Notes

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the incredible journey of life from
birth through infancy childhood puberty
adulthood and a slow maturity to old age
this is the story of our lives
from a unique perspective deep inside
Alba
this is the journey of a human life from
the outside
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a fetus develops in the womb it's an
astonishing 40 week journey from a
single cell to a baby ready to be born
it's body is a miracle of microscopic
design tiny perfectly formed organs each
made up of billions of perfectly
functioning cells
these cells are the building blocks of
our bodies they make us what we are a
hundred thousand billion cells all
working in harmony
inside every cell is the same
extraordinary engine the machine that
tells each cell how to grow and what
functions to perform DNA is unique to
every person a chemical blueprint of
instructions that creates each new life
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this baby is ready to enter the world
a newborn person whose journey is about
to begin
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the journey starts with a challenge
breathe or die
these lungs have never breathed before
they're still full of amniotic fluid
that protected them for nine long months
the newborn is in danger of drowning
then the body kicks into survival mode
the adrenal glands right above the
kidneys send adrenaline surging around
the body it shocks the lungs into life
muscles we need to breathe suddenly
start to spasm and we take our first
breath it's the most important breath of
our lives
the first of 700-million our lungs will
pump air every single second as long as
we live
air rushes down the windpipe down
thousands of branching tubes and into
nearly 30 million tiny air sacs the
alveoli these air sacs pull oxygen into
our blood and pump out the carbon
dioxide we exhale with every breath and
they do it non-stop for 80 years at the
moment of birth everything changes
the physical link between mother and
baby is broken for the first time the
first hour brings rapid change all the
baby's organs have to adapt to life
outside the womb
it's a challenging and risky time at
this age the heart is no bigger than a
walnut it's been pumping in the womb for
eight months but now it has flaws that
could be fatal two holes one in the
aorta and one in the heart
in the womb they diverted blood away
from our inactive lungs now that we need
the lungs the holes sealed shut
the heart is working normally pumping
blood through tens of thousands of miles
of blood vessels
other systems are also gearing up the
digestive tract is ready to clear itself
out to make room for its first meal the
bowels are full of digested amniotic
fluid and dead cells a sticky green
black tar like material called meconium
it's corrosive stuff if it ends up in
the baby's lungs during labor it can
attack the delicate lining but here in
the gut meconium is harmless the
digestive tract flushes it out within
days as time passes more sophisticated
systems start to kick in our next
challenge is the cold it was a hundred
degrees in the womb here at home 65
degree room temperature is a shock to
the system
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the area that controls temperature is
deep within the base of our brains when
an adult is too cold or hot this area
sends out instructions for our cells to
produce more or less energy it's called
the hypothalamus and like all our other
organs at this age it's still immature
the brain is under pressure making 100
trillion calculations per second just to
keep our bodies functioning but it's
still learning how and now we're in
danger of hypothermia an infrared camera
shows the struggle to keep warm as we
lose precious body heat the yellow areas
show where we lose the most
luckily we're prepared
a layer of special tissue around our
blood vessels and vital organs actively
generates heat it's fat but this isn't
regular fat it's brown fat a specialized
type usually found in hibernating
animals it's packed with special heat
generating cells eventually most of this
fat will melt away as the hypothalamus
matures and the liver and other organs
take on the job of generating heat
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just hours old we know almost nothing
about the world everything we do relies
on instinct
feeding is a reflex normally we have no
more control over suckling than the urge
to breathe
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this is milk on its first journey down
the esophagus to the stomach
mother's milk is much more than the
ultimate superfood it also protects us
from hidden danger outside the womb
bacteria are everywhere invisible and
potentially deadly our day-old skin is
under constant attack there are 10 times
more bacteria than human cells in and on
our bodies our immune systems aren't
developed yet so we can't fight
infections for ourselves amazingly our
mother fights them for us through her
milk
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the close contact between mother and
baby means she absorbs the same germs
that are attacking us her immune system
creates antibodies then she delivers
those antibodies back to us in her milk
until our own immune systems develop she
will keep us safe
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it's time to take on the world it's been
four weeks since birth
the baby has drunk nearly 30 pints of
milk and has put on two pounds a quarter
of its body weight it's time for its
first trip outside
even a visit to the grocery store can
overload the senses it's noisy bright
and smelly
the nose is working overtime high up
inside specialized nerves dangled in the
Airstream they detect chemicals in the
air and send an electrical signal to the
brain which interprets the signals as
smells the nerves are super sensitive
every smell is a new sensation
the same goes for our hearing strange
new world strange new sounds
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sound waves vibrate the eardrum on the
other side of the eardrum these tiny
bones the ossicles vibrate in response
they're the smallest bones in the body
but without them we would never hear a
thing
they use leverage to amplify the
vibrations hitting the eardrum 22 times
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the amplified vibrations now enter the
inner ear or cochlea it's lined with
delicate hairs when vibrations pass
through the hairs vibrate at the base
are the fragile hairs for high-frequency
sounds at the top low frequency hairs
each one 200 times thinner than a hair
on our head
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over time loud noises will damage these
hairs but at this age they're perfect
our hearing will never be this good
again the story is different for
eyesight we're born with very
underdeveloped vision even at one month
the world is blurred and mostly black
and white every aspect of our vision is
rudimentary the eye muscles are immature
keeping us from pointing our eyes where
we want to
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inside the eye the lens muscles still
can't focus and the lens flips the image
it receives all through life we see the
world upside down the picture only gets
reoriented in our brains right now the
picture is on the retina the screen at
the back of the eye the retina has two
types of cells rods and cones which
transform the light that hits them into
electric signals the cones detect color
information but because they're not
developed yet we see mostly in black and
white during our first month from the
retina the signals travel along too
thick nerves under the brain at the back
is where we process visual information
when the image arrives the real
challenge begins our immature brains
haven't learned to interpret the data
yet that's changing fast
at two months we can distinguish colors
and shades at four months we can
identify our mother's face by eight
months we have 20/20 vision along with
our perfect eyesight comes a growth
spurt we start packing on pounds we add
a quarter to our body weight every month
after three months it slows down lucky
for us
if we kept growing that fast we'd weigh
150 tons by age four the same as a blue
whale
at eight months all our senses work
we're beginning to explore the world and
the sense we use most is touch touch
something too hot and temperature
sensors in the skins and nerve signals
racing up the arm up the spinal cord and
into the brain all at 200 miles per hour
the brain detects the signal interprets
it as pain and fires another signal back
to the muscles we move the hand away
we have sensory nerve receptors all over
our skin but some areas are more
sensitive than others the hands face and
mouth there are 9,000 sensory receptors
on the tongue alone which is why babies
use their mouths to explore but there's
another reason for all the knowing
something painful is happening inside
the baby's mouth her first teeth are
coming through milk teeth form deep in
our gums while we're still in the womb
now one by one they burst through it's
painful but its progress
at eight months into life's eighty year
journey the senses are operating at full
capacity every sensation is a new
surprise
and with her new teeth she can take on
more solid foods digestion starts in the
mouth teeth grind up the food then
special glands under the tongue pumped
out saliva to help break down and
lubricate the food on its 12-hour
13-foot journey through the gut
it'll pass from the stomach into the
coils of the small intestine before
finally passing into the large intestine
waves of contracting muscle keep the
food moving a process called peristalsis
these contractions are so powerful we
can even eat upside down
for the first time a new camera shows a
high-definition view of how food travels
through our bodies and into our stomachs
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food enters the stomach through a hole
at the top
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the stomach is a bag of muscle that
churns squashes and squeezes food into
liquid at the same time acids break the
food down the stomach walls protect
themselves with a lining of mucus
without it the acids could digest parts
of the stomach itself causing stomach
ulcers about an hour later the stomach
squeezes the broken down food out
through a tiny hole called the pyloric
sphincter
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the food enters the small intestine an
11 foot coil of tube where we absorb
most of the nutrients the interior wall
of the small intestine is lined with
millions of microscopic projections
called villi these increase the surface
area of the gut making it easier to
absorb nutrients
first the pancreas pumps out a juice
that neutralizes stomach acid then bile
from the liver breaks down the fats into
tiny droplets smaller droplets are
easier for the intestine to absorb after
an hour and a half the small intestine
has absorbed most of the nutrients from
the food it's time for what remains to
move on it enters the large intestine
through this the ileocecal sphincter a
valve that keeps our food from going
back where it came from what's left is a
mix of waste food and dead cells from
the walls of the gut the large
intestines main job is to extract water
from it
lots of bacteria live here too but it
isn't because of an infection we
actually need them they produce enzymes
that break down complex carbohydrates in
our food carbohydrates we couldn't
otherwise digest finally after about 12
hours we expelled what's left of our
first meal
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one year old we're mobile we've
perfected the art of chronic
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our bones are stronger they need to be
we're getting pretty heavy
at birth the skeleton is mostly
cartilage the same material as our ears
cartilage is flexible it's what allows
us to squeeze through the birth canal
but after birth our soft skeletons are a
problem they need to be rigid to support
our growing bodies and protect our vital
organs
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so right from birth the cartilage starts
to harden
[Applause]
special cells called osteoblasts lay
down minerals that turn soft cartilage
into hard bone
some bones even fused together at birth
we have gaps between the plates of the
skull which allow the skull to deform
during birth through our first year
these gaps gradually closed until the
skull is finally completed as our
skeletons develop so does our desire to
get around we're about to hit one of the
major milestones in life standing on two
feet
the key isn't strength its balance and
the secret to standing is hidden deep in
our ears
beyond the ossicles the bones we use for
hearing the inner ear is made up of
three looping structures each loop is
the size of a dime and they're oriented
to cover all three planes these
semicircular canals are part of our ears
but they have nothing to do with hearing
they're filled with lutely and they tell
us what's up what's down and what's on
the level the liquid inside sloshes
against sensor hairs lining the tubes
the hairs send data to the brain about
how we are oriented and our direction of
movement these are our organs of balance
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once we've mastered balance we're one
step closer to walking now there's no
limit to where we can go and what we can
learn from a baby to a toddler we're
embarking on our most formative years a
time when we'll put our growing brains
and developing immune systems to the
test
age two we've survived infancy and can
stand on our own two feet
next up is a uniquely human challenge
learning to talk
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talking takes a lot of brainpower a
two-year-old learns 10 new words a day
this is Broca's area the region at the
side of the brain used for speech
production and comprehension
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language is what separates us from other
animals we exchange complex thoughts and
ideas and teach our children not just by
showing but by telling as our brains
develop we gain other uniquely human
qualities we're aware of our own
identities and individuality we gain the
ability to think for ourselves and we're
forming memories that will last a
lifetime
like our first day at school
we may remember what was going on around
us but the real action is happening
inside the brain is a mass of 100
billion nerve cells between them they
generate enough electricity to keep a
light bulb burning for a day the cells
communicate using electric impulses each
impulse is a tiny fragment of thought or
memory when we hear a new word our ears
convert the sound into electrical
impulses in our brains
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the brain can learn because the
connections between brain cells aren't
permanent the brain rewires itself nerve
cells send out tendrils called axons
constantly forming new connections
the cells meet at a tiny gap called a
synapse chemicals bridge the gap to
allow the impulse to continue the chain
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the new connections form a pattern a new
memory we learn by making new
connections between brain cells and then
reinforcing them through repetition
the stronger the reinforcement the more
likely the memory will sting
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what does the word veteran mean when
someone asks us to recall that memory
the same pattern of axons fires and the
memory comes alive
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our brains respond by sending messages
to the nerves that drive the muscles in
our arms we raise our hands in childhood
our brains are primed to learn and are
grown fast the rapid growth allows our
brains to easily form new connections an
ability that will fade with age and
while our brains keep learning our
bodies do the same
it's the immune systems job to learn to
recognize infections
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every germ that enters the body carries
the potential threat of disease but
first the germ has to get their immunity
doesn't begin inside our bodies we start
fighting germs the moment they touch us
we have an arsenal of defenses against
infection our eyebrows and eyelashes ear
hairs and nasal hairs catch airborne
bacteria
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sweat tears and mucus washed them off
our skin constantly sheds its top layer
of cells taking bacteria with it the
mouth is especially vulnerable here too
we are armed and ready to fire
each squirt of saliva contains lysozyme
and enzymes specially targeted to
destroy bacteria our saliva glands are
tiny yet they produce nearly half a
gallon of saliva every single day
sometimes a pathogen breaks through
these external defenses and our immature
immune system reacts to prevent
infection tiny viruses travel through
our blood and probe our skin cells for
signs of weakness
the virus hijacks a cell and
manufactures thousands of copies of it
then the infected cell ruptures
spreading even more viruses around the
body
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this particular virus causes a rash
chickenpox the fever that comes with
infection is a sign that the body is
fighting back
heat slows down the spread of the
disease because viruses don't reproduce
well when it's hot the immune system
kicks into action white blood cells
latch on to infected cells and pump in
poisonous proteins which kills the cell
and the viruses
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crusty skin blisters signal the battle
waged between the immune system and its
viral assailants each one contains
cellular debris and the remains of a
hundred thousand viruses
it may be unpleasant but getting
diseases like this when we're young is
vital for our developing immune systems
our bodies create memory molecules
against a virus antibodies we used to
rely on antibodies from mother's milk
now we make our own
if we catch the same disease when we're
older the antibodies enable our bodies
to recognize the virus instantly white
blood cells wipe it out before it has a
chance to take hold this is why
childhood is the perfect time for
vaccination vaccines are harmless doses
of viruses like mumps polio or rubella
the body creates antibodies as if it had
really been infected now if we ever
catch the real thing the body will
recognize it and attack
in its first decade the human body
changes beyond recognition but now comes
the biggest change of them all the
roller coaster ride of puberty
by age 11 puberty is already underway
for most but there's no schedule for
some it happens later some earlier it
depends on our DNA clocks our lifestyles
even our diets whether 10 or 13 female
or male it begins in the brain for all
of us at the base the hypothalamus the
same region that controls our body
temperature
puberty starts when the hypothalamus
releases a protein kiss pep tip into the
brain the kiss pepsin triggers the
release of other hormones in a chain
reaction throughout the body
only then do our sex organs begin to
mature
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in girls that means ovulation
this is a high-definition view of a
woman's ovaries the off-white organs in
the center this unique footage from gold
coast IVF fertility Center in New York
shows an actual egg inside a protective
blister of fluid during ovulation an egg
bursts from the ovary and travels down
the fallopian tube to the uterus
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from now until menopause the same thing
will happen every month then
menstruation clears the uterus of
unfertilized eggs the ovaries not only
produce eggs they also produce a potent
cocktail of chemicals they release
hormones into the bloodstream including
estrogen these hormones have dramatic
lasting emotional and physical effects
both boys and girls experience a growth
spurt
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women and men's body shapes diverge
girls become women boys become men
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[Applause]
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male brains also release kiss pectin to
trigger puberty a flood of new hormone
stimulates the testicles to produce
sperm
the testicles also generate a tenfold
surge in testosterone the hormone that
creates the physical characteristics of
manly the larynx opens up and tilts
forward the vocal cords stretch wider
the longer cords vibrate at a lower
pitch the voice deepens
testosterone stimulates the growth of
body hair and doubles muscle mass
including 40% more heart muscle these
are changes we can see and hear but
changes are going on that we can't see
in the brain nerve cells undergo
extensive rewiring transforming our mood
and character
both sexes experience a flood of new
emotions and one beats them all for the
first time both sexes find the other
sexually attractive from the inside out
our bodies are overwhelmed by new
sensations our pulse races our blood
pressure rises our lips gorge
our cheeks flush with blood all signs
that we desire some and if the desire
turns out to be usual we hit another
major milestone our first kiss
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in its first two decades the human body
accomplishes something close to
miraculous we're nearly four times our
original height twenty-one times heavier
we've digested 9,000 tons of food
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our hearts have beaten over a billion
times our lungs have drawn over 200
million breaths now with puberty behind
us we're ready in mind and body to
become adults
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our early 20s childhood and puberty are
behind us this is the start of a new
phase in our lives
adulthood we've flown the nest what
happens now is up to us in our 20s we
look and feel better than at any other
time in our lives
we're in our prime both outside and in
trillions of cells make up our organs
and tissues over time these wear out or
get damaged but new cells grow and
divide to replace the old ones our body
replaces entire organs so it's no wonder
we feel good
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essentially every ten years we get a
brand new body
some tissues regenerate even faster like
our hair and nails which requires a
quick trip to the salon every so often
hairs are made from modified dead skin
cells each hair grows from a follicle
embedded in the skin the modified cells
grow here then die as new cells push
them upward the column of dead cells is
the hair each person grows an incredible
7 miles of hair every year our hair
grows whether we want it to or not but
other parts of our body are partially
under our control choices we make now
like exercising affect us for the rest
of our lives
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it has an effect throughout the body
helping cells and organs stay in peak
condition our muscles are also building
this is a new imaging technique that
combines the highest resolution CT scans
with cutting-edge computer power
it's called volume edek and it shows how
our 650 skeletal muscles make up to a
third of our adult body weight it's been
suggested that if all the muscles in the
body worked together they would generate
enough power to lift more than 11 tons
the weight of more than four SUVs
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muscles are made from bundles of fibers
a good workout rips these fibers apart
but our cells repair the damage by
adding extra material the muscle grows
back bigger and stronger through choices
we made unfortunately some choices are
less beneficial some exposes to damage
that even our youthful cells can't
repair
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parties are a part of life in our 20s
we all know smoke can damage the lungs
[Music]
but smoke isn't the only hazard here our
hearing is under threat - from loud
noise
the problem is deep inside the ear the
fragile sensory hairs in the cochlea or
stereocilia turns sound into nerve
impulses loud noise destroys these
irreplaceable cells
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the hairs that respond to high
frequencies are most affected
maybe because high-pitched sounds shake
their foundations more violently the
effect is too small to notice
but the frequency range of our hearing
is already shrinking
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another source of damage is alcohol
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as we absorb alcohol into our
bloodstream it affects both our organs
and our state of mind it raises our
blood pressure and makes our heartbeat
irregular we relax lose our inhibitions
and our coordination
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these symptoms are a consequence of
chemical reactions in the brain
especially in this region the cerebellum
it controls coordination and balance
when we drink alcohol affects the
cerebellums brain cells
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some synapses accept the signal more
frequently
others become totally blocked the more
we drink the more extremely effect
it may feel good now but there will be a
price to pay later
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after a party time passes and we get to
know our limits now new challenges are
on the horizon to find love
and have children of our own
our late 20s childhood is a distant
memory but not the thrill of our first
kiss that was pure lust now it's time
for something new it's time to fall in
love
many of us meet our future partners at
work we may think the attraction is
social or physical but a lot of it is
biological
we use our eyes to size up our date
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but looks aren't everything
attraction is also about smell inside
the nose olfactory nerves do more than
detect smells they also detect chemicals
we can't smell pheromones odorless
hormonal messages we release in our
sweat pheromones carry information about
our genetic health and our ability to
resist disease our brains use these
signals to help choose a partner with
the best possible genes for our children
love is more than just an emotion it's
all about chemistry
we release adrenaline into the blood our
heart pounds we can't sleep
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when that happens another hormone comes
into play
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the brain floods with dopamine the
feel-good hormone
it's as potent as cocaine makes us
euphoric and it's addictive it leaves us
wanting more we start thinking about
commitment and eventually marriage love
both chemical and emotional wins the day
it's a relationship we hope will last a
lifetime
and the process of long-term bonding is
chemical
sex isn't just about procreation or
recreation it chemically strengthens the
bond between us both partners pituitary
glands pump the blood full of a
substance called oxytocin sometimes
called the bonding hormone it's the very
same hormone that binds us to our
mothers as newborns some anthropologists
believe oxytocin could be evolutions way
of creating a bond that's strong enough
to endure the trials of parenthood
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and the time for Parenthood is now the
man releases sperm the goal to find the
egg an egg ripens and bursts from the
woman's ovary the largest cell in the
human body it passes into the fallopian
tube ready for fertilization sperm are
the smallest cells in the human body and
they have a tough journey ahead of them
first they have to survive the hostile
environment of the vagina its secretions
are acidic to prevent bacterial
infection but they also kill sperm
ejaculation releases 300 million sperm
but only thousands will make it as far
as the cervix
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[Music]
the surviving sperm swim into the uterus
and fallopian tube
muscular contractions in the walls of
the fallopian tube help guide the spine
toward the egg only a few hundred make
it this far
and only one will succeed in fertilizing
the egg
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this truly is survival of the fittest
ten hours later the strongest of 300
million sperm is the one to pass on its
genes
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so far there's no sign of conception
we're totally unaware that we're about
to embark on a new chapter in our lives
over the next 40 weeks a single cell
will develop into a perfectly formed
baby often the first symptom is morning
sickness no one knows for sure what
causes the nausea one theory is that it
protects the fetus from toxins in food
which could harm its organs during this
critical phase of development
another theory is that nausea is a side
effect of the mother's immune system as
it weakens to avoid attacking the
developing embryo the fetus is
effectively a parasite it saps the
mother's energy as it draws what it
needs from her body it has its own
life-support system
the placenta here the mother's blood
passes nutrients across a membrane into
the fetal blood
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with this constant supply of nourishment
the fetus grows over 30 ounces in its
first ten weeks the uterus expands to
1,000 times its normal size
just to hold it that extra space has to
come from somewhere
so the mother's body rearranges itself
internally this woman isn't pregnant but
her organs are still a tight fit in a
pregnant woman the organs get squeezed
and some are pushed up into her chest
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not only are the organ squished
now they're working for to the lungs and
heart work harder than ever before to
make space muscles and tendons in the
spine relax and it curves out of its
normal shape
the stomach is also compressed and
rotated through 45 degrees it can only
hold small amounts of food and drink and
still the growing baby demands more
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after nine months it's time to give
birth and pushing out a seven pound baby
can be quite a challenge
soften tendons allow the pelvis to open
up the birth canal but even so it's a
cramped space volume medic imaging shows
the claustrophobic route the baby has to
take with a tight twist to get around
the tailbone
sometimes it's too tight of a squeeze
for mother and baby the only option for
a safe delivery is surgery a cesarean
section
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from a newborn baby to becoming a parent
in 30 years the circle of life goes on
our twenties are behind us our bodies
are about to enter a new period of
change as the aging process takes over
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some experts believe that we all start
aging from the moment we're born
the body's repair systems compensate but
now the repair systems themselves are an
aging the changes in our appearance are
getting noticeable we're in our 40s
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the cumulative effect of gears in the
Sun causes the first symptom wrinkles
since birth our skin cells have
replenished our skin at an astonishing
rate we can make up to 30,000 new skin
cells every minute to replace the dead
cells we're constantly shedding
by 45 we've created more than 400 pounds
of dust from old skin cells whatever our
age our skin cells are never more than a
few months old
the skin cells are fine the problem is
the stuff that binds them together
collagen
ultraviolet radiation in sunlight
triggers a molecular chain reaction that
degrades collagen
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the fibers get thin and break
our skin loses elasticity and we get
wrinkles our eyesight is also changing a
few years ago we could easily read
without glasses the problem is in the
lens inner lens cells along with heart
cells and most brain cells are among the
only cells our bodies never replace
they're exactly the same lens cells we
had as babies as we get older the lens
is gradually stiffened they don't focus
as well and our eyes start to dry out we
produce less fluid to lubricate the eye
and fewer tears to flush out debris
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middle-aged also changes the shape of
our bodies exercise alone isn't enough
to keep us in shape anymore at 20 it was
easy we could eat what we wanted do what
we wanted
now our metabolism is changing and it's
easier to put on weight
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the explanation is in our blood in
middle-age the level of several hormones
start to drop estrogen testosterone and
growth hormones and we start to lose
lean muscle we lose about six and a half
pounds of muscle during each decade of
our adult lives less muscle means the
body burns fewer calories we need less
fuel if we continue to eat like we used
to the surplus food gets converted into
this fat
for women fat tends to go to their hips
it's the body's way of providing a
steady energy supply for pregnancy men
store fat in a different area their
bellies belly fat evolved for quick
energy release it helps sustain our male
ancestors during hunting trips
our ability to metabolize fat slows down
as we age
inside each cell in our bodies there are
tiny structures called mitochondria
these are the body's power plants they
combine nutrients from food with oxygen
from the lungs to release energy as we
get older the number of mitochondria
dwindles and we lose the ability to
metabolize fat as efficiently
too many calories and a drop in
metabolic rate can be a lethal
combination fat is much more than an
extra inch on our waistline it spreads
throughout the entire body
for the first time a high-definition
endoscope inserted through the navel
reveals the full extent of fat cover
inside the abdomen the intestines are
smothered in yellow fat deposits fat
finds its way into almost every
available space of our bodies even
inside our blood vessels deposits
buildup on the inner walls narrowing the
tube the heart has to work harder to
pump blood through the restricted
vessels in extreme cases fat can block
the vessels completely if that blocks
the arteries that supply the heart the
result can be fatal
the heart muscles are deprived of oxygen
and nutrients the muscle risks going
into spasm a heart attack
heart disease is the biggest killer in
the Western world fat isn't the only
risk to our health as we age stress also
plays a damaging role middle-aged life
is stressful holding down a job and
raising teenage kids stress is
exhausting but the damage doesn't stop
there
it also speeds up the aging process
50 years old our bodies may be slowing
down but our lifestyles aren't a growing
family and a demanding career add up to
another influence on the aging process
stress we all recognize the outward
signs of stress sweaty palms
shortness of breath a dizzy fever but
the real damage takes place inside our
bodies instinctively shift into
fight-or-flight mode
hormones adrenaline and cortisol flood
from the adrenal gland into our
bloodstream our muscles contract
arteries constrict the heart pumps
faster and our blood pressure hits the
roof
we evolved the fight-or-flight reflex to
quickly respond to attacks from
predators to have the reflex triggering
so constantly causes irreparable harm to
our cardiovascular Network
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stress accelerates the aging of our
blood vessels high blood pressure
damages cells in the artery walls they
become stiff and thick especially here
in the biggest artery the aorta arteries
with stiff walls restrict blood flow as
our blood pressure rises the heart is
forced to work harder
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it's a vicious cycle the more stressed
we get the more we damage our blood
vessels and the more we damage our blood
vessels the less we're able to deal with
the effects of stress
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if the problem gets out of control the
heart becomes enlarged as it struggles
to force blood through our narrow less
elastic blood vessels
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high blood pressure can even rupture
blood vessels in the brain a stroke most
of us learn to manage stress but for
women in their 50s
another factor compounds the problem
menopause
in her 50s a woman's ovaries stop
releasing eggs they also stop producing
the sex hormones estrogen and
progesterone which signals the end of a
woman's reproductive life
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as the supply of hormones winds down it
destabilizes the regions of the brain
that deal with mood sleep and
temperature control
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when the hypothalamus is thrown off
course hot flashes occur moments when
the body can't set its thermostat
correctly
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bone and muscle tissues weaken the
woman's body has spent its whole life
getting accustomed to these hormones now
they're gone and the aging process
accelerates
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our 60s come and go our kids leave home
and we leave work we enter a new phase
of life old age in 70 years we've grown
from a tiny baby to an adult from child
to parent to grandparent the aging
process began several decades ago now
we're in the grip of old age it's the
final chapter in the journey of life
when we retire from work we gain a
slower lifestyle and our bodies slow
down the outward signs of aging are only
the beginning
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aging also dramatically effects our
skeletons any of us could be at risk for
osteoporosis
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our bone cells are still hard at work
destroying old bone and replacing it
with new but old age upsets this balance
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osteoclast destroy the bone faster than
osteoblasts can rebuild it
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what remains is a hollowed-out cluster
of brittle bone fibers
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our bones slowly crumble as the years
slide by
broken bones become a very real danger
it can happen to men and women alike
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but the process is faster in women
because of the hormonal changes of
menopause
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the aging process is one of the great
mysteries of life why does our
appearance change so much between the
ages of 40 and 70 it's more than wear
and tear it's a process affecting every
cell in our bodies every day cells clone
themselves into billions to battle wear
and tear on our organs the DNA inside
each cell gets copied the old cells die
off and the new ones take their place
but the copying system isn't perfect any
imperfections in our DNA are also
duplicated
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over a lifetime we make so many copies
of ourselves that even the tiniest
defects accumulate it's like using a
photocopier copies made from copies
degrade in quality we have totally
replaced the bone in our face every 10
years since we were born our 70 year old
face is a seventh generation copy of our
baby face
the imperfections are exaggerated with
each copy
another reason for aging could be the
air that we breathe we need oxygen to
live but throughout our lives
it slowly poisons us
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inside each of our cells our
mitochondria are like tiny power plants
combining food with oxygen they create
the energy we need but just like a power
plant they also generate pollution in
this case the pollutant is oxygen the
mitochondria changed the molecules into
unstable forms called
free radicals over a lifetime free
radicals slowly suffocate the
mitochondria and damage our cells our
cells and DNA become more and more
damaged repair systems fail
imperfections accumulate eventually our
organs fail
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even with a healthy lifestyle and the
best medicine death is unavoidable our
DNA makes us what we are and guides our
development but it also determines how
long we live
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every time one of our cells copies
itself it loses a tiny piece from the
end of the DNA after billions of cell
divisions the end section is gone our
cells can't divide anymore
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death like life is a biological process
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scientists believe that near the moment
of death our bloodstream is flooded with
endorphins the body's natural
painkillers
now starved of oxygen tissues can't
function
within 10 seconds the brains electrical
activity drops
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hearing is the last sense to go it can
take 24 hours for our skin cells to stop
dividing its final impulse
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there's a saying that life goes on for
some of us it could go on for some time
thanks to modern medicine children born
in the US today can expect to live to
celebrate their 77th birthday and beyond
even when we're gone we live on through
our loved ones our children and their
children carry our genes in every cell
they carry memories of us to the moments
they've shared from our extraordinary
story all journeys must come to an end
but what a journey it's been
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English (auto-generated)