The Nervous System
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Created by:
rgideon123 on May 5, 2012
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124 terms
Terms | Definitions |
|---|---|
 function of the nervous system | CEO or boss of all of the others; job is to integrate and coordinate |
| integrate | to poll together |
| nerve net | loosely organized network of nerve cells that together allow cnidarians to detect stimuli, most primitive, found in hydra |
| primitive brain or ganglion | collection of nerve cells not referred to as brain, can process information picked up by other nerves (dark or light, jellyfish)) |
| earthworms are... | some of the first organisms on the tree of life to officially have a brain, have true nervous systems |
| one you have a brain... | can tell difference between head and tail region |
| hydrocephali | water on the brain |
| cephalization | having a head |
| crustaceans | 5 sensory structures; brain and nerve cords to sensory structures (crab, lobster, etc.) |
| nervous systems of higher animals | specialized brains (different parts do different jobs) with a spinal cord with No nervous tissue on the brain, no nerve endings |
| central nervous system | the portion of the vertebrate nervous system consisting of the brain and spinal cord, in charge of processing |
| peripheral nervous system | Peripheral "around": data-gathering part of the central nervous system, the sensory and motor neurons that connect the central nervous system to the rest of the body |
| control of the nervous system | increases with age, Sometimes difficult to control due to chemical in-balances, One-way pathways like an interstate system |
| nervous pathways | Sending messages to the brain: purple nerves, sensory division of the purple nerves, takes impulses to the brain , nerve impulses are conducted from receptors to effectors over neuron pathways; two-arc and three-arc |
| motor division | pulls impulses from the brain |
| somatic nervous system | voluntary movement, controls skeletal muscles |
| autonomic nervous system | The part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart). Its sympathetic division arouses; its parasympathetic division calms. |
| functional unit of the nervous system | Neurons: fire electrical signals across surface of their cells |
| milliseconds | unit to measure speed of impulses |
| motor neuron | goes away from the brain, links to form motor nerve , this carries information from the brain to the muscles; also called "efferent" |
| three types of neurons | sensory, motor, inter |
| sensory neurons | neurons that carry incoming information from the sense receptors to the central nervous system |
| inter-neurons | Central nervous system neurons that internally communicate and intervene between the sensory inputs and motor outputs |
| cell body of a neuron | Astrocyte astro "star" , receives information from dendrites and, if enough stimulation is received, the message is passed to the axon |
| dendrites | branching extensions of neuron that receives messages from neighboring neurons |
| axon | long fiber that carries impulses away from the cell body of a neuron |
| shwann cells | Form myelin sheath round axons in the PNS, one cell myelinates a single axon |
| myelin sheath | a layer of fatty tissue segmentally encasing the fibers of many neurons; enables vastly greater transmission speed of neural impulses as the impulse hops from one node to the next |
| nodes of ranvier | small gaps in the myelin sheath of medullated axons |
| impulses and speed | much faster when axon is myelinated , depressants like medicine and alcohol can also slow response and even cut them off |
| neuroglia | supporting cells that are also in the brain material but help with the job since the neuron is so busy and can barely process ATP |
| astrocyte | A type of CNS supporting cell with a star shape that assists in exchanges between blood capillaries and neurons. Helps to form the blood-brain barrier. |
| astro | star |
| reflex arc pathway | Reflex that does not involve the brain Reflex-arc pathway: sensory, motor, and interneuron No thinking about what happened Immediate response , Stimulus-->Receptor-->Afferent Pathway (nerves and hormones)-->Integrating Center (CNS or endocrine gland)--> Efferent Pathway-->Effector (muscle and glands)-->Response-->FEEDBACK |
| brain hemispheres | • Right controls left motor nerves • Left controls right motor nerves • Can compensate for each other |
| stroke | right hemispere causes weakness on the left side, left hemisphere causes weakness on the right side |
| afferent | sensory |
| efferent | motor |
| somatic vs. autonomic | 1. Somatic -- Carries information to skeletal muscles (voluntary) 2. Autonomic -- Carries information to smooth muscle, cardiac muscle and glands (involuntary) |
| all or none | If you can initiate enough energy at the dendrites of an impulse, it will not stop until it reaches the terminal buttons. |
| impulse | electrical current that runs across a neuron aka action potential ( a flow of electrons down or across the neuron) |
| action potential | the local voltage change across the cell wall as a nerve impulse is transmitted, There is a space, pre-synaptic and post-synaptic between, Electricity cannot jump across the synapse, So once we start an all-or nothing impulse, to get it through, neurotransmitters are used while the dendrite acts as a tube |
| synapse | the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron |
| neurotransmitters | chemical messengers that traverse the synaptic gaps between neurons |
| sodium Na (11) 8,2, 1 | If Na gives away electrons, charge of +1 since it has a valence 1, Dissociates as chloride takes electron away, Sodium ions are left, so small that it can go in or out of the membrane thru diffusion-->Until it reaches dynamic equilibrium |
| axons and dynamic equilibrium | hate dynamic eqilibrium so they use active transport protein to go against the concentration gradient (10 out and 0 in) by using the sodium-potassium pump and use the same pump to reload and introduce potassium |
| every time one cycle is completed... | one sodium is kicked out and one potassium is pumped in |
| negative molecules (juvis+ambassadors) | X,y, z (10) Now on the inside the charge is more negative than the outside. Because x y and in the room, they offset what was once neutral, making the neuron negative on the inside, Chemical dots make membrane polarized neuron at rest (Uneven distribution of charge across the membrane) o What is necessary to get the action potential to start and a new one must be started at the synapse of each new neuron o Calcium absorbed right before it hits the button and as soon as its absorbed, the vesicles filled with neurotransmitters |
| What happens when the chemicals trigger a portion of the membrane? | Sodium comes in , Chemicals can temporarily seize pumps and give sodium a way to dffuse inside (Makes the inside of the neuron more positive and overcome negativity) The sodium-potassium pumps try to kick out sodium but it is too late; Chemicals then seize pumps at next group and will happen all the way down until it hits the terminal button Signals pumps to seize (neurotransmitter) and allow for adjacent membranous portions to allow in sodium, next section is depolarized and next is repolarized down to the terminal buttons |
| depolarization | the process during the action potential when sodium is rushing into the cell causing the interior to become more positive |
| repolarization | after Na+ ions have rushed into the cell, K+ ions rush out of the cell to restore the balance and the original polarity |
| threshold | the level of stimulation required to trigger a neural impulse, controls the all or none feature; What is necessary to get the action potential to start and a new one must be started at the synapse of each new neuron; Calcium absorbed right before it hits the button and as soon as its absorbed, the vesicles filled with neurotransmitters |
| millivolts | unit of measurement of action potential |
| white matter | whitish nervous tissue of the CNS consisting of neurons and their myelin sheaths |
| arbor vitae | cerebellar white matter, brings sensory and motor information to and from the cerebellum "tree of life" |
| gray matter | Brain and spinal cord tissue that appears gray with the naked eye; consists mainly of neuronal cell bodies (nuclei) and lacks myelinated axons. |
| meninges | a membrane (one of 3) that envelops the brain and spinal cord |
| meningitis | infectious disease characterized by inflammation of the meninges (the tissues that surround the brain or spinal cord) usually caused by a bacterial infection |
| cerebrospinal fluid | fluid in the space between the meninges that acts as a shock absorber that protects the central nervous system, produced by ventricles 1 and 2, 80-90 percent water (connective tissue), drains constantly |
| concussion | injury (bruise) to the brain caused by a blow |
| spinal cord | cord of nerve tissue that conducts messages between the brain and the peripheral nerves, also made of white (around the outside) and gray matter (in the center) |
| spinal tap | a withdrawal of fluid from spinal cord for diagnostic reasons, to introduce antibiotics or anesthesia, between L3 and L4 |
| central canal | The narrow cavity in the center of the spinal cord that is continuous with the fluid-filled ventricles of the brain. |
| tracts | bundles of axons in the white matter of the CNS that share common origins, destinations and functions |
| cerebrospinal fluid flow | L/ R ventricles (1 and 2 that make the fluid) -> interventricular foramen -> 3rd ventricle -> cerebral aqueduct -> 4th v. -> central canal to create cushion around the brain |
| tube or shunt | what is needed to relieve the pressure of hydrocephali |
| cerebrum | large part of the brain that controls the senses and thinking (2 hemisperes), thinking, homework, most developed in primates, moving toes and limbs, etc.) |
| cerebellum | the "little brain" attached to the rear of the brainstem; it helps coordinate voluntary movement and balance (coordinated movement and muscle memory) |
| diencephalon | located between the midbrain and the cerebrum and consists of the thalamus, hypothalamus, optic chiasma, and pineal body; the control center for homeostasis, hunger, body temperature, etc.) |
| brain stem | controls vitals such as breathing and heart rate if nervous (takes over for the SA node) |
| frontal lobe | primary motor area which also controls speech, memory, critical thinking, problem solving, and consequences; |
| parietal lobe | general interpretation area |
| occipital lobe | in charge of sight and vision |
| temporal lobe | controls hearing |
| cerebral | fancy way of saying brainy or smart |
| encephalo" | brain |
| nurse cells | aka neuroglia |
| latent | not presently active, reaaly small window of time when another impulse cannot be immediately fired because repolarization is occurring |
| vesicle | houses neurotransmitters |
| aencephali | without a brain (children born this way only live about 1-2 hours because of the presence of the brain stem which controls vitals but die since the lack of a developed brain is too taxing on the body |
| lobotomy | a now-rare psychosurgical procedure once used to calm uncontrollably emotional or violent patients. the procedure cut the nerves that connect the frontal lobes to the emotion-controlling centers of the inner brain (using an icepick and used to treat anxiety, depression, etc. ex. Rosemary Kennedy) done by going above the eye thru a thin piece of bone to the frontal lobe and twisting around, causing permanent nerve damage often resulting in loss of emotion, feeling, etc. |
| 1940s and 50s | hot time for lobotomies (first by Walter Freeman) |
| lobo | lobe |
| tomy | process of cutting, incision, probing |
| 1967 | year of last lobotomy, doctor who pioneered procedure had to leave the country |
| hemisperectomy | half of brain removed (treated baby for sturge-Weber syndrome) |
| 12 | number of cranials nerve pairs coming off the base of the brain (one pair optic, one pair olfactory, one pair auditiory, and so on) |
| 31 | number of spinal nerves |
| 8 | number of cervical nerve pairs |
| 12 | number of thoracic nerve pairs |
| 6 | number of sacral nerve pairs |
| number of lumbar nerves | 6 |
| 1 | outlier coccygeal nerve |
| pinched nerve | A nerve entrapped by muscle, bone, tendons etc., very painful |
| cauda equina | "horse's tail", a fan of nerve fibers below the spinal cord |
| sight or hearing (Helen Keller's choice) | hearing |
| sclera | whitish fibrous membrane (albuginea) that with the cornea forms the outer covering of the eyeball |
| cornea | transparent anterior portion of the outer covering of the eye |
| choroid | a highly vascular membrane in the eye between the retina and the sclera |
| retina | the light-sensitive membrane covering the back wall of the eyeball |
| iris | muscular diaphragm that controls the size of the pupil, can be green, blue or brown depending on genetics |
| pupil | contractile aperture in the iris of the eye |
| anterior chamber | Area behind the cornea and in front of the lens and iris. It contains aqueous humor. |
| suspensory ligaments | a fibrous membrane that holds the lens of the eye in place |
| vitreous chamber | Behind the lens, filled with vitreous humor, gelatinous. |
| lens | a transparent optical device used to converge or diverge transmitted light and to form images |
| optic disk | the point where the optic nerve enters the retina |
| optic nerve | the nerve that carries neural impulses from the eye to the brain |
| ocular conjunctiva | covers the whites of the eyes |
| eye socket | composed of orbital muscles and optic nerve |
| refraction | the bending of light (objects shown upside down on retina) |
| how the eye focuses on a distant object | ciliary muscle relaxes, lens flattens and sensory ligament is taut |
| how the eye focuses on a near object | ciliary muscle contracts, lens rounds, and suspensory ligament relaxes |
| nearsightedness | eyeball is too long which causes rays to focus in front of retina when viewing distant objects |
| correcting nearsightedness | concave lens allows patient to see distant objects |
| farsightedness | eyeball is too short , causing rays to focus behind retina when viewing close objects |
| treating farsightedness | convex lens allows patient to see close objects |
| astigmatism | (ophthalmology) impaired eyesight resulting usually from irregular conformation of the cornea, rays do not focus evenly |
| treating astigmatism | uneven lens allows patient to see objects clearly |
| eyelids | protect eyes and clear the surface, voluntary skeletal muscle , but blinking is involuntary |
| lacrimal gland | constantly makes tears |
| lacrimal duct | tear duct |
| stye | clogged tear duct |
| crying | causes overstimulation of the lacrimal gland (nose runs since it is a drainage point) |
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