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Gavin Arias Per.1 Nervous System - Coggle Diagram
Gavin Arias Per.1 Nervous System
Major Functions of the Nervous System
Spinal-transmit impulses to and from the brain, and to house spinal reflexes
Cranial-controls thought, memory, emotion, senses, movement, and homeostasis
Major Divisions and Subdivisions of the Nervous System
Motor(efferent)-multipolar neurons that conduct impulses from the CNS to peripheral effectors
Interneurons(association/internuncial neurons)-multipolar neurons lying within the CNS that form links between other neurons
Sensory(afferent)-conduct impulses from peripheral receptors to the CNS;usually unipolar, although some are bipolar
Peripheral Nervous System-made up of cranial and spinal nerves that connect the CNS to the rest of the body
Central Nervous System-made up of brain and spinal cord and responsible for integration of information and decision making
Tissues
Myelin Sheath-increases conduction speed of nerve impulses
Axon-conducts impulses away from the cell body; it arises from a thickening extending from the cell body
Dendrites-conduct impulses toward the cell body; they are short and branching, and they provide the receptive surface for communication with other neurons
Soma-contains major organelles including nucleus
Neuroglia-cells that support neurons
Neurons-nervous cells
Classification of Neurons
Neuroglia-cells that support, nourish, protect, and insulate neurons
Multipolar Neuronshave many dendrites and one axon arising from their cell bodies; most neurons with cell bodies in CNS(interneurons and motor neurons) are multipolar
Neurons-cells that communicate, via electrical impulses, with other neurons or other tissues
Bipolar Neurons-have 2 processes extending from the cell body, a dendrite and an axon; found in some of the special senses, such as the eyes, nose, and ears
Unipolar Neuronshave only 1 process extending from the cell body; outside the cell body, it soon splits into 2 parts that function as 1 axon; the peripheral process has dendrites near a peripheral body part, and the central process runs into the CNS; the cell bodies are found in ganglia outside the CNS; these are sensory neurons
Connective Tissue Coverings
Arachnoid Mater-middle layer of protective tissue
Pia Mater-innermost layer of protective tissue
Dura Mater-outermost layer made up of tough DNS and is very thick
Major Parts and Functions of the Brain
Brainstem-coordinates and regulates visceral activities, and connects different parts of the nervous system
Cerebellum-coordinates muscular activity
Diencehalon-processes sensory input and controls many homeostatic processes
Cerebrum-largest portion; associated with higher mental functions, and sensory & motor functions
Major Parts and Functions of the Spinal Cord
Horse's Tail(Cauda Equina)-consists of spinal nerves in the lumbar and sacral areas
Lumbar Enlargement-gives rise to nerves that serve to lower limbs
Cervical Englargement-provides nerves to the upper limbs
Spinal Cord-transmits impulses to and from the brain, and to house spinal reflexes
Action Potential and the Nerve Impulse
Membrane Potential-the charge inside a cell
Resting Membrane Potential-the charge in a cell when it is at rest(about -70 mV)
Excitable-Respond to stimuli by moving their internal charge into the positive range
Threshold Stimulus-stimulus strong enough to cause so many Na+ ions to enter neuron
Polarized-charge inside the membrane is different from the charge outside the membrane
Depolarization-change from negative to positive charge
Repolarization-outward flow of potassium ions through potassium channels to return to polarized state
Hyperpolarization-a slight overshoot of potential
Cranial Nerves
Abducens-Motor fibers conduct impulses to muscles that move the eyes
Facial-Sensory fibers conduct impulses associated with taste receptors of the anterior tongue. Motor fibers conduct impulses to muscles of facial expression, tear glands, and salivary glands
Trigeminal-Consists of 3 parts that control regions and functions of the facial area
Vestibulocochlear-Sensory fibers conduct impulses associated with the sense of equilibrium and hearing
Trochlear-Motor fibers conduct impulses to muscles that move the eyes
Glossopharyngeal-Sensory fibers conduct impulses from the pharynx, tonsils, posterior tongue, and carotid
arteries
Oculomotor-Motor fibers conduct impulses to muscles that raise eyelids, move eyes, adjust
the amount of light entering the eyes, and focus lenses
Vagus-Somatic motor fibers conduct impulses to muscles associated with speech and swallowing; autonomic motor fibers conduct impulses to the heart, smooth muscle, and glands in the thorax and abdomen
Optic-Sensory fibers conduct impulses associated with the sense of vision
Accessory-Motor fibers conduct impulses to muscles of the soft palate, pharynx, and larynx and the neck and back
Olfactory-Sensory fibers conduct impulses associated with the sense of smell
Hypoglossal-Motor fibers conduct impulses to muscles that move the tongue
Spinal Nerves
Descending Tracts-carry motor information from the brain to muscles or glands
Spinal Reflexes-controlled by reflex arcs that pass through the spinal cord
Ascending Tracts-carry sensory information to the brain
Neurotransmitters
Dopamine-Creates a sense of feeling good
Serotonin-Primarily inhibitory; leads to sleepiness
Norepinephrine-Creates a sense of feeling good; low levels may lead to depression
Histamine-Release in hypothalamus promotes alertness
Acetylcholine-Controls skeletal muscle actions
Neurotransmitters-the chemical messengers in a synapse, that convey an electrical impulse from a neuron to another cell
Compare/Contrast ANS
The Autonomic nervous system connects the CNS to viscera and controls subconscious activities
ANS is a motor part of the PNS(peripheral nervous system)
The Somatic nervous system connects the CNS to skeletal muscles and the skin and oversees conscious activities
Reflex Arc
Interneuron-Carries information from sensory
neuron to motor neuron
Motor Neuron-Carries instructions from brain or
spinal cord out to effector
Sensory Neuron-Carries information from receptor
into brain or spinal cord
Effector-Responds to stimulation (or
inhibition) by motor neuron and
produces reflex or behavioral
action
Receptor-Senses specific type of internal or
external change
Disorders/Diseases
Alzheimer's Disease-a form of dementia associated with age
Spinal Cord Injury-damage to the spinal cord
Autism-brain disorder that makes it difficult to communicate
Meningitis-infection in the meninges surrounding the brain
Cerebrovascular Accident(Stroke)-occurs when blood flow to a portion of the brain is halted
Multiple Sclerosis-autoimmune disease that damages the myelin sheath
Drugs of Abuse-
Marijuana-drug that removes unnecessary short term memory and slows down movement
Methamphetamine-drug that gives intense pleasure and exhileration
Ecstasy-drug that affects mood, sleep, perception, and appetite; and increase in dopamine
Alcohol-drug that affects decision making and impulse control
Heroine-drug that alters the transmission of pain, stress, and emotional attachment
Cocaine-drug that causes pleasure, exhileration, and creates fidgety movement
LSD-drug that causes feelings of wakefulness and evokes a startle response to unexpected stimulus