Nervous System Review PDF

1st Year End Review Nervous System Functional Unit of Nervous System: Neuron (cell that carries out the nervous system’s primary actions) 3 parts: 1. Cell Body 2. Dendrites-receptive part of cell. Respond to incoming signals....

1st Year End Review Nervous System Functional Unit of Nervous System: Neuron (cell that carries out the nervous system’s primary actions) 3 parts: 1. Cell Body 2. Dendrites-receptive part of cell. Respond to incoming signals. 3. Axon-1 long, slender axon. Sends action potentials away to another tissue. Have synaptic vesicles at end, which release neurotransmitters into synaptic cleft. How does neuron conduct action potential? -Depolarization= Na+ or Ca++ influx -Repolarization=K+ Efflux Neuron vs Nerve vs Tract vs Ganglion: -Nerve: Bundle of axons (can be combo of motor and sensory) in PNS; i.e. sciatic nerve, radial nerve -Tract: Bundle of axons in CNS (brain and spinal cord) i.e. lateral spinothalamic tract -Ganglion: Cluster of cell bodies in peripheral nervous system i.e. Dorsal root ganglion (sensory input passes through these) Neuroglia: 6 types Supporting cell of nervous system. Support neurons. Protect, nourish, remove debris from neurons. 1. Astrocytes: Form blood/brain barrier 2. Oligodendrocytes: Form myelin in CNS 3. Schwaan Cells: Form myelin in PNS 4. Microglia: 5. Ependymal Cells: 6. Satellite cells: Parts of the brain: 1. Cerebrum 2 hemispheres -4 lobes: 1. Frontal 2. Temporal 3. Parietal 4. Occipital visual cortex -Wernicke’s area vs Broca’s area: Brocas=Speech production (Coming up with the proper words and saying them) (injury causes expressive aphasia), Wernickes=understanding of written and spoken language (injury causes fluent aphasia) 2. Cerebellum: Responsible for Coordination, Equilibrium, and Proprioception Coordination of skilled muscular activity (muscle memory). Proprioception-awareness of location of body parts in relation to each other and surrounding space. 3. Diencephalon: Contains thalamus, hypothalamus, pituitary gland, pineal gland  4. Brainstem: Organ regulation (involuntary-autonomic nervous system) -3 parts: 1. Midbrain (superior) 2. Pons 3. Medulla Oblongata (inferior) Pons/MO have a lot of centers (clusters of cell bodies) that regulate organ activity. i.e. respiratory center, cardiac center, vasomotor center Motor pathway: Primary Motor Cortexà Pyramids of Medulla Oblongata (axons cross or decussate in pyramids)à Down spinal cord via Corticospinal/Pyramidial Tracts àAnterior/Ventral HornàAnterior/Ventral Rootà Spinal NerveàPeripheral Nerveà Muscle Neurotransmitter=acetylcholine Sensory pathway: Peripheral Receptorà Peripheral Nerveà Spinal Nerveà Posterior/Dorsal Root including Dorsal Root Ganglionà Posterior/Dorsal Hornà Up spinal cord via Spinothalamic TractàThalamus(Relay station)àSomatosensory Cortex Where do tracts cross? -Corticospinal Tracts cross/decussate in the Pyramids of Medulla Oblongata -Lateral Spinothalamic Tract (Pain and Temperature) cross at spinal cord level Entire CNS (brain and spinal cord) is wrapped by connective tissue protective layer known as: Meninges 3 Layers: P: Pia Matar (deepest) A: Arachnoid Matar D:Dura Matar (Most superficial; thickest, toughest) CSF (Cerebrospinal Fluid) formed by: Choroid plexus (capillaries) in ventricles (hollow areas) of brain. CSF will circulate through ventricles and into subarachnoid space in meninges. CSF reabsorbed by: Arachnoid villi Peripheral Nerves How do we name Spinal Nerves? In cervical region, nerve is above corresponding vertebra (i.e. C1 nerve is above C1 Vertebra.; In thoracic and lumbar spine, nerve is below corresponding vertebra. i.e. Nerve between C1/C2-C2 Dermatome-Area of sensation that corresponds to 1 spinal nerve level Nerve between C7/T1-C8  Nerve between T2/T3-T2 Cranial Nerves: I-Olfactory: Sense of smell II-Optic: Sense of vision……..Light enters eye through pupil, is focused by the lens, light hits the retina in the back of the eye(photoreceptor), which will trigger action potential along CN 2. Ultimately, occipital lobe is where vision occurs III-Oculomotor:Moves eye every other direction, raises eyelid, and constrict pupil IV-Trochlear:Moves eye down and in V-Trigeminal: Facial sensation, Motor for mastication (chewing) VI-Abducens:Moves eyeball laterally VII-Facial: Motor for face (expression), sensory for taste on anterior 2/3 of tongue VIII-Vestibulocochlear: Hearing and equilibrium (inner ear) IX-Glossopharyngeal: Motor for swallowing and sensory for taste on posterior 1/3 of tongue X-Vagus:Longest cranial nerve in body. Parasympathetic control of organs. Ie. Slow HR, promote digestive activity/peristalsis. XI-Accessory: Controls SCM and trapezius (shrug shoulder, turn head) XII-Hypoglossal: Movement of tongue On Occasion Our Trusty Truck Acts Funny, Very Good Vehicle AnyHow. Autonomic Nervous System Fight or Flight Rest and Digest Body Part Sympathetic Parasympathetic Pupil of Eyes Dilate Constrict Heart Rate/Force Increase Decrease Blood Vessel Diameter Constricts(raises bp) Dilates(lowers bp) Bronchiole Diameter Dilates Constricts Peristalsis, Digestion, Bowel Suppress Promote Movements, Urination