Understanding Neurons, Synapses, and Neuroglia: A Comprehensive
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Saint Joseph's University**We aren't endorsed by this school
Course
BIO 1011
Subject
Psychology
Date
Dec 11, 2024
Pages
16
Uploaded by SuperBookDeer44
Study GuideNeuron, Synapse, and NeurogliaoDefine neuron, synapse, and neuroglia.oDescribe the structure and function of a neuron.oExplain the process of synaptic transmission.oDifferentiate between the types of neuroglia and their functions.NeuronsDefinition: Neurons are the fundamental units of the nervous system, specialized cells that transmit signals through electrical and chemical impulses. Structure:Cell body (soma): Contains the nucleus and other organelles. Dendrites: Branch-like extensions that receive signals from other neurons. Axon: A long, slender fiber that carries electrical impulses away from the cell body. Axon terminal: The end of the axon where neurotransmitters are released. Function: Neurons are responsible for receiving, processing, and transmitting information throughout the nervous system. They enable sensory perception, thought, emotion, and movement.SynapseDefinition: A synapse is the junction between two neurons where communication occurs. Process of synaptic transmission:Neurotransmitter release: An electrical impulse (action potential) travels down the axon and reaches the axon terminal. Vesicle fusion: Calcium ions trigger the release of neurotransmitters from vesicles into the synaptic cleft (the gap between neurons). Neurotransmitter binding: Neurotransmitters bind to receptors on the postsynaptic neuron. Postsynaptic potential: Binding of neurotransmitters causes changes in the electrical potential of the postsynaptic neuron, either excitatory or inhibitory. Neurotransmitter removal: Neurotransmitters are removed from the synaptic cleft by reuptake, enzymatic degradation, or diffusion. NeurogliaDefinition: Neuroglia, also known as glial cells, are supporting cells of the nervous system. They provide structural support, nutrition, insulation, and protection for neurons. Types and functions:Astrocytes:Most abundant glial cells. Provide structural support, regulate the extracellular environment, and contribute to the blood-brain barrier. Oligodendrocytes (CNS) and Schwann cells (PNS):Produce myelin, a fatty substance that insulates axons and increases the speed of nerve impulse conduction. Microglia:
Act as immune cells of the brain, removing debris and pathogens.Ependymal cells:Line the ventricles of the brain and central canal of the spinal cord, producing cerebrospinal fluid. Differentiation between neurons and neuroglia:FeatureNeuronsNeurogliaFunctionTransmit nerve impulsesSupport and protect neuronsStructureCell body, dendrites, axonVarious shapes and sizesAbility to divideLimitedCan divide and regenerateNumberFewer than glial cellsMore abundant than neuronsPhysioEx Neurophysiology 2 ExercisesoReview the specific exercises covered in PhysioEx Neurophysiology 2.oUnderstand the concepts and procedures involved in each exercise.oBe able to interpret and analyze the data obtained from the exercises.oApply your knowledge to answer questions related to the exercises.Spinal Cord ModelsoIdentify the major structures of the spinal cord (gray matter, white matter, spinal nerves, etc.).oUnderstand the functions of different spinal cord regions.oDescribe the spinal cord's role in sensory and motor pathways.oExplain the concept of spinal reflexes.Major Structures of the Spinal CordThe spinal cord is a complex bundle of nerves that connects the brain to the rest of the body. It is protected by the vertebral column. The major structures include: Gray Matter: Primarily composed of neuron cell bodies, dendrites, and synapses. It is divided into horns: Anterior (ventral) horn: Contains motor neurons that control skeletal muscles. Posterior (dorsal) horn: Primarily contains sensory neurons that receive input from sensory receptors. Lateral horn: Found in the thoracic and lumbar regions, contains neurons of the sympathetic nervous system. White Matter: Surrounds the gray matter and consists primarily of myelinated axons. These axons bundle together to form tracts that carry information up and down the spinal cord. Ascending tracts: Carry sensory information to the brain. Descending tracts: Carry motor commands from the brain to the body.
Spinal Nerves: These nerves emerge from the spinal cord and branch out to the rest of the body. They contain bothsensory and motor fibers. Opens in a new windowopenbooks.lib.msu.eduspinal cord structure with gray and white matter, spinal nervesFunctions of Different Spinal Cord RegionsThe spinal cord is divided into regions based on the vertebrae: cervical, thoracic, lumbar, sacral, and coccygeal. Each region has specific functions: Cervical: Controls the head, neck, shoulders, arms, and hands. Thoracic: Controls the chest, upper abdomen, and some back muscles.Lumbar: Controls the lower back and legs. Sacral: Controls the pelvis, bowel, bladder, and sexual organs.Coccygeal: Controls a small area around the coccyx. Spinal Cord's Role in Sensory and Motor PathwaysSensory Pathways: Sensory information from the body is carried to the spinal cord through sensory neurons. This information is then transmitted to the brain via ascending tracts for processing. Motor Pathways: Motor commands originate in the brain and are transmitted down the spinal cord through descending tracts. These signals activate motor neurons in the anterior horn, leading to muscle contraction and movement. Opens in a new windowwww.researchgate.netsensory and motor pathways in the spinal cordSpinal ReflexesSpinal reflexes are rapid, involuntary responses to stimuli that occur without conscious brain involvement. They involve a simple pathway called a reflex arc: Sensory receptor: Detects a stimulus. Sensory neuron: Transmits the signal to the spinal cord. Interneuron: Processes the information within the spinal cord. Motor neuron: Carries the signal to the effector (muscle or gland). Effector: Responds to the stimulus. Spinal reflexes help protect the body from harm and maintain homeostasis. Examples include the knee-jerk reflex and the withdrawal reflex.Human Brain Model
oIdentify the major lobes and structures of the brain (cerebrum, cerebellum, brainstem, etc.).oDescribe the functions of different brain regions.oUnderstand the concept of brain lateralization.oExplain the relationship between brain structures and their associated functions.Major Lobes and Structures of the BrainThe human brain is an incredibly complex organ divided into several key components:Cerebrum: The largest part of the brain, responsible for higher-level cognitive functions. It's divided into four lobes:Frontal Lobe: Involved in personality, decision-making, planning, and motor function. Parietal Lobe: Processes sensory information such as touch, temperature, and pain. Temporal Lobe: Responsible for auditory processing, memory, and emotion. Occipital Lobe: Primarily responsible for vision. Cerebellum: Located at the back of the brain, it coordinates movement, balance, and posture. Brainstem: Connects the brain to the spinal cord, controlling basic life functions like breathing, heart rate, and digestion. It consists of: Midbrain: Involved in motor control, vision, and hearing. Pons: Relays information between the cerebellum and the rest of the brain. Medulla Oblongata: Controls vital functions like breathing, heart rate, and blood pressure. Functions of Different Brain RegionsAs mentioned earlier, different brain regions have specialized functions:Frontal Lobe: Key for personality, decision-making, planning, and voluntary movement. Parietal Lobe: Processes sensory information from the body, including touch, temperature, and pain. It also plays a role in spatial awareness. Temporal Lobe: Primarily responsible for hearing, but also involved in memory, emotion, and language comprehension.Occipital Lobe: Dedicated to processing visual information. Cerebellum: Coordinates movement, balance, and posture. Brainstem: Controls essential life functions, regulates arousal and sleep, and helps in sensory motor integration. Brain LateralizationBrain lateralization refers to the specialization of functions in each hemisphere of the brain. The left hemisphere is typically dominant for language, logic, and analytical thinking, while the right hemisphere is associated with spatial
abilities, creativity, and emotional processing. However, it's important to note that both hemispheres work together in complex cognitive processes. Relationship Between Brain Structures and FunctionsThe intricate structure of the brain is directly linked to its functions. Different areas are specialized for specific tasks, but they also interact and communicate with each other to create a unified and complex system. For example, the visual cortex in the occipital lobe receives information from the eyes, but it interacts with other brain regions to interpret and understand what is seen. Understanding the relationship between brain structures and functions is crucial for fields like neuroscience, psychology, and medicine. It helps in diagnosing and treating brain disorders, developing new therapies, and gaining insights into human behavior and cognition.Sheep BrainoCompare and contrast the sheep brain with the human brain.oIdentify major structures in the sheep brain and relate them to human brain structures.oUnderstand the evolutionary implications of brain differences.oExplain the dissection techniques used to study the sheep brain.Sheep Brain vs. Human BrainComparison and ContrastThe sheep brain, while smaller and less complex than the human brain, shares a fundamental structure with it, reflecting our shared mammalian ancestry.Both possess the same basic components: cerebrum, cerebellum, brainstem, and diencephalon. Similarities:Basic structure: Both brains exhibit a similar overall structure with distinct lobes and functional areas.Neural tissue: The composition of neural tissue, including neurons and glial cells, is fundamentally alike.Neurotransmitters: Both brains utilize the same neurotransmitters for communication.Differences:Size and complexity: The human brain is significantly larger and more convoluted, with a greater number of neurons.Cerebral cortex: The human cerebral cortex, responsible for higher cognitive functions, is much more developed and expansive.Specialization: Certain brain regions, such as the prefrontal cortex, are more pronounced in humans and associatedwith complex behaviors.Major Structures and Comparison
Sheep BrainStructureHuman BrainEquivalentFunctionCerebrumCerebrumLargest part of the brain; responsible for conscious thought, memory, and sensory processing.CerebellumCerebellumCoordinates movement, balance, and posture.BrainstemBrainstemControls basic life functions like breathing, heart rate, and digestion.DiencephalonDiencephalonRelays sensory information, regulates body temperature, and controlsendocrine functions.Olfactory bulbsOlfactory bulbsProcess sense of smell.Evolutionary ImplicationsThe differences between the sheep and human brain reflect the evolutionary adaptations necessary for survival in different ecological niches. Humans, with their complex social structures and problem-solving abilities, have developed a larger and more complex brain.This evolutionary expansion of the cerebral cortex is linked to advancements in language, tool use, and abstract thought. Dissection TechniquesDissection of the sheep brain is a common educational tool to understand brain anatomy. Here's a basic overview of the process: Preparation: Obtain a preserved sheep brain. External examination: Observe the overall shape, size, and major divisions.Removal of meninges: Carefully remove the protective membranes (meninges) to expose the brain surface.Identification of structures: Locate and identify key structures using anatomical diagrams.Cutting and observation: Make careful incisions to expose internal structures. Comparison: Compare the observed structures with diagrams of the human brain.Important safety precautions:Wear gloves and protective eyewear.Use sharp instruments with care.Dispose of tissues and materials properly.Human Eye ModeloIdentify the major structures of the eye (cornea, lens, retina, optic nerve, etc.).
oExplain the process of light refraction and image formation.The Human Eye: A Marvel of OpticsMajor Structures of the EyeThe human eye is a complex organ responsible for capturing light and converting it into electrical signals that the brain interprets as vision. Here are some of the key structures:Cornea: The clear, dome-shaped front part of the eye that covers the iris, pupil, and anterior chamber. It helps focus light entering the eye.Pupil: The black opening in the center of the iris that controls the amount of light entering the eye.Iris: The colored part of the eye that controls the size of the pupil.Lens: A transparent structure behind the pupil that focuses light on the retina. Retina: The light-sensitive layer at the back of the eye that converts light into electrical signals.Optic Nerve: The bundle of nerve fibers that carries visual information from the retina to the brain.Light Refraction and Image FormationLight refraction is the bending of light as it passes through different mediums, such as air and the eye's lens. This process is essential for image formation.When light rays enter the eye, they first pass through the cornea, which bends the light and helps focus it on the lens. The lens further refines the focus by changing its shape. This process, called accommodation, allows the eye to focus on objects at different distances.The focused light rays then reach the retina, where they are converted into electrical signals by specialized cells called photoreceptors. These signals are transmitted through the optic nerve to the brain, where they are interpreted as an image.
The retina contains two types of photoreceptors: rods and cones. Rods are sensitive to light and dark and are responsible for peripheral vision and night vision. Cones are responsible for color vision and are concentrated in the central part of the retina, called the fovea.The image formed on the retina is actually inverted, but the brain automatically corrects it so that we perceive the world right-side up.Sheep EyeoCompare and contrast the sheep eye with the human eye.oIdentify major structures in the sheep eye and relate them to human eye structures.oExplain the dissection techniques used to study the sheep eye.Comparison and ContrastThe sheep eye is structurally very similar to the human eye, serving the same fundamental purpose of capturing light and converting it into electrical signals for the brain to interpret as vision.Both eyes have evolved to adapt to similar environmental conditions, resulting in analogous structures and functions. Similarities:Basic structure: Both eyes consist of a sclera, cornea, iris, pupil, lens, vitreous humor, and retina.Image formation: Light enters through the cornea, passes through the pupil, is focused by the lens onto the retina, where photoreceptor cells convert light into neural signals.Function: Both eyes are essential for vision, enabling organisms to perceive the world around them.Differences:Size: Sheep eyes are generally larger than human eyes.Tapetum lucidum: Sheep eyes possess a tapetum lucidum, a reflective layer behind the retina that enhances night vision. Humans lack this structure. Sclera thickness: The sclera (white part of the eye) is typically thicker in sheep eyes.Cornea curvature: The curvature of the cornea, which affects the eye's refractive power, may differ between species.Major Structures and Their Functions
StructureSheep EyeHuman EyeFunctionScleraTough, white outer layerTough, white outer layerProtects the eyeCorneaTransparent front part of the eyeTransparent front part of the eyeFocuses lightIrisColored part of the eyeColored part of the eyeControls the amount of light entering the pupilPupilOpening in the irisOpening in the irisAllows light to enter the eyeLensTransparent structure behind the pupilTransparent structure behind the pupilFocuses light on the retinaVitreous humorJelly-like substance filling the eyeballJelly-like substance filling the eyeballMaintains eye shape, transmits lightRetinaLight-sensitive layer at the back of the eyeLight-sensitive layer at the back of the eyeConverts light into electrical signalsOptic nerveTransmits visual information to the brainTransmits visual information to the brainCarries nerve impulses from the retina to the brainDissection TechniquesDissecting a sheep eye is a common educational activity to understand the structure and function of the eye.The following techniques are typically used: Preparation: Obtain a fresh or preserved sheep eye. Wear protective gloves and goggles. Dissect on a dissecting tray.External examination: Observe the overall structure of the eye, including the sclera, cornea, iris, and pupil.Incision: Carefully make an incision through the sclera, avoiding damage to internal structures.Removal of vitreous humor: Gently remove the vitreous humor, a jelly-like substance filling the eyeball.Identification of structures: Locate and identify the lens, retina, and other internal structures.Observation of the retina: Examine the retina for its appearance and the presence of the tapetum lucidum.Careful handling: Avoid damaging delicate structures like the retina during the dissection process.Note: Dissection should be conducted under the supervision of a qualified instructor, and proper disposal of the specimen is essential.By comparing and contrasting the sheep eye with the human eye, students can gain a deeper understanding of the anatomy and physiology of vision.Human Ear ModeloIdentify the major structures of the ear (outer ear, middle ear, inner ear).oExplain the process of hearing and balance.oUnderstand the functions of different ear structures.oRelate ear structures to their sensory roles.Structure of the EarThe human ear is divided into three main sections:Outer Ear
Auricle (Pinna): The visible part of the ear, funnels sound waves into the ear canal.Ear Canal: A tube that carries sound waves to the eardrum. Middle EarTympanic Membrane (Eardrum): A thin membrane that vibrates in response to sound waves. Ossicles: Three tiny bones (malleus, incus, and stapes) that amplify sound vibrations and transmit them to the inner ear. Eustachian Tube: Connects the middle ear to the back of the throat, helping to equalize air pressure. Inner EarCochlea: A spiral-shaped cavity filled with fluid, containing hair cells that convert sound vibrations into electrical signals. Vestibular System: Responsible for balance and spatial orientation, consisting of the semicircular canals and vestibule. The Process of HearingSound Waves:Sound waves enter the outer ear and travel through the ear canal. Vibration: Sound waves cause the eardrum to vibrate. Amplification: The ossicles in the middle ear amplify these vibrations. Fluid Waves: The stapes transmits vibrations to the fluid in the cochlea. Hair Cell Activation: The fluid waves cause hair cells in the cochlea to move, generating electrical signals. Auditory Nerve: These electrical signals are transmitted to the brain via the auditory nerve. Brain Interpretation: The brain processes the signals and interprets them as sound. The Process of BalanceThe vestibular system in the inner ear is responsible for balance. It consists of: Semicircular canals: Detect rotational movements of the head.Vestibule: Detects linear acceleration and gravity. Hair cells within these structures sense movement and send signals to the brain, which interprets them to maintainbalance. Functions of Ear StructuresOuter Ear: Collects and directs sound waves.Middle Ear: Amplifies sound vibrations and transmits them to the inner ear. Inner Ear: Converts sound vibrations into electrical signals (cochlea) and maintains balance (vestibular system).Ear Structures and Sensory RolesCochlea: Sensory receptor for hearing, converting sound vibrations into electrical signals. Vestibular system: Sensory receptor for balance, detecting head movement and position. The ear is a complex and fascinating organ that allows us to hear the world around us and maintain our balance.
Special Senses Stations and Student DocumentReview the definitions and concepts covered in the special senses stations and student document.Understand the tests performed and their significance.Explain the relationship between sensory receptors and perception.Apply your knowledge to interpret sensory data.Peripheral Nerve and Cranial Nerve AnatomyoIdentify the major peripheral and cranial nerves.oUnderstand the functions of different nerves.oExplain the relationship between the nervous system and the body.Understanding the Peripheral Nervous System (PNS)The PNS is the vast network of nerves branching out from the central nervous system (CNS), which includes the brain and spinal cord.It connects the CNS to the rest of the body, enabling sensory input, motor output, and internal organ regulation. The Major Peripheral NervesWhile there are countless peripheral nerves, some major ones include:Spinal Nerves: These emerge from the spinal cord and innervate specific regions of the body. They are grouped into cervical, thoracic, lumbar, sacral, and coccygeal nerves based on their origin. Plexuses: These are complex networks formed by the merging of spinal nerves. Major plexuses include the cervical,brachial, lumbar, and sacral plexuses.Understanding the Cranial NervesCranial nerves originate directly from the brain and primarily innervate the head and neck region.There are 12 pairs, each with a specific name and function.
Cranial NerveRoman NumeralFunctionOlfactoryISmellOpticIIVisionOculomotorIIIEye movement, pupil controlTrochlearIVEye movementTrigeminalVFacial sensation, chewingAbducensVIEye movementFacialVIIFacial expression, tasteVestibulocochlearVIIIHearing, balanceGlossopharyngealIXTaste, swallowing, salivary glandsVagusXHeart, lungs, digestive systemAccessoryXINeck and shoulder musclesHypoglossalXIITongue movementFunctions of Different NervesNerves can be classified based on their function:Sensory nerves: Carry information from the body to the CNS (e.g., pain, temperature, touch).Motor nerves: Transmit signals from the CNS to muscles or glands, causing movement or secretion. Mixed nerves: Contain both sensory and motor fibers. The Relationship Between the Nervous System and the BodyThe nervous system is the body's command and control center. It: Receives sensory information: Gathers data from the environment through sensory receptors. Processes information: The brain interprets sensory input and makes decisions.
Generates motor output: Sends signals to muscles and glands to produce responses.Maintains homeostasis: Regulates body functions like heart rate, breathing, and digestion.Enables higher cognitive functions: Supports thought, learning, memory, and emotions.In essence, the nervous system integrates the body's various systems, allowing for coordinated actions, responses to stimuli, and overall well-being. ANS and Cranial Nerve Number, Name, Function, SMB, Stations, Activities, and Unit QuizoDefine the autonomic nervous system (ANS) and its divisions.oIdentify the cranial nerves involved in the ANS.oUnderstand the functions of the ANS in regulating bodily processes.oReview the SMB, stations, and activities related to the ANS.oAnalyze questions from the unit quiz to assess your understanding.The Autonomic Nervous System (ANS) is a division of the peripheral nervous system that controls involuntary bodily functions such as heart rate, digestion, respiration, and pupil dilation. It operates largely unconsciously and maintains homeostasis. The ANS is divided into two main branches:Sympathetic Nervous System: Often referred to as the "fight-or-flight" response, it prepares the body for action by increasing heart rate, blood pressure, and respiration, while diverting blood flow away from non-essential organs.Parasympathetic Nervous System: Often referred to as the "rest-and-digest" system, it promotes calming and restorative functions, slowing heart rate, increasing digestion, and promoting relaxation.Cranial Nerves and the ANSSeveral cranial nerves play roles in the ANS:Cranial NerveNumberNameFunction Related to ANSIIIOculomotorControls pupil constriction and lens accommodation.VIIFacialStimulates tear glands and salivary glands.IXGlossopharyngealInfluences salivary glands and blood pressure.XVagusMajor player in the parasympathetic system, controlling heart rate, digestion, and respiration.Functions of the ANSThe ANS is crucial for maintaining bodily equilibrium. Its functions include:Cardiovascular regulation: Controlling heart rate, blood pressure, and blood vessel tone.Respiratory regulation: Adjusting breathing rate and depth.Digestive system control: Stimulating or inhibiting digestion, secretion of digestive enzymes, and peristalsis.Urinary system control: Regulating bladder function and urine output.Pupil control: Adjusting pupil size in response to light conditions.Sexual function: Contributing to arousal and orgasm.Temperature regulation: Promoting sweating or shivering to maintain body temperature.Reflex Arc Model
oDescribe the components of a reflex arc.oExplain the difference between a simple and complex reflex.A reflex arc is the neural pathway that controls a reflex action.It is a rapid, involuntary response to a stimulus. The components of a reflex arc include: Receptor: This is the sensory structure that detects the stimulus. Examples include touch receptors in the skin, lightreceptors in the eye, and sound receptors in the ear. Sensory neuron: This neuron carries the sensory information from the receptor to the central nervous system (spinal cord or brain). Integration center: This is where the information is processed. It can be as simple as a synapse between a sensory and motor neuron in the spinal cord (for simple reflexes) or involve multiple neurons and brain regions for more complex reflexes. Motor neuron: This neuron carries the signal from the integration center to the effector.Effector: This is the muscle or gland that responds to the stimulus. Simple vs. Complex ReflexesSimple Reflex:Involves a limited number of neurons. Typically processed in the spinal cord without significant brain involvement.Provides a rapid response to protect the body. Examples: knee-jerk reflex, withdrawal reflex from a hot object.Complex Reflex:Involves multiple neurons and often higher brain centers.Allows for more complex responses and integration of sensory information.Can be influenced by learning and experience. Examples: blinking in response to a bright light, maintaining balance, pupil dilation.Key difference: The main distinction between simple and complex reflexes lies in the number of neurons involved and the level of brain processing required. Simple reflexes are faster and more automatic, while complex reflexes offer greater flexibility and adaptability.
General Senses Handout and StationsoDefine general senses and their types (touch, temperature, pain, proprioception).oUnderstand the receptors involved in general senses.oExplain the process of sensory transduction.oReview the experiments and observations made during the general senses stations.Definition: General senses refer to sensory receptors distributed throughout the body that respond to various stimuli, including touch, temperature, pain, and proprioception. Unlike special senses (sight, hearing, taste, smell, balance), general senses do not have specialized organs.Types of General Senses:Touch: Sensation of pressure, vibration, and texture on the skin.Temperature: Sensation of hot and cold.Pain: Sensation arising from tissue damage or potential damage.Proprioception: Awareness of body position and movement in space.Receptors Involved in General SensesGeneral senses rely on various receptor types:Mechanoreceptors: Respond to mechanical stimuli like pressure, vibration, and stretch (touch, proprioception).Thermoreceptors: Respond to temperature changes (temperature).Nociceptors: Respond to potentially damaging stimuli (pain).Proprioceptors: Located in muscles, tendons, and joints, providing information about body position and movement(proprioception).Sensory TransductionSensory transduction is the process of converting a stimulus (e.g., pressure, temperature) into an electrical signal (nerve impulse) that can be interpreted by the brain.
Stimulus: A specific type of energy (e.g., mechanical, thermal) activates a sensory receptor.Receptor Potential: The stimulus causes a change in the receptor's membrane potential, creating a graded potential.Generation of Action Potential: If the receptor potential reaches threshold, it triggers an action potential in the sensory neuron.Propagation: The action potential travels along the sensory neuron to the central nervous system (CNS).CNS Interpretation: The brain processes the sensory information and creates a perception of the stimulus.Note: The strength of the stimulus is encoded in the frequency of action potentials generated, with stronger stimuli producing higher firing rates.Additional Information:The density of sensory receptors varies across different body regions, affecting sensitivity.Sensory adaptation occurs when receptors become less responsive to a constant stimulus over time.Pain pathways involve complex neural circuits and can be influenced by emotional and cognitive factors.