Unformatted text preview: billion neurons in humans # of neurons are in the human brain ~100,000,000,000 100 trillion synapses tho….
for perspective … 15 x the
population of the world !
! Rank !
! Country !
! Population 1 6,446,131,400 2 China
1,306,313,812 3 How many synapses are there
in the human nervous system? World India 4 European Union 5 United States 1,080,264,388 ! ! 456,953,258
295,734,134 as of July 2005 ~100,000,000,000,000
Some sources give the average
number of synapses on a
neuron as 1,000 to 10,000. 7 7/4/12 we lose 50,000 neurons a day after 20……. Until recently it was thought
that you are born with the all
the neurons you ll ever have.
It is now known that there is
some limited new cell
formation. However, some
estimates say we lose 50,000
neurons per/day between the
ages or 20 to 75. acending-- to the CNS0 affernt all mean the same thing Flow ofof Information
low Information these are synanyms !!!!
PNS to CNS
Ascending CNS to PNS
Descending deﬁne reﬂex--- its a involuntary speciﬁc response to a speciﬁc stimulus Reflexes
Patellar Reflex need to knw these things Crossed Extensor Reflex patella reﬂe...
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- Fall '08
- functional unit