Neuron Structure Cell body axon Dendrites Functional classification

신경계 구성요소 • Neuron – Structure • Cell body + axon • Dendrites – Functional classification • Sensory neuron/afferent neuron • Motor neuron/efferent neuron • Inter neuron/association neuron • Supporting cell – Schwann cell – myelin sheath of peripheral nervous system (PNS) – Oligodendrocyte – myelin sheath of central nervous system (CNS) • White matter – axon covered with myelin sheath • Grey matter – cell body and dendrites – Also contained in CNS are astrocytes, microglia, ependymal cell 2

척충동물의 뇌 기본부위 • Hind brain/rhombencephalon • Midbrain/mesencephalon • Forebrain/prosencephalon 3

어류의 뇌 limb control body motor control optic lobe olfactory lobe 4

파충류, 양서류, 조류, 포유류의 뇌 • Forebrain → dincephalon+telencephalon – Dincephalon (간뇌) • thalamus – sensory information processing → cerebrum • hypothalamus – pituitary gland control (instinct and emotion) – Telencephalon (종뇌) → cerebrum in mammals • activation of motor neurons through axons in spinal cord • brain+spinal cord → CNS 5

사람의 뇌 • Two hemispheres connected by corpus callosum – Functional section • • Frontal lobe Parietal lobe Temporal lobe – auditory cortex Occipital lobe – visual cortex • Cerebral cortex – 95% is association cortex (advanced metal activity) – Grey matter – >100억개 neurons – Primary motor cortex – Secondary somatosensory cortex central sulcus 6

• Basal ganglia (white matter) – Receiving center for sensory information and motor order from cerebrum and cerebellum • Thalamus – Primary unifying area for visual, auditory, and sensory information • Limbic system – emotional control – Hypothalamus • Temperature/hunger/satiety/thirst/emotion • Neuronal & endocrinal control – Hippocampus – Amygdala 7

뇌의 영역 • Reticular activating system – Alertness and sleep control – Can be detected by EEG (electroencephalogram) • Wernicke’s area – facial movement • Broca’s area – language – 90% of right handed & 2/3 of left-handed – left hemisphere • Spatial logic and musical ability – Non-dominant hemisphere (mostly right hemisphere) • Inferior temporal cortex – prosopagnosia when damaged • Memory and learning – Cerebral cortex – long term-memory – Hippocampus and amygdala • Short-term memory, consolidation into long-term storage 8

알츠하이머병 • External protein – -amyloid → forms aggregates → plaque – Autopsies of people without Alzheimer’s disease had plaques • Internal protein – Abnormal tau ( ) → formation of helical segments → tangles 9

척수 (Spinal cord) • Protected by meninges and spinal column – Inner zone – grey matter • Interneurons, motor neurons, cell body of neuroglia – Outer zone – white matter – axons • Ventral – motor axons • Dorsal – sensory axons • Reflex – Involuntary movement of muscles – Synaptic connection is minimum • Monosynaptic – fast response – (ex) knee reflex, blinking reflex 10

말초신경계 • Nerves+ganglia – Nerves – cable-like collections of axons – Ganglia – aggregations of neuron cell bodies locate outside the CNS • Dorsal root ganglia – sensory neurons’ cell bodies • Ventral – cell bodies of motor neurons resides inside the spinal cord and do not form ganglia 11

의식적 somatic nervous system 비의식적 sympathetic nerves automatic nervous system parasympathetic nerves 12

신경자극 전달 기작 • Testing potential – -40~-90 m. V due to negative charge inside the cell membrane – Na+–K+ pump • 2 K+in, 3 Na+out – More K+ channels than Na+ channels in the membrane • K+ diffuses out – Creates negative charge inside cell membrane – Creates force to bring back K+ inside the cell Formation of an equilibrium potential 13

Na+ channel activation gate opens Na+ channel inactivation gate closes K+ channel opens K+ channel gate closes K+ channel voltage gated Na+ channel voltage gated K+ channel Na+ channel inactivation gate closes excess K+ diffuses out – undershoot 14

활동전위 • Action potentials are only produced at node of Ranvier where axons are myelinated • Action potentials quickly spreads beneath the sheath to trigger opening of voltage-gated channel at the next node • The impulse jumps from node to node – Saltatory conduction • https: //www. youtube. com/watch? v=WQ 5 h 0 d. W 3 D 2 o 15

시냅스 (Synaps) • • presynaptic cell postsynaptic cell electrical synaps – directly connected by gap junction chemical synaps – most synapses synaptic cleft synaptic vesicle contains neurotransmitters are removed by 1. enzymatic digestion 2. reuptake by the neuron 3. uptake by glia cells 16

신경전달물질 • Acetylcholine – neuromuscular junction – Formation of excitatory postsynaptic potential, EPSP – Achetylcholinesterase • Glutamate – in vertebrate CNS – forms EPSP • Glycine, GABA – forms inhibitory postsynaptic potential, IPSP • Biogenic amine – Ephinephrine (Adrenaline) – hormone not a neurotransmitter – Dopamine – brain – controls body movements – Norephinephrine – sympathetic nerves – fight or flight response – Serotonin – brain – sleep/emotion/depression control 17

• Neuropeptide – neuromodulators – Substance P – released in CNS by sensory neurons activated by painful stimuli – Enkephalins – released by axons descending from the brains into the spinal cord, inhibit the passage of pain info back up to the brain – Endorphins – released by neurons in the brain stem, block the perception of pain – (cf) opium, morphine, and heroin have similar structure and bind to enkephalin and endorphin receptors – (cf) cocaine – dopamine resorption protein blocker 18

감각수용기 • • Mechanoreceptor – touch and pressure Chemoreceptor – taste, olfactory receptors Electromagnetic receptor – photoreceptors The path of sensory information – Stimulation – depolarization, similar to EPSP – Transduction of stimulus into receptor potential in sensory receptor – Transmission of action potential in sensory neuron – Interpretation of stimulus in CNS 19

기계적 감각수용기: 접촉과 압력 • Pain receptor – Nociceptor – Free nerve endings – Hot and cold • Transient receptor potential (TRP)→ spinal cord neuron → glutamate → EPSP → pain • (ex) perception of capcisin • Thermoreceptor – TRP ion channels responsive to hot and cold – Cold receptors=3~4 warm receptors – Also found in hypothalamus 20

• Mechanoreceptors of the skin – Phasic receptors – intermittent activation when pressure is present (fingertips and face) • Hair follicle receptors • Meissner corpuscle – where no hair • Pacinian corpuscle – monitors only the onset/removal of pressure – Tonic receptors – continuous activation • Ruffini corpuscle • Merkle cell Duration and extent of touch 21

• Proprioceptors – muscle spindles – proprioception – “grasp ones own” – “sense of relative position” – Provide information about the relative position or movement of the animal’s body parts – Golgi tendon organ (a type of proprioceptor) • Monitors the tension on the tendons when muscle contracts • Too high, elicit a reflex that inhibits the motor neurons innervating the muscle • Baroreceptors – carotid sinus, aortic arch – Detect blood pressure – When low, • Low frequency of baroreceptors • CNS stimulates the sympathetic division of the automatic nervous system • Increase in heart rate & vasoconstriction 22

청각 및 진동의 감지 • Pressure/wave → nerve stimuli • Ear cannel → tympanic membrane → movement of the ossicles (소골편) against oval window → pressure wave in the fluid in the vestibular (전정기관) and tympanic canals (고실관) of the cochlea → vibration in the basiliar membrane cilia → bending in organ of Corti 23

• Basiliar membrane – bunch of elastic fibers of varying length and stiffness – Near oval window – short and stiff • Resonance frequency↑ (response to higher pitch) – Apex – 5 X longer, 100 X flexible • Resonance frequency↓ (response to lower pitch) • Hearing range – Child – 20 -20, 000 Hz (higher pitch decays with age) Tectorial membrane Hair cells Stereocilia (부동섬모) basal membrane Organ of Corti 24

몸의 위치 인식 • Invertebrates – Statocyst – structure that allows orienting body relative to gravity • Ciliated hair embedded in gelatinous membrane containing calcium carbonate crystals (statholith, 평형석) • Increases the mass of the gelatinous membrane → bend the cilia when positions are change 25

• Vertebrates – Labyrinth • Utricle – horizontal acceleration • Saccule – vertical acceleration • Semicircular canals Sterocilia are bent by otolith embedded in gelatinous matrix Linear acceleration – Continuous with utricle and saccule – Oriented in different planes – angular acceleration can be detected in any direction • Vestibular apparatus – Utricle – Saccule – semicircular canals semicirular canals vestibular nerve cochlea kinocillium stereocillia utricle saccule otolith 26

화학수용기 • Taste – Papilla (유두) – taste buds (미뢰) 50 -100 on a tongue • Salty – diffusion of Na+ • Acidic – diffusion of H+ • Sweet, bitter, umami – G-protein-coupled receptor foliate papilla 27

• Smell – Can detect tens of thousands of different smell – Different protein receptors might be involved olfactory bulb • p. H – Internal chemoreceptors nasal passage • Sensory receptors in blood or fluids cribiform plate olfactory receptor 28

시각 • Invertebrates – Eye spot – cannot form image • Detects the direction of light – Image forming visual organ – Insets, Mollusk, Chordate • Developed independently and converged (convergent evolution) • Vertebrates – Focus on fovea suspensory ligament • contraction of cililary muscle • puts slack on the suspensory ligament Fovea • rounded lens – focus near objects iris pupil lens cornea ciliary muscle retina sclera 29

• Photoreceptors on retina – rods – black & white when dim • rhodopsin • cis-retinal bound to opsin protein – cones – visual acuity and color vision • photopsin • 3 different types • cis-retinal bound to proteins • Horizontal cell, Amacrine cell – Inhibit lateral response of the photoreceptors – contrast and sharpness↑ ganglion cell bipolar cell amacrine cell horizontal cell optic nerve rods and cones wikipedia rod cell 30

• Signal transduction in the vertebrate eye 31

시각 가공과정 (Visual Processing) • Action potential of ganglion cell → lateral geniculate nuclei of the thalamus → occipital lobe of the cerebral cortex (visual cortex) – Frequency of impulse → light intensity at each point – Relative activity of ganglion cells connected with 3 types of cones → color information • Fovea – highest of [cones] – one-to one connection of • cone↔bipolar cell↔ganglion cell • high acuity of foveal vision • Color blindness – lack of one or more types of cones • Binocular vision – parallax (시차) – 3 D image 32

화학신호물질에 의한 인체 반응조절 • Direct contact • Synaptic signaling • Endocrine signaling – Endocrine glands • Secrete hormones • Use circulatory system to reach target • Paracrine signaling – Regulate cell within same tissue • Autocrine signaling – regulates self 33

호르몬의 유형 • Peptides and proteins – antidiuretic H, insulin, growth H, thyroid stimulating H, lutenizing H • Amino acid derivatives – biogenic amines • H of adrenal medulla, thyroid (←Y), pineal gland (melatonine ←W) – catecholamines • epinephrine, norepinephrine • Steroids – enzymatic modification of cholesterol – testosterone, estradiol, progesterone, aldosterone, cortisol 34

뇌하수체와 시상하부 • Pituitary gland – Anterior lobe adenohypophysis • Makes 7 tropic Hs (Table 14. 2) • Responds to RH & IH of hypothalamus come through hypothalamohypohyseal portal system – Posterior lobe neurophypophysis • Directly connects to hypothalamus • Antidiuretic H, oxytocin • Made by neurons of hypothalamus proper stimulus releases these Hs to blood vessels in the posterior lobe by an neuroendocrine mechanism 35

뇌하수체 전엽의 조절 negative feedback 36

주요 말초 내분비샘 • Thyroid gland • Parathyroid gland • Adrenal gland – Adrenal medulla – Adrenal cortex • Pancreas – Langerhans gland –cells – insulin – Langerhans gland –cells – glucagon • Diabetic – Type I – lack of –cells – Type II – non-responsive to insulin 37

호르몬의 작용 • Gonad – sex H • Pineal gland – melatonine – Sleep/wake regulation – Reproduction cycle regulation • Thymus – Atrial natriuretic H (ANH) (antagonistic to aldosterone) • Kidney – Erythropoetin – generation of erythrocytes • Skin – Vitamin D 38