Term
| The nervous system has three broad activities |
|
Definition
1) Its sensory systems permit it to sense events occurring inside and outside the body
2) It interprets, integrates and may store this sensory information (in the form of memories), then it decides on an appropriate response, if any.
3) It sends commands to muscles and glands (this is called the motor function of the nervous system) |
|
|
Term
|
Definition
| tracts of nerve fibers that transmit sensory information up the spinal cord to the brain. |
|
|
Term
|
Definition
| of nerve fibers that transmit motor commands down the spinal cord from the brain to the muscles. |
|
|
Term
|
Definition
| the spinal cord is actually a continuation of the brain stem. Its exits the cranial cavity through the foramen magnum at the base of the skull and extends into the vertebral canal of the vertebral column |
|
|
Term
|
Definition
| The brain consists of the brain stem, the cerebellum, the diencephalon and the cerebral hemispheres |
|
|
Term
|
Definition
| the brain and spinal cord lie within the cranial cavity and the vertebral canal, respectively. The brain and spinal cord are covered by three membranes that make up the meninges. |
|
|
Term
|
Definition
The outermost layer (means tough mother)
is composes of fibrous connective tissue containing blood vessels and nerves. It often extends between the lobes of the brain, forming partial partitions. In some areas, it splits into two layers, enclosing the dural sinuses.
Extends from the cranial cavity into the vertebral canal and ends as a blind sac just below the end of the spinal cord. |
|
|
Term
|
Definition
| in the spinal cord, between the dura mater and the wall of the vertebral canal. It is filled with fat, connective tissue and blood vessels. The epidural space inferior to the second lumbar is the site for the injection of anesthetics, such as a saddle block in childbirth |
|
|
Term
|
Definition
| Is the middle layer of the meninges. it is a thin, spider’s web-like membrane lacking blood vessels. Beneath it lies the subarachnoid space that contains cerebrospinal fluid |
|
|
Term
|
Definition
| The innermost layer of the meninges. It is thin, and contains nerves and blood vessels. It follows the contours of the brain and spinal cord quite closely. |
|
|
Term
|
Definition
| A condition known as as meningitis can be caused by bacteria or viruses. The meninges (usually the arachnoid mater or pia mater) become inflamed. If not treated promptly, death, mental retardation, paralysis, or loss of sight and hearing can occur. |
|
|
Term
|
Definition
| A severe blow to the head can rupture meningeal blood vessels. If the blood realeased from the rupture pools beneath the dura mater, a subdural hematoma occurs. Because the blood has no place to go, its accumulation compresses the softer underlying brain tissue. If the increase in pressure in not relieved, brain damage or death can occur. |
|
|
Term
|
Definition
| The cerebral hemispheres and brain stem are hollow, and contain four inter connected cavities called ventricles. The ventricles are continuous with central canal of the spinal cord, and contain cerebrospinal flui. |
|
|
Term
|
Definition
1) The first is the right lateral ventricle
2) the secont is the left lateral ventricle
3) The third ventricle is small. It connects with lateral ventricles through interventricular foramina.
4) The fourth ventricle is connected at its anterior end to the third ventricle via the aqueduct of Sylvius (cerebral aqueduct), and is continuous with the central canal of the spinal cord at its posterior end. The fourth ventricle has openings in its roof that permit cerebrospinal fluid to pass into the subarachnoid space. |
|
|
Term
|
Definition
| Mosst of the cerebrospinal fluid (about 140 ml) is found in the four ventricles where it is formed as plasma ultrafiltrate from networks of capillaries called the choroid plexuses. The choroid plexus consists mainly of capillary networks surrounded by epithelial-like ependymal cells of the neuroglia. |
|
|
Term
|
Definition
| Cerebrospinal fluid flows from the lateral ventricles through the interventricular foramina into the third ventricle. From the third ventricle it flows into the fourth ventricle through the central canal of the spinal cord and also out of the fourth ventricle into the subarachnoid space. |
|
|
Term
| Absorption of Cerebrospinal |
|
Definition
| Cerebrospinal fluid is returned to the blood via arachnoid granulation (=arachnoid villi). these are finger-like processes that project into the lumen of the dural sinuses, which are filled the venous blood. |
|
|
Term
| Function of Cerebrospinal fluid: |
|
Definition
| Because it is in equilibrium with extracellular fluid of the brain, the cerebrospinal fluid is important in maintaing a constant external environment for the neurons and neuroglia. The cerebrospinal fluid provides a mechanical cushio that protects the brain from impact with the bones of the skull when the head moves. By it buoyant action, the cerebrospinal fluid allows the to float, reducing its effective weight from 1,400 grams in air to less than 50 grams in the head. Finally, the cerebrospinal fluid serves to remove wast substanes from the brain and transfer them to the blood, and may act to distribute some peptide hormones and nutrients. |
|
|
Term
|
Definition
| The brain stem consists of the medulla, pons, and midbrain. The brain stem contains many nerve fiber tracts and masses of gray matter called nuclei. |
|
|
Term
|
Definition
| consists of layer of white matter that surrounds a mass of gray matter. The white matter of the medulla consists of ascending and descending tracts that serve as the communication link between the spinal cord and the brain. |
|
|
Term
|
Definition
| On the lateral surfaces of the medulla are ovoal projection called olives. The olivary nuclei connect with the cerebellum. Other nuclei with the medulla function as control center of many vital processes |
|
|
Term
| Medulla: cardiac center, vasomotor center, respiratory center, |
|
Definition
| the cardiac center which regulates the heart rate, the vasomotor center, which causes the dilation or th constriction of blood vessels, and the respiratory center, which regulates rate, rhythm, and depth of breathing. Other nuclei are involved in certain nonvital reflexes such as coughing, sneezing, swallowing, and vomiting. |
|
|
Term
|
Definition
| appears as a bulge on the underside of the brain stem and separates the midbrain the medulla. Through it run the nerve fibers of the middle cerebellar pedunles. Also present are the nuclei for several of the cranial nerves that relay sensory impulses from peripheral nerves to higher brain centers, and nuclei that are involved in the regulation of the rate and depth of breathing. |
|
|
Term
| The Brain Stem:The midbrain |
|
Definition
| The mid brain in located just above the pons. It contains many myelinated nerve fibers that connect the brain stem and spinal cord with higher parts of the brain. The cerebral peduncles are two prominent bundles of nerve fibers on the underside of the midbrain. They contain corticospinal tracts and the certain sensory fibers. On the upper surface of the midbrain are four rounded eminences (two on each side of the midline) collectively called the corpora quadrigemina. The superior coliculi contain nuclei responsible for movements of the wyes and of the head and neck in response to visual stimuli. The inferior colliculi contain nuclei responsible for movement of the head and neck in response to auditory stimuli. |
|
|
Term
|
Definition
| is important for coordinated smooth movement and posture. Like the cerebrum, it consists of two hemispheres and is made up of an outer layer of gray mater, calle dthe cerebellar cortex, and an inner layer of white matter. like the cerebrum, there are deep masses of gray matter called fastigial, interposed, and dentate nuclei |
|
|
Term
| Inferior, middle and superior cerebellar peduncles |
|
Definition
| are nerve tracts that permit communication between the cerebellum and other parts of the brain. |
|
|
Term
|
Definition
| involved in the execution of smooth, coordinated voluntary movements. It regulates the rate, range, force, direction, and timing of movements by controling the activities of agonist, antagonist, and synergist muscles. |
|
|
Term
|
Definition
| is associated with optic tracts, optic chiasm, infundibulum, pituitary gland, mamillary bodies, and the pineal gland. However, the two major structures are the thalamus and hypothalamus. |
|
|
Term
|
Definition
| is the major relay and processing station for all information passing to cerebral cortex. The information may be sensory in nature; it may be from the cerebellum and basal ganglia |
|
|
Term
|
Definition
| contains many nuclei, as well as neuronal receptor cells that monitor the osmotic pressure of the body fluids and the body temperature. The hypothalamus is important in homeostasis, such as maintaining the body’s water balance.The hypothalamus also controls the autonomic nervous system, directs the release of hormones from the pituitary gland, and is involved in many of the emotional and motivational behaviors associated with the limbic system. |
|
|
Term
|
Definition
| The cerebrum develops from the anterior portion of the forebrain, and consists of left and right cerebral hemispheres. the surface layer of the cerebrum is composed of gray matter (nuerons), and is called the cerebral cortex. Other areas of gray matter (neurons) are found in mass located deep within the crebral hemispheres. They make up the cerebral basal gaglia: the putamen, caudate nucleus, and the globus pallidus |
|
|
Term
|
Definition
| The cerebral cortex overlies the cerebral white matter, composed of billions of myelinated nerve fibers that conduct nerve impulses into and out of the cerebral cortex, and also between different areas of the cerebral cortex. The corpus callosum is a huge band of these fibers that connects the two cerebral hemispheres |
|
|
Term
|
Definition
| During human embryonic develompment, the surface of the cerebral cortex increases enormously, in order to accommodate the increasing numbers os neurons, Consequently, it becomes highly convoluted and folded. The fold are called gyri. Gyri are separated from each other by grooves called sulci. Very deep grooves are called fissures |
|
|
Term
Lonitudinal fissure
Lateral fissure
Falx cerbri |
|
Definition
| The longitudinal fissure separates the right and left cerebral hemispheres. The lateral fissure sperates the temporal from the frontal lobe. An extension of the dura mate called the falx cerebri down into this fissure |
|
|
Term
|
Definition
| contains the precentral gyrus, which represents the primary motor |
|
|
Term
|
Definition
| separated from the frontal lobe by the central groove or sulcus. The postcentral gyrus represents the somatosensory area. |
|
|
Term
|
Definition
| separated from the frontal lobe by the lateral fissure |
|
|
Term
|
Definition
| Lies deep within the lateral fissure under parietal, frontal and temporal lobes. It cannot be seen in an external view of the brain unless the temporal lobe is pulled out and away from the rest of the brain. It is delineated by circular sulcus |
|
|
Term
| Cerebral Cortex - Functional Areas |
|
Definition
| The cerebral cortex has areas have different functions. Large regions of the cerebral cortex are committed to movement (the motor areas) and sensation (the sensory ares). Association areas are involved in out highest intellectual activities and often provide the link between sensation and action. |
|
|
Term
|
Definition
| The motor area contains primary and higher-order areas. primary motor ares execute voluntary movements, while hier-order motor areas are involved in the planning of movements. The major primary motor area is located in the precentral gyrus of the frontal lobe. Different parts of this area control movements in different parts of the body, which are roughly mapped on the surface of the cerebral cortex. |
|
|
Term
| The motor speech area (Broca’s area) |
|
Definition
| is in the frontal lobe (usually on the left side). Neurons in this region control the complex movements of mouth, tongue, larynx, and breathing that make speech possible. |
|
|
Term
|
Definition
| receive information from sensory receptors, while higher order sensory area process more complex aspects of the sensation, and analyze and integrate information that they receive from the primary sensory areas. |
|
|
Term
| The primary somatic sensory area |
|
Definition
| is located in the parietal lobe, in the postcentral gyrus. The body surface is mapped roughly on the surface of this gyrus. Damage to this area can lead to loss of fine localization of stimuli, loss of the ability to judge weights, shapes, and textures. |
|
|
Term
|
Definition
| is located on the medial surface of the occipital lobe, and the primary auditory area is located in the superior part of the temporal lobe near the lateral fissure. Primary areas for taste and smell are found in the parietal and temporal lobes, respectively. |
|
|
Term
|
Definition
| Association areas intergrate diverse information, often for purposeful action. In consequence they often provide the link between sansation and action. Association areas are found in region of the parietal, temporal, occipital and frontal lobes. One part of the parietal lobe is known to be important in our awareness of our bodies and where all the parts are located in relation to our surroundings |
|
|
Term
|
Definition
| The prefrontal association area is often considered part of the limbic system. The limbic system is a loose term for a group of gyri and associated structures (not necessarily cortical) that roughly encircles the corpus callosum and the diencephalon. In turn, the limbic system is encircled by the temporal, occipital, parietal, and frontal lobes. |
|
|
Term
| The limbic System Functions |
|
Definition
| Functions of the limbic system include self-preservation (feeding, fight, flight), reproduction (mating, care for offspring), emotions, goal-related behaviour; motivation, sensation of reward, pleasure and punishment, and memory. The limbic system provides a link between the conscious function of the cerebral cortex and the autonomic nervous system and endocrine system via the hypothalamus. |
|
|
Term
|
Definition
| The cerebral basal ganglia are masses of gray matter lying deep with the cerebral hemispheres. They are the caudate nucleus, the putamen, and the globus pallidus. Two midbrain stuctures are also included with the basal ganglia: the substantia nigra and the subthalamic nucleus. Neurons in the basal ganglia receive major input from the cerebral cortex. The output of the basal ganlia goes xia tha thalamas back to the cerebral cortex. One of the best understood function of the basal ganglia is related to voluntary movements. |
|
|
Term
| Basal Ganglia Clinical Application |
|
Definition
| Different parts of the basal ganglia facilitate movement, while other parts suppress them. This becomes very apparent when studying two well-known disorders of the basal ganglia - Parkinson’s disease and Huntington’s chorea. |
|
|
Term
| procedural memory or “knowing how” memory |
|
Definition
| is concerned with the learning of motor skills. Knowing how to type, play the piano, or ride a bicycle are examples. Some procedural memories appear to involve the cerebellum. |
|
|
Term
| Immediate or working memory |
|
Definition
working memory is a store that holds important information in the mind for brief periods of time. Working memory is temporary and its capacity seems to be limited. It seems to be associated with “inner speech,” helping us to express our ideas in a meaningful way.
Working memory seems to involve many brain areas, but particularly the prefrontal cortex. |
|
|
Term
| Declarative memory or “Knowing that” memory |
|
Definition
| The king of memory that most people think of as memory holds the names of things and people, occurrences, events, and other pieces of facts for periods ranging for days to a lifetime. |
|
|
