* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download The Nervous System - Livonia Public Schools
Donald O. Hebb wikipedia , lookup
Neurolinguistics wikipedia , lookup
Synaptic gating wikipedia , lookup
Feature detection (nervous system) wikipedia , lookup
Blood–brain barrier wikipedia , lookup
Biochemistry of Alzheimer's disease wikipedia , lookup
Brain morphometry wikipedia , lookup
Selfish brain theory wikipedia , lookup
Single-unit recording wikipedia , lookup
Human brain wikipedia , lookup
Haemodynamic response wikipedia , lookup
Synaptogenesis wikipedia , lookup
Brain Rules wikipedia , lookup
Neuroplasticity wikipedia , lookup
Cognitive neuroscience wikipedia , lookup
Aging brain wikipedia , lookup
History of neuroimaging wikipedia , lookup
Microneurography wikipedia , lookup
Development of the nervous system wikipedia , lookup
Clinical neurochemistry wikipedia , lookup
Molecular neuroscience wikipedia , lookup
Neural engineering wikipedia , lookup
Circumventricular organs wikipedia , lookup
Holonomic brain theory wikipedia , lookup
Neuropsychology wikipedia , lookup
Evoked potential wikipedia , lookup
Metastability in the brain wikipedia , lookup
Nervous system network models wikipedia , lookup
Stimulus (physiology) wikipedia , lookup
Neuroregeneration wikipedia , lookup
The Nervous System M. Trotter 2011 Color • The famous "Stroop Effect" is named after J. Ridley Stroop who discovered this strange phenomenon in the 1930s. Here is your job: name the colors of the following words. Do NOT read the words...rather, say the color of the words. For example, for the word BLUE, you should say "RED". Say the colors as fast as you can. It is not as easy as you might think! Phineas Gage Phineas Gage A system that controls all of the activities of the body. The nervous system is made of: The brain The nerves The spinal cord The senses The nervous system also allows you to react to a stimulus. A stimulus is a change in the environment. Example: A hot stove Or… tripping over a rock Your reactions are automatic. Automatic means that you do not have to think about your reactions. Example: If a bug flies by your eye, you will blink. The Nervous System Can also be thought of as the central processing unit 7 Nervous System Parts of the Nervous System • Central Nervous System (CNS): brain and spinal cord • Peripheral Nervous System (PNS): craniospinal nerves • Autonomic Nervous System (ANS): nerves that control vital organs: heart, lungs, brain, etc. 9 Neurons: nervous system cells • All neurons have: one axon one cell body one or more dendrite(s) 10 Basic nerve cell structure Types of Neurons type connected to carry impulses from sensory receptors (eyes, ears, other sense organs) other neurons sense organs spinal cord and brain (efferent) effectors (muscles and glands) other neurons spinal cord and brain muscles and glands connector other neurons other neurons other neurons (afferent) motor (interneuron) carry impulses to 12 3 main types of nerve cells sensory neurone relay neurone motor neurone Sensory neurons Carries impulses from receptors e.g pain receptors in skin to the CNS( brain or spinal cord) Relay neuron Carries impulses from sensory nerves to motor nerves. Motor neuron Carries impulses from CNS to effector e.g. muscle to bring about movement or gland to bring about secretion of hormone e.g ADH Transmission of signals The Synapse Receptors (eyes, ears, other sense organs) change information from outside the body ( for example, light waves) into electrical impulses. 19 Thermo-receptors Location: Skin Hypothalamus Body Core Function: Sensation of hot and cold Detects change in body core temp. Mechano-receptors • Location: – Skin – Skeletal muscle – Inner ear • Function: – – – – – Touch Pressure Muscle movement Motion Sound Chemo-receptors • Location: – Nose – Tongue (taste buds) – Blood vessels • Function: – Smell – Taste – Detects levels of CO2 in blood Photo-receptors Location: Eyes Function: Allow vision thru detection of light Pain-receptors Location: Everywhere, except the brain Function: Sensation of pain Detects chemicals released by damaged cells Neurons • What is grey matter? – Collective cell bodies and dendrites of all neurons • What is white matter? – Myelinated nerve fibers – Axons of all neurons – Can be approximately one meter in length White matter Gray matter What is a Nerve? • Bundle of axons held together by connective tissue. • What color is a nerve? • White! • Why? • Because axons are white matter and they compose nerves How are nerves held together? • Connective tissue • What is this connective tissue called? • Neuroglial cells (nerve glue) • Approximately half of the volume of the brain is composed of neuroglial cells • Most brain tumors develop in mesoglial cells – NOT neurons What do neuroglial cells do? • Support the axons • Insulate the electrical impulses • Like electrical tape insulates electric wires this prevents “leaking” of electric signals An example of a neuroglial cell • • • • • • Schwann cell This wraps around the axon in multiple layers It is composed of a fatty material called… Myelin Regular breaks in the myelin sheath are called… Node of Ranvier • • • Impulse speed Some neurons are fast, good conductors of impulses Other neurons are slow, poor conductors of impulses What distinguishes these two types? 1. Diameter of the axon 2. Myelination Fastest axons have a large diameter and are myelinated. How much faster? Up to 100 times faster! (Reflexes are this type) The Nerve Impulse • How are messages (impulses) carried by the nervous system? • As electrical and chemical signals. • How does the impulse develop? • Charged particles (ions) move across the cell membrane • A neuron is ready to transmit an impulse when it is in the resting state. • Resting membrane potential is -70 mV Resting Membrane Potential • The inside of the cell has a negative charge as compared to the outside of the cell membrane. • How does this charge difference develop? • There are more Na+ (sodium) ions outside and fewer K+ (potassium) ions inside. The Nerve Impulse • How does the impulse begin? • The neuron is stimulated by another neuron or by stimuli from the environment. The Nerve Impulse • If the stimulus is strong enough, it reaches threshold level. • This stimulates an impulse. • If the stimulus is not strong enough, no impulse occurs (allor-none principal) The Nerve Impulse • What happens if threshold is reached? • An action potential (nerve impulse) begins • What is an action potential? • Rapid reversal of membrane potential in response to a stimulus • How does this happen? • Sodium channels open allowing Na+ to flood into the cell. • The membrane potential rises to +30 mV (rising phase) as inside of cell becomes more positive The Nerve Impulse • Please, please, tell us what happens next… • When the membrane potential reaches +30 mV, the sodium channels close. • Potassium channels open and K+ flows out of the cell. • This causes the membrane potential to become more negative again (falling phase). The Nerve Impulse • What happens when the action potential passes down the axon? • The resting potential is restored via the sodium/potassium pump. • Now the membrane is ready to transmit another impulse. K+ extracellular fluid Na+ ATP cytoplasm ADP The Nerve Impulse • What happens when the impulse reaches the axon terminal? • It must pass thru the synapse. • What is a synapse? • It is the gap between two neurons, or between a neuron and organ (effector). • Why is there a gap? • So the neurons don’t short each other out!! The Synapse • How do neurons pass the impulse across the synapse? • Using chemicals called neurotransmitters • What do neurotransmitters do? • Stimulate the dendrites of other neurons or membranes of other cells. • If a dendrite is stimulated, it sends its message to the cell body and the message is passed on • If a muscle or gland is stimulated, a reaction occurs in that organ. The Synapse The Synapse Model of the Synapse synaptic vesicles Axon of presynaptic cell Glycoprotein (ligands) neurotransmitters synaptic cleft receptors for neurotransmitters receptors for glycoprotein The Synapse More nerve terms nerve fibers Dendrites and axions nerve A bundle of dendrites and axions nucleus A group of neuron cell bodies INSIDE the brain and spinal cord (plural: nucleii) ganglion (plural: ganglia) A group of neuron cell bodies OUTSIDE the brain and spinal cord synapse The space connecting one neuron to another neurotransmitter A chemical which transmits an electrical impulse from one neuron to the next 43 The CNS includes: White matter: bundles of axions and dendrites Gray matter: masses of nerve cell bodies The brain: The spinal cord: inside the cranium inside the vertebral column (the “backbone”) 44 The meninges: three membranes envelop the entire CNS (central nervous system) dura mater The outer, hardest, toughest arachnoid The middle, web like pia mater The inner, thinner 45 Spaces between the meninges Dura mater Subdural space Subarachnoid space Arachnoid Pia mater BRAIN 46 Spaces between the meninges . 47 What if a cell dies? • Neurons cannot reproduce. • Once a nervous system connection is broken, it is broken forever. 48 The Brain 49 Parts of the Brain • • • • brainstem cerebellum diencephalon cerebrum 50 Parts of the brainstem • pons: connects the medulla oblongata, the cerebellum, and cerebrum • midbrain: contains auditory (hearing), visual (sight), and muscle control centers. • medulla oblongata: lowest and most posterior (at the back of the brain) The hindbrain includes the pons and the medulla. 51 The brainstem www.daviddarling.info/images/brainstem.jpg 52 The pons (the bridge) Connects the medulla oblongata, cerebellum, and cerebrum Associates with sensory nerves: taste, hearing, and balance. Controls muscles of the face. 53 The medulla oblongata controls alertness heart action respiration (breathing) blood pressure connects the CEREBRUM with the SPINAL CORD the RIGHT side of the brain controls the LEFT side of the body. the LEFT side of the brain controls the RIGHT side of the body. 54 The midbrain controls vision hearing muscles 55 The cerebellum coordinates muscle activity. has three parts: the vermis the right cerebellar hemisphere the left cerebellar hemisphere 56 The diencephalon is located between the midbrain and the cerebrum has three parts: the thalamus: receives sensory information and sends it to the cerebral cortex. the epithalamus: contains the pineal body and olfactory centers. the hypothalamus: connects the endocrine and nervous systems. http://www.daviddarling.info/encyclopedia/A/anatomy_and_physiology.html 57 The hypothalamus connects the endocrine and nervous systems. controls the autonomic nervous system body temperature carbohydrate and fat metabolism appetite emotions www.brainexplorer.org 58 The cerebrum is divided into two cerebral hemispheres has an outer surface, or CORTEX, made of “gray matter” www.laskerfoundation.org 59 The cerebral cortex is divided into parts called lobes: 1. the frontal lobe 2. the parietal lobe 3. the temporal lobe 4. the occipital lobe www.colorado.edu 60 The frontal lobe is the center for voluntary movement is called the “motor area” (movement) includes the prefrontal area, for intelligence, creativity, memory, and ideas. 61 The parietal lobe Collects, recognizes, and organizes sensations: feelings of pain temperature touch position movement 62 The temporal lobe • processes auditory (hearing) information • stores auditory (hearing) and visual (seeing) memories • includes Broca’s speech area 63 The occipital lobe p. 282 is at the back of the cerebral hemisphere involves vision visual memory eye movements 64 Side to side? - The right hemisphere controls the left side of the body! The left hemisphere controls the right side of the body! 65 The limbic system p. 282 The limbic system controls emotions and memory 67 Cerebrospinal fluid • Cerebrospinal fluid: watery liquid is found inside the brain, spinal cord, and subarachnoid space supports the brain’s weight protects and cushions the brain and the spinal cord 68 PNS: Peripheral Nervous System • Includes all the nerves and ganglia outside the brain and spinal cord cranial nerves: 12 pairs of nerves connected directly to the brain spinal nerves: 31 pairs of nerves connected to the spinal cord 69 Nerve Pathways Somatic (body) motor pathways carry impulses from the CNS (central nervous system) to skeletal muscles • pyramidal pathways carry impulses that control voluntary actions that involve thought • extrapyramidal pathways carry impulses that control automatic movements, such as walking 70 Reflexes • A reflex is an action that: occurs below the brain, within in the spinal cord is an automatic reaction is not conscious (voluntary) can be inborn (a baby has it at birth, such as sucking, swallowing, urinating) can be learned (such as talking,walking, driving) 71 More reflexes • INBORN knee jerk reflex pupillary reflex Babinski swallowing coughing blinking • LEARNED reading typing swimming dancing skating playing football 72 Important reflexes • knee jerk: lower leg jerks when knee is tapped • Babinski: toes curl up when sole of foot is stroked • pupillary: pupils of eyes contract in bright light 73 The Autonomic Nervous System controls • involuntary, smooth, and cardiac (heart) muscles and glands. • systems that work automatically: digestive, circulatory, respiratory, urinary, and endocrine. 74 The Autonomic Nervous System has two parts • the sympathetic system • the parasympathetic system These parts work together to maintain homeostasis: normal balance of the systems in the body. 75 Autonomic Nervous System • http://faculty.washington.edu/ch udler/auto.html Organization of Nervous System Related Terms: Central Nervous System (CNS) • The part of the nervous system that includes: the brain the spinal cord 78 Related Terms: Autonomic System part of the peripheral nervous system serves automatic systems cannot be controlled voluntarily includes: parasympathetic system peripheral system 79 Related Terms: Peripheral System part of the nervous system includes nerves and ganglia outside the spinal cord and brain: cranial nerves spinal nerves autonomic nervous system 80 • • • • • Anatomy Related Terms: cerebellum: second largest part of the brain cerebrum: largest part of the brain cerebral cortex: outer part of the cerebrum; contains gray matter cerebrospinal fluid: watery fluid in the brain and spinal cord convolution: fold in the surface of the cerebrum 81 Related Terms: Anatomy • corpus callosum: connection between the two hemispheres (halves) of the cerebrum • dura mater: membrane surrounding the brain and spinal cord • fissure: deep groove on the surface of the brain • foramen magnum: hole in the back of the cranium through which the spinal cord passes 82 Related Terms: anatomy • hemisphere: either the right or the left side of the brain • hippocampus: memory center of the brain, may be related to learning and memory problems • lateral ventricle: open space in each hemisphere of the brain • limbic system: the “emotional brain” 83 Related terms: Anatomy • lobes (parts) of the cerebrum occipital (in the back) frontal (in the front) temporal (on top) parietal (on the sides) 84 Related terms: Anatomy • medulla oblongata: posterior part of the brain connected to the spinal cord • meninges: three membranes surrounding the central nervous system: dura mater pia mater arachnoid • midbrain: upper part of the brainstem 85 Related Terms: Spinal Nerves • spinal cord: lowest part of the central nervous system (CNS); extends from the medulla oblongata to the base of the spine • subarachnoid: space between the pia mater and the arachnoid • subdural space: space between the dura mater and the arachnoid. 86 Nerve Structures and Related Terms • myelinated nerves: nerves covered with white fatty material called myelin • neuron: single nerve cell; has a cell body, axon, and dendrites • neurotransmitters: chemicals that stimulate (start) or prohibit (prevent) the transmission of nervous impulses 87 Nerve Structures and Related Terms • plexus: network of spinal nerves • reflex: an action done without a person’s control, such as blinking • sensory neurons: nerves that carry information from the sense organs to the spinal cord • synapse: space between two neurons, across which an impulse is transmitted (passed) 88 Related Terms: Cranial Nerves There are 12 pairs of cranial nerves. Here are a few of them: • acoustic (also called auditory): hearing • facial: facial muscles and taste • olfactory: sense of smell 89 Related Terms: More Cranial Nerves • opthalmic: forehead, nose, and eye • optic: retina (back) of the eye • trigeminal: eye and upper and lower jaws • vagus: most of the trunk of the body 90 Cranial Nerves Cranial Nerve Mnemonic 1 (nerves) Mnemonic 2 (alternate) Mnemonic 3*(Sensory vs. Motor) I. Olfactory On Oh Some* II. Ocular Old Oh Say III. Oculomotor Olympus' Oh Marry* IV. Trochlear Towering To Money V. Trigeminal Tops Touch But* VI. Abducens A And My VII. Facial Fin Feel Brother VIII. Vestibulocochlear/Acoustic And A Says IX. Glossopharyngeal German Good Big X. Vagus Viewed Vein Business XI. Accessory (Spinal Accessory) Some Ah Makes XII. Hypoglossal Hops Heaven Money Cranial Nerves • http://www.pitt.edu/~anat/Neur o/CranialNerves/CN.htm Related Terms: Spinal Nerves There are many spinal nerves. Spinal nerves are identified by numbers and letters. C = A nerve connected to one of the cervical (neck) vertebrae T = A nerve connected to one of the thoracic (upper body) vertebrae L = A nerve connected to one of the lumbar ( middle body) vertebrae S = A nerve connected to one of the sciatic (lower body) vertebrae EX: L4 means the fourth lumbar vertebra 93 Related Terms: Infections encephalitis: inflammation of the brain herpes zoster: infection caused by herpes virus; characterized by small blisters on the skin; also called “shingles” meningitis: inflammation of the brain and meninges myelitis: inflammation of the spinal cord 94 Related Terms: Infections • Poliomyelitis (“polio”): virus infection of the spinal cord, caused by a polio virus • Polyneuritis: inflammation of a large number of spinal nerves at the same time • Rabies: infection of the CNS and salivary glands, transmitted by animal bite • Tetanus: acute bacterial infection caused by a bacterium found in soil, dust, or animal or human wastes 95 Related Terms: Hereditary and Congenital Disorders • hereditary: inherited from a parent • congenital: a disorder a child has at birth • developmental: a disorder that appears as a child grows 96 Related Terms: Hereditary and Congenital Disorders • anencephaly: congenital (a child is born with it) bones of cranium are defective brain and spinal cord do not develop • cephalocele: part of the contents of the cranium protrude through a hole in the cranium 97 Related Terms: Hereditary and Congenital Disorders • epilepsy nervous system disorder inherited or the result of trauma (injury) patient may have convulsions of four types: grand mal petit mal psychomotor focal 98 Related Terms: Hereditary and Congenital Disorders • hydrocephalus: enlarged head because of fluid accumulating inside the cranium • meningocele: the meninges protrude (stick out) through a defect in the cranium or spine • microcephaly: a baby is born with a very small head • spina bifida: a baby is born with defective vertebrae 99 Related Terms: Circulatory Disturbances • cerebral hemorrhage: bleeding into the cerebrum • CVA (cerebrovascular accident) also called stroke or apoplexy bleeding in the brain due to ruptured artery symptoms: headache, nausea, vomiting, confusion 100 Related Terms: Circulatory Disturbances • epidural hematoma: collection of blood outside the dura mater • intracranial hemorrhage: bleeding inside the cranium • subdural hemorrhage or hematoma: bleeding between the dura mater and the arachnoid membrane 101 Related Terms: Other Organic Abnormalities • Alzheimer’s disease: progressive brain disease, mainly of the elderly (people over 65) • ALS (amytrophic lateral sclerosis): progressive nervous system disease of the spinal cord with muscle weakness and twitching. • Aphasia: loss of the ability to speak or write • Ataxia: loss of muscle 102 Related Terms: Other Organic Abnormalities • Alzheimer’s disease: progressive brain disease, mainly of the elderly (people over 65) • ALS (amytrophic lateral sclerosis): progressive nervous system disease of the spinal cord with muscle weakness and twitching. • aphasia: loss of the ability to speak or write • ataxia: loss of muscle 103 Related Terms: Other Organic Abnormalities, • aura: before an epileptic seizure, a patient sees, smells, hears, or feels something unusual. • Bell’s palsy: weakness on one side of the face • cerebral palsy: brain damage affecting control of muscles • chorea: nervous disease with involuntary jerky movements. 104 Related Terms: Other Organic Abnormalities • coma: patient is unconscious, can’t be awakened • delirium: patient has hallucinations, is excited, restless, and incoherent ( talking in an illogical way) • dementia: brain deteriorates because of disease • dyskinesia: patient’s movements are incomplete or uncontrolled, because of disease 105 Related Terms: Other Organic Abnormalities • dysphasia: patient doesn’t speak clearly • hemiplegia: one side of the body is paralyzed • Jacksonian seizures: seizures that start in a distant part of the body, such as the fingers, and spread towards the center of the body • multiple sclerosis: progressive disorder of brain and spinal cord, starting early in life, resulting in tremors, lack of 106 Related Terms: Other Organic Abnormalities • narcolepsy: patient suddenly falls asleep • neuralgia: pain in a nerve • palsy: paralysis • paralysis: loss of ability to move a part of the body • paraplegia: paralysis of lower body and legs • paresis: a form of paralysis 107 Related Terms: Other Organic Abnormalities • Parkinson’s disease: nervous system disease of late life • amnesia: loss of memory • syncope: fainting 108 Related Terms: Oncology • glioma: any tumor (cancer) of the nervous system 109 Surgical Procedures • • • • • craniectomy: removing part of the skull cranioplasty: repairing the skull crainotomy: surgical opening of the skull lobectomy: removing a lobe of the brain lobotomy: cutting into the frontal lobe of the brain • neuroplasty: repair of a nerve 110 Laboratory tests • brain scan: using a scanner to diagnose defects of the brain • cerebrospinal fluid tests: check for blood, infection,and other abnormalities • echoencephalogram: using ultrasound to check the brain for abnormalities • electroencephalogram (EEG) using a machine to check for abnormal electrical activity in the brain • myelography: x-ray of the spinal cord 111