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Nervous System
True/False: Overview of the nervous system
True/False | Answer |
---|---|
The 4th ventricle lies anterior to the cerebellum and posterior to the pons. | True, the 4th ventricle lies anterior to the cerebellum and posterior to the pons. |
The calcarine sulcus is found in the frontal lobe. | False, the calcarine sulcus is found in the occipital lobe. |
The corpus callosum connects the two cerebral hemispheres. | True, the two cerebral hemispheres are connected by the corpus callosum. |
The amygdala is a frontal lobe structure. | False, the amygdala is a temporal lobe structure. |
The vermis of the cerebellum is a midline structure. | True, the vermis of the cerebellum is a midline structure. |
The vertebral arteries supply the medulla, pons and cerebellum. | True, the vertebral arteries join to form the basilar artery. Branches of both supply the medulla, pons and cerebellum. |
The anterior cerebral artery supplies the medial surface of the brain. | True, the anterior cerebral arteries project forwards on either side of the longitudinal fissure, supplying the medial surfaces of each cerebral hemisphere. |
The middle cerebral artery supplies the majority of the surface of the brain. | True, the middle cerebral artery also supplies parts of the basal ganglia. |
The occipital and temporal lobes are supplied by the posterior cerebral arteries. | True, the occipital and temporal lobes are supplied by the posterior cerebral arteries. |
The circle of Willis forms and anastomosis between the basilar artery and the internal carotid arteries. | True, the anterior and posterior communicating arteries connect the basilar artery to the internal carotid arteries, forming the circle of Willis. |
Deoxygenated blood drains from the cortex into the superior sagittal sinus. | True, the superior sagittal sinus runs in the longitudinal fissure, itself draining into the transverse sinus. |
Venous blood from the cerebellum drains into the cavernous sinus. | False, venous blood from olfactory, optic and certain facial structures drains into the cavernous sinus. |
Cranial nerve II passes through the cavernous sinus. | False, cranial nerves III, IV, VI and the ophthalmic and maxillary divisions of V are found in the cavernous sinus - not cranial nerve II. |
Cavernous sinus thrombosis can cause a palsy of cranial nerve III. | True, infection in the face or orbit can spread causing cavernous sinus thrombosis. This causes a red swollen eye and palsies of the nerves running through the sinus. |
Together, the straight and transverse sinuses drain into the internal jugular vein. | True, together the straight and transverse sinuses drain into the internal jugular vein. |
Development of the nervous system begins at 12 weeks gestation. | False, development of the nervous system begins early, at 3 weeks gestation. |
The entire nervous system is derived from mesoderm. | False, the nervous system and skin are derived from ectoderm. |
Ectoderm becomes muscles, connective tissues and blood vessels. | False, mesoderm becomes muscles, connective tissues and blood vessels. |
The neural plate thickens and folds to form the neural groove at 22 weeks gestation. | True, the neural plate thickens and folds to form the neural groove at 22 weeks gestation. |
Failure of the cranial neuropore to close results in anencephaly. | True, in anencephaly, the embryo continues to develop but the brain does not. This usually results in spontaneous abortion. |
Oligodendrocytes provide myelin insulation to neurons in the peripheral nervous system. | False, oligodendrocytes myelinate neurons in the central nervous system. Schwann cells myelinate neurons in the peripheral nervous system. |
One oligodendrocyte can myelinate just one axon. | False, each oligodendrocyte can myelinate many axons. |
Astrocytes can act as phagocytes and play a role in scar formation. | True, astrocytes provide a scaffold for the surrounding neurons, reducing signal interference, taking up excess neurotransmitters and storing glycogen for use in times of high metabolic demand. They play a role in scar formation and can act as phagoctes. |
Choroidal epithelial cells produce and secrete cerebrospinal fluid. | True, cerebrospinal fluid is produced and secreted by choroidal epithelial cells. |
Microglial cells are derived from macrophages within the central nervous system. | False, microglia are derived from macrophages outside the nervous system. In response to tissue damage or inflammation they multiply and act as phagocytes. |
CSF merely serves to provide a cushion to the CNS, preventing damage to nervous tissue by surrounding bony structures. | False, CSF is also involved in providing nutrition to the central nervous system and removing waste products. |
CSF is formed at a rate of approximately 50ml/day. | False, CSF is produced at a rate of 500ml/day. |
The total cerebrospinal fluid space is approximately 150ml. | True, this volume must be turned over approximately 3 times per day. |
CSF is normally more acidic than plasma. | True, normal CSF pH = 7.33, whereas normal plasma pH = 7.41. |
CSF goes back into the circulation at the Virchow-Robin space. | False, CSF reaches nervous tissue by travelling along blood vessels in the perivascular (Virchow-Robin) space. CSF goes back into the circulation via the arachnoid granulations and perineural lymph vessels of the cranial and spinal nerves. |