* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download File
Subventricular zone wikipedia , lookup
Psychoneuroimmunology wikipedia , lookup
Activity-dependent plasticity wikipedia , lookup
Endocannabinoid system wikipedia , lookup
Embodied language processing wikipedia , lookup
Neuromuscular junction wikipedia , lookup
Mirror neuron wikipedia , lookup
Neuroplasticity wikipedia , lookup
Signal transduction wikipedia , lookup
Embodied cognitive science wikipedia , lookup
Microneurography wikipedia , lookup
Electrophysiology wikipedia , lookup
Neural engineering wikipedia , lookup
Neural coding wikipedia , lookup
Haemodynamic response wikipedia , lookup
Multielectrode array wikipedia , lookup
Nonsynaptic plasticity wikipedia , lookup
Central pattern generator wikipedia , lookup
Caridoid escape reaction wikipedia , lookup
Clinical neurochemistry wikipedia , lookup
Neurotransmitter wikipedia , lookup
Premovement neuronal activity wikipedia , lookup
Optogenetics wikipedia , lookup
Evoked potential wikipedia , lookup
Chemical synapse wikipedia , lookup
Holonomic brain theory wikipedia , lookup
Biological neuron model wikipedia , lookup
Molecular neuroscience wikipedia , lookup
Axon guidance wikipedia , lookup
Node of Ranvier wikipedia , lookup
Metastability in the brain wikipedia , lookup
Neuroregeneration wikipedia , lookup
Circumventricular organs wikipedia , lookup
Single-unit recording wikipedia , lookup
Development of the nervous system wikipedia , lookup
Synaptogenesis wikipedia , lookup
Synaptic gating wikipedia , lookup
Feature detection (nervous system) wikipedia , lookup
Channelrhodopsin wikipedia , lookup
Neuropsychopharmacology wikipedia , lookup
Nervous system network models wikipedia , lookup
Chapter 15:Coordination Part 1 The Nervous System • Function to pass information between different parts of the body to coordinate activities of the body • Take in large amount of information from environment and allow organisms body to respond to it • Purpose of information transfer: 1. Coordinate regulation of substances within in an organism • Ex. Maintain blood glucose concentration 2. Change the activity of apart of organism ins response to external stimulus • Ex. Pulling hand away from hot stove • Two types of information transfer to coordinate activity in organism: 1. Nerves • Transmit info in form of electrical impulses 2. Chemical messengers • “Hormones” that travel in blood to different parts of organism to cause a change Organization of the Nervous System • Components: • Brain • Nerves • Spinal cord • White matter mostly axons • Grey matter mostly cell bodies; contain all synapses • Divisions by location: • Central Nervous System (CNS) • Brain and spinal • Function: processing of information received from PNS and coordinating a response • Peripheral Nervous System (PNS) • Nerves and receptors • Function: transmits information going in and going out of the body Peripheral Nervous System Divisions • Afferent/sensory component • Brings info INTO brain • Incoming signal • Efferent/motor component • Sends info/signal OUT of the brain • Outgoing signal • 2 types of efferent signals: • Somatic Nervous system (SNS): voluntary control • Skeletal muscle • Things under our control • Autonomic Nervous System (ANS): involuntary control • Heart rate, blood pressure, pupil dilation, rate of digestion, etc • Things not under our conscious control • Operate in TWO directions/Two Categories: • Sympathetic Nervous System Speed Up • Parasympathetic nervous system Slow Down Autonomic Nervous System Divisions • Sympathetic • • • • • Speed everything up “Gas pedal” Speeds up body during stress “Fight or Flight” response Sympathetic-Speed-Stress (all S’s) • Parasympathetic • Slows everything down • “Brake pedal” • Slows body down during nonstress • ‘Rest and digest” side of NS….no need to be ramped up b/c no stress in environment • Two systems work together…called ANTAGONISTIC CONTROL Nerve Cell Structure • Some nerves bring info INTO brain (afferent signal) • Some nerves bring info OUT of brain (efferent signal) • Nerve cells can transmit signals very quickly from brain to receiving structure • Nerve cells called NEURONS • Function: highly specialized cells adapted for rapid transmission of electrical impulses called ACTION POTENTIALS, from one part of the body to another part • Three Different Types of Neurons: • Sensory Neurons • Transmits impulses from receptors TO CNS • Intermediate Neurons • Aka relay or connector neurons • Transmit impulses from sensory neurons to motor neurons • Motor Neurons • Transmits impulses from the CNS to effectors (effectors carry out needed response…muscles and glands) 3 main Parts of Neuron: • Dendrite • • • • Antennae takes in lots of signals coming in Thin, cytoplasmic extensions from the cell body Some short, many branches Increases surface area for attachment to endings of other neurons • Soma (cell body) • Contains all organelles: mitochondria, ER, lots of ribosomes • Processes information received from the Dendrites • Axon • Very long structure that sends the signal processed by the soma down to another cell down LONG distances • Can be 3-4 ft long! • Cytoplasm contains organelles (mitochondria) • Thick areas surround axons SCHWANN CELLS • Secrete MYELIN biological insulator that protects signal that travels along axon; prevents signal degradation; allows signal to travel faster • Spaces between Schwann cells on axon NODES OF RANVIER • Important in propagation of signal down an axon • AXON TERMINAL: end of axon • Lots of mitochondria • Many vesicles containing TRANSMITTER SUBSTANCES (chemicals called NEUROTRANSMITTERS) • Important in passing impulses to effector cell • SYNAPSE: composed of the parts of the two adjacent neurons and the SYNAPTIC CLEFT (gap between two neurons that is about 20 nm wide) Motor vs. Sensory vs. Intermediate Neuron • All work together to bring about a response to a stimulus Motor vs. Sensory vs. Intermediate Neuron Structure Motor Neuron • Cell body lies in spinal cord or brain • Many dendrites coming off of cell body • Dendrites HIGHLY branched • LONG axons • Ends of axons contain lots of mitochondria and transmitter chemicals in vesicles • Some are myelinated • Cell body lies in the CNS • May form synapse with relay neuron Sensory Neuron Intermediate Neuron • Cell body lies within the spinal nerve • Relay neurons • One long axon with cell body that may • Found entirely in CNS be near source of stimuli or in swelling of a spinal nerve (GANGLION) • Dendron is usually longer than the axon • Contains many dendrites • Some are myelinated • May form synapse with relay neuron Schwann Cells • Specialized support cell • Wrap them selves around axons of MOTOR and SENSORY neurons • Encloses axons with many layers of its cell membrane • Inner most layer of Schwann cell that actually encloses axon is called the MYELIN SHEATH it secretes MYELINE • Secretes Myelin • • • • composed of lipids and protein Helps insulate axons Prevents signal degradation Helps neve impulses travel faster • Myelinated cat fiber = carry impulses up to 100 m/s • Unmyelinated cat fiber = carry impulses only 5 m/s • 1/3 of motor and sensory neurons are MYELINATED • 2/3 of motor and sensory neurons are UNMYELINATED • Nodes of Ranvier • Areas of the axon NOT covered by the Schwann cells • 2-3 um in diameter • Found every 1-3 mm in human neurons (between Schwann cells) Reflex Arc • Pathway along which impulses are transmitted from a receptor to an effector without involving conscious regions of the brain • Sensory neuron connects to motor neurons through interneurons in the central nervous system (either brain or spinal cord) • Sometimes interneurons NOT involved • Impulse passes directly from sensory neuron to motor neuron • Different types of reflex arcs • Brain reflex arc • Pupil dilation/constriction • Spinal reflex arc • Impulse is passed from neuron to neuron inside spinal cord Reflex Action • When an effector responds to the stimulus BEFORE there is any voluntary response involving conscious regions of the brain • Example • Receptor detects signal, impulse passed from one neuron to the next in spinal cord, heading to brain while attach same time impulses are traveling along the motor neuron to the effector and the effector responds first • Fast automatic response to a stimulus • Useful in response to danger signals • Touching hot object • Something flying at your head Practice Paper 4 Question 2 Optional portion of question 2