Chapter 14 - The Brain -...

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Chapter 14 - An Introduction to the Brain and Cranial Nerves The Adult Human Brain ranges from 750 cc to 2100 cc & contains almost 97% of the body’s neural tissue; average weight about 1.4  kg (3 lb); gets 20% of the resting cardiac output The Brain - Six Regions of the Brain i. Cerebrum ii. Cerebellum iii. Diencephalon iv. Mesencephalon v. Pons vi. Medulla oblongata 1. Cerebrum: largest part of brain & controls higher mental functions Divided into left & right  cerebral hemispheres; surface layer of gray matter ( neural cortex Neural cortex ( ) - folded surface increases surface area 0. ) 1. Shallow depressions ( sulci ) 2. Deep grooves ( fissures ) 2. Cerebellum: second largest part of brain; coordinates repetitive body movements Two hemispheres covered with  cerebellar cortex 3.   Diencephalon: located under cerebrum & cerebellum; links cerebrum with  brain stem   Three divisions: Left thalamus, Right thalamus & Hypothalamus Thalamus - relays and processes sensory information Hypothalamus - Hormone production, Emotion & Autonomic function Pituitary gland - major endocrine gland connected to hypothalamus via  infundibulum  (stalk) 3. Interfaces nervous and endocrine systems The Brain Stem processes information between spinal cord and cerebrum or cerebellum Includes 4. Mesencephalon 5. Pons 6. Medulla oblongata 4. Mesencephalon (midbrain): processes sight, sound & associated reflexes; maintains consciousness  5. Pons: connects cerebellum to brain stem & is involved in somatic and visceral motor control 6. Medulla oblongata: connects brain to spinal cord; relays information Regulates autonomic functions: heart rate, blood pressure, and digestion  Embryological Development determines organization of brain structures  Neural tube - Origin of brain Enlarges into three  primary brain vesicles   0. prosencephalon 1. mesencephalon 2. rhombencephalon Five Secondary Brain Vesicles: Telencephalon, Diencephalon, Mesencephalon, Metencephalon & Myelencephalon Diencephalon and mesencephalon persist Telencephalon: becomes cerebrum Metencephalon: forms cerebellum and pons  becomes medulla oblongata Ventricles   of   the   Brain:   origins  of   ventricles:   neural   tube   encloses   neurocoel & neurocoel   expands   to   form   chambers  ( ventricles ) lined with  ependymal  cells Each cerebral hemisphere contains one large  lateral ventricle separated by a thin medial partition ( septum pellucidum Third ventricle: ventricle of the diencephalon  Lateral ventricles communicate with third ventricle: via  interventricular foramen   Fourth ventricle: extends into medulla oblongata & becomes continuous with central canal of spinal cord; connects with  3 rd ventricle : via narrow canal in mesencephalon -  aqueduct of midbrain
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Chapter 14 - The Brain -...

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