Functional Anatomy of Nervous System PDF

Made with Xodo PDF Reader and Editor Functional Anatomy of Nervous system Nervous system consist of neurons and their extensions. Nervous system of pirimitive animals consists of simple sensory-motor circuits. In the complex animals, neural circuits include many interneurons and many conn...

Made with Xodo PDF Reader and Editor Functional Anatomy of Nervous system Nervous system consist of neurons and their extensions. Nervous system of pirimitive animals consists of simple sensory-motor circuits. In the complex animals, neural circuits include many interneurons and many connections with each other.  Made with Xodo PDF Reader and Editor Evolutinary, the specialized sensory neurons, motor neurons, and effector cells derived from undifferentiated epithelial cells. In simple animal, nerve network usually consist of simple reflex arc, no central control.  Made with Xodo PDF Reader and Editor In more advanced animal, the nerve body of sensory nerve clustered outside of the central nervous system and called as ganglia. In primitive animals, the nerve net is composed of longitiudinal nerve cords alongated dorsally and ventrally and transverse commussures that interconnect the longituidinal cords. uzunlamasına kordları birbirine bağlayan enine komissürler.  Made with Xodo PDF Reader and Editor Nerve Networks There is no neural network in unicellular organism. Cillia of these animals have a locomotory or feeding function. The coordination of ciliary activity in some protazoa, stentor is made by oral cilia. Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor This type of coordination is provided by some cytoplasmic fibrils under the surface. Paramecium can detect the danger and change the beating direction of cilia. Sponges are generally considered to lack nervous and sensory cells.  Made with Xodo PDF Reader and Editor Any portion of the sponge tissue can be stimulated, and there is a generalized spread of conduction over the entire sponge. Cnidarians (hydra) are radially symmetrical with a complex body wall structure. Most cniderians have a well-developed nerve net. Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor The neurons and nerve nets of cnidarians and ctenephores have many basic properties of the central nervous systems of higher animals. Made with Xodo PDF Reader and Editor Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor Nöronlar bütünleştirici mekanizmalar göstermektedir: uzaysal ve zamansal toplama, kolaylaştırma, engelleme ve yüksek hızlı iletim. The neurons show integrative mechanisms: spatial and temporal summation, facilitation, inhibition and high-velocity conduction. The nerve nets have pacemaker regions, The pacemaker region refers to a specific area in biological systems, usually in the heart or other specialized ganglia. excitable tissues, that generates and controls rhythmic activity or contractions. This region typically contains specialized cells that can produce spontaneous electrical impulses, which set the pace for a rhythmic function such as the heartbeat  Made with Xodo PDF Reader and Editor Animals Nerve Cords and Brains ın Invertebrate Animals Animals of most phyla higher than Cnideria have a bilateral rather than radial symmetry. In these animal there is cranial and caudal part of nervous system. Cephalization is developed. Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor Plaetylminth worms (flatworms) show well developed bilateral symmetric, cephalized nervous system. The brain of many platyhelminth worms is not essential for even normal function.  Made with Xodo PDF Reader and Editor In many platyhelminth worms (flatworms), such as Planaria, the brain is not essential for basic functions like movement, feeding, and sensory responses. This is because the nervous system of these organisms is relatively simple and distributed in a way that allows for function even in the absence of a centralized brain. Here’s why: Decentralized Nervous System: While platyhelminths have a primitive brain or cerebral ganglia at the anterior (head) end, much of their nervous system consists of longitudinal nerve cords running down the length of the body. These nerve cords are interconnected by transverse commissures, creating a network that can function independently of the brain. Made with Xodo PDF Reader and Editor Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor Nemertine worms, nematodes and annelids have a more organized nervous system than platyhelmints. The giant axons of annelids rapidly conduct information for reflex muscle contruction during defensive avoidance.  Made with Xodo PDF Reader and Editor The general plan of arthropod nervous system resembles that of annelids. The arthropod brain consist of three main regions; protocerebrum, deuterocerebrum, tritocerebrum. Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor Vertebrate Nervous System  The organization of the vertebrate nervous system is different from invertebrates.  Vertebrates have a well-organized hollow dorsal nervous system.  The central nervous sytem included a brain and spinal cord.  Made with Xodo PDF Reader and Editor The peripheral nervous system comprise peripheral nerves extending from spinal cord and peripheral ganglia. The central nervous system of the vertebrate animals is composed of gray and white matter. Gray matter contains neuron cell bodies, dentrides, axon, and synapses. The white matter is axon tracts. Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor Structure of gray matter  Made with Xodo PDF Reader and Editor The unipolar neurons of vertebrates are primarily sensory. Many interneurons and motorneurons are multipolar. Nervous sytem functionally comprise three type of neurons: Sensory, motor and interneurons.  Made with Xodo PDF Reader and Editor Unipolar neurons, also known as pseudounipolar neurons, have a single process that extends from the cell body and then splits into two branches. In vertebrates, these neurons are primarily sensory neurons, meaning they are responsible for transmitting sensory information from the peripheral nervous system to the central nervous system (CNS). Here's a breakdown of what this means: 1. Structure: Unipolar neurons have a single axon that bifurcates into two branches: one that extends to the sensory receptors (peripheral branch) and another that leads to the spinal cord or brain (central branch). 2. Function: They are involved in transmitting sensory data such as touch, pain, temperature, and proprioception. When sensory receptors detect a stimulus, the unipolar neuron carries this information as electrical impulses toward the CNS for processing. 3. Location: Unipolar neurons are typically found in sensory ganglia, such as the dorsal root ganglia of spinal nerves.  Made with Xodo PDF Reader and Editor 1. Sensory Neurons (Afferent Neurons) Function: Carry sensory information from sensory receptors to the central nervous system (CNS). Structure: Often unipolar (or pseudounipolar), with one axon that splits into two branches: one towards the sensory receptor and one towards the CNS. Location: Found in sensory ganglia, such as dorsal root ganglia. Types of Sensory Information: Can detect stimuli such as light, sound, temperature, pain, and pressure. 2. Motor Neurons (Efferent Neurons) Function: Transmit signals from the CNS to effectors (muscles or glands) to produce a response. Structure: Typically multipolar, with a single long axon and multiple dendrites. Location: Found in the spinal cord (lower motor neurons) and in the brain (upper motor neurons). Types of Motor Responses: Control voluntary movements (skeletal muscles) and involuntary movements (smooth muscles and glands). 3. Interneurons (Association Neurons) Function: Connect sensory and motor neurons and integrate information within the CNS. They play a key role in reflexes and higher brain functions like learning and memory. Structure: Usually multipolar, with many dendrites and a relatively short axon. Location: Predominantly located in the CNS, specifically within the spinal cord and brain. Types of Interneurons: Can be excitatory (promoting action potentials in other neurons) or inhibitory (suppressing action potentials). Summary Sensory Neurons: Input from sensory organs to CNS; primarily unipolar. Motor Neurons: Output from CNS to muscles/glands; primarily multipolar. Interneurons: Communication within CNS; primarily multipolar and integrate signals between sensory and motor pathways.  Made with Xodo PDF Reader and Editor Higher animals have neurons grouped into a more organised central nervous system and peripheral ganglia. Ganglia is neuron clustered outside of the central nervous system and may include sensory, motor or mixed of them.  Made with Xodo PDF Reader and Editor Anatomy of Vertebrate Nervous System Nervous system of animals examined in two region Peripheral nervous system; sensory neurons, afferent and efferent nerves and ganglia Central Nervous system; Spinal cord and brain Made with Xodo PDF Reader and Editor Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor Peripheral nervous sytem Peripheral nervous sytem comprise peripheral nerves; afferent and efferent, receptors or sensory cell, and autonomic ganglia. Afferent nerves carry impulses from sensory cells to the spinal cord or brain. Efferent nerves carry impulses from spinal cord or brain to the effector organs (Muscle etc.).  Made with Xodo PDF Reader and Editor There are two kind of afferent nerves; somatic, visceral. Afferent nerves enter into the cord dorsally, efferent nerves leave the cord ventrally. There are two kind of afferent and efferent system.  Made with Xodo PDF Reader and Editor Somatic afferents and efferents innervate somatic organs that are voluntarily controlled. Autonomic afferents and efferents innervate autonomic organs such as heart and digestive channal. Cranial nerves innervate usually the muscle and gland of head. They originate from brain stem. Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor Sensory or receptor cells are stimulated by physical stimuli and localized in various sensory region of the body. Environmental information is only recieved by receptor cell or sometimes free afferent nerve endings.  Made with Xodo PDF Reader and Editor Receptor or Sensory Cell There are various type of the receptor cells. They are classified according to their sensitivity to different physical stimuli. For example chemical receptors only are stimulated by chemical stimuli. Photoreceptors are stimulated by light,  Made with Xodo PDF Reader and Editor Mechanoreceptor by mechanical stimuli Baroreceptor by pressure Mechanical receptors are two type: phasic receptor (Paccini corpuscle), tonic mechanoreceptor (Strech receptor on the wall of urinary blood). Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor Phasic receptor generate action potential only at the begining of stimuli, but tonic receptor is stimulated continously in the presence of stimuli. Photoreceptor found in the retina of eye. Baroreceptor found in the wall of blood vessel, they are free nerve ending.  Made with Xodo PDF Reader and Editor Pain receptor is also free nerve ending and are stimulated by chemical mediators relased from damaged cell. Chemoreceptors are found in the tongue, olfactory nasal region. Receptors are localized in certain regions of the body. Every receptor can be stimulated by the stimuli applied to regions that they are localized.  Made with Xodo PDF Reader and Editor Information from around of the body are coded to the central nerveous system by the frequency of action potential. Olfactory stimuli is coded by the action potential frequency, since all receptor cell in olfactory region have more than one receptor molecule for different oder stimulant.  Made with Xodo PDF Reader and Editor Intensity of pressure is also coded by action potential frequency.  Made with Xodo PDF Reader and Editor Spinal Cord The spinal cord is the part of the central nervous system that is surrounded and protected by vertebral column. In cross section, the spinal cord is organized as a butterfly shaped mass of gray matter surrounded by white matter. Made with Xodo PDF Reader and Editor Made with Xodo PDF Reader and Editor Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor Gray matter of spinal cord are designated as name or romen numeral. The neuron cell bodies are organized into three discrete areas of the gray matter: the dorsal horn, the intermediate zone, and the ventral horn. Made with Xodo PDF Reader and Editor Made with Xodo PDF Reader and Editor Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor Afferents from periphery of body or internal organs, all enter to the cord dorsally and efferent leave the cord ventrally. The pathway of afferents in the spinal cord and their destination point in the higher brain center are different. But usually afferents from right side of the body destinate left side of the brain and from left side to the right side of the brain.  Made with Xodo PDF Reader and Editor The axon having similar originating point and also destination point are named with specific name. For example spinothalamic axon originate from spinal cord and destinate the thlamus region of the brain. And the pathway of muscle afferents and somatosensory afferents are different in the spinal cord.  Made with Xodo PDF Reader and Editor Afferent from spinal cord to the brain usually engage the dorsal side of the spinal cord. Otherwise efferents in the ventral side. All of the afferents synapse on the interneuron or directly on the motor neuron in the gray matter of spinal cord. But some afferents such as pain afferents, climb up to the brain without synaps in the entrance of the spinal cord. Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor Afferents in the spinal cord are transmitted to the brain by two way ; dorsal pathway, anterolateral pathway. On the dorsal pathway afferents pass to upward direction without making synapse in the entrance of the spinal cord. Destination point of dorsal afferent firstly on the neuron localised in the medulla region of brain stem and second to the neuron in the talamus. Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor In the anterolateral pathway, afferents entering to the spinal cord make synapse in the entrance and second order neuron climb up to the talamus without making synapse in the medulla region of the spinal cord. Otherwise muscle afferents entering to the spinal cord make synapse in the entrance and one branch climb up ipsilaterely to the cerebellum. Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor Pain sensation Pain is induced by mechanical damage of tissue cells. As a result of damage, bradykinin-like peptides are released. These peptides lead to the stimulation of IV type afferent fibers in the region.  Made with Xodo PDF Reader and Editor Pain sensation is transmitted to the brain by anterolateral pathway. The type IV afferents synapse on the neuron in lamina I and IV region of spinal gray matter. These second-order neurons are inhibited by somatosensory large afferent fibers. Made with Xodo PDF Reader and Editor Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor That is why the pain sense can be decreased by mechanical stimuli applied from same dermatomal region of pain.  Made with Xodo PDF Reader and Editor Efferent Fibers Efferent motor pathways from the cerebral cortex, midbrain, and cerebellum synapse with the motorneurons in the ventral horn of gray matter. The main motor tracts are the corticospinal, rubrospinal, tectospinal tracts and vestibulospinal and reticulospinal tracts. Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor There are many nucleus in the brain and mid brain giving efferent fiber to the spinal cord. Efferent fiber originatic cortex and ending spinal cord is called as corticospinal fiber. The tract is composed of many axon having same pathway. Corticospinal axons are collectively called as piramidal tract also. Made with Xodo PDF Reader and Editor Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor  The efferent fibers originating from other subcortical region and ending spinal cord is called as extrapiramidal tracts.  Rubrospinal tract afferents originate from red nucleus in the brain stem and end in the spinal cord neurons.  Vestibulospinal tract originates from n. vestubularis and end on the ventral horn of spinal cord.  Made with Xodo PDF Reader and Editor Function of Spinal Cord 1. Transmission of impulses from brain to spinal cord and from spinal cord to the brain or higher center than spinal cord. 2. Reflex action: Most of the muscle contruction in our body occur reflexly.  Made with Xodo PDF Reader and Editor Reflex action of spinal cord is very important to escape the dangerous situation. The neurons in the reflex action found in the segmental cord. These are afferent fibers, interneuron in the spinal cord and efferent neuron innervating the muscle. Made with Xodo PDF Reader and Editor Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor Brain The chordate brain is divided into three main parts: the prosencephalon ; telencephalon and diencephalon (forebrain), mesencephalon (midbrain) and rhombencephalon; medulla and pons ( hindbrain). Made with Xodo PDF Reader and Editor Made with Xodo PDF Reader and Editor Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor Each of these three parts of the brain in primitive vertebrates has a dorsal area of gray matter associated with the three main senses: olfaction (forebrain), vision (midbrain), and the acustico- lateralis system (hindbrain).  Made with Xodo PDF Reader and Editor Hind Brain Hind brain is divided into the more posterior myelencephelon (Most of the medulla) and metencephelon (Cerebellum, pons and part of the medulla). The medulla in lower vertebrates is similar to the spinal cord.  Made with Xodo PDF Reader and Editor In higher vertebrates, medulla is enlarged to form the forth ventricle. The channel in the medulla extended by the ventricles in the brain that is filled with serebrospinal fluid secreted by choroid plexus in the third and lateral ventricles. Made with Xodo PDF Reader and Editor Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor The medulla include several nuclei. These nuclei are the primary receptor areas for the acustico-lateralis system. In mammals, there is a seperate vestibular nucleus and cochlear nucleus. Medullary nuclei are also centers for control of specific motor functions, such as heart rate, respiration, digestion and salivation. Made with Xodo PDF Reader and Editor Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor The pons is the superior of the medulla that also includes some nuclei and adjacent to serebellum dorsally. All of the cranial nerve originates medulla and pons region.  Made with Xodo PDF Reader and Editor Pons and medulla together is also termed as brain stem. Brain stem is important region for vegatative function. Without brain stem animal goes to die. But with intact brainstem but without cortex cerebri animal going on to live.  Made with Xodo PDF Reader and Editor Reticular Formation The reticular formation is a neural network extending from the medulla to midportion of the brain. This system receives a variety of sensory inputs from spinal cord, cranial nerves, cerebrum,hypothalamus) and give rise to output, especially to the cortical region of the brain. Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor Reticular formation is related with the arousal and sleep activity of animals. Medullar reticular formation usually send inhibitory impulses to the the cortical region, but pontin reticular formation send facilatatory impulses to the cortical area of the brain. Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor  There are many synaptic connections in the reticular formation as like reticular meshwork.  There are synapse that only release one type of neurotransmitter such as norepinephrine, dopamine, or serotonin.  These groups of neurons are called according to the type of included neurotransmitter as; noradrenergic, serotonergic, or dopaminergic.  Made with Xodo PDF Reader and Editor Serebellum Serebellum is a structure that found dorsal region of medulla and pons. It coordinates and regulate the more complex motor activities, such as maintanence of posture and locomation.  Made with Xodo PDF Reader and Editor Serebellum is related with muscle motor function. If the serebellum is removed surgically, coordinated muscle contraction is disturbed and maintanence of body posture disappear. The serebellar structure is similar to the cortex cerebri. Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor  There is gray matter on the surface but white matter on the inner side.  The surface has many small invaginations that is called gyri as like cerebri.  Cerebellum receives impulses from the periphery by the spinocerebellar tract, and from some nuclei from brain stem and also fibers from motor cortex. Made with Xodo PDF Reader and Editor Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor It sends stimuli to the motor cortex and some nucleus in the brain stem; red nucleus, nucleus vestibularis, reticular formation. Efferent fibers to the cortex is conducted by the way of thalamus. There are three lobe of the serebellum; anterior lobe, posterior lobe, foliculonodular lobe. Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor The information related with equilibrium is conducted to serebellum by the way of n. Vestibularis. Fibers from N vestibularis is relayed on the neurons in the foliculonodular lobe of serebellum. Made with Xodo PDF Reader and Editor Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor Midbrain Mid brain is region just above the pons and under the cortex cerebri. It comprise some part of reticular formation and tectum. The midbrain is important in lower vertebrates for the processing of visual information and motor autput. The midbrain integrates different modes of information. Made with Xodo PDF Reader and Editor Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor For example some parts of the tectum correlate visual, auditory and somatic sensory information; In mammals, the corpora quadrogemina in the midbrain control reflex movement of the eyes and head in response to visual and other stimuli.  Made with Xodo PDF Reader and Editor Forebrain Forebrain is divided into the diencephelon and thelencephelon. The dorsal portion of the diencephelon is the epithalamus, the lateral portion is the thalamus and the ventral portion is the hypothalamus. Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor The epithalamus contains a small nucleus that transmits olfactory information to the brain stem, the pineal and parapineal bodies, and the anterior choroid plexus.  Made with Xodo PDF Reader and Editor In lower vertebrates epithalamus is well developed and important for the transmisison of impulses from periphery to cerebral cortex, but in mammales most of sensory information is transferred to the cerebral cortex via the thalamus.  Made with Xodo PDF Reader and Editor Thalamus Thalamus is localised in the diencephalon and is bilobed on the right and left sides. All of the sensory impulses from the periphery synapse on the neurons in the thalamus, lateral geniculate body for vision, medial geniculate body for hearing and ventral nucleus for somatic sensation. Made with Xodo PDF Reader and Editor Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor Then it goes to the cortex. Thalamus function as like a commander so that it recieves information from periphery and send commend to the certain area of cortex to control motor function. Thalamus is connected with structures of limbic system, which is involved in the processing and regulating emotions, formation and storage of memories, sexual arousal and learning Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor Hypothalamus Hypothalumus is a structure that is very important both autonomic and endocrine function. Hypothalamus is only 1% of the brain mass (in humans) but it is one of the brain’s most important outputs paths. The hypothalamus is located below the thalamus and is part of the limbic system Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor It controls most vegetative and endocrine functions of the body as well as emotions. The preoptic area of hypothalamus is involved in body temperature regulation.  Made with Xodo PDF Reader and Editor The lateral hypothalamus contains a thirst center and the group of nucleus called as supraoptic that secretes ADH hormone. Another nucleus in this region is called paraventricular nuclei which produce oxytocin. Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor There is a hunger center in the lateral hypothalamus and a satiety center in the ventromedial part of hypothalamus. The mamillary bodies in hypothalamus activate many feeding reflexes.  Made with Xodo PDF Reader and Editor Hypothalamus also have some regulatory role in the behavior of animals. The stimulation of some region in lateral hypothalamus stimulate angry behavior, but stimulation of ventromedial nucleus of hypothalamus produce silence behavior.  Made with Xodo PDF Reader and Editor Limbic System The limbic system is a part of structure both covers lower region of cortex ( orbitofrontal area, cingulate gyrus, parahypocampal gyrus) and some subcortical structure (epithalamus, anterior hypothalamus, basal ganglia, hippocampus and amygdala). Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor The lymbic system have many function by hypothalamus, and other function; olfaction by amygdala, emotions and learning by hippocampus, behaviour by limbic cortex.  Made with Xodo PDF Reader and Editor Telencephelon The telencephelon consist of the cerebral hemisphere, basal nuclei and olfactory bulb. In pirimitive vertebrates, the cerebral hemisphere are mainly involved with olfaction and related motor responses.  Made with Xodo PDF Reader and Editor In higher vertebrates the gray matter of the cerebral hemisferes, except for the basal ganglia is moved to the surface, forming the cerebral cortex. In mammals, the cortex forms the majority of the cerebral hemispheres. The cortex has convulated surface and many neurons. Made with Xodo PDF Reader and Editor Made with Xodo PDF Reader and Editor Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor  The various regions of the cortex have very specific functions; the three general areas are sensory cortex, association cortex and motor cortex.  The primary sensory cortex recieves sensory information, thalamocortical projection fibers, association fibers from the cortical areas and commissural fibers from other side of the brain.  Made with Xodo PDF Reader and Editor The motor cortex give rise to motor fibers that travel specific parts of the body. The visual cortex of the occipital lobe gets the stimuli from the retina of the eye. The auditory cortex of temporal lobe gets the stimuli from ear.  Made with Xodo PDF Reader and Editor The human motor map in the motor cortex is different from that of lower mammals. In the human the hands and mouth and facial region is represented by large facial regions. This is associated with human capacity for hand skills and speech.  Made with Xodo PDF Reader and Editor  There also is a supplemental motor area that elicits coordinated contructions of different muscle groups, rather than discrete muscle contructions.  The premotor cortex is located anterior to the primary motor cortex.  This association area elicits often complex coordinated contructions of group of muscles  Made with Xodo PDF Reader and Editor Brocas area controls word formation and vocalization of complex sounds. Other motor areas control eye movement and hand skills. Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor Basal Ganglia Basal ganglia is composed of some nuclei in the diencephelon; caudate nucleus, putamen, globus pallidus, and substantia nigra. These neural structure is related with motor function. Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor  Basal ganglia receive afferents from motor cortex and send efferents to the thalamus and then to the cortex.  Basal ganglia controls the motor impulses conducted from cortex to the spinal cord.  The complex fine movements is coordinated by the basal ganglia. Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor In the failure of the basal ganglia, spontenous contraction occur in the extremity muscle.  Made with Xodo PDF Reader and Editor Autonomic Nervous System In simpler animal, autonomic fibers directly originate segmentally arranged nerve cord and travel to the visceral organ as like peripheral nerves. In higher vertebrate and mammals, there are postganglionic ganglia in the periphery near to the innervated organ. Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor Autonomic nerves innervate involuntary internal organs of the body. After they emerge from spinal cord, it relays on a ganglia and the postganglionic fibers goes to the organ. Made with Xodo PDF Reader and Editor Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor When the autonomic nerves of a smooth muscle are cut, the smooth muscle continue to contruct and no atrophy seen. But somatic nerve is destroyed, atrophy occur in the innervated organ.  Made with Xodo PDF Reader and Editor Autonomic nervous system is divided into two functional branches: the parasymphatetic branch and symphatetic branch. The preganglionic fibers of the parasymphatetic system exit the central nervous system via cranial nerves and sacral spinal nerves and synapse at the peripheral organs. Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor The preganglionic fibers of symphatetic nerves leave the spinal cord via throracic and lumbar spinal nerves and synapse on to the ganglia close to the spinal cord or synapse in more peripheral sympathetic ganglia.  Made with Xodo PDF Reader and Editor  The symphatetic and parasymphatetic systems have antagonistic actions.  In general the symphatetic nervous system prepares the body for response to stressful or dangerous situations; it initiates the fight or flight reactions, elevation of heart rate and increased force of contraction, peripheral vasoconstriction, and sweating.  Made with Xodo PDF Reader and Editor In contrast, the parasymphatetic nervous system controls general bodily functions such as digestion. The neurotransmitter of postganglionic parasymphatetic synapse is acetylcholine, so the postsynaptyic receptors of these synapses are cholinergic.  Made with Xodo PDF Reader and Editor  The neurotransmitter of the symphatetic postganglionic synapse is usually norepinephrine, so these are adrenergic.  The symphatetic neurotransmitter is epinephrine rather than norepinephrine in some vertebrates.  The neurotransmitter at the preganglionic synapse of both the parasymphatetic and symphatetic branches is acetylcholine. Made with Xodo PDF Reader and Editor  Made with Xodo PDF Reader and Editor Ther are two types of acethylcholine receptors; nicotinic and muscarinic. There are also two basic types of norepinephrine / epinephrine receptor: α and β receptors. In mammals α receptors are stimulated by norepinephrine and epinephrine but β receptors mainly by norepinephrine. Made with Xodo PDF Reader and Editor Made with Xodo PDF Reader and Editor Made with Xodo PDF Reader and Editor Made with Xodo PDF Reader and Editor