Term
| A change in a membrane potential from +30 mV to -70 mV is an example of |
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Definition
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Term
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Definition
| the point at which there is an explosive increase in Na permeability |
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Term
| During the rising phase of hte action potential |
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Definition
| P Na is much greater that the P K |
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Term
| Characteristics of Graded potentials |
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Definition
-They are decremented
-They travel only short distances
-They may contribute to the development of an action potential
-They travel in both directions along the membrane |
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Term
| Temporal summation takes place when |
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Definition
| two EPSPs from the same (one) presynaptic input occur so closely together in time that they add together or sum |
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Term
| Sequence the synaptic events |
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Definition
| Neurotransmitter diffuses across cleft --> Calcium induces exocytosis of the neurotransmitter -> Permeability of postsynaptic membrane altered --> neurotransmitter binds to receptor on chemically-gated channel --> ion channels open |
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Term
| Spatial summation occurs in a postsynaptic neuron .... |
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Definition
| when EPSPs from several presynaptic inputs sum to reach threshold |
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Term
| myelinated axons conduct impulses much faster b/c: |
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Definition
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Term
| the nucleus of a neuron is housed in the |
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Definition
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Term
| What is the normal direction for the movement of an action potential along part of a neuron |
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Definition
| axon hillock to axon terminals |
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Term
| The Nodes of Ranvier are ..... |
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Definition
| breaks in the myelin covering |
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Term
| t/f: most homeostatic mechanisms in the body operate on the principle of positive feedback |
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Definition
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Term
| t/f: most homeostatic mechanisms in the body operate on the principle of positive feedback |
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Definition
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Term
| What is the normal sequence of structures activated for signal transmission and response in the body? |
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Definition
| receptor --> afferent neuron --> interneuron--> efferent neuron--> effector |
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Term
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Definition
| transmit messages to the spinal cord |
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Term
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Definition
| have cell bodies that originate in the CNS |
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Term
| Which component of hte nervous system is comprised of sympathetic and parasympathetic divisions? |
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Definition
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Term
| thare vast majority of cells in the nervous system are |
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Definition
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Term
| Characteristics of cerebrospinal fluid? |
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Definition
-its formed by the choroid plexuses and is reabsorbed across the arachoid villi into the blood w/in the dural sinuses
-serves as a shock-absorbing fluid to cushion the brain against jarring movements
-comes into direct contact w/ the neuronal and glial cells
-fills the subarachnoid space |
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Term
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Definition
-limits the direct exchange of materials b/t the cerebrospinal fluid and brain
-is formed in part by the tight junctions b/t the brain capillary cells
-consists of the astrocyte processes that encircle the brain capillaries |
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Term
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Definition
| a delicate, richly vascularized meningeal layer that is "cobwebby" in appearance |
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Term
| The region of the brain that is smallest and oldest in evolutionary development is the |
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Definition
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Term
| What is accomplished by the cerebral cortex? |
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Definition
-voluntary initiation of movement
-final sensory perception
-language ability
-personality traits |
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Term
| What applies to Wernicke's area? |
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Definition
-is usually developed only in the left cerebral hemisphere
-is concerned with language comprehension
-plays a critical role in understanding both spoken and written messages
-is responsible for formulation coherent patterns of speech |
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Term
| The sense of body position is : |
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Definition
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Term
| Broca's area is located on the cerebral cortex of the _______ lobe |
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Definition
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Term
| What is associated with the hypothalamus? |
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Definition
-control of thirst and urine output
-control of body temperature
-control of food intake
-extensive involvement with emotion and behavioral patterns |
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Term
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Definition
| involves transient modifications in the function of preexisting synapses |
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Term
| What is/are the function(s) of the basal nuclei? |
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Definition
-inhibition of muscle tone
-coordination of impulses related to posture
-suppression of unnecessary motor activity |
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Term
| most of hte cranial nerves originate from the |
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Definition
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Term
| What cranial nerve primary innervates visceral organs |
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Definition
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Term
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Definition
| conscious interpretation of external stimuli |
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Term
| characteristics of phasic receptors |
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Definition
=exhibit an "off-response"
-signal a change in stimulus intensity
-are rapidly adapting receptors |
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Term
| fast pain characteristics |
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Definition
-occurs on stimulatio nof mechanical and thermal nociceptors
-carried by small, myelinated A-delta fibers
-produces sharp, prickling sensation
-easily localized
-occurs first |
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Term
| Slow pain characteristics |
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Definition
-occurs on stimulation of polymodal nociceptors
-carried by small, unmyelinated C fibers
-produces dull, aching, burning sensation
-poorly localized
-occurs second, persists for longer time, more unpleasant |
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Term
| The first structure to intercept light as it enters the eye is the |
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Definition
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Term
| What must happen in order for accommodation to occur? |
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Definition
| the shape of the lens must be changed |
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Term
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Definition
-is the point on the retina at which the optic nerve leaves and blood vessels pass through
-contains no rods or cones |
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Term
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Definition
| they are responsible for color vision |
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Term
| What happens when a photoreceptor is exposed to light? |
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Definition
| Decrease in cyclic GMP in the outer segment --> closure of Na channels in the outer segment --> membrane hyperpolarization --> closure of Ca2 channels in the synaptic terminal -- decreased transmitter release from the synaptic terminal |
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Term
| vitamin A deficiency causes |
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Definition
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Term
| presbyopia is characterized by |
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Definition
| a reduciton in accommodative ability as a result of a loss of lens elasticity |
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Term
| what is the proper sequence of retinal processing? |
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Definition
| rods and cones --> bipolar cells --> ganglion cells |
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Term
| The pitch of a sound is ____ |
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Definition
| determined by the frequency of vibration of air molecules |
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Term
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Definition
| vibrates when struck by sounds waves |
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Term
| ther hair cells for hearing are located in |
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Definition
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Term
| fluid movement in the cochlea causes |
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Definition
| deflection of hte basilar membrane |
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Term
| vestibular information is important for what? |
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Definition
-maintenance of balance and desired posture
-control of eye movement
-perception of motion and orientation |
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Term
| the various taste buds are stimulated by what? |
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Definition
-Salty = chemical salts
-Sour = acids
-bitter = alkaloids, toxic plants, poisnous
-umani = meat or savory taste |
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Term
| The structure associated with pheromonal reception is |
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Definition
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Term
| The autonomic nervous system is |
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Definition
| considered to be the involuntary branch of the efferent division of the peripheral nervous system |
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Term
| What are some characteristics of sympathetic pathways? |
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Definition
-fibers issue from the thoracic lumbar levels
-postganglionic fibers release ACh
-short preganglionic fibers
-most preganglionic fibers synapse in the chain ganglia |
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Term
| What system would suppres the digestive organs during times of greater physical activity? |
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Definition
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Term
| t/f: long parasympathetic preganglionic fibers end on the terminal ganglia, which lie in or near the effector organ |
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Definition
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Term
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Definition
| respond to acetylcholine released from both sympathetic and parasympathetic preganglionic fibers |
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