Transcript Document
The Cerebellum Figure 13–7b The Cerebellum. Copyright © 2010 Pearson Education, Inc. The Cerebellum Copyright © 2010 Pearson Education, Inc. The Mesencephalon • Structures of the Mesencephalon • Tectum • Two pairs of sensory nuclei (corpora quadrigemina): • superior colliculus (visual) • inferior colliculus (auditory) • Tegmentum • Red nucleus (many blood vessels) • Substantia nigra (pigmented gray matter) Copyright © 2010 Pearson Education, Inc. The Mesencephalon • Structures of the Mesencephalon • Cerebral peduncles • Nerve fiber bundles on ventrolateral surfaces • Contain: • descending fibers to cerebellum • motor command fibers Copyright © 2010 Pearson Education, Inc. The Mesencephalon Figure 13–8a The Mesencephalon. Copyright © 2010 Pearson Education, Inc. The Mesencephalon Figure 13–8b The Mesencephalon. Copyright © 2010 Pearson Education, Inc. The Mesencephalon Copyright © 2010 Pearson Education, Inc. The Diencephalon • Integrates sensory information and motor commands • Thalamus, epithalamus, and hypothalamus • The pineal gland • Found in posterior epithalamus • Secretes hormone melatonin Copyright © 2010 Pearson Education, Inc. The Diencephalon • The Thalamus • Filters ascending sensory information for primary sensory cortex • Relays information between basal nuclei and cerebral cortex • The third ventricle • Separates left thalamus and right thalamus • Interthalamic adhesion (or intermediate mass): • projection of gray matter • extends into ventricle from each side Copyright © 2010 Pearson Education, Inc. The Diencephalon • The Thalamus • Thalamic nuclei • Are rounded masses that form thalamus • Relay sensory information to basal nuclei and cerebral cortex Copyright © 2010 Pearson Education, Inc. The Diencephalon • Five Groups of Thalamic Nuclei • Anterior group • Anterior nuclei • Part of limbic system (emotions) • Medial group • Provides awareness of emotional states • Ventral group • Relays sensory information Copyright © 2010 Pearson Education, Inc. The Diencephalon • Five Groups of Thalamic Nuclei • Posterior group • Pulvinar nucleus (sensory) • Lateral geniculate nucleus (visual) • Medial geniculate nucleus (auditory) • Lateral group • Affects emotional states • Integrates sensory information Copyright © 2010 Pearson Education, Inc. The Diencephalon Figure 13–9 The Thalamus. Copyright © 2010 Pearson Education, Inc. The Diencephalon Figure 13–9a The Thalamus. Copyright © 2010 Pearson Education, Inc. The Diencephalon Figure 13–9b The Thalamus. Copyright © 2010 Pearson Education, Inc. The Diencephalon Copyright © 2010 Pearson Education, Inc. The Diencephalon • The Hypothalamus • Mamillary bodies • Process olfactory and other sensory information • Control reflex eating movements • Infundibulum • A narrow stalk • Connects hypothalamus to pituitary gland • Tuberal area • Located between the infundibulum and mamillary bodies • Helps control pituitary gland function Copyright © 2010 Pearson Education, Inc. The Diencephalon Figure 13–10a The Hypothalamus in Sagittal Section. Copyright © 2010 Pearson Education, Inc. The Diencephalon Figure 13–10b The Hypothalamus in Sagittal Section. Copyright © 2010 Pearson Education, Inc. The Diencephalon • Eight Functions of the Hypothalamus • Provides subconscious control of skeletal muscle • Controls autonomic function • Coordinates activities of nervous and endocrine systems • Secretes hormones • Antidiuretic hormone (ADH) by supraoptic nucleus • Oxytocin (OT; OXT) by paraventricular nucleus Copyright © 2010 Pearson Education, Inc. The Diencephalon • Eight Functions of the Hypothalamus • Produces emotions and behavioral drives • The feeding center (hunger) • The thirst center (thirst) • Coordinates voluntary and autonomic functions • Regulates body temperature • Preoptic area of hypothalamus • Controls circadian rhythms (day–night cycles) • Suprachiasmatic nucleus Copyright © 2010 Pearson Education, Inc. The Diencephalon Copyright © 2010 Pearson Education, Inc. The Limbic System • The Limbic System • Is a functional grouping that • Establishes emotional states • Links conscious functions of cerebral cortex with autonomic functions of brain stem • Facilitates memory storage and retrieval Copyright © 2010 Pearson Education, Inc. The Limbic System • Components of the Limbic System • Amygdaloid body • Acts as interface between the limbic system, the cerebrum, and various sensory systems • Limbic lobe of cerebral hemisphere • Cingulate gyrus • Dentate gyrus • Parahippocampal gyrus • Hippocampus Copyright © 2010 Pearson Education, Inc. The Limbic System • Components of the Limbic System • Fornix • Tract of white matter • Connects hippocampus with hypothalamus • Anterior nucleus of the thalamus • Relays information from mamillary body to cingulate gyrus • Reticular formation • Stimulation or inhibition affects emotions (rage, fear, pain, sexual arousal, pleasure) Copyright © 2010 Pearson Education, Inc. The Limbic System Figure 13–11a The Limbic System. Copyright © 2010 Pearson Education, Inc. The Limbic System Figure 13–11b The Limbic System. Copyright © 2010 Pearson Education, Inc. The Limbic System Copyright © 2010 Pearson Education, Inc. The Cerebrum • The Cerebrum • Is the largest part of the brain • Controls all conscious thoughts and intellectual functions • Processes somatic sensory and motor information Copyright © 2010 Pearson Education, Inc. The Cerebrum • Gray matter • In cerebral cortex and basal nuclei • White matter • Deep to basal cortex • Around basal nuclei Copyright © 2010 Pearson Education, Inc. The Cerebrum • Structures of the Cerebrum • Gyri of neural cortex • Increase surface area (number of cortical neurons) • Insula (island) of cortex • Lies medial to lateral sulcus • Longitudinal fissure • Separates cerebral hemispheres • Lobes • Divisions of hemispheres Copyright © 2010 Pearson Education, Inc. The Cerebrum • Structures of the Cerebrum • Central sulcus divides • Anterior frontal lobe from posterior parietal lobe • Lateral sulcus divides • Frontal lobe from temporal lobe • Parieto-occipital sulcus divides • Parietal lobe from occipital lobe Copyright © 2010 Pearson Education, Inc. The Cerebrum Figure 13–12a The Brain in Lateral View. Copyright © 2010 Pearson Education, Inc. The Cerebrum Figure 13–12b The Brain in Lateral View. Copyright © 2010 Pearson Education, Inc. The Cerebrum Figure 13–12c The Brain in Lateral View. Copyright © 2010 Pearson Education, Inc. The Cerebrum • Three Functional Principles of the Cerebrum • Each cerebral hemisphere receives sensory information from, and sends motor commands to, the opposite side of the body • The two hemispheres have different functions, although their structures are alike • Correspondence between a specific function and a specific region of cerebral cortex is not precise Copyright © 2010 Pearson Education, Inc. The Cerebrum • White Matter of the Cerebrum • Association fibers • Commissural fibers • Projection fibers Copyright © 2010 Pearson Education, Inc. The Cerebrum • White Matter of the Cerebrum • Association fibers • Connections within one hemisphere: • arcuate fibers: • are short fibers • connect one gyrus to another • longitudinal fasciculi: • are longer bundles • connect frontal lobe to other lobes in same hemisphere Copyright © 2010 Pearson Education, Inc. The Cerebrum • White Matter of the Cerebrum • Commissural fibers • Bands of fibers connecting two hemispheres: • corpus callosum • anterior commissure Copyright © 2010 Pearson Education, Inc. The Cerebrum • White Matter of the Cerebrum • Projection fibers • Pass through diencephalon • Link cerebral cortex with: • diencephalon, brain stem, cerebellum, and spinal cord • Internal capsule: • all ascending and descending projection fibers Copyright © 2010 Pearson Education, Inc. The Cerebrum Figure 13–13a Fibers of the White Matter of the Cerebrum. Copyright © 2010 Pearson Education, Inc. The Cerebrum Figure 13–13b Fibers of the White Matter of the Cerebrum. Copyright © 2010 Pearson Education, Inc. The Cerebrum • The Basal Nuclei • Also called cerebral nuclei • Are masses of gray matter • Are embedded in white matter of cerebrum • Direct subconscious activities Copyright © 2010 Pearson Education, Inc. The Cerebrum • Structures of Basal Nuclei • Caudate nucleus • Curving, slender tail • Lentiform nucleus • Globus pallidus • Putamen Copyright © 2010 Pearson Education, Inc. The Cerebrum Figure 13–14a The Basal Nuclei. Copyright © 2010 Pearson Education, Inc. The Cerebrum Figure 13–14b The Basal Nuclei. Copyright © 2010 Pearson Education, Inc. The Cerebrum Figure 13–14c The Basal Nuclei. Copyright © 2010 Pearson Education, Inc. The Cerebrum • Functions of Basal Nuclei • Involved with • The subconscious control of skeletal muscle tone • The coordination of learned movement patterns (walking, lifting) Copyright © 2010 Pearson Education, Inc. The Cerebrum • Motor and Sensory Areas of the Cortex • Central sulcus separates motor and sensory areas • Motor areas • Precentral gyrus of frontal lobe: • directs voluntary movements • Primary motor cortex: • is the surface of precentral gyrus • Pyramidal cells: • are neurons of primary motor cortex Copyright © 2010 Pearson Education, Inc. The Cerebrum • Motor and Sensory Areas of the Cortex • Sensory areas • Postcentral gyrus of parietal lobe: • receives somatic sensory information (touch, pressure, pain, vibration, taste, and temperature) • Primary sensory cortex: • surface of postcentral gyrus Copyright © 2010 Pearson Education, Inc. The Cerebrum • Special Sensory Cortexes • Visual cortex • Information from sight receptors • Auditory cortex • Information from sound receptors • Olfactory cortex • Information from odor receptors • Gustatory cortex • Information from taste receptors Copyright © 2010 Pearson Education, Inc. The Cerebrum Figure 13–15a Motor and Sensory Regions of the Cerebral Cortex. Copyright © 2010 Pearson Education, Inc. The Cerebrum • Association Areas • Sensory association areas • Monitor and interpret arriving information at sensory areas of cortex • Somatic motor association area (premotor cortex) • Coordinates motor responses (learned movements) Copyright © 2010 Pearson Education, Inc. The Cerebrum • Sensory Association Areas • Somatic sensory association area • Interprets input to primary sensory cortex (e.g., recognizes and responds to touch) • Visual association area • Interprets activity in visual cortex • Auditory association area • Monitors auditory cortex Copyright © 2010 Pearson Education, Inc. The Cerebrum • Integrative Centers • Are located in lobes and cortical areas of both cerebral hemispheres • Receive information from association areas • Direct complex motor or analytical activities Copyright © 2010 Pearson Education, Inc. The Cerebrum • General Interpretive Area • Also called Wernicke area • Present in only one hemisphere • Receives information from all sensory association areas • Coordinates access to complex visual and auditory memories Copyright © 2010 Pearson Education, Inc. The Cerebrum • Other Integrative Areas • Speech center • Is associated with general interpretive area • Coordinates all vocalization functions • Prefrontal cortex of frontal lobe • Integrates information from sensory association areas • Performs abstract intellectual activities (e.g., predicting consequences of actions) Copyright © 2010 Pearson Education, Inc. The Cerebrum Figure 13–15b Motor and Sensory Regions of the Cerebral Cortex. Copyright © 2010 Pearson Education, Inc. The Cerebrum • Interpretive Areas of Cortex • Brodmann areas • Patterns of cellular organization in cerebral cortex Copyright © 2010 Pearson Education, Inc. The Cerebrum Figure 13–15c Motor and Sensory Regions of the Cerebral Cortex. Copyright © 2010 Pearson Education, Inc. The Cerebrum Copyright © 2010 Pearson Education, Inc. The Cerebrum • Hemispheric Lateralization • Functional differences between left and right hemispheres • Each cerebral hemisphere performs certain functions that are not ordinarily performed by the opposite hemisphere Copyright © 2010 Pearson Education, Inc. The Cerebrum • The Left Hemisphere • In most people, left brain (dominant hemisphere) controls • Reading, writing, and math • Decision making • Speech and language • The Right Hemisphere • Right cerebral hemisphere relates to • Senses (touch, smell, sight, taste, feel) • Recognition (faces, voice inflections) Copyright © 2010 Pearson Education, Inc. The Cerebrum Figure 13–16 Hemispheric Lateralization. Copyright © 2010 Pearson Education, Inc. The Cerebrum • Monitoring Brain Activity • Brain activity is assessed by an electroencephalogram (EEG) • Electrodes are placed on the skull • Patterns of electrical activity (brain waves) are printed out Copyright © 2010 Pearson Education, Inc. The Cerebrum • Four Categories of Brain Waves • Alpha waves • Found in healthy, awake adults at rest with eyes closed • Beta waves • Higher frequency • Found in adults concentrating or mentally stressed • Theta waves • Found in children • Found in intensely frustrated adults • May indicate brain disorder in adults • Delta waves • During sleep • Found in awake adults with brain damage Copyright © 2010 Pearson Education, Inc. The Cerebrum Figure 13–17a-d Brain Waves. Copyright © 2010 Pearson Education, Inc. The Cerebrum • Synchronization • A pacemaker mechanism • Synchronizes electrical activity between hemispheres • Brain damage can cause desynchronization • Seizure • Is a temporary cerebral disorder • Changes the electroencephalogram • Symptoms depend on regions affected Copyright © 2010 Pearson Education, Inc. Cranial Nerves • 12 pairs connected to brain • Four Classifications of Cranial Nerves • Sensory nerves: carry somatic sensory information, including touch, pressure, vibration, temperature, and pain • Special sensory nerves: carry sensations such as smell, sight, hearing, balance • Motor nerves: axons of somatic motor neurons • Mixed nerves: mixture of motor and sensory fibers Copyright © 2010 Pearson Education, Inc. Cranial Nerves • Cranial nerves are classified by primary functions • May also have important secondary functions • Distributing autonomic fibers to peripheral ganglia • The 12 cranial nerve groups are identified by • Primary function • Origin • Pathway • Destination Copyright © 2010 Pearson Education, Inc. Cranial Nerves Figure 13–18 Origins of the Cranial Nerves. Copyright © 2010 Pearson Education, Inc. Cranial Nerves • Olfactory Nerves (I) • Primary function • Special sensory (smell) • Origin • Receptors of olfactory epithelium • Pathway • Olfactory foramina in cribriform plate of ethmoid • Destination • Olfactory bulbs Copyright © 2010 Pearson Education, Inc. Cranial Nerves • Olfactory Nerve Structures • Olfactory bulbs • Located on either side of crista galli • Olfactory tracts • Axons of postsynaptic neurons • Leading to cerebrum Copyright © 2010 Pearson Education, Inc. Cranial Nerves Figure 13–19 The Olfactory Nerve. Copyright © 2010 Pearson Education, Inc. Cranial Nerves • Optic Nerves (II) • Primary function • Special sensory (vision) • Origin • Retina of eye • Pathway • Optic canals of sphenoid • Destination • Diencephalon via optic chiasm Copyright © 2010 Pearson Education, Inc. Cranial Nerves • Optic Nerve Structures • Optic chiasm • Where sensory fibers converge • And cross to opposite side of brain • Optic tracts • Reorganized axons • Leading to lateral geniculate nuclei Copyright © 2010 Pearson Education, Inc. Cranial Nerves Figure 13–20 The Optic Nerve. Copyright © 2010 Pearson Education, Inc. Cranial Nerves • Oculomotor Nerves (III) • Primary function • Motor (eye movements) • Origin • Mesencephalon • Pathway • Superior orbital fissures of sphenoid • Destination • Somatic motor: • superior, inferior, and medial rectus muscles • inferior oblique muscle • levator palpebrae superioris muscle • Visceral motor: • intrinsic eye muscles Copyright © 2010 Pearson Education, Inc. Cranial Nerves • Oculomotor Nerve Structures • Oculomotor nerve • Controls four of six eye-movement muscles • Delivers autonomic fibers to ciliary ganglion: • ciliary ganglion: controls intrinsic muscles of iris and lens Copyright © 2010 Pearson Education, Inc. Cranial Nerves • The Trochlear Nerves (IV) • Primary function • Motor (eye movements) • Origin • Mesencephalon • Pathway • Superior orbital fissure of sphenoid • Destination • Superior oblique muscle Copyright © 2010 Pearson Education, Inc. Cranial Nerves • The Abducens Nerves (VI) • Primary function • Motor (eye movements) • Origin • Pons • Pathway • Superior orbital fissures of sphenoid • Destination • Lateral rectus muscle Copyright © 2010 Pearson Education, Inc. Cranial Nerves Figure 13–21 Cranial Nerves Controlling the Extra-Ocular Muscles. Copyright © 2010 Pearson Education, Inc. Cranial Nerves • The Trigeminal Nerves (V) • Primary function • Mixed (sensory and motor) to face • Origin • Ophthalmic branch (sensory): • orbital structures • nasal cavity • skin of forehead, upper eyelid, and eyebrow • part of nose Copyright © 2010 Pearson Education, Inc. Cranial Nerves • The Trigeminal Nerves (V) • Origin • Maxillary branch (sensory): • • • • lower eyelid upper lip, gums, and teeth cheek and nose palate and part of pharynx • Mandibular branch (sensory): • lower gums, teeth, and lips • palate and part of tongue • Mandibular branch (motor): • motor nuclei of pons Copyright © 2010 Pearson Education, Inc. Cranial Nerves • The Trigeminal Nerves (V) • Pathway • Ophthalmic branch: • superior orbital fissure • Maxillary branch: • foramen rotundum • Mandibular branch: • foramen ovale Copyright © 2010 Pearson Education, Inc. Cranial Nerves • The Trigeminal Nerves (V) • Destination • Sensory nerves: • sensory nuclei in pons • Motor nerves of mandibular branch: • muscles of mastication Copyright © 2010 Pearson Education, Inc. Cranial Nerves • Trigeminal Nerve Structures • Trigeminal nerves • Largest cranial nerves • With three major branches • Semilunar ganglion • Contains cell bodies of sensory neurons Copyright © 2010 Pearson Education, Inc. Cranial Nerves Figure 13–22 The Trigeminal Nerve. Copyright © 2010 Pearson Education, Inc. Cranial Nerves • The Facial Nerves (VII) • Primary function • Mixed (sensory and motor) to face • Origin • Sensory: • taste receptors on anterior 2/3 of tongue • Motor: • motor nuclei of pons • Pathway • Internal acoustic meatus to facial canals (stylomastoid foramina) Copyright © 2010 Pearson Education, Inc. Cranial Nerves • The Facial Nerves (VII) • Destination • Sensory: • sensory nuclei of pons • Somatic motor: • muscles of facial expression • Visceral motor: • tear and nasal mucous glands • submandibular and sublingual salivary glands Copyright © 2010 Pearson Education, Inc. Cranial Nerves • Facial Nerve Structures • Facial nerve branches • Temporal • Zygomatic • Buccal • Mandibular • Cervical branches Copyright © 2010 Pearson Education, Inc. Cranial Nerves • Facial Nerve Structures • Geniculate ganglia • Hold cell bodies of sensory neurons • Pterygopalatine ganglia • Postganglionic fibers innervate glands (lacrimal, nasal cavity, and pharynx) • Submandibular ganglia • Innervate salivary glands Copyright © 2010 Pearson Education, Inc. Cranial Nerves Figure 13–23a The Facial Nerve. Copyright © 2010 Pearson Education, Inc. Cranial Nerves Figure 13–23b The Facial Nerve. Copyright © 2010 Pearson Education, Inc. Cranial Nerves • The Vestibulocochlear Nerves (VIII) • Primary function: special sensory • Vestibular branch: • balance and equilibrium • Cochlear branch: • hearing • Origin • Receptors of inner ear • Pathway • Internal acoustic meatus of temporal bones • Destination • Vestibular and cochlear nuclei of pons and medulla oblongata Copyright © 2010 Pearson Education, Inc. Cranial Nerves • Vestibulocochlear Nerve Structures • Vestibular branch • Originates at receptors of vestibule (balance) • Connects to vestibular nuclei of pons and medulla oblongata • Cochlear branch • Originates at sensors of cochlea (hearing) • Connects with cochlear nuclei of pons and medulla oblongata Copyright © 2010 Pearson Education, Inc. Cranial Nerves Figure 13–24 The Vestibulocochlear Nerve. Copyright © 2010 Pearson Education, Inc. Cranial Nerves • The Glossopharyngeal Nerves (IX) • Primary function • Mixed (sensory and motor) to head and neck • Origins • Sensory: • posterior 1/3 of tongue • part of pharynx and palate • carotid arteries • Motor: • motor nuclei of medulla oblongata Copyright © 2010 Pearson Education, Inc. Cranial Nerves • The Glossopharyngeal Nerves (IX) • Pathway • Jugular foramina between occipital and temporal bones • Destination • Sensory: • sensory nuclei of medulla oblongata • Somatic motor: • nerves involved in swallowing • Visceral motor: • parotid salivary gland Copyright © 2010 Pearson Education, Inc. Cranial Nerves • Glossopharyngeal Nerve Structures • Superior and inferior ganglion • Sensory neurons of tongue and pharynx • Otic ganglion • Synapse visceral motor fibers Copyright © 2010 Pearson Education, Inc. Cranial Nerves Figure 13–25 The Glossopharyngeal Nerve. Copyright © 2010 Pearson Education, Inc. Cranial Nerves • The Vagus Nerves (X) • Primary function • Mixed (sensory and motor) • Widely distributed in thorax and abdomen • Origins • Sensory: • • • • part of pharynx auricle and external acoustic meatus diaphragm visceral organs of thoracic and abdominopelvic cavities • Motor: • motor nuclei in medulla oblongata Copyright © 2010 Pearson Education, Inc. Cranial Nerves • The Vagus Nerves (X) • Pathway • Jugular foramina • Between occipital and temporal bones • Destination • Sensory: • sensory nuclei and autonomic centers of medulla oblongata • Visceral motor: • muscles of the palate and pharynx • muscles of the digestive, respiratory, and cardiovascular systems in thoracic and abdominal cavities Copyright © 2010 Pearson Education, Inc. Cranial Nerves • Vagus Nerve Structures • Vagus nerves • Branch and radiate extensively • Superior (jugular) ganglion and inferior (nodose) ganglion • Hold sensory neurons Copyright © 2010 Pearson Education, Inc. Cranial Nerves Figure 13–26 The Vagus Nerve. Copyright © 2010 Pearson Education, Inc. Cranial Nerves Figure 13–26 The Vagus Nerve. Copyright © 2010 Pearson Education, Inc. Cranial Nerves • The Accessory Nerves (XI) • Primary function • Motor to muscles of neck and upper back • Origin • Motor nuclei of spinal cord and medulla oblongata • Pathway • Jugular foramina between occipital and temporal bones • Destination • Internal branch: • voluntary muscles of palate, pharynx, and larynx • External branch: • sternocleidomastoid and trapezius muscles Copyright © 2010 Pearson Education, Inc. Cranial Nerves • Accessory Nerve Structures • Spinal root • Motor fibers that originate in anterior gray horns of first five cervical segments of spinal cord • Cranial root • Motor fibers that originate in medulla oblongata • Internal branch • Joins the vagus nerve • External branch • Controls muscles of neck and back Copyright © 2010 Pearson Education, Inc. Cranial Nerves • The Hypoglossal Nerves (XII) • Primary function • Motor (tongue movements) • Origin • Motor nuclei of medulla oblongata • Pathway • Hypoglossal canals of occipital bone • Destination • Muscles of tongue Copyright © 2010 Pearson Education, Inc. Cranial Nerves Figure 13–27 The Accessory and Hypoglossal Nerves. Copyright © 2010 Pearson Education, Inc. Cranial Nerves Copyright © 2010 Pearson Education, Inc. Cranial Nerves Copyright © 2010 Pearson Education, Inc. Cranial Reflexes • Cranial Reflexes • Monosynaptic and polysynaptic reflex arcs • Involve sensory and motor fibers of cranial nerves • Clinically useful to check cranial nerve or brain damage Copyright © 2010 Pearson Education, Inc. Cranial Reflexes Copyright © 2010 Pearson Education, Inc.