Brain Outline

Brain Outline - Chapter 14: The Brain and Cranial Nerves I....

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Chapter 14: The Brain and Cranial Nerves I. An Introduction to the Organization of the Brain, p. 452 The human brain ranges in size from 750 cc to 2100 cc and contains 98% of the body’s neural tissue. The average brain weighs about 1.4 kg (3 lb.). A Preview of Major Regions and Landmarks, p. 452 The largest part of the brain is the cerebrum , which controls the higher mental functions such as thought, memory and conscious movement. The cerebrum is divided into left and right cerebral hemispheres , and covered by a surface layer of gray matter or neural cortex (cerebral cortex ). The surface is folded to increase surface area, forming elevated ridges (gyri ), shallow depressions, (sulci ), and deep grooves (fissures ). The second largest part of the brain is the cerebellum , which coordinates repetitive body movements. The cerebellum also has 2 hemispheres and is covered in cerebellar cortex . Underneath the cerebrum and cerebellum is the diencephalon , which links the cerebrum with the brain stem . The diencephalon is divided into the left thalamus and right thalamus , which relay and process sensory information, and the hypothalamus , which is involved in hormone production, emotion and autonomic function. The hypothalamus is connected to the pituitary gland (a major endocrine gland) via a small stalk called the infundibulum . The hypothalamus and pituitary gland are the interface between the nervous system and the endocrine system. The brain stem , which processes information between the spinal cord and the cerebrum or cerebellum, includes the mesencephalon , the pons , and the medulla oblongata : - The mesencephalon (midbrain) processes sight and sound (and their associated reflexes) and maintains consciousness. - The pons connects the cerebellum to the brain stem, and is involved in somatic and visceral motor control. - The medulla oblongata connects the brain to the spinal cord. In addition to relaying information, the medulla oblongata regulates autonomic functions such as heart rate, blood pressure and digestion. Embryology of the Brain, p. 452 The origin of the brain is the neural tube , which enlarges into 3 areas called primary brain vesicles (the prosencephalon , mesencephalon and rhombencephalon ). The prosencephalon and rhombencephalon subdivide to form 5 secondary brain vesicles . The telencephalon becomes the cerebrum. The metencephalon forms the cerebellum and pons. The myelencephalon becomes the medulla oblongata. Ventricles of the Brain, p. 453 The cerebral hemispheres each contain a large lateral ventricle , separated from each other by a thin medial partition called the septum pellucidum . The ventricle of the diencephalon is called the third ventricle . The lateral ventricles communicate with the third ventricle via the interventricular foramen (foramen of Monro ). The mesencephalon contains a narrow canal called the mesencephalic aqueduct
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Brain Outline - Chapter 14: The Brain and Cranial Nerves I....

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