Term
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Definition
| special membranes that cover the brain and spinal cord |
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Term
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Definition
Inflammation of the meninges
1) Viral (“aseptic”) meningitis is usually caused by enteroviruses. It is contagious, serious but rarely fatal
2) Bacterial meningitis, is usually caused by Streptococcus pneumoniae or Neisseria meningitidis. It can be serious and result in disability or death |
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Term
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Definition
| The outermost membrane. The dura mater is composed of fibrous connective tissue containing blood vessels and nerves. The dura mater often extends between the lobes of the brain, forming partial partitions. |
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Term
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Definition
| in some areas the dura mater is split in 2 layers enclosing "dural sinuses" (which are filled with blood) |
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Term
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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 vertebra is the site for the injection of spinal anesthetics. |
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Term
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Definition
-The middle membrane.
-The arachnoid mater is a thin, spider-web like membrane lacking blood vessels.
-Beneath it lies subarachnoid space that contains cerebrospinal fluid |
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Term
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Definition
-The innermost membrane.
-The pia mater is thin, and contains nerves and blood vessels.
-It follows the contours of the brain and spinal cord quite closely |
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Term
| Structures in order, from exterior to interior |
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Definition
1. skull bones
2. dura mater
3. arachnoid mater, with arachnoid villi (granulations) projecting into the dural sinuses - cerebrospinal fluid moves through these structures from the subrachnoid space into the blood filling the dural sinuses
4. subarachnoid space - filled with cerebrospinal fluid
5. pia mater
6. surface of the brain - cerebral cortex (gray matter)
7. cerebral white matter. |
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Term
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Definition
-The cerebral hemispheres and brain stem are hollow, and contain four interconnected cavities called ventricles.
-The ventricles are continuous with the central canal of the spinal cord, and contain cerebrospinal fluid. |
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Term
| There are four ventricles: |
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Definition
-right lateral
-left lateral
-third (connects through interventricular foramina)
-fourth (aqueduct of Sylvius) |
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Term
| Interventricular foramina |
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Definition
| connect the third ventricle to the leteral ventricles (right and left) |
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Term
| Aqueduct of Sylvius (cerebral aqueduct) |
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Definition
| connects the fourth ventricle at its anterior end to the third ventricle. |
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Term
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Definition
| forms cerebrospinal fluid |
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Term
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Definition
| Choroid plexuses are found in all ventricles. They consist mainly of capillary networks surrounded by epithelial-like ependymal cells of neuroglia |
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Term
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Definition
1)Cerebrospinal fluid flows from the lateral ventricles through the interventricular foramina into the third ventricle.
2)From the third ventricle it flows into the fourth ventricle through the aqueduct of Sylvius.
3)From the fourth ventricle, cerebrospinal fluid flows into the central canal of the spinal cord and also out of the fourth ventricle into subarachnoid space.
4)Within the subarachnoid space, cerebrospinal fluid bathes the surface of the pia mater covering the brain and spinal cord. |
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Term
| Absorption of Cerebrospinal fluid |
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Definition
| Cerebrospinal fluid is reabsorbed into the blood through herniations of the arachnoid membrane through the dura mater. These herniation are finger-like processes that are called "arachnoid granulation" or "arachnoid villi". They project into the lumina of the dural sinuses, which are filled the venous blood that will be returned to the heart. |
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Term
| Composition of Cerebrospinal Fluid |
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Definition
| The major difference between cerebrospinal fluid and serum is that cerebrospinal fluid has much, much less protein. |
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Term
| Function of CSF: external environment |
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Definition
| Important in maintaining a constant external environment for the neurons and neuroglia of the brain |
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Term
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Definition
| the brain effectively floats in the cerebrospinal fluid, which provides a liquid cushion that protects the brain from impact with the bones of the skull when the head moves. |
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Term
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Definition
| The cerebrospinal fluid serves to removes waste substances from the brain and transfer them to the blood, and may act to distribute some peptide hormones and nutrients. |
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Term
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Definition
| consists of the medulla, pons and midbrain. It is made up of nerve fiber tracts and masses of nerve cells (gray matter) that are called nucleri (NOT the same as the nuclei of individual cells) |
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Term
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Definition
| An enlarged continuation of the spinal cord, and resembles the spinal cord in its organization. It contains all of the ascending and descending tracts that communicate between the spinal cord and various parts of the brain. These tracts constitute the white matter of the medulla. |
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Term
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Definition
| On the ventral side, there are two roughly triangular structures called the pyramids. They carry the fibers of the large motor tracts from the cerebral cortex to the spinal cord - the corticospinal tracts. Fibers in these tracts cross over to opposite sides in the pyramidal decussation. |
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Term
| Medulla: Nucleus gracilis and Nucleus cunneatus |
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Definition
| The dorsal side of the medulla contains two pairs of prominent nuclei, the "nucleus gracilis" and "nucleus cunneatus", which receive sensory fibers from the fasciculus gracilis and fasciculus cuneatus |
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Term
| Reticular formation is found in the medulla |
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Definition
| It is a diffusely-organized system of dispersed gray matter, nuclei and some white fibers extends upwards throughout the rest of the brain stem and up into the diencephalon. The reticular formation is important in maintenance of consciousness and in arousal from sleep. It has other functions including the modulation of pain impulses and spinal reflexes. The term reticular formation is rarely used now, except when we are addressing generalities. |
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Term
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Definition
| The medulla contains a number of reflex centers. The most important are concerned with the heart (the cardiac center), breathing (medullary rythmicity center) and the blood vessels (the vasomotor center). |
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Term
| The medulla contains the nuclei of origin of the following cranial nerves. |
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Definition
1) the cochlear and vestibular branches of VIII (hearing and balance)
2) the glassopharyngeal nerves (IX, swallowing, salivation, taste)
3) The vagus nerve (X, innervates many thoracic and abdominal viscera)
4) The cranial portion of the accessory nerve (XI), which conveys nerve impuleses related to head and shoulder movements (note that there is a spinal portion to this nerve, which originates in the upper five cervical segments of the spinal cord)
5) The hypoglossal nerve (XII), conveys nerve impulses relating to tongue movements. |
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Term
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Definition
| On each lateral surface of the medulla is an oval projection called the olive, which contains the olivary nuclei whose cells have axons that connect with the cerebellum and probably play a role in learning motor tasks (such as riding a bicycle) |
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Term
| Inferior Cerebellar Peduncles |
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Definition
| The medulla is connected to the cerebellum by nerve fiber called the inferior cerebellar peduncles. |
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Term
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Definition
| These nuclei play a vital role in maintaining balance. |
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Term
| Middle cerebellar peduncles |
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Definition
| Large bundles of transvers fiber that transmit information from the cerebrum to the cerebellum |
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Term
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Definition
| a motor nerve for chewing and sensory nerve innervating head and face |
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Definition
| regulates certain eyeball movements |
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Term
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Definition
| conducts impulses related to taste, salivation, facial expression |
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Term
| Pons: the vestibular branches of the vestibulocochlear nerve (VIII) |
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Definition
| are concerned with balance |
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Term
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Definition
| Several nuclei in the pons relay sensory impulses from peripheral nerves to higher brain centers, and other nuclei in the reticular formation of the pons work together with nuclei in the medulla to regulate the rate and depth of breathing. |
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Term
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Definition
| passes through the center of the midbrain. |
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Term
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Definition
| Large fiber tracts pass through the midbrain. Two prominent bundles of fibers on the underside of the midbrain comprise the cerebral peduncles. These the include the corticospinal tracts and sensory fibers that connect with the thalamus in the diencephalon. |
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Term
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Definition
| Two pairs of rounded eminences called the corpora quadrigemina on the surface of the midbrain contain four important nuclei serving as reflex centers for nuclei serving as reflex centers for movements of the eyeballs and head and nexk in response to visual and other stimuli ( the superior colliculi), and movements of the head and trunk in response to auditory stimuli (the inferior colliculi) |
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Term
| substantia nigra, red nucleus, Also, there is the subthalamic nucleus |
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Definition
| Two important colored nuclei are found in the midbrain. There is the black substantia nigra, and the red nucleus. Also, there is the subthalamic nucleus. |
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Term
| The midbrain contains the nuclei for the following cranial nerves |
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Definition
1) The oculomotor nerves (III)
2) Th trochlear nerves (IV) Both these nerves control the extraocular muscles, which produce eye movements |
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Term
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Definition
| Made up of thalamus and hypothalamus |
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Term
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Definition
| Major relay and processing station for all information passing to the cerebral cortex |
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Term
| Thalamus strategic position |
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Definition
| In its strategic position between the midbrain and the cerebral hemispheres, the thalamus fulfills its important function as the major relay and processing station for all information passing to the cerebral cortex. |
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Term
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Definition
| The hupothalamus is located below the thalamus, and is widely interconnected with the rest of the brain. The pituitary gland is connected to the base of the hypothalamus by the pituitary stalk, or infundibulum. The hypothalamus contains many regions and nuclei. There are receptors in the hypothalamus that monitor salt concentration of the body fluids, blood temperature, and even certain hormones concentration |
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Term
| Homeostatic activities: Hypothalamus |
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Definition
| regulation of heart rate and blood pressure, regulation of body temperature, regulation of electrolyte and water balance, control of hunger and body weight, control of visceral movements and glandular secretions. |
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Term
| Functions of Hypothalamus: Control and integration of the autonomic nervous system |
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Definition
| the hypothalamus controls and integrates the autonomic nervous system, which regulates the contraction of smooth muscle, heart contractions, glandular secretions, vasomotor activity. |
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Term
| Functions of Hypothalamus: Association with the pituitary gland |
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Definition
| the hypothalamus has a very close anatomical and physiological association with the pituitary gland, and regulates its hormonal out put. Some hormones are actually synthesized in the hypothalamus itself and transported to the pituitary for release into the blood stream. |
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Term
| Function of Hypothalamus: Output pathway for the limbic system |
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Definition
The hypothalamus is a major output pathway for the limbic system, which is involved in many aspects of emotional behavior and motivations.
a) feeding and feeling of satiety
b) drinking
c) fear, punishment, unease
d) feelings of reward, pleasure and well-being
e) rage
f) sexual drive |
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Term
| Functions of Hypothalamus: Regulation of cyclic activities |
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Definition
affecting sleep wake cycles,
regulating day-and-night rhythmic events (circadian rhythms), including temperature fluctuations keyed day and night, feeding cycles. etc. It may do this in conjunction with the retina |
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Term
| Other Parts of the Diencephalon |
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Definition
| - optic tracts (fibers of the optic nerves, II) - optic chiasma (region where the optic nerve fiber partially decussate, or cross over) -the pituitary gland which is attached to the floor of the diencephalon -the mammillary bodies (part of the hypothalamus) -and the pineal gland which projects from the roof of the diencephalon. secretes the hormone melatonin during the hours of darkeness |
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