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77 Cards in this Set
- Front
- Back
Structural Divisions of the Nervous System
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Central Nervous System- Brain and spinal cord
Peripheral Nervous System- All nerves outside CNS |
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Functional Divisions of Nervous System
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Somatic Nervous System
Autonomic Nervous System |
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Somatic Nervous System
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Voluntary
Effector-skeletal muscle Motor nerve travels from spinal cord to skeletal muscle |
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Autonomic Nervous System
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Involuntary
Effector-glands, cardiac muscle, smooth muscle Subdivisions: Sympathetic, Parasympathetic |
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Neuron Structures
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Dendrites
Axons Myelin Sheath Neurilemma |
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Dendrites
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Tree-like appearance
Send impulses to the cell body Contain receptors that receive a stimulus |
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Axons
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Send impulses away from the cell body
A single fiber with end branches |
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Myelin Sheath
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Provides insulation around some nerves
Fatty material Speeds up the conduction of action potentials |
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Neurilemma
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Outer membrane of Schwann cells
Not found in CNS cells |
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Types of Neurons
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Afferent (sensory) Neurons
Efferent (motor) Neurons Interneurons |
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Afferent Neurons
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Toward the CNS
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Efferent Neurons
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Away from the CNS
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Interneurons
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Within the CNS
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Neuroglia
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Glial Cells
Found in CNS and PNS Nonconducting cells Multiply throughout life Schwann Cells- Neuroglia in PNS Astrocytes- Neuroglia in CNS |
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Functions of Neuroglia
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Help repair cells
Protect the nervous systems Regulate fluid composition around the cells Provide Scaffolding or support system for the nervous system |
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Astrocytes
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Star shaped
Twist around nerve cells to support the CNS Attach neurons to capillaries Protect brain from harm |
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Microglia
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Small in size
Grow from monocytes Act as brain macrophages Engulf and destroy pathogens |
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Oligodendrocytes
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Produce myelin sheath around CNS axons
Provide support in CNS |
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Resting Potential
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Ionic charge along the plasma membrane of an unstimulated nerve
Inside membrane- resting potential is negative Outside membrane- resting potential is positive |
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Nerve Impulse
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Reverses membrane potential because of reversal of ion concentrations
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Action Potential
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Sudden electrical change in ion concentrations of a nerve
AP=Nerve Impulse=Salutatory Conduction |
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Resting State
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More Sodium outside the cell and more Potassium inside the cell
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Depolarization
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Energy allows diffusion of sodium into cell membrane. Increases the charge inside to be more positive
Electrical Chemical Mechanical |
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Repolarization
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Membrane electrical charge returns to resting potential
Potassium channels open allowing it to leave the cell Cells use active transport to return Sodium and Potassium concentrations back to normal |
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Types of Synapses
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Chemical (gap) Synapse
Electrical Synapse |
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Chemical Synapse
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Axon of presynaptic cell to dendrite of postsynaptic cell
Axon stores neurotransmitters in end bulbs Action Potential causes end bulbs to fuse with dendrite and release neurotransmitters into synaptic cleft Neurotransmitter acts as a chemical signal generating action potential of postsynaptic cell |
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Electrical Synapse
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CNS, Cardiac, and smooth muscle
The membranes of presynaptic and postsynaptic cells are close enough for electrical charge to spread |
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Function of Neurotransmitters
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Stimulate or inhibit postsynaptic cells
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Most Common Neurotransmitters
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Epinephrine (adrenaline)
Norepinephrine (noradrenaline) Acetylcholine (ACh) |
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Reflex Arc
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Receptor-Detects Stimulus
Afferent Neuron-Transmits impulse toward CNS CNS-Interprets and organizes response Efferent Neuron-Transmits impulse from CNS to PNS Effector-Response Unit (muscle or gland) |
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Stretch Reflex Path
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1) Receptor
2) Sensory Neuron 3) Dorsal Horn 4) Interneuron 5) Ventral Horn 6) Motor Neuron 7) Effector |
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Spinal Nerves
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31 pairs
Two Roots: Dorsal Root-Sensory Ventral Root-Motor |
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Primary Plexuses in the Body
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Cervical Plexus
Brachial Plexus Lumbar Plexus Sacral Plexus |
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Autonomic Nervous System
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Regulates actions of glands, smooth muscles of hollow organs and vessels, as well as cardiac muscle
Automatic-no conscious awareness Two Divisions: Sympathetic Parasympathetic |
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Sympathetic Nervous System
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Fight or flight stress response
Thoracic and lumbar spinal areas (T1-L2) Adrenergic actions-activated by adrenaline Acts as an accelerator of organ function |
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Fight or Flight Response
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Increases rate and force of heart contractions
Increases blood pressure Increases metabolic rate Decreases activity of urinary and digestive systems Dilates pupils, bronchial tubes, and skeletal blood vessels |
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Parasympathetic Nervous System
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Reverses the fight or flight stress response
Craniosacral region-brainstem and sacrum Cholinergic actions activated by acetylcholine Acts as a depressor or decelerator of organ functions |
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Cranial Nerve I
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Olfactory-sense of smell
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Cranial Nerve II
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Optic-Vision
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Cranial Nerve III
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Oculomotor-PEARL, Elevation of upper eyelid, Eye adduction and downward rolling
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Cranial Nerve IV
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Trochlear-Upward eye rolling
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Cranial Nerve V
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Trigeminal-Sensation of nose, forehead, temple, scalp, lips, tongue, and lower jaw
Muscles of mastication |
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Cranial Nerve VI
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Abducens-Lateral Eye Movement
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Cranial Nerve VII
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Facial-Taste
Muscles of Expression |
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Cranial Nerve VIII
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Vestibulocochlear-Hearing and Equilibrium
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Cranial Nerve IX
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Glossopharyngeal-Taste
Swallowing |
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Cranial Nerve X
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Vagus-Gag Reflex
Muscles of Pharynx and Larynx |
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Cranial Nerve XI
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Accessory-Shoulder Shrug
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Cranial Nerve XII
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Hypoglossal-Tongue Protrusion
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Areas of the Brain
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Cerebrum
Diencephalon Brainstem Cerebellum |
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Cerebrum
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Five paired lobes
Largest portion of the brain Two convoluted hemispheres Corpus Collosum connects right and left hemispheres Cerebral Cortex-Oute layer |
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Diencephalon
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Between the cerebrum and brainstem
Thalamus and hypothalamus Thalamus sorts and redirects sensory inputs Hypothalamus is responsible for homeostasis, ANS control and pituitary gland control |
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Brainstem
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Below the cerebrum connects the cerebrum with the spinal cord and diencephalon
Three Parts: Midbrain Pons Medulla Oblongata |
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Midbrain
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Vision and hearing
Connects the lower portion of the brain to the cerebrum |
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Pons
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Helps regulate respiration
Mostly myelinated nerves Bridges the cerebrum, cerebellum, and brainstem |
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Medulla Oblongata
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Connects brain with spinal cord
Controls vital functions Highly Myelinated Motor fibers decussate Three Centers: Respiratory Cardiac Vasomotor |
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Cerebellum
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Coordinates voluntary muscles
Balance and muscle tone maintenance Outer covering-gray matter Inner area-white matter |
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Lobes of the Cerebrum
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Frontal Lobe
Parietal Lobe Temporal Lobe Occipital Lobe Insula |
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Frontal Lobe
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Primary motor control area
Speech centers Conscious control of skeletal muscle |
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Parietal Lobe
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Primary sensory area
Somatesthetic sensation Temperature Interpretation Distance, size, and shape interpretation |
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Temporal Lobe
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Auditory centers including interpretation and association of auditory information
Olfactory area |
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Occipital Lobe
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Vision and coordination of eye movements
Visual receiving and association areas Read with understanding |
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Insula
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Memory
Integration of other cerebral activities Deep within each hemisphere |
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Basal Nuclei (Basal Ganglia)
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Masses of gray matter composed of neuron cell bodies
Located deep within the white matter of the cerebrum Function to control voluntary movements Secrete dopamine |
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Cerebral Cortex
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Outer 2-4 mm covering of the cerebrum
Conscious thought, memory, reasoning, abstract mental functions Thought processes Voluntary actions Gray matter with underlying white matter Folds and grooves called convolutions Left hemisphere of the cerebral cortex is responsible for language |
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Corpus Callosum
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Band of white matter
Bridge that permits impulses to cross between cerebral hemispheres |
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Cerebrospinal Fluid
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Formed in the ventricles of the brain
Supports nervous tissue Acts as a shock absorber Carries nutrients and waste |
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Limbic System
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Part of the brain that controls the emotional state
Nuclei and fibers that form a ring around the brainstem Stimulates the reticular formation Hippocampus-long term memory and learning |
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Meninges
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Dura Mater
Arachnoid Mater Pia Mater |
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Dura Mater
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Outermost layer
Thickest and toughest |
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Arachnoid Mater
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Middle layer
Web-like Allows the CSF to flow between dura and arachnoid |
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Pia Mater
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Innermost layer
Attached to CNS nervous tissue Follows contours of CNS structures Holds blood vessels supplying oxygen and nutrition to CNS |
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Divisions of the Rhombencephalon
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Metencephalon
Myelencephalon |
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Metencephalon
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Pons- Respiratory centers
Cerebellum-Proprioceptors connect here |
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Myelencephalon
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Medulla Oblongata
Vital centers involved in regulation of breathing and cardiovascular responses |
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Thalamus
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Part of the diencephalon
Gray matter Sorts impulses and directs to appropriate areas in the cerebral cortex |
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Hypothalamus
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Part of the diencephalon
Maintains homeostasis Controls body temperature Maintains water balance Controls sleep Controls appetite Controls emotions of fear and pleasure Controls pituitary gland Controls both portions of the ANS Influences many major body functions |