BIOL 2160 Test 3 Part 1
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107 terms
Terms | Definitions |
|---|---|
Central Nervous System | Brain and Spinal Cord |
Nuclei | Grouping of neuron cell bodes within CNS |
Tracts | Grouping of Nerve fibers that interconnect regions of CNS |
Peripheral Nervous System | Nerves, ganglia, and nerve plexuses |
Cranial Nerves | nerves that emerge directly from the brain; twelve pairs of cranial nerves. Only the first and the second pair emerge from the cerebrum; the remaining ten pairs emerge from the brainstem. |
Spinal Nerves | emerge from segments of the spinal cord; carries motor, sensory, and autonomic signals between the spinal cord and the body. Humans have 31 left-right pairs of spinal nerves, The spinal nerves are part of the peripheral nervous system (PNS). |
Nerve | cable like collection of many axons, may be mixed with sensory and motor fibers |
Ganglia | grouping of neuron cells located outside of CNS |
Sensory Neurons | afferent neuron, neurons that transmits impulses from a sensory receptor in the CNS |
Motor Neurons | efferent neuron, neuron that transmits impulse from the CNS to effector organ |
Effector Organs | a muscle or gland which has an effect when it is turned on by a motor neurone |
Somatic Motor | Nerve that stimulates contraction of skeletal muscles |
Autonomic Motor | nerve that stimulates or inhibits contraction of smooth and cardiac muscle and stimulates glandular secretions |
Smooth Muscles | involuntary non-striated muscle, excited by external stimuli, which causes contraction |
Cardiac Muscles | involuntary striated muscle found in the walls and histological foundation of the heart, specifically the myocardium; Coordinated contractions of cardiac muscle cells in the heart propel blood out of the atria and ventricles to the blood vessels of the left/body/systemic and right/lungs/pulmonary circulatory systems. |
Sympathetic Branch | one of the three parts of the autonomic nervous system, aids in the control of most of the body's internal organs, Stress—as in the flight-or-fight response—is thought to counteract the parasympathetic system |
Parasympathetic Branch | responsible for stimulation of "rest-and-digest" activities that occur when the body is at rest, including sexual arousal, salivation, lacrimation (tears), urination, digestion, and defecation. |
Guillain - Barre Syndrome | a disorder affecting the peripheral nervous system. Ascending paralysis, weakness beginning in the feet and hands and migrating towards the trunk, is the most typical symptom, and some subtypes cause change in sensation or pain as well as dysfunction of the autonomic nervous system. |
Ganglionic Gliocytes | It gives support to the cell bodies in the preipheral nervous system, or PNS. |
Multiple Sclerosis | an inflammatory disease in which the fatty myelin sheaths around the axons of the brain and spinal cord are damaged, leading to demyelination and scarring as well as a broad spectrum of signs and symptoms. |
Astrocytes | CNS; covers capillaries and induce the blood-brain barrier, interact metabolically with neurons and modify the extracellular environment of neurons |
Microglia | CNS, phagocytose pathogens and cellular debris in CNS |
Ependyma | form the epithelial lining of brain cavities and central canal of spinal cord, covers tufts of capillaries to form choroid plexuses |
Schwann Cells | surrounds axons of peripheral nerve fibers, forming a neurilemmal sheath, also form myelin sheaths; PNS |
Satellite Cells | support functions of neurons within sensory and autonomic ganglia; PNS |
Oligodendrocytes | form myelin sheaths around central axons, producing white matter of CNS; CNS |
Mass Activation | a large number of ganglionic neurons activate many effector organs; causes a heightened sense of alertness due to stimulation of reticular activation system |
Splanchnic Nerves | aired nerves that contribute to the innervation of the viscera, carrying fibers of the autonomic nervous system (visceral efferent fibers) as well as sensory fibers from the organs (visceral afferent fibers). |
Abdominal Ganglia | control movements of abdominal muscles. |
Divisions of Automatic Nervous System | Parasympathetic (craniosacral) DivisionAdrenergic and cholinergic synaptic transmission Other autonomic neurotransmittors Organs with dual innervation |
Neurotransmitters in Automatic Nervous System | the chemicals which allow the transmission of signals from one neuron to the next across synapses |
Synapses en Passant | Some synaptic junctions appear partway along an axon as it extends |
Action Potential | short-lasting event in which the electrical membrane potential of a cell rapidly rises and falls, following a consistent trajectory, "nerve impulses" or "spikes" |
Refractory Period of Cardiac Muscles | Heart contracts as syncytium & thus can sustain forceIts AP lasts about 250 msec Has a refractory period almost as long as AP Cannot be stimulated to contract again until has relaxed |
Components of Total Refractory Period | Absolute Refractory Period - due to inactivated Na channelsRelative Refractory Period - due to continued outward K diffusion |
Saltatory Conduction | propagation of action potentials along myelinated axons from one node of Ranvier to the next node, increasing the conduction velocity of action potentials without needing to increase the diameter of an axon. |
2 Types of Nerve Fibers | Myelinated Fibers - rapid conduction velocity; Control rapid body movements by skeletal muscles; Transmit sensory signals from receptors to CNSUnmyelinated fibers - slower conduction velocity Control subconscious activities via ANS |
Function of Myelin Sheath | to increase the speed at which impulses propagate along the myelinated fiber, provides a track along which regrowth can occur |
All or None Law in Nerve Fibers | principle that the strength by which a nerve or muscle fiber responds to a stimulus is not dependent on the strength of the stimulus. If the stimulus is any strength above threshold, the nerve or muscle fiber will give a complete response or otherwise no response at all; Henry Pickering Bowditch in 1871 |
Speed of Conduction Velocities | ... |
Summation | frequency summation is the method of signal transduction between neurons, which determines whether or not an action potential will be triggered by the summation of postsynaptic potentials. |
Neural physiology | the additive effects of graded nerve potentials |
Muscle physiology | The additive effects of contractions of different muscle fibers |
Types of Summation | Spatial summation and temporal summation |
Spatial Summation | recruitment of variable numbers of nerve fibers in a nerve1. Minimal stimulus or threshold stimulus - voltage at which only one nerve fiber stimulated to fire 2. Maximal stimulus - voltage all the nerve fibers in the nerve fire |
Temporal Summation | frequency modulation - variation in number of action potentials sent along a nerve fiber per second: (frequency is limited by the refractory period of the nerve fiber) |
Neuronal Junctions | Electrical synapses, synaptic transmission, neuromuscular junction |
Electrical Synapses | Cardiac muscleSome smooth muscles Some neurons in the brain |
Synaptic Transmission | 1. Action Potentials reach axon terminals2. Voltage gated Ca channels open 3. Ca in cytoplasm activates proteins, leading to fusion of vesicles with plasma membrane 4. Pore forms in fused vesicle and exocytosis releases neurotransmitter |
Neuromuscular Junction | Motor UnitPhysiological anatomy Details of transmission Effect of drugs on the neuromuscular junction Effect of ions on the neuromuscular junction |
Morphology of Gap Junctions | plasma membrane of one cell, plasma membrane of connecting cell, connexin proteins forming gap junctions, surrounding cytoplasm |
Skeletal Muscle Neuromuscular Junction | terminal bouton of axon, mitochondria, synaptic vesicles, synaptic cleft, post synaptic cell/skeletal muscle |
Excitatory Postsynaptic Potential | a temporary depolarization of postsynaptic membrane potential caused by the flow of positively charged ions into the postsynaptic cell as a result of opening of ligand-sensitive channels. |
Inhibitory Postsynaptic Potential | result from the flow of negative ions into the cell or positive ions out of the cell. |
Drugs and Effects on Neurol Control of Skeletal Muscles | Botulinium toxin - stops release of acetylcholine (ACH) Curare - Prevents interaction of ACH with post synaptic receptor protein Saxitoxin/Tetrodotoxin - blocks voltage gated Na channels Nerve gas/Neostigmine - stops acetylcholinesterase in postsynaptic membrane Strychnine - prevents IPSPs in spinal chord |
Basic Neuronal Pools | Accumulations of neurons making up the numerous anatomical regions of the CNS |
Area of Stimulation | sphere of influence upon neurons with which the neuron synapses |
Discharge Zone | Presynaptic neuron causes the postsynaptic neuron to fire |
Facilitated Zone | presynaptic neuron fires causes the postsynaptic neurons membrane potential to approach but not reach the threshold potential |
Circuits in Neuronal Pools | One oncoming/outgoing, Diverging, Converging, inhibitory |
One oncoming - outgoing Circuit | Relay |
Diverging/ Amplifying Circuit | 1 →many neuronsAmplifying - CNS control of skeletal muscles Diverging circuit → multiple tracts Sensory information in dorsal columns of spinal cord to: Cerebellum and Thalamus and cerebral cortex |
Converging Circuit | simultaneous control of one neuron by two or more input neurons - sensory branch of the nervous system |
Inhibitory Circuit | - shuts off one pathway while opening another |
Sensory Receptors | detect intensity gradients of such sensory stimuli as touch, sound, light, smell, taste, cold and warmth; produce generator (= receptor) potentials in proportion to the strength of the environmental stimulus and send pulse encoded information to the CNS for processing |
Receptor Potential | produced by sensory transduction., form of graded potential, a depolarizing event resulting from inward current flow. The influx of current will often bring the membrane potential of the sensory receptor towards the threshold for triggering an action potential. |
Types of Sensory Receptors | MechanoreceptorsThermoreceptors Nociceptors Electromagnetic receptors Chemoreceptors |
Mechanoreceptors | Mechanical force, deforms cell membranes of sensory dendrites or deforms hair cells that activate sensory nerve endings |
Pain Receptors | Tissue damage, damaged tissues release chemicals that excite sensory endings |
Chemoreceptors | dissolved chemicals, chemical interactions affects ionic permeability of sensory cells |
Photoreceptors | light, photochemical reactions affect ionic permeability of receptor cells |
Cutaneous Receptors | Free Nerve Endings - light touch, hot, cold, painMerkel's Disc - sustained touch and pressure Ruffini's Corpuscles - sustained pressure Meissner's Corpuscles - change in texture, slow vibrations Pacinian Corpuscles - deep pressure, fast vibrations |
Fibrous Tunic | Outer eyeball, gives shape to eyeball |
Sclera | white of eye, supports and protects eyeball |
Cornea | inside surface of eyeball, transmits and refracts light |
Vascular Tunic | uvea, middle layer of eyeball, supplies blood, prevents reflection |
Choroid | middle layer of posterior of eyeball, supplies blood to eyeball |
Ciliary Body | anterior portion of vascular tunic, supports lens through suspensory ligaments and decides thickness, secretes aqueous humor |
Iris | continous to ciliary body, regulates diameter of pupil, and amount of light that enters |
Internal Tunic | inner layer of eyeball, provides location and support for robs and cones |
Retina | principal portion of internal tunic, photoreception, transmits impulses |
Lens | between posterior and vitreous chamber, refracts light and focuses on fovea centralis |
Emmetropia | normal vision, rays focus on retina, no correction needed |
Myopia | nearsightedness, rays focus on front of retina, concave lens |
Hyperopia | farsightedness, rays focus behind retina, convex lens |
Astigmatism | rays do not focus, uneven lens |
Pupil Reflex | reflex that controls the diameter of the pupil, in response to the intensity (luminance) of light that falls on the retina of the eye, thereby assisting in adaptation to various levels of darkness and light, in addition to retinal sensitivity. |
Rod Cell | photoreceptor cells in the retina of the eye that can function in less intense light, approximately 125 million rod cells in the human retina, rod cells are almost entirely responsible for night vision. |
Cone Cell | photoreceptor cells in the retina of the eye that are responsible for color vision; they function best in relatively bright light, six million in the human eye was found |
Optic Nerve | known as cranial nerve 2, transmits visual information from the retina to the brain, does not regenerate after transection. |
Tympanic Membrane | ear drum, cone-shaped membrane that separates the external ear from the middle ear in humans and other tetrapods; transmit sound from the air to the ossicles inside the middle ear |
Ossicular System | MalleusIncus Stapes → Oval window |
Spiral Organ of Corti | the organ in the inner ear found only in mammals that contains auditory sensory cells, or "hair cells." |
Vestibular Apparatus | contributes to balance in most mammals and to the sense of spatial orientation, is the sensory system that provides the leading contribution about movement and sense of balance. |
Ear Anatomy | Outer Ear - helix, auricle, external auditory meatus, earlobeMiddle Ear - auditory ossicles, tympanic membrane, semicircular canals Inner Ear - Semicircular canals, facial nerve, vestibular nerve, cochlear nerve, cochlea, temporal bone, round window, cavity cavitiy, auditory tube |
Primary Sensations of Taste | Sour - H channelsSweet - Na Channels Sweet and meaty - sugars and glutamate via g-protein receptors Bitter - quinine vi g protein receptors |
Taste Buds | on papillae of tongue, includes tongue surface, taste pore, taste hair, taste bud - gustatory cell, supporting cell, sensory nerve fiber |
Olfactory Cells | bipolar nerve cells derived initially from the CNS, |
Primary Sensations of Smell | CamphoraceousMusky Floral Pepperminty Ethereal Pungent Putrid |
General Sensory Receptors | Primary receptors = free nerve endings (taste, pain, touch)Secondary receptors - specialized epithelial cells which form synapses with sensory neurons |
Acetylcholine | neurotransmitter responsible for much of the stimulation of muscles, including the muscles of the gastro-intestinal system, has a part in scheduling REM (dream) sleep. |
Norepinephrine | neurotransmitter strongly associated with bringing our nervous systems into "high alert." It is prevalent in the sympathetic nervous system, and it increases our heart rate and our blood pressure. It is also important for forming memories. |
Dopamine | It is an inhibitory neurotransmitter, is strongly associated with reward mechanisms in the brain. Drugs like cocaine, opium, heroin, and alcohol increase the levels. |
GABA | acts like a brake to the excitatory neurotransmitters that lead to anxiety, and associated with epilepsy |
Glutamate | most common neurotransmitter in the central nervous system, actually toxic to neurons, and an excess will kill them. Sometimes brain damage or a stroke will lead to an excess and end with many more brain cells dying than from the original trauma. (ALS disease) |
Serotonin | inhibitory neurotransmitter that has been found to be intimately involved in emotion and mood. Too little has been shown to lead to depression, tied to migraines, irritable bowel syndrome, and fibromyalgia. |
Endorphin | short for "endogenous morphine.", Inhibitory, it is involved in pain reduction and pleasure, drug associated (heroin) |
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