-Nervous System3 functions of the nervous system:-Receives and relays information-Monitors and responds to internal and external changes-Controls and coordinates all body functionsSensory: become aware of stimuli: change in environmentIntegative: memory, emotions, conscience, decisions Response: muscles, what did you do?Neuron- (nerve cell) cells that carry messages throughout the nervous systemNerve impulse- electrical signals, coded method from neuronSensory neuron: neuron that carries impulses from the sense organs to the brain and spinal cordMotor neuron: neuron that carries impulses from the brain and spinal cord to muscles and glandsInterneuron: cell that connects the motor and sensory neurons (only found in brain)Cell body- center part of the neuron that contains the nucleus and much of the cytoplasmDendrite- part of the neuron that is an extension from the cell body of a neuron that carries impulses from the environment to the cell bodyAxon- long fiber that carries impulses away from the cell body of a neuronAxon terminals- small swellings in a neuron at the end of an axon that makes connections with next neuronMyelin- substance composed of liplids and protein that forms an insulated sheath around an axon, and makes a better impulseNeurilemma- outermost covering of a neuron allows nerve to grow backThreshold stimulus- minimum level of a stimulus required activating a neuronReceptor- special sensory neuron in a sense organ that receives stimuli from external environment (nose, eyes, ears)Effector- muscle of gland that brings about a coordinated response to a stimuliSynapse- point of contact at witch an impulse is passed from one cell to anotherNeurotransmitters- substance used by one neuron to signal another-EyeSclera- white part of the eye that helps maintain the shape and provides muscle that moves the eyeChoroid- pigmented, contains blood vessels of eye, and becomes the disk-like structure called the irisIris- part of the eye that gives it its colorPupil- in the middle of the iris, small opening light enters here, (black disk)Retina- innermost layer of eye contains photoreceptor cells (rods, cones)Rods- photoreceptor cells, really sensitive to color of light, DONT detect colors Cones- photoreceptor cells, gives us color visionConjunctiva- transparent coat on outside of eye (pink eye)Cornea- outer, part of eye where light enters transparent layerLens- part of eye you see out of, it focuses thingsSuspensory Ligaments- holds lens in placeCiliary Body- allows us to focus close-upVitreous Humor- behind lens, filled with transparent jelly fluid, keeps eye roundedAqueous Humor- inside cornea filled with fluid keeps cornea rounded shape Optic nerve- nerve cell carries information to brain for interpreting Fovea- cells are cones, can see color and bright lightMyopia- near sided, long strongHyperopia- far sided, short weak-Spinal Cord and Brain2 major divisions of the nervous system:-Central: control center, consists of brain and spinal cord, relays messages, processes information, compares and analyzes information-Peripheral: outside the central, all nerves, receptors, and ganglionsThe cerebrum has a left and a right hemisphere; it is the biggest part of the brain.
Fissures- valleys on the brainConvolutions- ridges on the brainLobes- regions of the brainCerebral Cortex- gray matter on the surface of the brainFunctions include: voluntary muscles/activities, instincts, behavior, intelligence, emotions learning, memory, and sensesThe cerebellum coordinates muscle actions Brain Stem- structure that connects the brain with the spinal cord and is composed of the medulla, pons, and mid-brain, coordinates information coming into brainMedulla Oblongata- contains white matter that conducts impulses between spinal cord and brain, controls involuntary functions such as; breathing, blood pressure, swallowing, coughing, and heart ratePons- contains white matter that provides link between the cerebral cortex and cerebellumMid-brain- involved with hearing and vision reflexThalamus- gray matter, serves as the switching station for sensory input, passes information to the proper regionHypothalamus- serves as the control center for hunger, thirst, fatigue, anger, and body temperatureEGG- electroencephalogram, shows activities of the brainShort-term memory- only last a few days, such as what you had for breakfastLong-term memory- memories that are permanent and last a long timeStructure of the spinal cord:Acts as a communications link between the brain and the peripheral nervous system.
Carries impulses and regulates reflexes. (2 types of nerve tissue)What are ways in which the brain and spinal cord are protected?Bone-hard over-top of the brain and spinal cordMeninges- membranes on surface of brain and spinal cord protect against rubbingCerebrospinal fluid- surrounds brain and spinal cord and acts as shocks or cushions Peripheral Nervous System: takes information and sends it to the brain and spinal cord and back (31 pair of vertebrate nerves, 31 pair of spinal nerves, and 12 pair of cranial nerves)Parts of the Peripheral Nervous System:Somatic- regulates activities we have control over such as moving, talking, running, and jumpingAutonomatic- regulates activities we dont have control over such as digestion, breathing, and heart rateWhat is a reflex arc?-Path that an impulse will travel during a reflex3 parts of the reflex arc:-Sensory neuron-Interneuron-Motor neuron-EarAuricle- outside ear, channels sound waves into earAuditory Canal- contains small hairs and wax producing glands (then sound waves go to eardrum) Eardrum- the beginning of the middle earMalleus-tiny boneIncus- tiny bone, transfers sound from the outer ear to the inner earStapes- tiny bone, transfers sound from the outer ear to the inner earEustachian tube- mid ear, where yawn air comes in and out or swallow, also transfers sound from the outer ear to the inner earOval window- transmits the vibrations to the cochlea Cochlea- begins the inner ear, snail shaped cavity full of fluid Acoustic nerve- carries impulses from cochlea to brain where we hearSemicircular canals- 3 canals that lie at right angles, sense of balanceCompare senses of taste and smell:Chemoreceptors detect taste and smellOlfactory receptors: detect smellTaste buds: detect taste with saliva (found on lips, roof of mouth, and tongue)4 types of tastes:-Sour-Sweet-Salt-BitterCerumen: ear wax, prevents anything from getting into direct contact with eardrum, and also keeps eardrum soft and flexible Sound:Pitch: high or low a sound isQuality: a persons voice, unique to each others, (telling the difference)Loudness: loud or soft a sound is
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