permanent NEW memories 459 |
Retrograde Amnesia |
loss of memories that were stored before a traumatic event 459 |
Memory, Molecular Basis |
1 neuronal RNA content is altered and newly synthesized mRNA’s are dilivered to axons and dendrites 2 dendritic spinnes change shape 3 unique extracellualr porteins are diposited at synapses involved in LTM 4 number and size off presynaptic terminals may increase 5 more neurotransmitter is released by the presynaptic neurons –aspect of LTP – Long term Potential 460 |
Long Term Potential |
An increase in a synapses firing potential after a brief rapid stimulation. Believed to be the neural basis for learning and memory 460 |
NMDA Receptor |
A hippocampal receptor site that influences the flow of information from one neuron to another across the synapse by controlling the initiation of long-term potentiation. 460 |
Brain, Protection |
–Skull –Membranes / Meninges –Watery cushion / cerebrospinnal fluid –blood-brain barrier / protection from harmful substances 461 |
Meninges |
three membranes that cover the brain and spinal cord, consisting of the –dura mater / external — pia mater, and –arachnoid mater / internal 1 Cover and protect CNS 2 protect blood vessels and enclose venous sinuses 3 contain cerebrospinal fluid 4 form partitions in the skull 461 |
Meninx |
singular for meninges |
Dura Mater |
the outermost (and toughest) of the 3 meninges –two layered sheet –fibrous connective tissue –superficial ——periosteal layer / attached to inner surface of skull – periosteum –deeper ——–Meningeal layer / forms true external covering of brain, continues caudally in vertebral canal as the spinal dura mater 461 – picture |
Periosteal layer |
Its outer layer forms the periosteum of the skull 460 |
Meningeal Layer |
deeper layer of dura mater forms true external covering of brain 461 |
Dural Venous Sinuses |
Are large veins that drain blood from the brain into the internal jugular 461 – picture |
Dural Septa |
flat partitions the subdivide cranial cavity; limit excessive movement of brain within the cranium including…. — Falx Cerebri, –Falx Cerebelli, and —-Tentorium Cerebelli 461 – picture |
Arachnoid Mater |
delicate web-like layer of the meninges; middle layer 461 – picture |
Subdural Space |
between dura and arachnoid– contains small amount of lymphatic fluid which reduces friction 461 |
Subarachnoid Space |
a space in the meninges beneath the arachnoid membrane and above the pia mater that contains the cerebrospinal fluid 461 |
Arachnoid Villi |
structures that return cerebrospinal fluid to the venous blood in the dural sinuses 461 |
Pia Mater |
the highly vascular innermost of the 3 meninges –delicate connective tissue –clings tightly to brain like cellopane wrap 463 |
Meningitis |
infectious disease characterized by inflammation of the meninges (the tissues that surround the brain or spinal cord) usually caused by a bacterial infection 463 |
Encephalitis |
inflammation of the brain usually caused by a virus 463 |
Cerebrospinal Fluid |
fluid in the space between the meninges that acts as a shock absorber that protects the central nervous system –reduce brain weight by 97% –helps nourish brain –carries cheical signals –contains more Na+, CI -, and H+ than blood plasma –150 ml replaced every 8 hours –500 ml of CFS produced daily 462 – picture |
Choroid Plexuses |
hang from roof of each ventricle form CSF; frond shaped clusters of broad thin walled capillaries enclosed first by pia mater and then by layer of ependymal cells lining the vetricles; permeable –cleanse by removing waste products and unnecessary solutes 463 |
Hydrocephalus |
an abnormal condition in which cerebrospinal fluid collects in the ventricles of the brain 463 – picture |
Blood Brain Barrier |
Blood vessels (capillaries) that selectively let certain substances enter the brain tissue and keep other substances out 463 |
Brain, Homeostatic Imbalances |
Traumatic Brain injury –concussion –contusion –subdural or subarachnoid hemorrhage –cerebral edema Crebrovascular Accidents –Ischemia –transient ischemic attacks Degenerative Brain Disorders –Alzheimers –Parkinson’s Disease –Huntingtons Disease 464-466 |
Contrecoup |
also known as a counter blow, is an injury that occurs beneath the skull opposite to the area of impact 464 |
Concussion |
injury to the brain caused by a blow 464 |
Contusion |
an injury that doesn’t break the skin but results in some discoloration 464 |
Subarachnoid hemorrhage |
bleeding caused by a ruptured blood vessel just outside the brain (usually a ruptured cerebral aneurysm) that rapidly fills the space between the brain and skull (subarachnoid space) with blood; the patient may experience an intense, sudden headache accompanied by nausea, vomiting, and neck pain 464 |
Cerebral Edema |
Swelling of the brain 464 |
Cerebrovascular Accidents |
CVA –‘Strokes’, caused by blood clots in the brain 464 |
Ischemia |
to hold back blood; decreased blood flow to tissue caused by constriction or occlusion of a blood vessel 464 |
Hemiplegia |
paralysis of one side of the body 464 |
Transient Ischemic Attacks |
temporary stroke; lasts 5-50 minutes; numbness, impaired speech, etc 464 |
Glutamate |
a major excitatory neurotransmitter; involved in memory 465 |
Excitotoxin |
After brain injury neurons deprived of oxygen begin to disintegrate unleashing cellular euivalent of buckets of glutamate, –Glutamate act as ___________ literally exciting surrounding cells to death 465 |
Alzheimers Disease |
Characteristic physiologic changes are neurofibrillary tangles and amyloid plaques (deposits of protein), found throughout the cortex, which interfere with cells’ ability to transmit impulses are found in what disease? 465 |
Parkinsons Disease |
A chronic, progressive disease that affects the brain area that controls movement. Depletion of dopamine interferes with inhibition of excitatory impulses w/result in dysfunction of extra-pyramidal tracts, which results in dysfunctions of extrapyramidial tracts. 465 |
Huntingtons Disease |
genetic disorder that causes progressive deterioration of brain cells. caused by a dominant allele. symptoms do not appear until the age of 30 or so 466 |
Spinal Cord, Embryonic Development |
–develops from caudal portion of embryonic neural tube –6th week each side of developinng cord 2 recgnizable cluster off neuroblasts –dorsal alar plate –ventral basal plate 466 – picture |
Alar Plate |
dorsal portion of the neural tube – future site for sensory neurons and tracts 466 |
Basal Plate |
Region of the developing nervous system situated ventral to the sulcus limitans that will become motor in function. 466 |
Spinal Cord, Gross Structure |
467 – picture |
Spinal Cord |
a major part of the central nervous system which conducts sensory and motor nerve impulses to and from the brain –two way conduction pathway to and from the vbrain 466 |
Spinal Dura Mater |
single layered; not attached to bony walls of vertebral column 466 |
Epidural Space |
separates the dura mater from the inner walls of the vertebral canal 468 |
Lumbar Tap |
468 – picture, the process of obtaining a sample of cerebrospinal fluid by inserting a needle into the sucarachnoid space of the lumbar region to withdrawl fluid |
Conus Medullaris |
where the spinal cord tapers to a conical tip, which is at or inferior to the level of the first lumbar vertebrae (L1) 468 |
Filum Terminale |
a strand of fibrous tissue, originating at the conus medullaris and extending through the vertebral canal to the second sacral vertebra, ultimately becoming part of the coccygeal ligament 468 |
Denticulate Ligaments |
Lateral extensions of pia mater that pass through the arachnoid layer and attach to the internal surface of the dura mater • Function to anchor the spinal cord 468 |
Spinal Nerves |
31 pairs of nerves arising from the spinal cord –attach by paired roots 468 |
Cervical Enlargements |
expanded regions with increased gray matter to provide innervation of the pectoral girdle and upper limbs 468 |
Lumbar Enlargements |
expanded region of the spinal cord with increased gray matter to provide innervation of the pelvic girdle and lower limbs 468 |
Cauda Equina |
collection of spinal nerves below the end of the spinal cord 468 |
Ventral Median Fissure |
the anterior spinal artery sits in the 468 |
Dorsal Median Sulcus |
Shallow midline groove on the dorsal surface of the entire length of the spinal cord. 468 |
Gray commissure |
surrounds the central canal 468 |
Dorsal Horns |
the two dorsal arms of the spinal gray matter 468 |
Ventral Horns |
The anterior columns of the gray matter of the spinal cord. 468 |
Lateral Horns |
additional pair of gray matter columns; present in thoracic and superior lumbar segments of the cord 468 |
Ventral Roots |
These nerve roots carry motor impulses from the spinal cord and brain to the body/muscles. Aka Anterior 468 |
Dorsal Roots |
These nerve roots carry sensory impulses from the body to the brain. Aka Posterior 468 |
Spinal Cord, Anatomy |
489 – picture |
Dorsal Root Ganglion |
AKA; spinal ganglion A group of sensory neuron cell bodies found just posterior to the spinal cord on either side. A pair of root ganglia exists for each spinal nerve that expands from the spinal cord. The ganglia are part of the peripheral nervous system (PNS). 470 |
Spinal Ganglion |
enlargement of the posterior root where cell bodies of sensory nerurons are located AKA Dorsal root ganglion 470 |
Spinal Gray Matter |
looks like a butterfily or a modified "H" and is more centrally located than the white matter; the gray matter is divided into the anterior, lateral, and posterior gray horns and consists of nerve cell bodies and dendrites –4 zones –somatic sensory –visceral – autonomic sendory –visceral motor –somatic metor 470- picture |
Spinal Cord White Matter |
–myelinated and unmyelinated nerve fibers –allow communication in spinal cord and to brain –fibers run 3 directions —–ascending to higher sensory inputs —–descending down to dord form brain or within cord to lower levels – motor outputs —–transversely across / commissural fibers divided into 3 white columns / funiculi according to position –dorsal lateral ventral 470 |
Funiculi |
white matter columns on each side of the cord; 3 on each side 470 |
Spinal Tracts |
The white columns of the spinal cord that provide two-way conduction paths to and from the brain; ascending tract carries information to the brain, whereas descending tracts conduct impulses from the brain 1 decussation 2 relay 3 somatotopy 4 symmetry 470 |
Brain, Ascending Pathways |
–conduct sensory impulses upward –3 successive neurons First order Second order Third order Dorsal column medial lemniscal Anterolateral / spinothalamic spinocerebellar 471 |
First Order Neurons |
soma reside in dorsal root or cranial ganglia, and conduct impulses from the skin to the spinal cord or brain stem 471 |
Second Order Neurons |
their cell bodies reside in the dorsal horn of the spinal cord or in meduallry nuclei, and they transmit impulses to the thalamas or to the cerebellum where they synapse 471 |
Third Order Neurons |
located in the thalamus and conduct impulses to the somatosensory cortex of the cerebrum 471 |
Somatosensory Information |
3 pathways –dorsal column medial lemniscal –spinothalamic / anterolateral –spinocerebellar 471 |
Dorsal Column Medial Lemniscal Pathways |
mediate precise, straight through transmission of inputs from a single type of sensory receptor that be localized precisely on the body surface (such as discriminative touch and vibrations); — formed by paired tracts of dorsal white column of spinal cord – –fasciculus cuneatus and –fasciculus gracilis – and –medial lemniscus 471 |
Dorsal White Column |
ascending tracts sending sensory information to brain 471 |
Fasciculus Cuneatus |
First-order sensory neurons contained in the dorsal funiculus that project to the nucleus cuneatus and that convey the modalities of conscious proprioception and tactile sensation from the ipsilateral side of the upper limb. 471 |
Fasciculus Gracilis |
First-order sensory neurons contained in the dorsal funiculus that project to the nucleus gracilis and that convey the modalities of conscious proprioception and tactile sensation from the ipsilateral side of the lower limb. 471 |
Medial Leminiscus |
What are crossed over sensory fibers called? –arises in medulla and terminates in thalamus 471 |
Anterolateral Pathways |
recieve input from many different types of sensory receptors and make multiple synapses in the brain stem; these pathways are largley formed by lateral and ventral (anterior) spinothalamic tracts; 471 |
Lateral Spinothalamic Tracts |
tracts whose functions are crude touch, pain, and temperature 471 |
Ventral Spinothalamic Tracts |
pathway from the spinal cord to the thalamus that carries info about pain and temp 471 |
Spinocerebellar Tracts |
ventral (anterior) and dorsal (posterior) tracts convey information about muscle or tendon stretch to cerebellum, which uses this information to coordinate skeletal muscle activity; do not contribute to conscious sensation; these fibers do not cross over twice (decussate) 471 |
Spinal Cord Tracts, ascending |
472 – picture 473 Table |
Spinal Cord, Descending Pathways and Tracts |
–deliver efferent impulses –brain to spinnal cord 2 groups –direct pathways = pyramidal tracts –indirect pathways, all others 473 474 – table / 475 – picture |
Direct Pyramidal system |
originate mainly with pyramidal neurons located in precentral gyri; these neurons send impulses through brain stem via large pyramidal (corticospinal) tracts , maintenance of muscle tone, controlling speed and precision of skilled movements 474 |
Pyramidal Corticospinal tracts |
Major motor pathways concerned with voluntary movement; descend from pyramidal cells in the frontal love of each cerebral hemisphere 474 |
Indirect Extrapyramidal system |
includes brain stem motor nuclei and all motor pathways except pyramidal pathways; these tracts are formerly lumped together as extrapyramidal sytem because their nuclei of origin were presumed to be independent of the pyramidal tracts 476 |
Extrapyramidal system |
system that provides unconscious control (reflex like that can be overriden) by modulating or altering sensitivity of lower motor neurons to descending pyramidal control output; helps control gross and precise movements 476 |
Multineuronal Pathways |
476 |
Indirect pathways |
involved with coordination of body movements, skeletal muscle tone, posture & equilibrium 476 |
Reticulospinal Tracts |
maintain balance by varying the tone of postural muscles 476 |
Vestibulospinal Tracts |
Controls Fine Motor, Balance (Postural Reflexes), & Tone-Descending Tracts 476 |
Rubrospinal Tracts |
control flexor muscles476 |
Tectospinal Tracts |
Assists in Head Turning Responses in Response to Visual Stimuli 476 |
Superior Colliculi |
Visual movement (tracking 476 |
Paresthesias |
Abnormal sensations such as burning, numbness, or tingling 476 |
Flaccid Paralysis |
weakness or loss of muscle tone resulting from injury or disease of the nerves innervating the muscles 476 |
Spastic Paralysis |
a loss or deficiency of motor control with involuntary spasms caused by permanent brain damage present at birth 476 |
Amyotorphic Lateral Sclerosis |
Lou Gehrigs 476 |
Paraplegia |
both lower limbs paralyzed; caused by a cut of the spinal cord between T1 and L1 476 |
Spinal Shock |
Cessation of motor, sensory, autonomic, and reflex impulses below the level of injury; characterized by flaccid paralysis of all skeletal muscles, loss of spinal reflexes, loss of sensation, and absence of autonomic functions below the level of injury. Aka Neurogenic shock 476 |
cerebral Angiography |
X-ray record of blood vessels in the brain after intravenous injection of contrast material. 477 |
Central Nervous System, Developmental Aspects |
477 |
Myelomeningocele |
a congenital defect of the central nervous system in which a sac containing part of the spinal cord and its meninges protrude through a gap in the vertebral column 477 |
Chapter 12- The Central Nervous System
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