Answer:
The addition and response to the net effect of postsynaptic potentials is called Spatial summation
Explanation:
Signal summation occurs when impulses received by a neuron are eummed together to reach the excitation threshold to fire a neuron. It occurs at the axon hillock of a neuron. Signal summation occurs since each neuron is connected to many other neurons, often receiving multiple impulses from them, both excitatory and inhibitory.
Signal summation can either be temporal or spatial.
Temporal summation, occurs when impulses received at the same place on the neuron in close temporal succession add up to initiate an action potential in the neuron.
Spatial summation occurs when impulses received simultaneously at different places on the neuron add up to initiate an action potential in the neuron.
The correct answer is D.
Girls in general tend to spend more time with friends. This isn't to say that boys don't spend a lot of time with their friends but girls tend to engage more in their social relationships, whereas boys spend more time in competitive sports, more time in clubs and less time engaging in social relationships.
Answer: depolarization; hyperpolarization
Explanation:
At resting potential (absence of stimulus), the cell membrane of a neuron is said to be polarized with a net negative charge within due to more potassium (K+) ions present than sodium (Na+) ions.
However, an impressed stimuli reverses the ions content as K+ ions flows out and quickly replaced by Na+ ions, resulting in a decrease in membrane potential and a more positive cell membrane. Thus, depolarization occurs.
An increase in the membrane potential (so that it becomes more negative) is called hyperpolarization.
Answer:
They have uncoiled to form long, thin strands.
Explanation:
Chromosomes are present in cell nucleus and consist of chromatin. Genes are present in linear order on chromosomes. The chromosomes become visible under the microscope as distinct structures during cell division. When cells are not dividing, the chromosomes decondense to loose their individuality and make the mass of chromatin.
Chromatin is complex of DNA and packing proteins. As the cells enter the prophase stage of cell division, condensation of chromatin occurs and individual chromosomes become visible under microscope. Before that (during interphase), chromosomes are not visible as they are present in decondensed form.
