Of 100 billion nerve cells in the human brain, how many form after birth For years, the official answer was "zero". Scientists thought people were born with all the neurons they’d ever have. But from 1980s, biologists overturned that doctrine, finding a reservoir of stem cells that becam...
One of the challenges here is that scientists aren’t even 100% sure how many cells in general of any type are in the human body. Estimates vary from 30-40 trillion, which seems more impressive when written out (like on the lower end): 30,000,000,000,000. If we took a wild stab ...
which are highly mobile immune cells in the central nervous system, a demonstration by Paolicelli and colleagues showing the involvement of microglia in the development of brain circuitry in newborn mice, and how the disruption of microglia-synapse interactions delays the maturation of synaptic circuit...
Brain cells use a lot of nutrients. This means they produce a lot of waste. Scientists believe the brain has special structures to take out this “cellulartrash,” especially during sleep. They have reported observing this process happening in...
understand the guts inside us.Ancient Egyptianshandled human organs as they removed them for embalming. Medical manuscripts found in an ancient Chinese tomb may be theearliest-known anatomical writingabout the human body. Thousands of years later, do we know how many organs are in the human body...
Scientists are not sure how the brain follows the tracks of time. One theory holds that it has a group of cells specialized to record the intervals (间隔)of time while another theory holds that some neural processes(神经突)act as an inside clock. Whichever theory it may be studies find ...
Learn about the long bones in the body, including the long bone definition and how many long bones are in the body. Discover examples of long bones, types of long bones, and where in the human skeleton long bones are found. Related to this QuestionHow...
8. How many species are there on Earth? 8.地球上有多少物种? 9. How do organisms evolve? 9.有机体是如何进化的? 10. Why did dinosaurs grow to be so big? 10.为什么恐龙长得如此之大? 11. Did ancient humans interbreed with other human-like ancestors?
Somatic cells of the fruit fly have 8 chromosomes. How many sex chromosomes are in a somatic cell?Somatic cells of the fruit fly have 8 chromosomes. How many chromosomes does a fruit fly receive from its father?Somatic cells of the fruit fly have 8 chromosomes. What is the haploid num...
I learned about the number of bones in sixth grade. I remember exactly the day because after the presentation we had, it was a special day about health and science, they asked some review questions. One of them was "Does the child human body have more or less bones than the adult human...