Ch.13 - Brain and Cranial Nerves
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185 terms
Terms | Definitions |
|---|---|
 Neural Plate | region of the dorsal surface of the embryo that is transformed into the neural tube and neural crest. A flat plate of ectodermal tissue, on the dorsal surface of the embryo. |
| Notochord | Small rod of tissue lying ventral to the neural tube. the underlying rod-shaped tissue. |
| Neural folds | The lateral sides of the neural plate become elevated as waves. |
| Neural crest | The crest of each fold. Edge of the neural plate as it rises to meet at the midline to form the neural tube. |
| Neural groove | The center of the neural plate. |
| neural tube | Tube formed from the neuroectoderm by the closure of the neural groove; develops into the spinal cord and brain. |
| Neural crest cells | are cells that separate from the neural crests and give rise to sensory, autonomic, and the enteric neurons of the peripheral nervous system. Cells derived from the crests of the forming neural tube in the embryo;together with the mesoderm, they form the mesenchyme of the embryo; they give rise to part of the skull, the teeth, melanocytes, sensory neurons, and autonomic neurons. |
| forebrain | (or Prosencephalon), divides into the telencephalon and the diencephalon. |
| midbrain | (or mesencephalon), remains a single structure as in the embryo |
| hindbrain | (or rhombencephalon), divides into the metencephalon and the myelencephalon. |
| Telencephalon | which becomes the cerebrum. Anterior division of the embryonic brain from which the cerebral hemispheres develop. |
| diencephalon | second portion of the embryonic brain; in the inferior core of the adult cerebrum. |
| metencephalon | Second most posterior division of the embryonic brain; becomes the pons and cerebellum in the adult. |
| myelencephalon | which becomes the medulla oblongata. Most caudal portion of the embryonic brain. |
| mesencephalon | Midbrain in both the embryo and adult; consists of the cerebral peduncle and the corpora quadrigemini. |
| Ventricles | in the brain, a fluid filled cavity. |
| brainstem | made up of the medulla oblongata, pons, and the midbrain. |
| Medulla Oblongata | is the most inferior part of the brainstem and is continuous inferiorly with the spinal cord. |
| nuclei | clusters of gray matter composed mostly of neuron cell bodies. |
| Pyramids | are 2 prominent enlargements on the anterior surface of the medulla oblongata. They are descending tracts involved in conscious control of skeletal muscles. |
| decussate | To cross to the opposite side. |
| Olives | are 2 rounded, oval structures, protrude from the anterior surface of the medulla oblongata just lateral to the superior ends of the pyramids. They are nuclei involved in functions such as balance, coordination, and modulation of sound from the inner ear. |
| Pons | The part of the brainstem just superior to the medulla oblongata. |
| Pontine nuclei | located in the anterior portion of the pons. |
| Midbrain | or mesencephalon, is the smallest region of the brainstem, most superior. |
| tectum | roof of the midbrain; consists of 4 nuclei that form mounds on the dorsal surface. |
| Corpora quadrigemina | 4 nuclei that form mounds on the dorsal surface collectively. (bodies, 4 twins) |
| Colliculus | is each mound |
| Superior colliculi | the 2 superior mounds. One of 2 rounded eminences of the midbrain; aids in coordination of eye movements. |
| inferior colliculi | the 2 inferior mounds. One of 2 rounded eminences of the midbrain; involved with hearing. |
| Tegmentum | of the midbrain largely consists of ascending tracts. Floor of the midbrain. |
| red nuclei | aid in unconscious regulation and coordination of motor activities. |
| Cerebral peduncles | constitute the portion of the midbrain ventral to the tegmentum (the foot of a column). Consist primarily of descending tracts. |
| Substantia nigra | (black substance), is a nuclear mass between the tegmentum and cerebral peduncles containing cytoplasmic melanin granules that give it a dark gray or black color. |
| reticular formation | is a diffuse system consisting of several loosely packed nuclei scattered throughout the length of the brainstem. |
| Cerebellum | (little brain), is attached to the brainstem posterior to the pons. Separate portion of the brain attached to the brainstem at the pons; important in maintaining muscle tone, balance, and coordination of movement. |
| Superior, middle, and inferior cerebellar peduncles | which connect the cerebellum to the midbrain, pons, and medulla oblongata, respectively. |
| folia | ridges in the cerebellar cortex. |
| arbor vitae | (tree of life), The white matter of the medulla resembles a branching tree. |
| nuclei | of the cerebellum are located in the deep inferior center of the white matter. |
| Purkinje cells | are the largest and probably most interesting cells in the CNS. are inhibitory neurons, and are the only cerebellar cortex neurons that send axons to the cerebellar nuclei. |
| flocculonodular lobe | a small inferior part of the cerebellum. The simplest part of the cerebellum, helps control balance and eye movements. |
| Vermis | (worm-shaped), the narrow central part of the cerebellum. is involved in controlling posture, locomotion, and fine motor coordination, thereby producing smooth, flowing movements. |
| lateral hemispheres | function in concert with the frontal lobes of the cerebral cortex in planning, practicing, and learning complex movements. |
| Primary fissure | divides the lateral hemispheres into anterior and posterior lobes |
| Anterior lobe | is at the front of the brain near the frontal lobe |
| Posterior lobe | is at the back of the brain near the occipital lobe |
| lobules | is subdivided by the lobes into this. |
| diencephalon | is the part of the brain between the brainstem and the cerebrum. It consists of the thalamus and the hypothalamus. |
| Thalamus | is by far the largest part of the diencephalon, constituting about 4/5 of its weight. |
| interthalamic adhesion | (or intermediate mass),A cluster of nuclei shaped somewhat like a yo-yo, with 2 large, lateral portions connected in the center by a small stalk. |
| Sensory relay center | is what the thalamus is called. |
| medial geniculate nucleus | Axons carrying auditory information synapse in this area. |
| lateral geniculate nucleus | Nucleus of the thalamus where fibers from the optic tract terminate. |
| ventral posterior nucleus | is the somato-sensory relay nucleus in thalamus of the brain. Most other sensory impulses synapse in this area. |
| dorsal tier | Axons originating in the ventral posterior nucleus project to this area of nuclei, which register pain |
| ventral anterior nucleus | are involved with motor functions, communicating among the basal nuclei, the cerebellum, and the motor cortex |
| ventral lateral nucleus | are involved with motor functions, communicating among the basal nuclei, the cerebellum, and the motor cortex |
| Anterior and medial nuclei | are connected to the limbic system and to the prefrontal cortex. These nuclei are involved in mood modification. |
| lateral dorsal nuclei | are connected to other thalamic nuclei and to the cerebral cortex, are involved in regulating emotions. |
| lateral posterior nuclei and pulvinar | have connections to other thalamic nuclei and are involved in sensory integration. |
| Pulvinar | cushion- shaped |
| Subthalamus | is a small area immediately inferior to the thalamus. |
| subthalamic nuclei | A small portion of the red nucleus and the substantia nigra of the midbrain extend into this area. is a small lens-shaped nucleus in the brain where it is from the functional point of view part of the basal ganglia system. Anatomically, it is the major part of subthalamus. As suggested by its name, the subthalamic nucleus is located ventral to the thalamus. It is also dorsal to the substantia nigra and medial to the internal capsule |
| epithalamus | is a small area superior and posterior to the thalamus. it consists of the habenula and the pineal gland. |
| habenula | is influenced by the sense of smell and is involved in emotional and visceral responses to odors. |
| Pineal gland | (or pineal body), is shaped somewhat like a pinecone, from which the name pineal is dervied. It plays a role in controlling the onset of puberty, it also influences the sleep-wake cycle. |
| hypothalamus | is the most inferior portion of the diencephalon. |
| mammillary glands | appear as bulges on the ventral surface of the diencephalon. They are involved in olfactory reflexes and emotional responses to odors. Also involved in memory. |
| infundibulum | A funnel-shaped stalk, extends from the floor of the hypothalamus and connects it toe the pituitary gland. |
| Pituitary gland | Endocrine gland attached to the hypothalamus by the infundibulum; also called the hypophysis. |
| longitudinal fissure | divides the cerebrum into right and left hemispheres. |
| gyri | (gyrus), the most conspicuous features on the surface of each hemisphere are numerous folds, which greatly increase the surface area of the cortex. |
| sulci | The grooves between the gyri |
| central sulcus | which extends across the lateral surface of the cerebrum from superior to inferior, is located about midway along the length of the brain. |
| Precentral gyrus | is anterior to the central sulcus, which is the primary motor cortex. |
| Primary motor cortex | is a brain region that in humans is located in the posterior portion of the frontal lobe. It works in association with pre-motor areas to plan and execute movements. |
| Postcentral gyrus | Posterior to the central sulcus, which is the primary somatic sensory cortex. |
| Primary Somatic sensory cortex | The region of the cerebral cortex receiving the somatic sensory data from the ventrobasal nucleus of the thalamus. |
| Frontal lobe | is the region in the front of the brain. It is important in voluntary motor function, motivations, aggression, the sense of smell, and mood. It is the region involved in personality and decision making. |
| Parietal lobe | is the region at the back of the top of the brain. It is the major center for receiving and evaluating most sensory information, except for smell, hearing, and vision. |
| occipital lobe | is the region at the bottom and back of the brain. it functions in receiving and integrating visual input and is not distinctly separate from the other lobes. |
| Temporal lobe | is the region at the sides, at your temples. It receives and evaluates input for smell and hearing and plays an important role in memory. |
| Psychic cortex | the temporal lobe's anterior and inferior portions are this area. is associated with such brain functions as abstract thought and judgement. |
| lateral fissure | separates the temporal lobe and the cerebrum. |
| insula | is deep within the lateral fissure, also referred to as a 5th lobe. |
| Cerebral cortex | The gray matter on the outer surface of the cerebrum. |
| Cerebral medulla | The white matter of the brain between the cortex and the nuclei. |
| Association fibers | connect areas of the cerebral cortex within the same hemisphere |
| Commissural fibers | connect one cerebral hemisphere to the other. |
| Corpus callosum | largest commissure of the brain, connecting the cerebral hemispheres. |
| Projection fibers | connect the cerebrum to other parts of the brain and spinal cord. Form the internal capsule |
| Internal capsule | A layer of white matter separating the caudate nucleus and thalamus from the lentiform nucleus and serving as the major route by which the cerebral cortex is connected with the brainstem and the spinal cord. |
| basal nuclei | are a group of functionally related nuclei located bilaterally in the inferior cerebrum, diencephalon, and midbrain. These nuclei are in charge of controlling motor functions. |
| Corpus striatum | The nuclei in the cerebrum are collectively called this and include the caudate nucleus and the lentiform nucleus. Caudate nucleus, putamen, and globus pallidus; so-named because of the striations caused by intermixing of gray and white matter, which result from the number of tracts crossing the anterior portion of the corpus striatum. |
| Caudate nucleus | having a tail. The one of the four basal ganglia in each cerebral hemisphere that comprises a mass of gray matter in the corpus striatum, forms part of the floor of the lateral ventricle, and is separated from the lentiform nucleus by the internal capsule called also caudate |
| lentiform nucleus | lens-shaped, is divided into a lateral putamen and the medial globus passidus the one of the four basal ganglia in each cerebral hemisphere that comprises the larger and external nucleus of the corpus striatum including the outer reddish putamen and two inner pale yellow globular masses constituting the globus pallidus called also lenticular nucleus. |
| lateral Putamen | The outer, larger, and darker gray of the three portions into which the lentiform nucleus of the brain is divided. |
| medial globus pallidus | is also known as paleostriatum, is a sub-cortical structure of the brain. Topographically, it is part of the telencephalon, but retains close functional ties with the subthalamus - both of which are part of the extrapyramidal motor system.[1] The globus pallidus is a major component of the basal ganglia core along with the striatum and its direct target, the substantia nigra. The latter are made up of similar neuronal elements, have similar afferents from the dorsal striatum and have a similar synaptology; neither receive cortical afferents. |
| subthalamic nucleus | an oval mass of gray matter that is located in the caudal part of the subthalamus along the medial part of the internal capsule, receives fibers from the lateral part of the globus pallidus, sends fibers through the internal capsule to the medial part of the globus pallidus, and when affected with lesions is associated with hemiballismus of the contralateral side of the body |
| substantia nigra | black nuclear mass in the midbrain; involved in coordinating movement and maintaining muscle tone. |
| limbic system | Parts of the cerebrum and diencephalon are grouped together under this system. It plays a central role in basic survival functions, such as memory, reproduction, and nutrition. It is also involved in interpreting sensory input and emotions in general. |
| cingulate gyrus | to surround; located along the inner surface of the longitudinal fissure just above the corpus callusum. |
| Parahippocampal gyrus | is located on the medial side of the temporal lobe. |
| dentate gyrus | a narrow strip of cortex associated with the hippocampal sulcus that continues forward to the uncus. |
| hippocampus | an enfolding of cerebral cortex into the lateral fissure of a cerebral hemisphere, having the shape in cross section of a sea horse. |
| amygdala | Nucleus in the temporal lobe of the brain, amygdaloid nucleus; also called amydaloid nuclear complex. |
| olfactory cortex | Termination of the olfactory tract in the cerebral cortex within the lateral fissure of the cerebrum. |
| fornix | which connects the hippocampus to the thalamus and mammillary bodies. |
| Meninges | connective tissue membranes that surround and protect the brain and spinal cord. |
| dura mater | is the most superficial and thickest membrane of the meninges. |
| epidural space | This is a true space between the walls of the vertebral canal and the dura mater. |
| Periosteal dura | The outer layer, is the inner periosteum of the cranial bones. |
| meningeal dura | The inner layer, is continuous with the dura of the spinal cord. This is separated from the periosteal dura in several regions to form structures called folds and dural venous sinuses. |
| dural folds | are tough connective tissue partitions that extend into the major brain fissures. |
| falx cerebri | is the largest of the dural folds, which lies in the longitudinal fissure and is anchored anteriorly to the crista galli of the ethmoid bone. (sickle-shaped) |
| tentorium cerebelli | is oriented horizontally between the cerebrum and the cerebellum. |
| falx cerebelli | lies between the 2 cerebellar hemispheres. |
| dural venous sinuses | are spaces that form where the 2 layers of the dura mater are separated from each other. |
| Superior sagittal sinus | The largest of the sinuses, forms between the falx cerebri and the periosteal dura and runs along the median plane. |
| Arachnoid mater | The 2nd meningeal membrane is the very thin, wispy; spiderlike, as in cobwebs. |
| subdural space | The space between the dura matter and the arachnoid mater, it contains only a very small amount of serous fluid. |
| Pia mater | The 3rd meningeal membrane, the innermost layer, is bound very tightly to the surface of the brain. |
| subarachnoid space | The space between the arachnoid matter and the pia matter, which contains weblike strands of arachnoid mater and the blood vessels supplying the brain. |
| ependymal cells | type of neuronal support cell (neuroglia) that forms the epithelial lining of the ventricles (cavities) in the brain and the central canal of the spinal cord |
| lateral ventricle | Each cerebral hemisphere contains a relatively large cavity, they are separated from each other by thin septa pellucida. A horseshoe-shaped cavity conforming to the general shape of each cerebral hemisphere and communicating with the third ventricle. |
| Septa pellucida | (Septum pellucidum; translucent walls), which lie in the midline just inferior to the corpus callosum and are usually fused with each other. |
| Third ventricle | A smaller midline cavity, is located in the center of the diencephalon between the 2 halves of the thalamus. |
| Open brain injuries | when some of the cranial cavity contents are exposed to the outside. |
| Closed brain injuries | when the cranial cavity remains intact. |
| Coup injury | occurring at the site of impact. |
| Contrecoup injury | occurring on the opposite side of the brain from the impact as a result of the brain moving within the skull. |
| Concussion | characterized by immediate, but transient, impairment of neural function, such as loss of consciousness or blurred vision. |
| Diffuse brain injury | involves damage to many small vessels and nerves, especially around the brainstem. Usually results from shaking; as in shaking a child or when a person is thrown out of a car accident. |
| Contusions | (bruisings), caused by direct impact to the brain, or hemorrhages in or around the brain. are usually superficial and involve only the gyri. |
| (extradural, or epidural) | hemorrhagic brain injury is characterized by bleeding outside the dura. |
| subdural | between the dura and the brain |
| intracerebral | within the dura |
| hematoma | an accumulation of blood. |
| Extradural hemorrhages | or epidural hematomas, usually affect the middle cranial fossa and involve a tear in the middle meningeal artery(85%) or in the middle meningeal vein or dural sinus (15%). |
| Subdural hematomas | most commonly involve tears in the cortical veins or dural venous sinuses, occur in the superior portion of the cranial cavity, and appear within hours of the head injury. |
| Chronic subdural hematomas | involve slow bleeding over an extended period of time (weeks to months), are common in elderly people and in those who abuse alcohol. |
| Intracerebral hematomas | occur in about 2-3% of major head injuries and are often associated with contusions. They involve damage to small vessels within the brain itself and are most common in the frontal and temporal lobes. |
| interventricular foramina | are channels that connect the paired lateral ventricles with the third ventricle at the midline of the brain. |
| 4th ventricle | is in the inferior part of the pontine region and the superior region of the medulla oblongata at the base of the cerebellum. |
| cerebral aqueduct | a narrow canal, which passes through the midbrain. A short canal in the cerebrum, lined with ependymal cells and leading downward through the mesencephalon from the third to the fourth ventricle. Also called sylvian aqueduct . |
| Cerebrospinal fluid | (CSF), is a clear fluid similar to blood serum with most of the proteins removed. |
| Choroid Plexuses | These specialized ependymal cells, their support tissue, and the associated blood vessels are collectively called this. |
| median aperture | (foramen of Magendie), which opens through the roof of the 4th ventricle. |
| lateral apertures | (foramina of Luschka), which opens through the walls, allow the CSF to pass from the 4th ventricle to the subarachnoid space. |
| Arachnoid granulations | masses of arachnoid tissue, penetrate into the dural venous sinuses, especially the superior sagittal sinus. |
| internal hydrocephalus | or noncommunicating hydrocephalus, if the apertures of the 4th ventricle or the cerebral aqueduct are blocked, CSF can accumulate within the ventricles, resulting in this condition. |
| external hydrocephalus | or communicating hydrocephalus, if CSF accumulates in the subarachnoid space this condition results. |
| internal carotid arteries | which ascend to the head along the anterior-lateral part of the neck. |
| vertebral arteries | which ascend along the posterior part of the neck, through the transverse foramina of the cervical vertebrae. |
| basilar artery | which lies on the ventral surface of the pons. |
| cerebral arterial circle | (circle of willis), branches from this circle and from the basilar artery supply blood to the brain. |
| anterior cerebral artery | supplies the medial portion of the parietal and frontal lobes |
| middle cerebral artery | supplies most of the lateral surface of each cerebral hemisphere. |
| Posterior cerebral artery | supplies the occipital lobe and the medial surface of the temporal lobe. |
| blood-brain barrier | The epithelial cells with their tight junctions form this, which regulates the movement of materials from the blood into the brain. |
| Sensory | functions include the special senses, such as vision, and the more general senses, such as touch and pain. |
| Somatic motor | functions involve the control of skeletal muscles through motor neurons. |
| Proprioception | informs the brain about the position of various body parts, including joints and muscles. |
| Parasympathetic | function involves the regulation of glands, smooth muscles, and cardiac muscle. |
| Olfactory (1) nerve | exclusively sensory and are involved in the special senses of smell and vision respecively |
| Optic (II) nerve | exclusively sensory and are involved in the special senses of smell and vision respecively |
| Oculomotor nerve (III) | innervates 4 of the 6 muscles that move the eyeball (the superior, inferior, ad medial rectus muscles and the inferior oblique muscle) and the levator palebrae superioris muscle, which rises the superior eyelid. |
| trochlear nerve (IV) | is a somatic motor nerve that innervates one of the 6 eye muscles responsible for moving the eyeball (superior oblique) |
| trigeminal nerve (V) | has somatic motor, proprioceptive, and cutaneous sensory functions. |
| sensory cutaneous innervation | refers to the area of the skin which is supplied by a specific nerve, that is, by a cutaneous nerve. |
| Trigeminal | meana 3 twins. |
| ophthalamic (V1) | one of the branches of the trigeminal nerve, arise directly from the trigeminal ganglion, which serves the same function as the dorsal root ganglia of the spinal nerves. |
| maxillary (V2) | one of the branches of the trigeminal nerve, arise directly from the trigeminal ganglion, which serves the same function as the dorsal root ganglia of the spinal nerves |
| mandibular (V3) | one of the branches of the trigeminal nerve, arise directly from the trigeminal ganglion, which serves the same function as the dorsal root ganglia of the spinal nerves. |
| Alveolar nerves | The various nerves innervating the teeth. |
| Superior alveolar nerves | to the maxillary teeth are derived from the maxillary branch of the trigeminal nerve. |
| inferior alveolar nerves | to the mandibular teeth are derived from the mandibular branch of the trigeminal nerve. |
| abducens nerve (VI) | is a somatic motor nerve that innervates one the 6 muscles responsible for moving the eyeball (lateral rectus). |
| facial nerve (VII) | is somatic motor, sensory, and parasympathetic in function. It controls all the muscles of facial expression, a small muscle in the middle ear, and 2 hyoid muscles. |
| Vestibulocochlear nerve (VIII) | like the olfactory and optic nerves, is exclusively sensory and transmits action potentials from the inner ear responsible for special senses of hearing and balance. |
| glossopharyngeal nerve (IX) | like the facial nerve, is somatic motor, sensory, and parasympathetic in function and has both sensory and parasympathetic ganglia. |
| Vagus nerve (X) | like the facial and glossepharyngeal nerves, is somatic motor, sensory, and parasympathetic in function and has both sensory and parasympathetic ganglia. |
| Accessory nerve (XI) | is a somatic motor nerve that has both cranial and spinal roots. The cranial root joins the vagus nerve (hence the name accessory) and participates in its function. |
| hypoglossal nerve (XII) | is a somatic motor nerve that arises from the ventral surface of the medulla oblongata. it supplies the intrinisic tongue muscles, 3 of the 4 extrinsic tongue muscles, and the thyrohyoid and the geniohyoid muscles. |
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