* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download chapter 11 ppt additional
Embodied language processing wikipedia , lookup
Time perception wikipedia , lookup
Patch clamp wikipedia , lookup
Brain Rules wikipedia , lookup
Development of the nervous system wikipedia , lookup
Membrane potential wikipedia , lookup
Nonsynaptic plasticity wikipedia , lookup
Activity-dependent plasticity wikipedia , lookup
Clinical neurochemistry wikipedia , lookup
Cognitive neuroscience of music wikipedia , lookup
Single-unit recording wikipedia , lookup
Neuromuscular junction wikipedia , lookup
Metastability in the brain wikipedia , lookup
Limbic system wikipedia , lookup
Human brain wikipedia , lookup
Premovement neuronal activity wikipedia , lookup
Environmental enrichment wikipedia , lookup
Feature detection (nervous system) wikipedia , lookup
Neuroplasticity wikipedia , lookup
Resting potential wikipedia , lookup
Biological neuron model wikipedia , lookup
Neuroeconomics wikipedia , lookup
Neuroanatomy of memory wikipedia , lookup
Electrophysiology wikipedia , lookup
Holonomic brain theory wikipedia , lookup
Anatomy of the cerebellum wikipedia , lookup
Circumventricular organs wikipedia , lookup
Aging brain wikipedia , lookup
Neurotransmitter wikipedia , lookup
Nervous system network models wikipedia , lookup
Neural correlates of consciousness wikipedia , lookup
Molecular neuroscience wikipedia , lookup
Synaptogenesis wikipedia , lookup
End-plate potential wikipedia , lookup
Stimulus (physiology) wikipedia , lookup
Neuroanatomy wikipedia , lookup
Synaptic gating wikipedia , lookup
Chemical synapse wikipedia , lookup
Neuropsychopharmacology wikipedia , lookup
Nervous Tissue Nervous System Organization Chapter 11 Histology of Nervous Tissue • Made of two different varieties of cells 1. Neuroglia or supporting cells 2. Neurons Quiz Pic p.390 11.3a-e QUIZ PIC p. 392 11.4b Axons • Myelinated and unmyelinated • CNS covered by olidodendocytes • PNS Schwann cells Change in Membrane Potential • Two types of signals are produced 1. Graded Potentials- signal over short distances 2. Action Potentials- long distance signals Types of Membrane Changes A. Graded Potentials- short lived, local changes in the membrane • depolarization or hyperpolarization • cannot travel all the way to an effector organ • dies out over time Steps of Potential Creation A. Depolarization- change in which inner membrane becomes more positive compared to resting membrane B. Repolarization- membrane going back to the resting state C. Hyperpolarization- change in which membrane becomes more negative compared to resting membrane Change in Membrane Potential • Changes in membrane potential are used to send, receive, and integrate information • Can be produced by anything that 1. changes permeability to an ion 2. alters ion concentration on both sides of the membrane What changes membrane Potential? • Heat, light, pressure • Chemical • Little bit of the unknown Homeostatic Imbalance • Anesthetics • Prevent Na+2 channels from opening • Prevent oxygen needed to function Continuous Propagation of AP • This occurs in unmyelinated axons – If enough stimulus is applied to the membrane, an action potential is generated; the in rush of sodium ions at the site of the stimulus causes local changes in the membrane that cause more voltage gated channels to open and depolarize more and more membrane until threshold is reached and the action potential moves along the membrane Saltatory Conduction of AP • Occurs only on myelinated axons • all voltage gated sodium channels are concentrated between the nodes of Ranvier • when a stimulus causes the AP the AP will not stimulate neighboring membrane but jump from node to node • much faster travel time than continuous conduction Homeostatic Imbalance • • • • • Multiple Sclerosis (MS) Myelin sheaths destroyed Become hard scleroses Current can not jump nodes Axons are fine and try to fix by making more Na+2 pumps • Causes major irregularity in impluses Synapse • The location or junction between 2 neurons where the transmission of information occurs - the neuron sending information is the presynaptic neuron - the neuron receiving information is the post synaptic neuron Chemical Synapses • Specialized for release and reception of chemical neurotransmitters • Contains 3 parts 1. Axon Terminal- filled with vesicles containing neurotransmitter 2. Synaptic Cleft- space between the neurons 3. Neurotransmitter Receptor Region- located on the post synaptic neuron Electrical Synapses • Far less common than chemical synapses • Provide a means to synchronize activity between neurons • Gap junctions Termination of Neurotransmitter Effects • Degradation by enzymes associated with the post synaptic membrane (Can you think of where you have already seen this?) • Reuptake of the neurotransmitter at the presynaptic terminal • Diffusion away from the synapse Neurotransmitter types • • • • p. 415-417 (skim through) ACh acetylcholine ???? AChe acetylcholinesterase ???? Dopamine inhibitory, cocaine blocks uptake • Serotonin Prozac blocks uptake, LSD blocks Mechanism of Action of Neurotransmitter • Direct- neurotransmitters that open ion channels • Indirect- act through Second Messenger molecules • Excitatory- cause depolarization of the membrane • Inhibitory- cause hyperpolarization of the membrane Central Nervous system Bio 105 Chapter 12 Quiz Picture Ventricles Homeostatic Imbalance Hydrocephalus •Water on the brain •Ventricles have to much cerebral fluid Three Regions of Cerebral Hemispheres • Cortex- Conscious mind Gray matter containing cell bodies Dendrites Unmyelinated axons • Cerebral White Matter- Myelinated fibers bundled into fiber tracts - Communication between cortex and lower CNS structures • Basal Ganglia- complex role in motor control attention, and cognition Brodmann Areas Brodmann Areas Somatotopy Cerebral Cortex Continued Premotor Cortex- just anterior to the precentral gyrus • controls learned motor skills of patterned nature • planned movements Broca’s Area- special motor speech area; planning of motor activities Frontal Eye Field- controls voluntary motor movement of the eyes Homeostatic Imbalance Stroke Stoppage of blood flow to brain Ex: • Damages region of primary motor cortex, body parlayed • Damage to premotor cortex relearnable Cerebral Cortex • Sensory Areas- conscious awareness of sensation; located in parietal, temporal and occipital lobes Primary somatosensory cortex • Spatial discrimination Somatosensory Association cortex Visual areas Auditory areas Gustatory areas Brodmann Areas Somatotopy Homeostatic Imbalance • Damage to primary visual or auditory stop sight or hearing • Damage to the association area allow sight or hearing, but lack comprhension Multimodal Association Areas • Rest of cerebral cortex • Front and side of cerebral cortex • Pulls together all info received from primary somatosensory cortex and passes on to primary motor cortex • Helps in judgment, reasoning, persistence Cerebral White Matter • Commissures- connect corresponding hemispheres gray matter enabling coordinated function; largest is corpus callosum • Association Fibers- connect different parts of same hemisphere • Projection Fibers- fibers that enter brain from cord; fibers that leave brain for cord Diencephalon- three parts • 1.Thalamus- 80% of total; gets sensory inputs, regulates emotion & visceral function • 2. Hypothalamus- responsible for several functions including body temperature regulation; regulation food intake; emotional response, autonomic control, thirst, sleep-wake cycle; endocrine system function • 3. Epithalamus- pineal secretes melatonin; choroid plexus for CSF Brain Stem • Produce the autonomic functions necessary for survival • provides pathway for fiber tracts between cord and hemispheres • contain the nuclei for 10 of 12 pairs of cranial nerves • Three parts- midbrain, pons, and medulla oblongata 1. Midbrain • Contains the substantia nigra which produces the precursor for dopamine which is a neurotransmitter • degeneration of these neurons causes Parkinson's Disease 2. Pons • Contains mostly projection fibers • contains centers for breathing 3. Medulla Oblongata • Most inferior part of brain stem • decussation of the pyramids -the fibers cross over to the opposite side of the cord 3. Medulla: Centers Contains important centers of AUTONOMIC nervous system: – respiratory center – cardiac center – vasomotor center – vomiting – swallowing – hiccuping – coughing – sneezing Cerebellum • 11 % of total brain mass • Located under cerebral hemispheres posterior to pons and medulla • Provides precise timing and appropriate patterns for smooth, coordinated smooth muscle contractions • Activity occurs subconsciously A. Limbic System • consists of parts of cerebrum (limbic lobe, hippocampus and amygdaloid body) and diencephalon (thalamus, hypothalamus) • parts linked by white tracts (fornix connects hippocampus to hypothalamus) Protection for Brain • Bone • Meninges • Cerebral Spinal Fluid inside ventricles Layers of Meninges • Dura Mater- strongest, thickest, tough external membrane - 2 layers with outer forming periosteum of bone and inner covering the brain - extends to cord but, no periosteal layer • Arachnoid Mater- middle layer - subdural space between it and the dura - subarachnoid space below it filled with CSF • Pia Mater- delicate CT that clings to the brain into every sulci Blood Brain Barrier • Produced by the characteristics of the capillaries that supply the brain which include: – Thick basal lamina – Continuous endothelium of vessel walls Provide selection of substances that reach the neurons Spinal Cord • Gray/white matter reversed compared to the hemispheres • Gray is on the inside and white is on the outside • Enclosed in vertebral column • 18 inches long; ¾ inch thick Spinal Cord • Meninges- same as brain except no periosteal layer on outside of the dura • CSF- fills the space between the pia and arachnoid meninges - these layers extend beyond the end of the cord at L1 - space here is for spinal tap or lumbar puncture Quiz Picture Categories of Memory 1. Declarative memory (factual knowledge) – Explicit information – Related to our conscious thoughts and our language ability – Stored in LTM with context in which it was learned Categories of Memory 2. Nondeclarative memory – Less conscious or unconscious – Acquired through experience and repetition – Best remembered by doing; hard to unlearn – Includes procedural (skills) memory, motor memory, and emotional memory Thalamus Basal forebrain Touch Prefrontal cortex Hearing Vision Taste Smell Hippocampus Sensory input (a) Declarative memory circuits Association cortex Thalamus Medial temporal lobe (hippocampus, etc.) Prefrontal cortex ACh ACh Basal forebrain Figure 12.23a Sensory and motor inputs Association cortex Basal nuclei Thalamus Dopamine Premotor cortex Premotor cortex Substantia nigra Thalamus Basal nuclei Substantia nigra (b) Procedural (skills) memory circuits Figure 12.23b Molecular Basis of Memory • During learning: – Altered mRNA is synthesized and moved to axons and dendrites – Dendritic spines change shape – Extracellular proteins are deposited at synapses involved in LTM – Number and size of presynaptic terminals may increase – More neurotransmitter is released by presynaptic neurons PNS Bio 105 Chapter 13 Organization of the Nervous System Peripheral Nervous System • 12 pairs of Cranial nerves • 31 pairs of Spinal nerves Quiz Picture Reflex Arc The Eye • Sphere with a 1 inch diameter • Accessories to eye include: – Eyebrows – Eyelids- palbebrae fissure, lacrimal punctum, eyelashes, Meibomian glands – Conjunctiva- mucous membrane covering – Lacrimal apparatus (tears) lacrimal gland, lacrimal canal, nasolacrimal duct – Extrinsic Eye Muscles Layers of the eyeball • Fibrous Tunic- outermost layer; dense avascular CT – Sclera- white part; posterior; continuous with dura – Cornea- clear, anterior part; part of light refraction apparatus Layers of the eyeball • Vascular Tunic (Uvea)- highly pigmented; 3 regions – Choroid- highly vascular; posterior part – Ciliary body- smooth muscle to control lens shape; ciliary process to make fluid of anterior chamber – Iris- most anterior; colored part of eye; round opening is pupil Layers of the eyeball • Sensory Tunic (Retina)- contains the neurons that allow for vision; 2 layers including the outer pigmented layer and inner neural layer • Optic disc- Optic Nerve II leaves the eye; also called blind spot • Macula Lutea- area of sharpest vision • Rods- dim light, peripheral vision • Cones- bright light, high acuity vision Eye Chambers • Posterior Segment- behind lens; contains gel like vitreous • Anterior Segment- filled with fluid; plasma like; forms and circulates continuously; made from capillaries in ciliary process Lens Changes for focusing • Close vision– Accommodation- ciliary muscles contract; lens bulges and gets fat – Constriction of pupils- circular muscles of iris contract; pupil gets small – Convergence of eyeballs- both eyes move medially to see object Lens changes for focusing • Distant Vision – Ciliary muscles are completely relaxed; lens is as thin and flat as it can get – Eyes are best adapted for this type of vision Physiology of seeing • Pigmented layer absorbs light • Photoreceptors (Rods and Cones) have visual pigments • Retinal and opsins (Rods=rhodopsin) • Rhodopsin (and other proteins) control nuerotransmitter release • Light breaks down rhodopsin, release neurotransmitter, cause Na+1 release starts action potential Homeostatic Imbalances Eye • Glaucoma fluid build up • Detached retina neural layer separates from pigmented layer • Cataract under nourishment of lens • Strabismus weakness of eye muscle • Watery eyes lacrimal apparatus • Conjunctivitis inflammation of conjunctiva