The depolarization phase (or phase I ) of action potentials is caused by the A.
ID: 3477400 • Letter: T
Question
The depolarization phase (or phase I ) of action potentials is caused by the A. B. C. D. activation of voltage-sensitive Na" channels opening of K' channels& net loss of K' cations massive influxes of Na" cations net loss of K' cations E.activation of voltage-sensitive Na channels & massive influxes of Na cations Na channels & massive influxes of Na' Presynaptic modulation involves A. presynaptic facilitation B. presynaptic inhibition C. D. A&B; E. A, B&C; presynaptic reuptake The ability to store learned facts/events into declarative/explicit memory involves the- A. hypothalamus B. cerebellum C. D. basal nuclei E. hippocampus pons Which of the following is used to transport GLUCOSE across cell membranes? Simple diffusion Facilitated diffusion via carriers Facilitated diffusion via channels A & B A, B&C; A. C. D. E. h of the following types of hormonal interactions is an example of SYNERGISTIC effects? A. Epinephrine& norepinephrine on heart rate B. GHRH&GHIH; on growth hormone levels at systemic tissues C. Insulin & glucagon on glucose metabolism D. PTH&calcitonin; on calcium homeostasis E. Epinephrine& thyroid hormones on bronchiolar smooth muscle Which of the following STRUCTURAL features influences the speed of action potential propagation? A. Dendrites B. Axon myelination C. Continuous conduction D. A& B E. A, B&C; Which of the following types of neurotransmitters would lead to IPSPs by activating ANION channels? A. GABA & Glycine B. ACh C. Only Glycine D. ATP E. Only GABA Plasticity of the nervous system is first developed by activating receptors, which leads to A. NMDA; Ca2 influxes B. AMPA; Na* influxes C. ACh; Mg effluxes D. A &B; E. A, B& C Page 5 of 8Explanation / Answer
1. the answer is option e
The membrane potential of neuron must depolarize from resting voltage of -70 mV to threshold value of -55 mV. ( which is minimum value required to open enough the voltage-gated Na+ channels so that depolarization is irreversible)
2. the answer is option d
The presynaptic modulation could be excitatory or inhibitory. It provide more specific response and a more precise control of the action potentials. It is as specific as the neuron target specific axon terminal so that it can inhibit a specific pathway.
3. the answer is option e
THe Declarative memoryis further sub-divided into the episodic memory and the semantic memory. Both requires similar encoding process. However, the semantic memory mainly activates frontal and temporal cortexes, whereas the episodic memory activity is concentrated in hippocampus
4. the answer is option b
A glucose molecule is very large to pass through cell membrane through simple diffusion. Instead, the cells assist glucose diffusion through process called facilitated diffusion through carriers. The carrier protein binds to the glucose, which causes glucose to change the shape and translocate glucose from one side of membrane to other. Red blood cells also use facilitated diffusion to absorb the glucose.