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MCAT Bio: NS
| Term | Definition |
|---|---|
| dendrites | send messages toward soma |
| axon | sends impulses away from soma |
| myelin | insulator, wrapped around axon, increases speed of impulse transmission |
| ogliodendrocytes | myelin-producing cells in CNS |
| schwann cells | myelin-producing cells in PNS |
| saltatory conduction | AP transmission down a myelinated axon in which the impulse jumps from Node of Ranvier to Node of Ranvier |
| axon hillock | this structure of the neuron has the greatest number of voltage-gated channels |
| unipolar | _________ neurons only have one nerve process extending from the cell body: an axon that extends into dendrites |
| bipolar | _________ neurons have two distinct structures extending from the cell body. One is an axon, and the other is a dendrite |
| multipolar | _________ neurons have one axon but many dendrites |
| unipolar | least abundant type of neuron |
| bipolar | type of neuron that is typically in sensory structures such as visual structures |
| multipolar | most abundant type of neuron |
| slow | K+ voltage-gated channels are __________ open/close |
| fast | Na+ voltage-gated channels are __________ open/close |
| threshold | at __________, both Na+ and K+ channels open, but only Na+ are fully open |
| inactivated | at +35 mV, Na+ channels are _____________ and K+ channels are fully open |
| depolarization | _________ occurs from -70 mV --> +35 mV |
| repolarization | __________ occurs from +35 mV --> -70 mV |
| hyperpolarization | __________ occurs from -70 mV --> -90 mV |
| repolarization | __________ occurs from -90 mV --> 70 mV |
| close | during repolarization, when the cell passes -50 mV, Na+ channels ______ |
| unidirectional | travelling AP is ___________ due to refractory period |
| absolute | _________refractory period occurs when Na+ channels are inactivated, and it is impossible for another AP to fire; cell is too positive and close to Na+ equilibrium potential. |
| relative | __________ refractory period occurs when Na+ channels are closed, and it is possible but difficult to fire another AP; cell is too negative and close to K+ equilibrium potential |
| gap junctions | electrical synapses are in cells that are physically connected via _____ __________; thus, they're important in cardiovascular cells |
| electrical | ____________ synapses are always excitatory |
| unregulated | electrical synapses are __________, thus they are very rare |
| synapsin | in chemical synapses, vesicles with NTM are held by cytoskeleton filaments via __________ bonds, which can be broken by Ca 2+ |
| chemical | _____________ synapses can be excitatory (Na+) or inhibitory (K+ or Cl-) |
| ligand | chemical synapses have __________-gated ion channels |
| spatial | __________ summation adds up inputs from multiple sources |
| temporal | __________ summation adds up frequent impulses from a single source |
| afferent | sensory input (PNS) involves sensory information, carried by __________ neurons, travelling to the CNS |
| efferent | motor output (PNS) involves commands sent out to the body from the CNS by ___________ neurons |
| interneurons | integration (CNS) contain ___________ and is involved in decision making |
| spinal cord | part of the CNS that controls primitive reflexes |
| medulla | part of the brain that is the respiratory center, involved in BP regulation, and controls basic respiratory and digestive functions |
| pons | part of the brain that is involved in balance |
| pituitary gland | part of the brain that is the master gland |
| limbic system | system in the brain that is involved in emotion regulation |
| midbrain | part of the brain that is the relay station for audio and visual information |
| cerebellum | part of the brain that coordinates movement and can be severely affected by drugs, such as alcohol |
| diencephalon | the ______________ contains the epithalamus, thalamus, and hypothalamus |
| epithalamus | part of the diencephalon which contains the pineal gland, which secretes melatonin to control the circadian rhythm |
| thalamus | part of the diencephalon where all sensory information (except olfactory information) relays through first |
| hypothalamus | part of the diencephalon which maintains body homeostasis by controlling the pituitary gland |
| white matter | makes up anything that is myelinated; axons |
| inside, outside | white matter is found on the _________ of the brain and on the ___________ of the spinal cord |
| tract | white matter in the brain |
| column | white matter in the spinal cord is called tract/___________ |
| nerve | white matter in the PNS |
| grey matter | makes up anything that is unmyelinated; somas, dendrites, some axons |
| outside, inside | grey matter is found on the _________ of the brain and on the ___________ of the spinal cord |
| nucleus | grey matter in the deep brain |
| cortex | grey matter on the surface of the brain |
| horn | grey matter in the spinal cord |
| ganglion | grey matter in the PNS |
| telencephalon | part of the brain that consists of a right and a left hemisphere, where each hemisphere has 4 lobes |
| frontal | __________ lobe is involved in problem solving and voluntary movement; located behind forehead |
| parietal | __________ lobe is involved in general sensation (somatosensation), taste, and smells; located behind frontal lobe |
| temporal | __________ lobe is involved in auditory sensation and memory processing; located behind the ears |
| occipital | __________ lobe is involved in vision; located at the back of the head |
| somatic | the division of the PNS - voluntary - skeletal muscle only - ACh only --> excitatory only |
| single | somatic division of the PNS only uses a __________ neuron from the CNS to the effector organ |
| automatic | the division of the PNS - involuntary - ACh and NE --> can be excitatory or inhibitory |
| 2 | automatic division of the PNS uses a chain of _______ neurons from the CNS to the effector organ |
| parasympathetic | the division of the autonomic nervous system involved in rest and digest |
| sympathetic | the division of the autonomic nervous system involved in flight or fight |
| decreases | the parasympathetic nervous system generally ____________ BP, HR, and RR |
| increases | the parasympathetic nervous system _____________ blood flow to organs |
| acetylcholine | the parasympathetic nervous system uses _____________ at the organ level |
| increases | the sympathetic nervous system generally ____________ BP, HR, RR, and blood flow to skeletal muscles |
| norepinephrine | the sympathetic nervous system uses ____________ at the organ level |
| epinephrine | in the sympathetic nervous system, direct stimulation of the adrenal medulla releases ____________ into blood to prolong effects |
| mechanoreceptors | receptors stimulated by physical shape change: baroreceptors, Golgi tendon receptors, touch receptors |
| chemoreceptors | receptors stimulated by chemicals: pH receptors, O2 receptors, taste buds |
| thermoreceptors | receptors stimulated by temperature: hot and cold receptors |
| nociceptors | receptors stimulated by pain: free nerve endings that respond to touch, chemicals, heat, etc. |
| photoreceptors | receptors stimulated by light: rods and cones aka. electromagnetic receptors |
| absolute | __________ threshold is the minimum stimulus level required to activate a receptor |
| difference | __________ threshold is the amount a stimulus must change before we notice it |
| sensory adaptation | the process in which our body ignores unchanged stimuli; can be retriggered if stimulus changes |
| bottom-up processing | the process by which sensory receptors register information and brain identifies the information - afferent neurons --> CNS - data analysis |
| top-down processing | the process by which the brain applies prior knowledge and experience to form a holistic view of what is going on |
| lens | the biconvex structure of the eye that focuses light on the retina |
| cornea | the external transparent layer of the eye |
| iris | the colored part of the eye that regulates the diameter of the pupil |
| pupil | the black opening in the middle of the eye |
| retina | the layer at the back of the eye that is sensitive to light |
| fovea centralis | the part of the eye that is responsible for extreme visual activity |
| optic disk | the place on the retina where the optic nerve forms; blind spot |
| optic nerve | bundle of axons leaving the eye toward the brain |
| ciliary muscle | the type of muscle in the eye that regulates the curvature of the lens |
| bipolar | organization of the retina: posterior wall of the retina --> rod and cone cells --> __________ cells --> ganglionic cells ---> axons of ganglionic cells (optic nerve) --> occipital nerve |
| cone cells | cells that respond to high intensity light; color vision (R, G, B), concentrated in fovea centralis |
| rod cells | cells that respond to low intensity light; black and white vision, not found in fovea centralis |
| no light | when there is (light/no light) Na+ channels are open --> depolarization --> cells release NTMs |
| light | when there is (light/no light) Na+ channels are inhibited --> Na/K+ pump polarizes cells --> stops release of NTMs |
| eustachian | ____________ tube is an auditory tube that connect the middle ear to the pharynx (food pipe) in order to decrease pressure in the ear |
| pinna | part of the outer ear that routes sound waves into the auditory canal |
| auditory canal | part of the outer ear in which sound waves travel through |
| tympanic membrane | part of the outer ear which is hit with sound waves and cause vibrations in ossicles (aka. ear drum) |
| malleus | the first ossicle in the middle ear that sends pressure waves to the incus |
| incus | the second ossicle in the middle ear that sends pressure waves to the stapes |
| stapes | the third ossicle in the middle ear that sends pressure waves to the inner ear |
| perilymph | fluid held in the outer part of the cochlea |
| endolymph | fluid held in the inner part of the cochlea |
| basilar membrane | pressure waves moving through the perilymph and endolymph cause vibrations of the ___________ __________ and movement of hair cells |
| tectorial membrane | cilia of hair cells are dragged across the _________ ____________ causing the hair cells to bend and release NTMs --> auditory neuron sends signal to the brain |
| oval window | at the _____ ________, the basilar membrane is thick and stiff |
| high | at the oval window, the basilar membrane responds to _______ frequency/pitch sounds |
| apex | at the _______ of the cochlea, the basilar membrane is thin and flat |
| low | at the apex of the cochlea, the basilar membrane responds to _____ frequency/pitch sounds |
| loud | _______ tones are determined by amplitude and produce more frequent APs |
| vestibular | the ____________ complex helps maintain head positive while the body is moving |
| semicircular canals | the __________ _____________ are a part of the vestibular complex and maintain head position during rotational movements (dynamic equilibrium) |
| vestibule | the __________ is a part of the vestibular complex and maintain head position during linear movements (static equilibrium) |
Created by:
coletty218
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