Medical Sciences II Lecture Notes Chapter 1 PDF

Medical Sciences II Physiological control of biological function (Human) Nervous System (9) Muscular Skeletal System (3) Endocrine System (3) Renal System (1) Gastrointestinal System (1) Julien Vermot [email protected] office hour:Tuesday 1-2pm Recommended textbooks Medical Sciences II 9...

Medical Sciences II Physiological control of biological function (Human) Nervous System (9) Muscular Skeletal System (3) Endocrine System (3) Renal System (1) Gastrointestinal System (1) Julien Vermot [email protected] office hour:Tuesday 1-2pm Recommended textbooks Medical Sciences II 9 lectures on: Human Nervous System „From simple reflexes to voluntary movements“ Example1: Brain Machine Interface for movement restoration Pandarinath et al eLife 2017 Example2: Robots engineering https://www.bostondynamics.com https://www.youtube.com/watch?v=WcbGRBPkrps …But we have still lots to learn from humans Simon Biles https://www.youtube.com/watch?v=khz4sD1j0QU Chapter1: Basic Neuroanatomy of the nervous system 1. Major divisions of the Central Nervous System, CNS 2. Microanatomy of neuronal cells 3. The different non neuronal cell types divisions of the Central Nervous System, CNS ctions with the peripheral nervous system underlies function Studying the Nervous System 15 Studying the Nervous System 15 nervous system (A) Central Peripheral (B) nervous system (A) nervous system Central nervous system Peripheral (B) Cerebral hemispheres, diencephalon, Central nervous system nervous system Cerebral hemispheres, cerebellum, diencephalon, brainstem, and spinal cord Central cerebellum, brainstem, (analysisand andspinal cord of integration (analysis and integration sensory and motor of information) Brain Cranial nerves sensory and motor information) Brain Cranial nerves Spinal cord Spinal cord Spinal Spinal nerves nerves SensorySensory Motor Motor components components components components Visceral Visceral Somatic Somatic motor system motor system nervous system motor system motor system nervous system SensorySensory ganglia ganglia Peripheral Peripheral and nerves (sympathetic, (sympathetic, and nervesparasympathetic, parasympathetic, and enteric Motor nerves divisions)and enteric Motor nerves Sensory receptors divisions) Sensory (at surface and receptorsAutonomic surface and ganglia Autonomic (atbody) within the within the body)and nerves ganglia and nerves Effectors Internal and Effectors Smooth muscles, externalInternal cardiac muscles, Skeletal (striated) environmentand muscles Smooth muscles, and glands external Skeletal (striated) cardiac muscles, environment and glands muscles FIGURE 1.12 The major anatomical components Figure of 1.1 single glial covering that protects otherwise unmyelinated the nervous system and their functional relationships. axons within peripheral nerves. (A) The CNS (brain and spinal cord) and PNS (spinal and Two grossglial single histological covering terms that distinguish protects otherwiseregions richunmyelinated FIGURE 1.12 The major anatomical components of cranial nerves). (B) Diagram of the major components of the in neuronal cell bodies versus regions rich in axons. Gray the nervous system and their functional relationships. CNS and PNS and their functional relationships. Stimuli from axons within peripheral nerves. (A) matter refers Two to any accumulation histological of cell bodies and neu- theThe CNS (brain environment and information convey spinal cord) to and PNS (spinal processing circuitsand in gross terms distinguish regions rich cranial the brain and spinal cord, which in turn interpret their signifi-of the nerves). (B) Diagram of the major components ropil in the brain and spinal cord. White matter (named in neuronal cell bodies versus regions rich in axons. Gray CNS andand cance PNSsend andsignals their functional to peripheral relationships. effectors thatStimuli move the from for its relatively light appearance, the result of the lipid matter refers to any accumulation of cell bodies and neu- content of myelin) refers to axon tracts and commissures. the environment body and adjust convey information the workings to processing of its internal organs. circuits in the brain and spinal cord, which in turn interpret their signifi- Within ropil grayinmatter, the brain nerveandcellsspinal cord. White are arranged in twomatter dif- (named cance and send signals to peripheral effectors that move the ferent ways. A local accumulation with neurons that haveof the lipid for its relatively light appearance, the result conventionally body and adjustdivided the vertebrate the workings nervous of its internal system an- organs. roughlycontent similarofconnections myelin) refers to axon tracts and functions anda commissures. is called nu- atomically into central and peripheral components (Figure cleusWithin gray matter, (plural: nuclei, not to benerve cellswith confused are the arranged nucleusin two dif- 1.12). The central nervous system, typically referred to as of a cell); such ferent collections ways. A localare found throughout accumulation withthe cere- that have neurons the CNS, comprises conventionally the brain divided (cerebral hemispheres, the vertebrate nervous systemdien- an- brum,roughly diencephalon, similar connections and functionscon- brainstem, and spinal cord. In is called a nu- cephalon, cerebellum, and brainstem) and the atomically into central and peripheral components (Figure spinal cord. trast, cortex (plural: cleus (plural:cortices) describes nuclei, not to besheetlike confused arrays withofthe nucleus The peripheral nervous system (PNS) includes the sen- nerve cells. The cortices of the cerebral hemispheres and 1.12). The central nervous system, typically referred to as of a cell); such collections are found throughout the cere- sory neurons that link sensory receptors on the body sur- of the cerebellum provide the clearest examples of this the CNS, comprises the brain (cerebral hemispheres, dien- face or deeper within it with relevant processing circuits in brum, diencephalon, brainstem, and spinal cord. In con- organizational principle. Within the white matter of the cephalon, the CNS. cerebellum, and brainstem) The motor portion of the PNS in andturn spinalof theconsists cord. axons cortex CNS, trast, (plural: are gathered intocortices) tracts thatdescribes are more sheetlike or less arrays of twoperipheral The components.nervous The motor system (PNS axons that ) includes connect the sen- the brain nervetocells. analogous nerves The cortices in the of the periphery. Eachcerebral hemispheres and tract contains sory andneurons spinal cord that to link sensory skeletal musclesreceptors make upon thethe body sur- somatic axonsofthatthetypically cerebellum provide originate in thethesame clearest examples of this gray matter face or deeper motor division within of theitPNS, withwhereas relevantthe processing cells and circuits axons in organizational structure, are organized principle. in parallel, Within and oftenthe terminate white matter of the that innervate smooth muscle, cardiac muscle, the CNS. The motor portion of the PNS in turn consists of and glands in theCNS, same division axons are of gray matterinto gathered at some tractsdistance from that are more or less PURVES make up: Neuroscience the visceral6e or autonomic motor division. their analogous origin. Tracts that cross the midline of the brain, two components. Figure: 0112 The motor axons that connect the brain to nerves in the periphery. Each tract contains and Those nerve cell bodies that spinal cord to skeletal 7.21.17 residemake muscles in theup PNStheare lo- somatic such as the corpus axons callosum that that typically interconnects originate in the the same cere- gray matter cated in ganglia, which are simply local accumulations of bral hemispheres, are referred to as commissures. The motor division of the PNS, whereas the cells and axons structure, are organized in parallel, and often terminate nerve cell bodies and supporting cells. Peripheral axons sensory tracts of the dorsal spinal cord are referred to as that are innervate gathered into smooth muscle, bundles calledcardiac muscle, and glands nerves, many of which in the same division of gray matter at some distance from columns. PURVES make up : Neuroscience the visceral 6e or autonomic motor division. are enveloped Figure: 0112 by the glial cells of the PNS; as mentioned Thetheir origin.ofTracts organization thatmotor the visceral crossdivision the midline of the PNSof the brain, Those earlier, 7.21.17 nerve these cell bodies peripheral thatcalled glia are reside in the cells Schwann PNS(see are lo- suchcells (the nerve as thethatcorpus callosum control the functions that interconnects of the visceral or- the cere- cated above),in ganglia , which and they either are simply myelinate theselocal axonsaccumulations or provide a of gans, bral hemispheres, including are referred the heart, lungs, to as commissures gastrointestinal tract, and. The nerve cell bodies and supporting cells. Peripheral axons sensory tracts of the dorsal spinal cord are referred to as are gathered into bundles called nerves, many of which columns. are enveloped by the glial cells of the PNS; as mentioned The organization of the visceral motor division of the PNS earlier, these peripheral glia are called Schwann cells (see (the nerve cells that control the functions of the visceral or-  Medical Sciences II L1 1.2 Processes required to control motor action Nervous System Biological systems operate under closed-loop conditions Figure 1.2  The nerve fibers to and from the spinal cord are distinct areas. sory andbundled a motor division. The sensory division (the in 31 spinal nerves, each of which has a sen- immediately rostral to the spinal cord—the medulla The three divisions of the central nervous system dorsal root) carries information sory and a motor division. from The muscles and skin sensory division (the and immediately rostral tocollectively midbrain—are termedmedulla, the spinal cord—the the brain ste pons dorsal root) carries information from muscles and skin and midbrain—are collectively termed the brain stem. 1. Major divisions of the Central Nervous System, CNS 1.3 Learning about function requires knowledge of CNS anatomy Lateral view Medial view Lateral view Medial view Cerebral Cerebral cortex Cerebral Cerebral cortex cortex cortex Diencephalon Diencephalon Cerebellum Cerebellum Brain Brain Midbrain stem Midbrain stem Brain Pons Spinal cord stem Brain Pons Spinal cord stem Medulla Medulla Cerebellum Cerebellum Spinal cord Spinal cord CNS “in situ” There are 7 major divisions. Figure 15–3 The major divisions of the central nervous Brain and spinal cord are protected by the skull and the backbone, respectively. system. Drawings show a lateral view of the left side of the brain and the medial surface of the right side of the brain. Figure Brain and spinal cord are bathed in cerebrospinal fluid, CSF. It provides 15–3 further (Adapted, The with major divisions mechanical permission, of the central from protection Nieuwenhuys, andnervous Voogd, and system. Drawings van Huijzen 1988.) show a lateral view of the left side of the is separated form the general vascular system by the blood-CSF barrier. brain and the medial surface of the right side of the brain. Figure 1.3 (Adapted, with permission, from Nieuwenhuys, Voogd, and van Huijzen 1988.)  1 Ventral Dorsal A Rostral-caudal and dorsal-ventral axes B Medial-lateral axis 1 (anterior) (posterior) Dorsal Rostral Rostral Rostral Caudal Caudal Caudal Caudal Ventral Rostral Rostral C Section planes 2 Ventral Horizontal plane C Ventral (inferior) (inferior) Lateral Medial Lateral Dorsal V (superior) Dorsal 1 2 2 Rostral Caudal Ventral Ventral Dorsal Dorsal Rostral (anterior) (anterior) (posterior) (posterior) Chapter 15 / The Organization of the Central Nervous System 339 Ventral Caudal Caudal V (inferior) rostral = towards the nose Ventral ( caudal = towards the tail Dorsal 2 Ventral C Section C Section Dorsal planes planes dorsal = towards the back (posterior) (anterior) (posterior) ventral plane = towards the belly Coronal plane Horizontal Horizontal plane Figure 15–2 The Coronal plane nervous system is Sagittal central plane described Sagittal along plane superior = upper Caudal inferior = lower three major Ventral (anterior) axes. (Adapted, with permission, from Martin AC Rostral-caudal and dorsal-ventral axes medial = in theB middle Medial-lateral2003.) axis Section planes 1 Horizontal plane Dorsal lateral = at/towards the side Coronal plane Sagittal A. Rostral means toward the nose and caudal toward the plane tail. Dorsal means toward the back of the animal and ventral Rostral Caudal toward the belly. In lower mammals the orientations of these Ventral two axes are maintained through development into adult life. In humans and other higher primates the longitudinal axis flexes in the brain stem by approximately 110°. Because of this flexure the same positional terms have different mean- 2 ings when referring to structures below and above the flexure. Figure 15–2 The central nervous system is described along spinal column), ventral (anterior) means toward the belly, and three major axes. (Adapted, with permission, from Martin dorsal (posterior) means toward the back. Below Abovethe flexure, in the spinal cord, rostral means toward the the flexure, 2003.) Figure Figure 15–2 15–2 TheThe central central nervous nervous rostral means systemsystem toward the is described nose, Lateral iscaudal described Figure head, along 1.4toward means Medial caudalalong the back means spinal Lateral column), spinal toward column), ventral the coccyx ventral(anterior) (the lower endmeans (anterior) meanstowa of the to Dorsal of the head, ventral means toward the jaw, and dorsal means A. Rostral means towardthree the nosemajor three and caudalaxes. major (Adapted, toward the axes. (Adapted, with permission, with permission, from fromMartinMartin dorsal dorsal(posterior) Dorsal (posterior)meansmeans toward the toward back. the Ab back. Figure 1.4: toward the belly. In lower Anatomical tail. Dorsal means toward(superior) 2003.) 2003.) mammals terminology. the back of the animal and ventral the orientations of these toward the top of the synonymously with dorsal, head. The term superior is 1 and inferior means the same as often used rostral means rostral means toward toward thethe nose, caudal nose, mean caudal me two axes are maintained through development into adult life. ventral. Rostral A. primates themeans toward the nose andtoward caudal toward thethe of the of head, the ventral head, ventralmeansmeans toward the toward jaw, the a jaw In humans and other higher A. Rostral means longitudinal axis toward B. the Medial nose means and caudal the middle toward of the brain and lateral Note flexes in the brain stem by approximately tail.tail. Dorsal that 110°. in Because humans of the toward orientation the side. of the spinal cord toward relative to toward the the top the of top the of head. the The head. term The superio term sup this flexure the same positional terms havemeans Dorsal means different toward mean- toward the back the C. When ofarethe back brains animal ofsectioned the animal andand for analysis, ventral slicesventral are typically ings when Rostral toward referring to structures brain theand below is rotated belly. above by In flexure. the lower 90 Caudal degrees mammals compared in one ofthe orientations to the ofsituation these synonymously or in rodents. This withwith synonymously dorsal, andand dorsal, inferior mean inferior m toward the belly. In lower mademammals threethe orientations cardinal planes: horizontal,ofcoronal, these Below the flexure, in the spinal cord, rostral means toward the two axesRostral is axes arelower because maintained humans sagittal. through arethrough walkingdevelopmentupright,into which adult ventral. ventral. life.life. an adjustment required head, caudal means toward two the coccyx (the are maintained end of the development into adult In humans of head In humans andorientation. other and otherhigher primates higher primates thethe longitudinal longitudinal axisaxis B. Medial B. Medial meansmeans toward towardthethemiddle of the middle br of the flexes flexesin thein brain the stem brain stem by approximately by approximately 110°. 110°.Because Because of of toward toward thetheside. side. Ventral this flexure this (inferior)flexure thethe same same positional positional termsterms have havedifferent different mean- mean- C. When brains are are sectioned for for analysis, sli When C.Ventral brains sectioned analysis, ingsings when when referring referring to structures to structures belowbelow andand above above thethe flexure. flexure. made in one of three cardinal planes: horizon made in one of three cardinal planes: hori Below Below thethe flexure, flexure, in the spinal in the spinalcord, cord,rostral rostralmeans means towardtoward thethe sagittal. Dorsal 2 sagittal. (posterior) head, head,caudalcaudal meansmeans towardtowardthethe coccyx coccyx (the(thelower lowerendend of the of the Ventral Dorsal (anterior) (posterior) Caudal Ventral (anterior) C Section planes Horizontal plane Coronal plane Sagittal plane Figure 15–2 The central nervous system is described along spinal column), ventral (anterior) means toward the belly, and three major axes. (Adapted, with permission, from Martin dorsal (posterior) means toward the back. Above the flexure, 2003.) rostral means toward the nose, caudal means toward the back A. Rostral means toward the nose and caudal toward the of the head, ventral means toward the jaw, and dorsal means tail. Dorsal means toward the back of the animal and ventral toward the top of the head. The term superior is often used toward the belly. In lower mammals the orientations of these synonymously with dorsal, and inferior means the same as two axes are maintained through development into adult life. ventral. In humans and other higher primates the longitudinal axis B. Medial means toward the middle of the brain and lateral flexes in the brain stem by approximately 110°. Because of toward the side. this flexure the same positional terms have different mean- C. When brains are sectioned for analysis, slices are typically ings when referring to structures below and above the flexure. made in one of three cardinal planes: horizontal, coronal, or  2 seful anatomical definitions Lateral Medial Lateral Dorsal -lateral axis 1 1 Caudal stral Ventral Dorsal 2 (posterior) 2 ral Dorsal erior) (posterior) Medial Caudal Lateral Ventral Figure 1.5 (anterior) Dorsal tal plane Coronal plane Sagittal plane s system is described along spinalVentral column), ventral (anterior) means toward the belly, a h permission, from Martin dorsal (posterior) means toward the back. Above the flexur rostral means toward the nose, caudal means toward the b Dorsal e and caudal toward the of the(posterior) head, ventral means toward the jaw, and dorsal mea ck of the animal and ventral toward the top of the head. The term superior is often use als the orientations of these synonymously with dorsal, and inferior means the same as development into adult life. ventral. ates the longitudinal axis B. Medial means toward the middle of the brain and lateral ximately 110°. Because of toward the side. Ventral erms have different mean- C. When brains are sectioned for analysis, slices are typical  the regulation of homeostasis. The overhanging por- pathways are not nearly as prominent but can be dem- tion of the cerebral cortex that buries the insula within onstrated with neuroanatomical tracing techniques the lateral sulcus is called the operculum. (see Box 4–2). 1.5 Anatomical structures of the CNS Central sulcus Cingulate gyrus Cingulate sulcus Parietal Parietal lobe lobe Corpus Parietal Frontal callosum occipital lobe sulcus Occipital lobe Frontal Occipital lobe lobe Lateral sulcus Calcarine sulcus Temporal Temporal lobe lobe Medulla Cerebellum Pons Cerebellum Spinal cord Medulla Figure 15–4 Anatomical The major structures: lobes sulci and some = grooves prominent & gyri = elevated of the brain sulci areas (singular: atgyrus) sulcus, right. (Reproduced, with permission, from of the human cerebral cortex. A lateral view of the left side Martin 2003.) The most prominent of the brain sulci is shown define at left and athe borders medial view ofbetween the brain’s lobes the right side Figure 1.6 Figure 1.6: Major lobes of the cortex. The frontal lobe, separated by the lateral sulcus from the temporal lobe, and the central sulcus from the parietal lobe. The cingulate sulcus (visible in a sagittal section) separates the frontal lobe from the parietal lobe internally.  Medical Sciences II L1 Chapter 15 / The Organization of the Central Nervous System 1.6 Further structures invisible from the surface Cingulate gyrus Caudate nucleus Ventricle Parietal lobe Globus pallidus Operculum Putamen Lateral sulcus Insular cortex Caudal Rostral Ventricle Amygdala coronal section Folding the cortex increases the brain surface Temporal lobe area: more surface area means more computing power! Frontal lobe Guess which “animal” has got an enormous cortical surface area? Figure 15–5 Structures in the middle of the cerebral hemi- called ventricles are filled with cerebrospinal fluid. (Adapt spheres. These include theFigure 1.7 (caudate nucleus and basal ganglia with permission, from England and Wakely 1991.) globus pallidus) and insular cortex. Large cavities in the brain Cross section to illustrate folded structure of the cortex and showing CSF- filled ventricles in the brain. The Major Functional Systems the arousal level of the animal. A single neuron Are Similarly Organized cally receives signals from thousands of presyn neurons, and the summation of all of these i The central nervous system consists of several func- determines the output of the neuron. The inform tional systems that are relatively autonomous. There encoded by each successive neuron in a func are, for example, discrete systems for each of the five pathway is typically more complex than the outp special senses (touch, vision, hearing, taste, smell), for the preceding neuron. different classes of movement (eye movements, arm movements, hand movements), and for language. Neurons at Each Synaptic Relay Are Organized Each functional system comprises numerous intercon- a Neural Map of the Body nected anatomical sites throughout the brain. These several functional systems of the brain must One of the most striking features of the orga act together cooperatively. In sensory systems, for tion of most sensory systems is that the inputs example, sensory neurons in the periphery project, peripheral receptive surfaces—the retina o directly or indirectly, to one or more regions in the eye, the cochlea of the inner ear, and the su spinal cord, brain stem, and thalamus. The thalamus of the skin—are arranged topographically thro projects to the primary sensory areas of cerebral cortex, out successive stages of processing. Neighb which in turn project to other regions of cortex. groups of cells in the retina, for example, proj neighboring groups of cells in nuclei of the t mus, which, in turn, project to neighboring re Information Is Transformed at Each Synaptic Relay of the visual cortex. In this way the neurons at The output of each synaptic relay in a functional path- successive relay of a sensory pathway for way is rarely the same as its input. For example, infor- orderly neural map of information from the r mation may be amplified or attenuated depending on tive surface.  nized in the cortex to the white matter (Figure 15–6). Layer I, the molecular layer, is occupied by the den- drites of cells located in deeper layers and axons that cortex near- travel through this layer to make connections in other d into layers areas of the cortex. Pial surface Golgi stain Nissl stain Weigert stain I Molecular 1.7 Cellular organization of the cortex layer External II granule cell layer External III pyramidal cell layer Internal IV granule cell layer The cortex is organized Internal V pyramidal in distinct layers. cell layer Note that depending on the staining technique VI Multiform you get different things to layer see White matter Figure 1.8 Figure 1.8: Golgi stains mark only a few cells more or less completely. It is unknown “why” the many other cells are not stained. Note the pyramidal cell the soma of which is located in layer V – its apical (single long process above the soma) and basal dendrites (shorter processes arranged around the soma) are nicely stained. The process right below the soma might be the axon carrying information to other cells. Nissel, and Weigert stains mark mostly only cell bodies and processes but no cell bodies, respectively.  Chapter 15 / The Organization of the Central Nervous IV System 347 V IV IV V Chapter 15 / The Organization of theV Central NervousV System 347 VI Prefrontal Primary Parietal Primary association motor association visual cortex cortex cortex VI cortex 1.8 Cortical layers and Brodmann‘s areas VI I I VI I I II II Prefrontal Primary II Parietal II Primary association motor association visual III cortex cortex cortex cortex III 6 4 31 III III 8 2 I I I I IV 5 9 IV II II V 7 9 II II IV IV 19 III V 46 V V VI 40 10 10 III 39 18 VI 45 44 III III 43 41 IV VI 42 11 VI 47 22 11 17 IV 21 18 V 38 37 19 IV IV Lateral view 20 V 6 4 31 Figure 15–8 The extent 6 of each cell 4 3 1 of the neocortex layer layer V V 8 VI 2 2 5 varies throughout the cortex. Sensory areas of5 cortex, such work 8 9 as the primary visual cortex, tend to have a very prominent 7 vario 7 internal 9 granular cell layer (layer IV), the site of sensory input. sion Motor areas of cortex, such 31 24 as the primary motor cortex, have hum VI 19 a very meager32layer IV but prominent output23 layers, such as19 2003 VI 46 VI