Post on 28-Dec-2015
transcript
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Anatomy and Physiology, Sixth Edition
Rod R. SeeleyIdaho State UniversityTrent D. StephensIdaho State UniversityPhilip TatePhoenix College
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
*See PowerPoint Image Slides for all figures and tables pre-inserted into PowerPoint without notes.
Chapter 13Chapter 13
Lecture OutlineLecture Outline**
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Brain and Cranial Nerves
Chapter 13
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Brain and Cranial Nerves
• Brain– Part of CNS contained in cranial cavity– Control center for many of body’s functions– Much like a complex computer but more
• Parts of the brain– Brainstem– Cerebellum– Diencephalon– Cerebrum
• Cranial nerves– Part of PNS arise directly from brain
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Brainstem
• Connects spinal cord to brain• Parts
– Medulla oblongata– Pons– Midbrain
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Brainstem
• Medulla oblongata or medulla– Regulates: Heart rate, blood vessel diameter,
respiration, swallowing, vomiting, hiccupping, coughing, and sneezing
– Pyramids: Decussate
• Pons– Sleep and respiratory center
• Midbrain– Integral part of auditory pathways in CNS
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Brainstem and Diencephalon
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Cerebellum
• Involved in control of: balance, posture, locomotion, and fine motor coordination producing smooth flowing movements
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Diencephalon
• Components– Thalamus, Subthalamus, Epithalamus, Hypothalamus
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Diencephalon• Thalamus
– Largest part of diencephalon
– Most sensory input projects to here
– Influences mood and actions as fear or rage
• Subthalamus– Involved in controlling
motor functions
• Epithalamus– Pineal gland may influence
sleep-wake cycle
• Hypothalamus– Functions
• ANS control
• Endocrine control
• Muscle control
• Temperature regulation
• Regulation of food and water intake
• Emotions
• Regulation of sleep-wake cycle
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Cerebrum
• Largest portion of brain• Divisions
– Right
– Left
– Lobes: Frontal, parietal, occipital, temporal, insula
• Cortex: Outer surface• Medulla: Center
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Basal Nuclei and Limbic System
• Basal nuclei– Motor function control
• Limbic system– Basic survival
functions as memory, reproduction, nutrition
– Emotions
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Limbic System
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Meninges
• Connective tissue membranes– Dura mater: Superficial
– Arachnoid mater
– Pia mater: Bound tightly to brain
– Spaces • Subdural: Serous fluid
• Subarachnoid: CSF
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Ventricles
• Ventricles: Lateral ventricles (2), third ventricle, fourth ventricle
• Choroid plexuses produce CSF which fills ventricles and other parts of brain and spinal cord– Blood-cerebrospinal fluid barrier: Substances do not pass between
cells but through due to tight junctions of blood endothelial cells
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Cerebrospinal Fluid (CSF)
• Similar to serum with most of proteins removed
• Bathes brain and spinal cord
• Provides a protective cushion around CNS
• Provides some nutrients to CNS tissues
• Produced by ependymal cells
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Flow of CSF
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Brain Blood Supply
• Brain – Requires tremendous amount of blood– Receives 15-20% of blood pumped by heart– Interruption can cause unconsciousness and irreversible
brain damage– High metabolic rate and dependence on constant supply
of oxygen and glucose– Receives blood through arteries
• Blood-Brain barrier– Capillary endothelial cells along with astrocytes and
basement membrane– To be considered when developing drugs
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Formation of the Neural Tube
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Development of Brain Segments and Ventricles
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Cranial Nerves
• Indicated by Roman numerals I-XII from anterior to posterior
• May have one or more of 3 functions– Sensory (special or general)
– Somatic motor (skeletal muscles)
– Parasympathetic (regulation of glands, smooth muscles, cardiac muscle)
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Cranial Nerves
• Olfactory (I)• Optic (II)• Oculomotor (III)• Trochlear (IV)• Trigeminal (V)• Abducens (VI)
• Facial (VII)• Vestibulocochlear (VIII)• Glossopharyngeal (IX)• Vagus (X)• Accessory (XI)• Hypoglossal (XII)