من تزخ مطر دنیاك ترجعلي مھموم امشي ما عندى اي شك ترجع لحضن عشك اتحملت يامه يامه روح ودرب السلامة يعنى قابل اغشك ااااني

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2 طیر انت وانى الگاع ترجعلى ترجعلى ما و فارگنى علگ فوگ من تزخ مطر دنیاك ترجعلي مھموم لابد تحط يوم ناجي/ للدوم ایفان تطیر مابین الغیوم طیر انتھ امشي ما عندى اي شك ترجع لحضن عشك يعنى قابل اغشك ااااني اتحملت يامه يامه روح ودرب السلامة تجي تبجى بندامه تاني التعب کل وضاع اتعب انی سنین ذاک ویاک ما غزرت وگفاتی وگفاتی یاطیر دنیا محد میعرف تدور غیر بیک وبلیاک غیر اللی رباک امشي ما عندى اي شك ترجع لحضن عشك يعنى قابل اغشك ااااني

3 Arrangement of the central nervous system in humans

4 Relationship between the central and peripheral nervous systems

5 The nervous system Nervous system Allows for communication between cells through sensory input, integration of data and motor output 2 cell types: neurons and neuroglia neurons 3 types of neurons: Sensory takes impulses from sensory receptor to CNS Interneurons receive information in the CNS and send it to a motor neuron Motor takes impulses from the CNS to an effector (i.e. gland or muscle fiber) Neuron structure Cell body main cell part where organelles and nuclei reside Dendrite many, short extensions that carry impulses to a cell body Axon (nerve fiber) single, long extension that carries impulses away from the cell body

6 Types of neurons

7 The myelin sheath A lipid covering on long axons that acts to increase the speed of nerve impulse conduction, insulation and regeneration in the PNS Schwann cells neuroglia that make up the myelin sheath in the PNS Nodes of Ranvier gaps between myelination on the axons Saltatory conduction conduction of the nerve impulse from node to node Neurons/ cell body, dendrites, axon Oligodendrocyte Schwann cells Impulse conduction velocity/ regeneration Grey. White matter

8 Cl - Na + Na + Na + Cl - K + A - A - A K - K + + K + A - A - K + Na + Na + Na + Cl - Cl - Cl - K + Cl - A - Na + Cl - K + Na + Na + A - K + K Cl Na + Na - + A - + Cl - K + A - Cl A - - Na + Na + K + Cl -

9 The nerve impulse: resting potential (RP) Resting potential when the axon is not conducting a nerve impulse More positive ions outside than inside the membrane There is a negative charge of - 65mV inside the axon More Na + outside than inside More K + inside than outside

10 The nerve impulse: action potential Action potential rapid change in the axon membrane that allows a nerve impulse to occur Sodium gates open letting Na + in Depolarization occurs Interior of axon loses negative charge (+40mV) Potassium gates open letting K + out Repolarization occurs Interior of axon regains negative charge (-65mV) Wave of depolarization/repolarization travels down the axon Resting potential is restored by moving potassium inside and sodium outside

11 The nerve impulse: action potential

12 Continuous Conduction Occurs in unmyelinated axons. In this situation, the wave of de- and repolarization simply travels from one patch of membrane to the next adjacent patch. APs moved in this fashion along the sarcolemma of a muscle fiber as well. Analogous to dominoes falling.

13 Saltatory conduction Insulated with myelin for speeding up 1. Unmyelinatd axons speed of AP is 10 m/s. 2. Myelin sheath has spaces= Nodes of Ranvier. The AP jumps from node to next node (speed 120 m/s).

14 The synapse A small gap between the sending neuron (presynaptic membrane) and the receiving neuron (postsynaptic membrane) Transmission is accomplished across this gap by a neurotransmitter (e.g. ACh, dopamine and serotonin) Neurotransmitters are stored in synaptic vesicles in the axon terminals How does transmission across the synapse occur? Nerve impulse reaches the axon terminal Calcium ions enter the axon terminal that stimulate the synaptic vesicles to fuse with the presynaptic membrane Neurotransmitters are released on diffuse across the synapse and bind with the postsynaptic membrane to inhibit or excite the neuron ( inactivation, AcetylCholine esterase)

15 A synapse and how it functions Ach,Dopamine, GABA, Glutamate Norepinephrine: AutoNS, wakefullness, dreaming, mood. Serotonine: thermoregulation, sleeping, emotion Depression (Serotonine & Epineph. Theory- Antidepressive drugs are serotonergic drugs) Excitatory signal, and Inhibitory signal

16 Synaptic integration Integration is the summation of the inhibitory and excitatory signals received by a postsynaptic neuron This occurs because a neuron receives many signals

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18 The nervous divisions 2 divisions: Central nervous system (CNS): Brain and spinal cord Peripheral nervous system (PNS): Nerves and ganglia (cell bodies)

19 The central nervous system Consists of the brain and spinal cord Both are protected by: Bones skull and vertebral column Meninges 3 protective membranes that wrap around CNS Cerebral spinal fluid (CSF) space between meninges is filled with this fluid that cushions and protects the CNS (Hydrocephalus) Both made up of 2 types of nervous tissue: Gray matter contains cell bodies and nonmyelinated fibers White matter contains myelinated axons

20 The CNS: Spinal cord Extends from the base of the brain and along the length of the vertebral canal formed by the vertebrae. The spinal nerves project from the cord through small openings. Between the vertebrae there are the fibrocartilage *Intervertebral* discs. If the disc raptures or herniates, it will compress the spinal nerves and causing pain. Functions to provide communication between the brain and most of the body Center for reflex arcs Gray matter is in the center is a butterfly shape (H) White matter surrounds the gray matter Disc herniation

21 What does the spinal cord look like? Gray matter: Dorsal horn (sensory) Ventral horn (motor) White matter: Descending (motor) and ascending (sensory) tracts Pain and gate control (endorphine) Paraplegia (both lower limbs paralysis) Quadriplegia (all limbs) Hemeplegia (half of the body) Spinal reflexes (somatic and visceral)

22 The CNS: Brain 4 major parts: 1. Cerebrum 2. Diencephalon 3. Cerebellum 4. Brain stem

23 The brain: Cerebrum Cerebral hemisphere (sulci, gyri and lobes, frontal, parietal, temporal, occipital)) Cerebral cortex: thin, outer layer of gray matter:(1 B cells, sensation, movement, thinking) Primary motor (control voluntary movement) and sensory (analyze sensations) areas of the cortex (along the central sulcus, Primary motor, primary sensory, ( also primary taste, visual auditory and olfactory areas). Association areas / Integrative centers (prefrontal area, premotor area, somatosensory association area, visual, auditory) Processing centers: Higher levels of analysis ( Prefrontal/ thinking, Wernick s, Broca s areas/ speech). Central white matter (myelination, ascending/ sensory, descending/ motor tracts, crossing fibers/ Medulla Oblongata). Corpus callosum connects the two brains)

24 Cerebrum the lobes Cerebrum largest portion of the brain Divided into 4 lobes/hemispheres: Frontal lobe: primary motor area and conscious thought Temporal lobe: primary auditory, smell and speech area Parietal lobe: primary somatosensory and taste area Occipital lobe primary visual area Deep Nuclei eg Basal nuclei: Initiation, coordination, smoothing movements (parkinson s disease)

25 The brain: Cerebrum the cerebral cortex