<span>Ptosis refers to drooping of an upper eyelid of one or both eyes. The droop may be hardly visible, or the lid can move down over the entire pupil. Ptosis can affect both children and adults, however more often than not happens for the reason that of aging. In some cases, droopy eyelid is caused by additional grim circumstances, such as a stroke, brain tumor, or cancer of the nerves or muscles. Neurological disorders that affect the nerves or muscles of the eyes , such as myasthenia gravis can also lead to ptosis.</span>
Answer: Na+ channels are closed
Explanation:
The refractory period describes a period between the initiation of an action potential (where Na+ channels are active/open), and immediately after the action potential’s peak. In the absolute refractory period, action potentials cannot be generated, as Na+ channels are in an inactive or closed state, they usually take around one or two minutes.
After the absolute refractory period the relative refractory period (RRP) occurs. During the RRP, it is hard to send another action potential. Na+ channels are once again open, but the cell remains hyperpolarized- its membrane potential, remains negative. Recovery from inactivation is voltage and time-dependent; Action potentials would require an influx of more positively charged ions. These must be more than a specific threshold in order to have the cells send along more action potentials which helps with figuring out stimulus intensity.
Answer:
I think it's D
Explanation:
Don't take my word for it
a. redwood trees. K-selected species are living organisms that tend to be larger than those in the r-selected species. They also have relatively stable population and live longer, but produce relatively fewer number of offspring. Redwood trees are the biggest and tallest trees in the planet; they can live up to a thousand years.
Answer: Option A.
Explanation:
Maltoporin is a membrane protein. It forms trimetric structure that facilitate the translocation of maltodextrins across outer membrane of E.coli bacteria. It is responsible for the guided diffusion in E.coli. it recognised bacteriophage sequence. It formed water filled pores across the outer membranes of gram negative bacteria. The lining of channel with maltoporin has a series of aromatic side chains stranded in a helical pattern matching the relative curvature of the protein backbone, thus providing little restriction to transport.
