Chapter 8 CNS
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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Central Nervous System (CNS) Brain Spinal Cord Peripheral Nervous System (PNS) Sensory Neurons Motor Neurons Somatic Nervous System Autonomic Nervous System Sympathetic Parasympathetic The Nervous System
The Spinal Cord White Matter Gray Matter Central Canal Dorsal Root Dorsal Root Ganglion Dorsal Root Peripheral Nerve
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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Embryonic Development Forms as a tube! Ectoderm (skin, nervous system): neural tube by day 20 Part of ectoderm where fusion occurs becomes neural crest which then forms PNS ganglia. by 4th week: Forebrain, Midbrain, Hindbrain
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The Cerebral Cortex Frontal Lobe Higher Intellectual Functions Primary Motor Area Premotor Area Speech Motor Area leg trunk arm hand face tongue Parietal Lobe Primary Sensory Area Sensory Association Area Occipital Lobe Primary Visual Area Visual Association Area Temporal Lobe Memory Primary Auditory Area Language Comprehension & Formation
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Info comes from… Surgeries Accidents Illness Anatomy (autopsies) Open brain studies Animals Live Imaging
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Imaging CAT scans: soft tissues xrays PET scans: positron emitting fluid glucose metabolism, blood flow. MRI and fMRI blood flow magnets spin protons, radio waves are emitted
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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. CNS CNS = Brain plus spinal cord - Gray matter consists of neuron cell bodies and dendrites. - White matter (myelin) consists of axon tracts. - Ventricles - CSF secreted by meninges, cushions brain - Skull protects - No pain sensors! - Blood-brain barrier.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. CNS Cell bodies in CNS: nuclei Cell bodies in PNS: ganglia Nerves: bundles of axons!
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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Brain Prosencephelon (Forebrain) Telencephalon (cerebrum) Diencephelon (thalamus, hypothalamus) Mesencephalon (Midbrain) Rhombencephalon (Hindbrain) Metencephalon (pons, cerebellum) Myencephalon (medulla)
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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. BRAINS Forebrain Midbrain Hindbrain Embryonic Shark Goose Human
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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cerebrum Telencephalon= cerebrum Largest portion of brain (80% mass). Responsible for cognitive mental functions. Five lobes. Cortex (2-4 mm of gray matter) White matter and basal nuclei (gray)
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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cerebrum Central sulcus= between frontal and parietal lobes. Frontal lobe: precentral gyrus: motor neurons. Parietal lobe: Poscentral gyrus: somatesthetic sensation (cutaneous touch, pain, heat, muscles and joints). MAP of motor and of sensory control (homunculus)
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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cerebrum Basal Nuclei gray matter located deep within white matter. Corpus striatum Functions in the refinement of voluntary movements. Parkinson’s: degeneration of neurons that connect caudate nucleus to substantia nigra of midbrain
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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Language Aphasia: speech and language disorder due to head injuries and strokes. Speech impediment: vocal cord or tongue injury.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Language Broca’s area: articulation of speech. Damage: slow to speak, comprehension is fine Wernicke’s area: language comprehension. Damage: rapid speech, word salad To read, hear words: visual, auditory -> Wernicke’s (concept of words) To speak: Werknicke’s -> arcuate fasciculus -> Broca’s -> motor Angular gyrus: Center of integration of auditory, visual, and somatesthetic information.
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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Emotion and Motivation Rage, aggression: Amygdala and hypothalamus. Fear: Amygdala and hypothalamus. Feeding: Hypothalamus (satiety centers). Sexual drive and behavior: Hypothalamus and limbic system. Goal directed behavior (reward and punishment): Hypothalamus and frontal cortex.
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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Thalamus Thalamus: Acts as relay center through which all sensory information (except olfactory) passes to the cerebrum. Lateral geniculate nuclei: Relay visual information; stripes! Medial geniculate nuclei: Relay auditory information. Epithalamus contains: Choroid plexus where CSF is formed. Pineal gland which secretes melatonin (circadian rhythms).
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Hypothalamus Contains neural centers for hunger, thirst, and body temperature. Contributes to the regulation of sleep, wakefulness, emotions, sexual arousal, anger, fear, pain, and pleasure. Stimulates hormonal release from anterior pituitary. Produces ADH and oxytocin. Coordinates sympathetic and parasympathetic reflexes.
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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Hindbrain Hindbrain: connects spinal cord to rest of brain. Metencephalon: Pons: Connects other parts. several nuclei associated with cranial nerves respiratory centers. Cerebellum: “little brain” Receives input from proprioceptors (joints, muscles, tendons). Refinement/coordination of movement.
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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. RAS Reticular Activating System (reticular formation) network of nuclei and nerve fibers within hindbrain (medulla, pons), midbrain, forebrain (thalamus and hypothalamus). Maintains wakefulness and alertness Turned off ( by hypothalamus) to sleep Anaesthesia, alcohol, tranquillizers Coma
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Continue to engage the RAS and … onto lab!