* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download The nervous system
Lateralization of brain function wikipedia , lookup
Neuroplasticity wikipedia , lookup
Haemodynamic response wikipedia , lookup
Proprioception wikipedia , lookup
Neuropsychology wikipedia , lookup
Metastability in the brain wikipedia , lookup
Time perception wikipedia , lookup
Node of Ranvier wikipedia , lookup
Premovement neuronal activity wikipedia , lookup
Dual consciousness wikipedia , lookup
Single-unit recording wikipedia , lookup
Molecular neuroscience wikipedia , lookup
Human brain wikipedia , lookup
Psychoneuroimmunology wikipedia , lookup
Feature detection (nervous system) wikipedia , lookup
Embodied cognitive science wikipedia , lookup
Holonomic brain theory wikipedia , lookup
Embodied language processing wikipedia , lookup
Emotional lateralization wikipedia , lookup
Neuroscience in space wikipedia , lookup
Cognitive neuroscience of music wikipedia , lookup
Development of the nervous system wikipedia , lookup
Nervous system network models wikipedia , lookup
Neuropsychopharmacology wikipedia , lookup
Circumventricular organs wikipedia , lookup
Microneurography wikipedia , lookup
Neural engineering wikipedia , lookup
Synaptogenesis wikipedia , lookup
Neuroanatomy of memory wikipedia , lookup
Stimulus (physiology) wikipedia , lookup
Evoked potential wikipedia , lookup
Physiology, drugs and disease The Nervous System Fd(Sc) FISM Year 2 08/01/2010 Objectives • Describe the levels of organisation in the nervous system. • Outline the functions of the nervous system. • Describe the structure and function of a nerve cell or neuron • Research the affects of stimulants on the nervous system Introduction • The nervous system is the master controlling and communicating system of the body. • Cells of the nervous system communicate through electrical signals, which are rapid, specific and usually immediate. The Nervous System • Major division – Central and Peripheral • Central or CNS – brain and spinal cord • Peripheral – nerves connecting CNS to muscles and organs Central Nervous System Peripheral Nervous System Peripheral Nervous System • The nervous system has 3 overlapping functions – motor – sensory – integration • Motor - – CNS to muscles and gland • Sensory – – sensory receptors to CNS. Provides sensation or information about internal and external environment • Integration – – Processes and interprets sensory information and coordinates activities. Brain Spinal Cord Nerves Autonomic System • Two divisions: – Sympathetic – fight or flight! Mobilises the body during emergency situations. – Parasympatheitic – Conserves energy. Nonemergency situations • Control involuntary functions – – – – – heartbeat blood pressure respiration perspiration digestion Sympathetic CENTRAL NERVOUS SYSTEM SYMPATHETIC Brain • “ Fight or flight” • • • • response Release adrenaline and noradrenaline Increases heart rate and blood pressure Increases blood flow to skeletal muscles Inhibits digestive functions Dilates pupil Stimulates salivation Relaxes bronchi Spinal cord Salivary glands Lungs Accelerates heartbeat Inhibits activity Heart Stomach Pancreas Stimulates glucose Secretion of adrenaline, nonadrenaline Relaxes bladder Sympathetic Stimulates ejaculation ganglia in male Liver Adrenal gland Kidney Parasympathetic CENTRAL NERVOUS SYSTEM PARASYMPATHETIC • “ Rest and response ” system • Calms body to conserve and maintain energy • Lowers heartbeat, breathing rate, blood pressure Brain Contracts pupil Stimulates salivation Spinal cord Constricts bronchi Slows heartbeat Stimulates activity Stimulates gallbladder Gallbladder Contracts bladder Stimulates erection of sex organs Summary of autonomic differences Autonomic nervous system controls physiological arousal Sympathetic division (arousing) Pupils dilate Decreases Parasympathetic division (calming) EYES Pupils contract SALVATION Increases Perspires SKIN Dries Increases RESPERATION Decreases Accelerates HEART Slows Inhibits DIGESTION Activates Secrete stress hormones ADRENAL GLANDS Decrease secretion of stress hormones • So how do the various divisions and systems of the nervous system communicate with each other and the rest of the body? • The next few slides illustrate the structural units of the nervous system that enable information to be conducted throughout the body. Nervous tissue Nerve cells or neurons • Structural units of the nervous system. Specialised cells that conduct messages in the form of impulses to one part of the body to another. Dendrites • Receive small electrical signals from other neurons and conducts electrical signals (graded potentials) toward the cell body. The cell body (Grey matter) • Collects the electrical signals together. It decides whether to respond with a large electrical signal called the action potential. • The AXON (white matter) conducts the action potential or electrical impulse to the AXON TERMINAL. • Any long axon is called a NERVE FIBER. A bundle of fibres is called a NERVE (myelinated) • The axon terminals make contact with other nerve cells, muscle cells or glands. • A SYNAPSE is the structure at the point of contact of an axon and another cell. • An action potential travelling along an axon is called a nerve impulse and carries information as follows: Transmission of a nerve impulse • Electricity is the key!!! Neurons are irritable and when stimulated by an electrical impulse are conducted along the length of the axon. • The transmission is quite a complicated procedure, but it basically involves changing the inside of a cell’s axon from being negatively charged to being Transmission of a nerve impulse continued…. • At rest, the inside of the nerve axon is negatively charged and the outside is positively charged – RESTING POTENTIAL. • When the CNS stimulates a nerve, the inside of an axon becomes positively charged and outside becomes negatively charged. This change is called the ACTION POTENTIAL. Transmission of a nerve impulse continued… • When the CNS stops stimulating the nerve, the axon is negatively charged and the outside is positively charged. This process is called REPOLARISATION. Reflex action • Many of the body’s control systems belong to the general category of stimulusresponse sequences known as reflexes. • Reflexes are used to protect the body without having to think about what is happening. A reflex is a rapid, predictable motor response to a stimulus. It is unlearned and Knee jerk reflex • Knee jerk is a well known reflex. • It is called a MONOSYNAPTIC reflex which means there is only one synapse in the circuit. • The movement it produces is very rapid as there is only one synapse. (allows reflex actions to occur relatively quickly by activating spinal motor neurons without the delay of routing signals through the brain) • The reflex works by tapping just below the knee, which makes the quadriceps muscle stretch. This information travels to the spinal cord. There, after one synapse in the spinal cord, the information is sent back out to the muscle making it contract and the knee extends. Central Nervous System Brain • Consists of the brain and spinal Cord. • Brain Processes and coordinates sensory data and motor commands. Higher functions – intelligence, learning, memory and emotion. • Spinal Cord – Relays information to and from brain – Performs less complex integration Spinal Cord Brain has 2 Hemispheres • Left & Right sides are separate • Corpus Callosum : major pathway between hemispheres • Some functions are lateralised – language on left – math, music on right • Lateralisation is never 100% Corpus Callosum Right Hemisphere Left Hemisphere Each hemisphere is divided into 4 lobes Frontal – Personality, Emotion Cognitive Parietal – Motor Sensory Occipital – Vision Temporal – Speech Memory Contra-lateral Motor Control • Movements controlled • • • by motor area Right hemisphere controls left side of body Left hemisphere controls right side Motor nerves cross sides in spinal cord Motor Cortex Somatosensory Cortex Temporal Lobe Contains primary auditory cortex • Inputs are auditory, Auditory Cortex visual patterns – – – – speech recognition face recognition word recognition memory formation Temporal Lobe Parietal Lobe • Inputs from multiple senses Outputs to Frontal lobe hand-eye coordination eye movements attention Somatosensory Parietal Cortex Lobe Frontal Lobe • Contains primary motor cortex • Important planning and sequencing areas Frontal Lobe Working Broca’s Memory Area Motor Cortex The Nervous System: Summary • Major structures of the nervous – CNS, Somatic, Autonomic – Two hemispheres & 4 lobes • Organization – contralateral input & output – primary sensory areas – motor areas • Localization of functions Central Nervous System Peripheral Nervous System Research • Research information on central nervous system stimulants and sports • Include amphetamines and cocaine • Present your info to the rest of the group.