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ASCI 438 Midterm
Question | Answer |
---|---|
What two tissue types are "Excitable"? | Nerve & muscle |
Definition of "membrane potential": | Separated charges have the potential to perform work |
What 3 influences make the cell interior negatively charged relative to the exterior? | 1. Na/K pumps pump 3 Na+ out of cell for 2K+ in cell 2. Large negatively charged proteins are in the cell & can't leave 3. K+ leak channels are more active than Na+ leak channels |
What are the 4 types of gated channels? | Voltage; chemically; mechanically; thermally |
Depolarization makes the membrane potential ___ ___ than the resting potential (approaching ____) | less negative; zero |
What kind of cells have resting membrane potentials? | ALL CELLS |
Is K+ ion permeability (higher/lower) than Na+? | Higher |
Resting membrane potential is much closer to equilibrium potential of ___ than ___ | K+; Na+ |
Graded potentials spread by ___ ___ ___ and are hindered by ___ | Passive current flow; resistance |
Permeability changes during an action potential change membrane potential from ___ mV to __ mV (threshold potential is ___) | -70; +30; -50 |
What part of the neuron is where AP arise? | Hillock ("trigger zone") |
Give an example of a positive feedback cycle during depolarization | Decreased membrane potential causes opening of some voltage-gated Na+ channels, which causes opening of more Na+ channels; (Na+ channels trigger more to open, which trigger more to open... ) |
Two phases of refractory period: ___ and ___ Also: how does the neuron ensure AP travel in only one direction? | Absolute (no stimulus will elicit new AP) and relative (second AP can be produced ONLY if stimulus is greater than normal) Cell needs to repolarize so refractory period follows the AP; new AP follows path that has been repolarized |
AP travels down neuron from ___ to ___ ____; in other ways, travels away from the ___ ___ | Axon hillock; axon terminals; cell body |
A graded potential can have greater strength based on a stronger stimulus, but how does an AP code stimulus strength? | Greater potential frequency |
Myelin sheath: in CNS, called ____; in PNS, called ____ | oligodendrocytes (CNS): Schwann cells (PNS) |
Myelin sheath allows neuron to conduct ____ impulses as opposed to ___ | Saltatory; contiguous |
2 factors determine the speed of the electrical signals through nerve fibers: | Myelination (makes it faster) and size of the fiber (larger= faster) |
Synaptic actions: AP at axon terminal of presyn neuron opens ___ ___; ___ flows from ECF through channels into the __ ___; induces vesicles to release neurotransmitter molecules which enter synaptic cleft by ____; bind to receptors on subsynaptic membrane | calcium ion channels; calcium; synaptic knob; exocytosis |
Neurotransmitter binding to subsynaptic membrane of postsynaptic neuron causes opening of ___ gated ion channels | chemically |
Two types of synpases that are determined by the ___ released from pre-synaptic knob: ___ and ____ whcih produce ___ and ___, respectively | Neurotransmitter; excitatory & inhibitory; excitatory post-synaptic potential (EPSP) and inhibitory post-synaptic potential (IPSP) |
An excitatory synpase signals ___ ____ in postsynaptic neuron which typically depolarizes; inhibitory synapse signals outflow of ___ ___ in postsynaptic neuron (sometimes influx of ___); Synapse is always EITHER excitatory or inhibitory | influx of sodium ions; outflux of potassium ions; influx of chloride ions |
Presynpatic inputs determine a postsynpatic potential using two types of summation (___ and ___): called the ___ ____ ____ ____ | temporal and spatial summation; grand post-synaptic potential |
Presynpatic facilitation or inhibition can change ____ of presynaptic input | Effectiveness |
What's the difference between spatial and temporal summation? | Spatial: simultaneous activation of two+ excitatory presynaptic inputs Temporal: frequent presynpatic inputs from the same synapse |
Difference between converging and diverging neural communication: | Convergence: a single cell is influenced by thousand of presynaptic cells Divergence: a single cell affects thousands of postsynaptic cells via branching axon terminals |
Two afferent divisions to CNS: | Somatic and visceral |
Draw the table of nervous system hierarchy, starting with CNS and PNS and ending with effector organs (include afferent and efferent divisions) | Slide 74 of neurological powerpoint |
Efferent neurons have cell bodies within ___; afferent neurons have cell bodies with ___; inter-neurons exist entirely in the ___ | CNS; PNS; CNS |
4 types of glial cells: | Astrocytes, oligodendrocytes, microglia, ependymal cells |
Astrocyte cells: give ___ support to neurons and ___ neurotransmitters, communicate with neurons & among themselves via ___ | physical; degrade; chemical means |
Microglia act as ____ in the brain and release ___ ___ factor | Phagocytic scavengers; nerve growth |
Ependymal cells line ____ of brain & spinal cord; contribute to formation of ___ and serve as neural ___ cells | internal cavities; CSF; stem cells |
CSF serves 3 functions in CNS, and is produced in brain ____ | Produced in brain ventricles 1. Surrounds/cushions brain & spinal cord 2. Shock absorber 3. Material exchange between neural cells and interstitial fluid surrounding brain |
3 meninges from superficial to deep: | dura mater; arachnoid mater; pia mater |
Major parts of brain from most complex to most primitive levels (6): | Cerebral cortex; basal nuclei; thalamus; hypothalamus; cerebellum; brain stem |
Cerebrum is divded into ___ hemispheres, hemisphere divided into ___; outer surface is ___ ___ which is most complex integrating area | Right and left; lobes; cerebral cortex |
Draw a brain and label the lobes (include cerebellum and brain stem) | Slide 88 of neurological powerpoint |
BASIC lobe functions of occipital, temporal, parietal, and frontal lobes: | 1. Occipital: visual 2. Temporal: auditory 3. Parietal: reception and perception of somatosensory input 4. Frontal: voluntary motor movement |
What's the form and function of basal nuclei? | Form: masses of gray matter located deep within white matter Function: suppress unwanted patterns of movement |
Thalamus: reinforces ___ motor behavior initiated by motor cortex; serves as "relay station" for ___ input; directs attention towards _____ | Voluntary; sensory; stimuli of interest |
Hypothalamus is integrating center for ___ functions; link between ___ nervous system and ___ system | Homeostatic; autonomic; endocrine |
3 distinct parts of cerebellum & functions: | Vestibulocerebellum: balance & eye movements Spinocerebellum: muscle tone and coordinates skilled movements Cerebrocerebellum: plan & initiate voluntary activity and stores procedural memories |
3 parts of brain stem Also: what does brain stem control? (3 main) | Midbrain, pons, medulla Controls cardiovascular, respiratory, digestive functions |
2 main functions of spinal cord: | Neuronal link between brain & PNS: integrating center for spinal reflexes |
White matter oragnized into ___ ___ (bundles of nerve fibers with similar function) that are divided into ___ and ____ tracts that relay ___ and ___ info respectively | Nerve tracts; ascending & descending; afferent and efferent |
Gray matter divided into 3 spinal horns Also: which horn contains which cell bodies | 1. Dorsal horn: cell bodies of interneurons that afferent neurons terminate on 2. Ventral horn: cell bodies of somatic efferent motor neurons 3. Lateral horn: cell bodies of autonomic sympathetic nerve fibers |
5 basic components of a reflex arc: | Receptor; afferent pathway; integrating center; efferent pathway; effector |