The Body: A Guide for Occupants by Bill Bryson

This book is INTENSE. It’s long, it’s dense, it’s full of crazy, weird, awesome, amazing, random, ridiculous, stupefying facts about how our body works, and why, and how, and when, and … yeah, intense. But very, very well written and very interesting — at least, if you are a health and wellness guy like me and someone who is geniunely curious as to how the body functions and why it does what it does. I think this one takes the prize for most notes I have ever written because there were just so many interesting facts I couldn’t put my highlighter down, but the cool thing is that whenever I need to look something up — like, say, how a kidney works or why we have earwax, for example — I can just scroll through my notes and it’s like having a textbook on hand for Health Class. Bryson has a whole heaping host of history, science, data, and knowledge in here, and I really, truly enjoyed reading it.

• 59 elements are needed to construct a human being
• deficiency in selenium linked to hypertension, arthritis, anemia, some cancers, possibly reduced sperm
• found in nuts, whole wheat bread, fish
• too much can poison your liver
• full cost of building a new human being is 150K if you are just scouring for elements
• only thing special about the elements that make you is that they make you - miracle of life
• you blink 14,000 times a day - eyes are shut for 23 minutes of every waking day
• in the past second your body has made a million red blood cells
• 7 billion billion billion atoms to make you
• DNA in your body would stretch 10B miles, to beyond pluto
• basic unit of life is a cell - compartment, a kind of little room
• heart of the cell is the nucleus, contains the cell's DNA
• DNA exists to create more DNA
• DNA is an instruction manual for making you - length of DNA is divided into segments called chromosomes and shorter individual units called genes
• sum of all of your genes is a genome
• DNA can last for tens of thousands of years
• not once in 3B years since life began has your personal line of decent been broken
• genes provide instructi9ons for building proteins
• proteins are within us few hundred thousand to a million or more
• all humans share 99.9% of their DNA, and yet no two humans are alike
• 2 percent of the human genome codes for proteins, only 2% does anything practical
• dark DNA - we don't know what it does or why it's there
• body works 24/7 for decades
• your body maintains and preserves you
• every day, estimated, between one and five of your cells turns cancerous and your immune system captures and kills them
• most cells in the body replicate billions and billions of times without going wrong
• bodies have 37.2T cells, thousands of things that can kill us (8,000) in total (educated guess)
• your genes come from ancestors who most of the time weren't even human
• you are the product of three billions years of evolutionary tweaks
• skin is our largest organ, looks after us, cutaneous system, 10 - 15 pounds of it
• thickest on the heels of our hands and feet
• we shed skin copiously - million pieces every hour
• two to five million hair follicles and perhaps twice that number of sweat glands
• pimples plague young people simply because they are sebaceous glands - like all glands - are highly active
• acne related to greek acme, high and admirable achievement, not clear why they are intertwined
• Meissner's Corpuscles - abundant in our errogenous zones and other areas of heightened sensitivity - named after german anatomist Georg Meissner in 1852 (corpuscle, latin, little body)
• brain doesn't just tell you how something feels but how it ought to feel
• caress of a lover feels wonderful, but a touch by a stranger would make you feel creepy
• skin about a millimeter thick - sliver of epidermis
• biologically, there is no such thing as race
• skin gets color from melanin, gives birds the color of their feathers, fish the texture of scales, involved in making fruits go brown
• also colors our hair, production slows dramatically as we age which is why older people's hair tends to turn gray
• skin color = convergent evolution, similar outcomes that have evolved in two or more locations
• skin evolved to deal with conditions of where they lived
• advantage to have lighter skin in a way because it synthesizes extra vitamin D
• D builds strong bones, teeth, boosts immune system, fights cancers, nourishes the heart
• from food or sunlight
• human body adapts to altered circumstances, process known as phenotypic plasticity
• sunburn is when tiny blood vessels in the affected areas become engorged with blood, making the skin hot to the touch
• mobility means that lots of people end up in places where sun levels and skin tones don't get along
• some 50 percent of people globally vitamin D deficient, northern climes, as much as 90 percent
• lighter colored eyes and hair developed only pretty recently - we still have a lot to learn as far as skin is concerned
• comes in two varieties - with or without hair
• hairless skin is called glaborous
• conspicuous hair, called terminal hair, as on your head
• we are actually as hair as our cousins the apes - just our hair is much wispier and fainter
• estimated to have 5M hairs
• hair provides warmth, cushioning, camouflage, shields the body from UV light, allows members of a group to signal to each other that they are angry or aroused
• horripilation - goose bumps - no psychological benefit
• dark skin wasn't necessary when we were still furry
• hair on the head acts as a good insulator in cold weather and good reflector of heat in hot weather
• also a tool of seduction
• human pheromones probably don't exist
• secondary hair is for display - announces sexual maturity
• we each grow about 25 ft of hair in a lifetime
• no single strand can ever get longer than about 3 ft
• 1902 in Paris - Alphonse Bertillion - Bertillionage - concept of a mug shot to catch recidivists, he also gets credit for fingerprinting
• the idea that all fingerprints are unique is a supposition
• fingerprints = dermatoglyphics
• plowlines assumed to be gripping, but not proven
• no one has ever come close to explaining why our fingers wrinkle when we have long baths
• completely smooth fingertips is called adermatoglyphia
• sweating is a crucial part of being human - we are a living A/C
• sweating made possible the enlargement of our most temperature sensitive organ, the brain
• man who weighs 155 if he does nothing at all but sit and breathe will lose about one and a half quarts of water per day through a combination of sweat, perspiration and urination
• sweat is 99.5 percent water - rest is about half salt and half other chemicals
• important to replenish salt, as as sweating is activated by the release of adrenaline, when you are stressed, you break into a sweat
• palms only sweat from stress
• sweat glands - eccrine (produce watery sweat) apocrine (groin and armpits, axilla, produce a thicker, stickier sweat)
• eccrine sweat in your feet, lush odor, sweat on it's own is actually ordorless
• 100K microbes per square centimeter of your skin, not easily eradicated
• should wash your hands for a full minute, part of the reason why every year some 2M americans pick up a serious infection every year and 90K die of it
• 200 different species of microbes on skin
• problem with antibacterial soaps is that they kill good bacteria on your skin as well as bad - same true of sanitizers
• head - tiny mites called demoted folliculorum
• itch - beyond explanation really
• confined to the outer layer of the skin, moist outposts
• lose our hair as we age, you lose 50 - 100 hairs per day
• hormone called dihydrotestosterone, goes haywire as we age, directing hair follicles on the head to shut down - only known cure for baldness is castration
• 80 percent of the air your breathe is nitrogen
• thank you to your microbes
• humans produce twenty digestive enzymes - bacteria produce 10K or 5K
• genes you are born with are all you are ever going to have - bacteria can swap genes among themselves
• this is a planet of microbes
• 40K species of microbes calling you home
• thin people have more gut microbes than fat people
• each of us thirty trillion human cells and between thirty and fifty trillion bacterial cells
• passionate kissing alone results in the transfer of up to 1B bacteria from one mouth to another
• of the million or so microbes that have been identified, 1415 are known to cause disease in humans
• kissing is sampling another person's genes, in a sense, to see if they would make a good mate from an immunological perspective
• microbes - to them, you are not a person but a world
• virus - we must go out and collect them, they hitchhike
• terribly small, Dutch botanist, 1900, Martinus Bejjerinck, latin word for toxin
• most viruses infect only bacterial cells and have no effect on us at all
• only 263 effect humans
• ones that cause disease tend to get studied
• average person harbored 174 species of virus
• virus that gives you chicken pox may sit inert, can erupt in shingles
• cingulum (latin) kind of belt, scindula, meaning a stepped tile
• common cold - family of symptoms generated by a multiplicity of viruses, rhinovirus
• on a metal door handle, only took four hours for the virus to spread throughout the entire building (study)
• active for up to 3 days
• least effective way to spread germs is kissing
• only really reliable way to transfer cold germs is physically by touch
• microbes thrive on fabrics of seats and on plastic handgrips
• transfer of germs happens when folding money and nasal mucus
• fungi and protists
• molds and yeasts
• fungi are responsible for about a million deaths globally every year
• protists - anything that isn't obviously plant, animal or fungus
• most notable protists Plasmodium - give us malaria
• 1992, West Yorkshire, Bradford coccus genes, a thousand
• all together there are five groups of giant viruses - existence of a 4th domain in life, in addition to bacteria, archaea, eukaryotes, latter of which include complex life like us
• Petri - shallow dish with a protective lid that bears his name (Juluis Richard Petri)
• Alexander Fleming - accidental discovery of penicillin, mold of the genus penicillium drifted into his lab and landed on a petri dish that he had left unattended
• principal investigator at Oxford, German emigre named Ernst Chain
• penicillin not only killed pathogens in mice but had no evident side effects
• growing mold and patiently extracting from it tiny amounts of penicillin
• lab assistant in Peoria named Mary Hunt found a cantaloupe with golden mold on it, and from that cantaloupe descended the means to make bulk penicillin
• within a year, around WWII, american companies were producing 100B units of penicillin a month
• the more we expose microbes to antibiotics, the more opportunity they have to develop resistance
• antibiotics wipe out good microbes as well as bad
• rate of antibiotic withdrawals, because they don't work anymore or have become obsolete, is twice the rate of new introductions
• almost 3/4 of the 40M antibiotic prescriptions written each year in the US are for conditions that cannot be cured with antibiotics
• US 80 percent of antibiotics are fed to farm animals - americans consume secondhand antibiotics in their food without knowing it
• death rate for infectious dieseaes has been climbing and is back to the level of about 40 years ago
• superbugs - MRSA, today MRSA and its cousins kill an esimtaated 700K people around the world annually
• too expensive to make new antibiotics, all but two of the 18 largest companies in the world have given up the search for new antibiotics
• antimicrobial resistance is forecast to lead to 10M preventable deaths a year
• antibiotic crisis - current crisis - possibility where we can't do hip replacements or other routine procedures because the risk of infection is too high
• brain - 75 to 80 percent water, rest split mostly between fat and protein
• brain exists in silence and darkness, no feelings
• brain is you - churns through more information in thirty seconds than the Hubble Space Telescope has processed in thirty years
• uses 20 percent of our energy
• in newborn infants, 65 percent - partly why babies sleep all the time
• efficient - requires only about 400 calories energy a day
• hardest working brains are usually the least productive
• most efficient brains solve a task quickly and then go into kind of standby mode
• same components as a dog or a hamster
• complex synaptic entanglement that our intelligence lies - although it is curious that the brain is largely unnecessary, at least historically, in a sense
• cerebrum is the brain, has the higher functions
• two hemispheres - right side of the cerebrum controls the left side of the body and vice versa
• connected by corpus callous - "calloused body" in latin
• parietal lobe - sensory, occipital - visual, temporal - auditory and visual
• frontal - higher functions, personality
• cerebellum - latin for "little brain", more than half of the brain's neurons, controls balance and complex movements
• stem - sleeping, breathing, keeping the heart going
• limbic system - peripheral - regulating basic processes like memory, appetite, emotions, drowsiness and alertness, and the processing of sensory information
• hypothalamus - under the thalamus (inner chamber) - relay station for sensory information, controls the chemistry of the body
• hippocampus - memories, greek for "sea horse"
• amygdala - greek for almond, emotions - grows lively when we are asleep, may account for disturbing dreams
• physiologically we don't know what thinking is
• memories we don't know why we keep some and not others
• eyes send a hundred billion signals to the brain every second
• biggest part of seeing visual images is making sense of them
• one fifth of a second for information to be processed and interpreted
• brain forecasts what the world will be like a fifth of a second from now, and that is what it gives us as the present
• what you see is not what is but what your brain tells you it is
• color is perception
• we all sometimes completely miscall even the most vivid events - 9/11 is a major example after studies
• memory storage is idiosyncratic and strangely disjointed - more like a wiki page, hazy and mutable
• declarative memory is the kind you can put into words - as fact
• procedural memory - how to swim, drive a car
• working memory is where short term and long term memories combine - mathematical problem
• short term memory no more than half a minute - six random words or digits is about all of us can reliably retain for more than a few moments
• we retain a great deal more than we can easily summon to mind
• hippocampus has a central role in laying down memories
• higher processes - cerebral cortex - German Korbinian Brodmann - Brodmann areas - gray matter
• beneath it is white matter - myelin sheath
• you imply all your brain in one way or another
• a teenagers brain is only about 80 percent finished - teenage years effectively extend well into adulthood
• nucleus accumbent - forebrain associated with pleasure, grows to its largest size in ones teenage years
• dopamine - pleasure for teenagers, crazy sensations as a teenager
• glia - glue or putty, cells that support neurons in the brain and CNS
• producing myelin to clearing away wastes
• disagreement over whether the brain can make new neurons
• once you pass early childhood, you have all the brain cells you are ever going to have
• frontal lobe damage can transform personality
• US - Walter Jackson Freeman labotomized 225 people in 12 days in the 40's
• Rosemary Kennedy - sister of JFK, father had her lobotomized because of mood swings, which destroyed her - spent from 1941 for the rest of her life 64 years in a care home unable to speak, incontinent, bereft of personality - mother did not visit for 20 years - obedient lifeless shells
• brain is one of our most vulnerable organs
• strokes are the second most common cause of death globally
• epilepsy - caused by misfiring neurons in the brain - seizure from out of the blue - no one knows what causes it, the heart just stops
• 15 to 20 percent of people thought to be in a permanent vegetative state are in fact fully aware
• brains are smaller today than they were thousands of years ago - presumption that they are more efficient, or if we have grown dimmer, skulls have become thinner
• decaptiated head willl still have some oxygenated blood in it, 2 to 7 seconds
• phrenology - correlating bumps on a skull with mental powers and attributes of character - crackpot science
• craniometry - measurements of brain, preposterous conclusions in the past of intelligence
• modern craniology - used by anthropologists and paleontologists to study anatomical differences in ancient peoples
• instinct on the part of european authorities to prove all other races inferior was widespread if not universal
• John Langdon Haydon Down, English, found Downs Syndrome
• Cesare Lombroso, italy, criminal anthropology - thought that criminal instincts were through a range of anatomical features - no scientific validity, but he was the father of modern criminology
• Pierre Paul Broca - french, discovered the brains speech center in the frontal lobe
• Darwin - 1872, Expression of the Emotions in Man and Animals - certain expressions appear to be common to all peoples, all people have a common heritage, which was a revolutionary thought in 1872
• in the 60's Paul Elkman, professor of Psych at san francisco, six expressions are universal - fear, anger, surprise, pleasure, disgust, sorrow - most universal expression of all is the smile
• micro expression - flashes of emotion, betray our true inner feelings - quarter of a second in duration
• by primate standards we have a very odd head
• eyebrows convey feelings
• eyelashes waft away motes of dust - benefit also of interest and allure to faces
• nose - breathing efficiency, keeps us from being overheated on long runs, biologically
• chin is unique to humans, no one knows why we have one - do we just find chins dashing?
• facial features interpret the world through our senses
• eye is essentially a camera - cornea captures passing images and projects them onto the back wall of the eye - the reina - where photoreceptors convert them into electrical signals that are passed to the brain via the optic nerve
• cornea does 2/3 of the eyeball's focusing
• tears keep our eyelids gliding smoothly but also even out tiny imperfections on the eyeball surface making focused vision possible
• tears come in three varieties - reflex (onions), emotional, and basal (provide lubrication)
• we are the only creatures that cry from feeling as far as we can tell
• five to ten ounces of tears per day
• iris is what gives the eye its color
• white of the eye is the sclera - greek word for hard, monitor the gazes of others
• rods help us see in dim conditions
• cones - divide the world into blue green red
• we sacrificed cones for rods - to gain better night visions
• we still have three kinds of color receptors compared with four for birds, fish and reptiles
• human eyes can distinguish between 2 and 7.5M colors
• movements of the eye are called saccades, french "to pull violently" - 1/4M per day
• floppy shell on the side of our heads we call the "ear" formally the pinna, from latin fin or feather
• tympanic membrane = eardrum, marks boundary between the outer and middle ear
• three smallest bones of the body in the ear - known as ossicles - malleus, incus, stapes
• ossicles exist to amplify sounds and pass them to inner ear via the cochlea, means "snail"
• our ears are built for a quiet world
• decibel - coined by Colonel Sir Thomas Fortune Purves, engineer of the british post office which was also in the charge of the telephone system
• pain threshold for noise is about 120 decibels, noises above 150 decibels can burst the eardrum
• vestibular system - inside is a gel that moves from side to side or up and down to tell the brain in which direction we are traveling
• gel thickens as we age and doesn't slosh around as well - why elderly are often not as steady on their feet
• land in an airplane is known as the valsalva effect - air pressure inside your head fails to keep up with the changing air pressure outside it - ears pop = valsalva maneuver
• great deal we still don't know about smell
• receptors acitvated by something called resonance - receptors are stimulated not by the shape of the molecules but how they vibrate
• odors are complex and hard to deconstruct
• we can detect at least a trillion and possibly more odors
• smell is only one of the basic five senses not mediated by the hypothalamus
• smell goes right to the olfactory cortex near the hippocampus, where memories are shaped
• smell is an intensely personal experience - we are better at detecting odors than most of us realize
• smell is much more important to us than we appreciate
• total smell loss is known as ansonia, partial loss is hyposmia - 2 to 5% of people in the world suffer from one or the other
• cacosmia - everything smells like feces
• one of the early symptoms of alzheimers is smell loss
• we depend on smell to interpret the world and get pleasure from it
• we choke to death more easily than any other mammal
• tonsils - no one knows quite what they do
• swallowing is "deglutition" - two thousand times per day or once every 30 seconds on average
• people who had their tonsils removed while young had a 44 percent greater chance of having a heart attack in later life - coincidence perhaps
• fifty muscles can be called into play just to get a piece of food from your lips to your stomach
• when we became bipedal, our necks became longer and straighter
• uniquely among mammals, we send our air and food down the same tunnel
• epiglottis opens when we breathe and closes when we swallow, sending food in one direction and air in the other
• extraordinary that we don't choke more often
• fourth most common cause of accidental death in america today
• Heimlich maneuver, Dr. Henry Judah Heimlich, surgeon in NY in the 70;s
• burst of air known as a bechic blast
• Heimlich was a showman - former colleague called him a liar and a their
• Chevalier Quixote - american doctor, father of bronchoesophagoscopy - specialized in objects that were swallowed or inhaled, designed instruments and refining methods for retrieval - saved hundreds of lives
• we recreate about 31,700 quarts of saliva in a lifetime
• saliva also contains a powerful painkiller called opiorphin, but only in very small doses
• saliva is almost entirely water - we produce very little while we sleep so that's why our breath stank in the morning
• tongue, teeth, gums, and the like are separate continents, each with it's own colonies of microorganisms
• candle blowing across a cake increased the coverage of bacteria on it by up to 1400 percent
• outside of tooth is the enamel, hardest substance on the human body - can't be replaced if it is damaged
• teeth are called ready made fossils because they are so hard and they last a really long time
• typical adult male has 400 newtons of force when they bite
• tongue is a muscle but super sensitive - coated with taste buds - among the most regenerative of all cells in the body and are replaced every ten days
• about 10K taste buds, mostly distributed around the tongue
• taste receptors evolved to help us find energy rich foods - avoid dangerous ones
• more pain and other somatosensory receptors than taste receptors in our mouths
• active ingredient in chili peppers is a chemical called capsaicin
• has been reported to lower blood pressure, fight inflammation and reduce susceptibility to cancer
• taste - sweet, salty, sour, bitter, unami japanese meaning savory or meaty
• synthetic unami is MSG - monsodium glutamate
• MSG has never been found to have deleterious effects on anybody when eaten in normal quantities
• flavor = taste + smell
• smell is said to account for at least 70 percent of flavor
• we are easily fooled with respect to flavor
• orange flavored drink is colored red, you cannot help but taste it as cherry
• texture and chemicals - your brain reads these scentless, flavorless molecules and vivifies them for pleasure
• you experience the world that you brain allows you to experience
• speech - respiration (pushing air past vocal ligaments) phonation (turning air into sound) articulation (refinement of speech into sound)
• stuttering is effects 1 percent of adults and 4 percent of children, 80 percent of sufferers are male
• more common among left handers, especially those who have been made to write right handed
• ceases when they sing words or speak another language or talk to themselves
• majority recover by teenage years
• females seem to recover more easily than males - no reliable cure though
• uvula - latin for little grape - mud flap for mouth
• helps with production of saliva, has a role in triggering gag reflex, component of snoring, but a curious thing, inconsequential
• heart beats slightly more than once every second, 100K per day, 3.5B in a lifetime
• miracle it lasts as long as it does - every hour you dispense 70 gallons of blood
• course of life heart does an amount of work sufficient to lift a one ton object 150 miles into the air
• weighs less than a pound
• blood enters through the atrial (latin for entry rooms) exits via the ventricles (latin for chambers)
• two pumps, one that sends blood to the lungs and one that sends in around the body
• systole - heart contracts and pushes blood out into the body/diastole - relaxes and refills
• 120/80 = measures the highest and lowest blood pressures your blood vessels experience with each heart beat
• higher = systolic, lower = diastolic
• measures how many millimeters of mercury is pushed up a calibrated tube
• blood pressure is highest during the day
• well into the 20th century, authorities believed that high blood pressure was a good thing because it indicated vigorous flow
• 2017 - AMA downgraded to 130/80 - almost half of all american adults are on the wrong side of that number
• death rate from heart diseases has fallen from almost 600 per 100LK in 1950 to just 168 per 100K today
• still the leading cause of death
• in the US, more than 80M people suffer from cardiovascular disease, 300B in costs per year
• when hearts rhythms is too slow, bradycardia, too fast it's tachycardia
• heart attack occurs when oxygenated blood can't get to the heart muscle because of blockage in a coronary artery
• cardiac arrest is when the heart stops pumping altogether - failure of electrical signaling - brain is deprived of oxygen
• heart attack will often lead to cardiac arrest but you can suffer cardiac arrest without having a heart attack
• require different treatments
• more than half of all first heart attacks occur in people who are fit and healthy and have no known obvious risks
• a virtuous life just improves your chances of not having one
• women and men have heart attacks in different ways
• women more likely to have abdominal pain and nausea
• 28K women suffer fatal heart attacks in the UK each year, twice as many die of heart disease as die of breast cancer
• hypertrophic cardiomyopathy when athletes die suddenly on the field
• thickening of the ventricles and causes 11K deaths per year among people under 45 in the US
• FDR had 300/190 BP in 1945, people started to become aware of heart disease
• Framingham Heart Study - 1948, 5K adults and followed them for the rest of their lives
• identified or confirmed diabetes, smoking, obesity, poor diet, chronic indolence - major risks
• "risk factor" coined in Framingham
• Werner Forsmann - Berlin, doc, fed a catheter into an artery until it reached his heart in 1929 and revolutionized heart surgery, unfortunately he was a nazi supporter
• U penn, John Gibbon, worlds first heart-lung machine at Jefferson College in Phily
• Walton Lillehei - father of open heart surgery
• first pacemaker was the size of a pack of cigarettes - today's are no bigger than one american quarter and can last up to 10 years
• coronary bypass - taking a length of a healthy vein from the persons leg and transplanting it to direct blood flow around a diseased coronary artery, 1967, Rene Favaloro at the Cleveland Clinic
• today some 4 to 5K heart transplants are performed globally each year with an average survival time of 15 years
• you are 70 percent more likely to die from heart disease today than you were in 1900 - western worlds number 1 killer
• one in three americans die of heart disease and more than 1.5M suffer a heart attack or stroke each year
• by 200, million precautionary angioplasties were being undertaken in the US every year but without any proof they saved lives
• they still remain popular
• Charles Thomas Stent - 19th century London dentist - inventor of compounds to make dental molds, stent came from him for whatever reason - used to describe any type of device used to keep tissue in place during corrective surgery
• how much blood you have depends on how big you are
• 25 thousand miles of blood vessels
• hemoglobin - molecule that transports oxygen throughout your body
• blood carries oxygen to our cells
• transports hormons and other vital chemicals, carries off wastes, tracks down and kills pathogens, makes sure oxygen is directed to the parts of the body where its most needed, signals our emotions, regulates body temp, male erection
• single drop of blood may contain 4K different types of molecules
• red cells, white cells, platelets plasma (plasma most abundant)
• antibodies, clotting factors, and other constituent parts can be separated out and used to treat autoimmune diseases or hemophilia - huge business
• plasma sales make up 1.6 % of all goods exported in the US more than America earns from the sale of airplanes
• blood delivers oxygen
• hemoglobin presfers carbon monoxide to oxygen
• each red corpuscle survives for about four months
• collected by scavenger cells and sent to the spleen for disposal
• you discard about 100B red blood cells every day - partially what makes your stools brown
• white blood cells vital for fighting off infections - we have 700 x as many red blood cells as white ones
• platelets - central role in clotting
• as soon as a bleed starts, millions of platelets begin to cluster around the wound - must be constantly replenished
• our veins look blue only because of a quirk of optics
• immune response and tissue regeneration
• William Harvey - english - blood circulates in a closed system - he was ridiculed and rejected in the 1600;s
• now know that blood traveling from the lungs is full of oxygen and shiny crimson, blood returning to the lungs is depleted of oxygen and duller
• richard duller, english - blood circulated to pick up and discharge nitrous oxide in the 1660's
• medicine sank into a dark age soon after - duller was intreated in transfusions
• Washington had a sore throat and then 40 percent of his blood was removed over two days, prevailing theory at the time was to remove blood - the illness and treatment left him dead at 67
• practices lasted for a long time - most docs approached diseases generalized imbalances affecting the whole body
• docs at the time wanted to bring the whole body back into the state of equilibrium by purging it of toxins
• Benjamin Rush, american, believed that overheated blood was the problem, and was an enthusiast of "bleeding"
• 1900 Vienna, Karl Landsteiner - discovery of blood types explained why transfusions often failed - donor and recipient had incompatible types - won nobel prize in 1930
• all blood cells are the same inside, but he outsides are covered with different kinds of antigens - proteins that project outward from the c ell surface
• don't actually know why different blood types exist - benefit the species?
• but it did establish parenthood, chicago, 1930 - babies were swapped and given back to the right parents
• taking and storing blood is expensive and risky
• nitric oxide - primary signaling molecules - maintaning blood pressure fighting infections, powering penile erections, regulating blood flow - transfused blood can kill you
• in some cases it can be better to let patients be anemic tan to give them someone elses blood
• 20K people die per year in america from bleeding to death before they can get to a hospital - artificial product?
• for now the best approach is to reduce the volume of transfusions
• diabetes - youngsters with it generally died within a year of diagnosis, and it was a miserable death
• 1920 - London ontario, Frederick Banting, who was just a young general practitioner, wanted to give a shot at a cure - read an article about the pancreas
• insulin is a small protein - vital in maintaining balance of blood sugar in the body
• Banting and his assistant ended up producing insulin by experimenting on dogs, even though they didn't know what they were doing
• impact was miraculous - resurrection in people
• type 1 = body stops producing insulin altogether
• type 2 - insulin is less effective, insulin resistance
• type 1 = tends to be inherited
• type 2 - usually a consequence of lifestyle
• tends to run in families, genetic component, but there is an unrecognized trigger
• rates everywhere are soaring, between 1980 and 2014, 100M to over 400M
• 90 percent of them had type 2
• type one is also growing, rise at a rate of about 3 to 5 percent a year
• insulin is a hormone - hormones are the bicycle couriers of the body, delivering chemical messages
• endocrine gland is one that secretes its products directly into the bloodstream, as opposed to exocrine glands, which secrete onto a surface
• pituitary gland, buried deep within your brain directly behind your eyes, size of a baked bean, effects are enormous
• Robert Wadlow of Illinois was 8 ft 11.1 inches tall - such a large body resulted from a malfunction of the gland
• gland produces growth hormone, cortisol, estrogen, testosterone, oxytocin, adrenaline, and much else
• when you exercise vigorously, the pitituatry squirts endorphins into your bloodstream - runners high, example
• modern endocrinology - Charles Edouard Brown Sequard, 1800's - enthusiasm for testosterone promted others to look more closely
• 1905 - British physiologist EH Starling coined the term hormone, from greek meaning to set in motion
• endocrine system, coined in 1927 by brit JBS Haldane
• Thomas Addison, London, found addison's disease, a degenerative disorder of the adrenal glands - first hormonal disorder to be identified - JFK suffered from it from 1947 on - imbalance of cortisol levels (stress hormone) that regulates blood pressure
• 1995 - Jeff Friedman, geneticist at Rockefeller University, found leptin - greek for thin
• produce not in an endocrine land but in fat cells - arresting discovery
• helps to regulate appetite
• still haven't figured out how it works, nowhere near being able to use it as an aid for weight control
• when it is absent, you just keep on eating, but when it is added to the diet, it makes no difference to appetite
• tells the brain whether you have enough energy reserves to undertake comparatively demanding challenges like getting pregnant or starting puberty
• puberty starts years earlier now than it did years ago - improved nutrition?
• ghrelin - growth hormone related - when we get hungry ghrelin levels rise - helps to control insulin levels and the release of growth hormone
• range of regulatory jobs any hormone does can be bewilderingly diverse
• German biochemist Adolf Butendandt - discoveries made possible synthetic steroids for medical use to birth control pills
• testosterone + estrogen - men and women produce and use both
• in males, test makes a man fertile, virile attributes, influences his behavior
• in women, test boosts libido
• evidence that it improves sexual performance or general virility is thin at best - greater evidence it can lead to an increased risk of heart attack or stroke
• gland is any organ in the body that secretes chemicals - liver is a gland
• liver manufactures hormones, proteins, and bile, filters toxins, converts glucose, body's laboratory, has a capacity to regenerate
• nonalcoholic fatty liver disease (NAFLD)
• hep c - one in thirty people in american born between 1945 - 1965 will have it without knowing it - contaminated blood transfusions, sharing of needles by people doing drugs in those times
• pancreas is a gland and the spleen is not - pancreas is essential to life - spleen is expendable
• pancreas produces glucagon, regulates blood sugar, digestive enzymes which help with cholesterol and fats
• spleen is size of your fist - left side of your chest, monitors the condition of circulating blood cells and dispatches white blood cells to fight infections, reservoir for blood, aids the immune system
• gall blader - stores bile from the liver and passes it on to the intestines - gal is an old word for bile
• mystery as to why we have two kidneys
• workhorses of the body - each day they process about 190 quarts of water - bottom of the rib cage
• flittering wastes, regulate blood chemistry, maintain BP, metabolize vitamin D, vital balance between salt and water levels
• as kidneys become less efficient, sodium levels in your blood go up, blood pressure high
• kidneys lose functi9on as you age - each one is connected to the bladder by a tube called a ureter
• bladder is like a balloon in that it is designed to swell as we fill it
• stones - hardened balls of calcium and salts
• most of the best technology that exists on earth is right here inside us
• in britain, there were never enough bodies to meet demand for med school dissections
• brisk trade arises in illicit bodies stolen from churchyards
• Gray'S Anatomy - 1858, Henry Gray, London doc
• 206 bones the body but can vary between people
• hands and feet together have more than half the bones in the body - that's where evolution left them
• bones protect our interiors, manufacture blood cells, store chemicals, transmit sound in the middle ear, possibly bolster our memory, buoy our spirits, produce hormones
• osteocalcin, produced in bones
• regular exercise helps to stave off alzheimers, exercise builds stronger bones an stronger bones produce more osteocalcin
• most fundamental element of bone is collagen - most abundant protein in the body
• bones are living tissue - grow bigger with exercise and use just as muscles do - strong and light, doesn't scar
• tendons connect muscle to bone, ligaments connect bone to bone
• tendons are strong, lot of force to tear them, but a long time to heal/cartilage has almost no capacity to heal
• more than 600 muscles altogether
• takes one hundred muscles just to get us to stand up
• flexor muscles close joints, extensor muscles open them
• levators lift, depressors lower
• abductors move body parts away, adductors draw them back
• sphincters contract
• you are about 40 percent muscle if you are a reasonable slender man
• we sacrifice muscle tone really quickly when we are not using it
• thumbs are muscles not found in any other animals - allow us to grasp and manipulate tools with sureness and delicacy
• thumbs are on sideways
• human crucifixion - if nails were driven through the wrists, body would stay in position indefinitely - wrists are much more robust than hands
• foot is a shock absorber, platform and pushing organ - you will take somewhere around 200 million in a life
• average human walks at a pace of 4.25 feet per second, 120 steps per minute but it varies
• becoming upright put extra pressure on the cartilage disks
• estimated 60 percent of adults have taken at least a week off work at some time with back pain
• every year in the US 800K joint replacements, hips and knees mostly
• cartilage - best way to maintain it is to move around a lot, keep it bathed in its own synovial fluid
• hips provide mobility for the lower limbs and they support the weight of the body
• in england, john charnley found that the femur was replaced with a stainless steel head and line the socket with plastic for hip replacements
• our bones lose mass at a rate of about 1 percent a year from late middle age onward - why elderly people and broken bones are synonymous - about 40 percent of people over 75 who break their hips are no longer able to take care of themselves
• not less than two hours a day should be devoted to exercise and the weather should be little regarded. if the body is feeble, the mind will not be strong - jefferson
• no one knows why we walk
• walking came at a price - ancient forebears exceedingly vulnerable
• Lucy - 3.5 feet tall, just 60 pounds, famous skeleton
• walking is a permanent defiance of gravity
• our necks became longer and straighter as we evolved
• no pate can be trained to walk like a human
• to keep from overheating we became relatively hairless, abundant sweat glands
• back of your head, nuchal ligament, holds the head steady when running
• panting - large animals can't run for more than about 9M before they drop
• we evolved into a new genus called homo - became walkers and climbers, then we became walkers and runners but no longer climbers
• 6M years ago we started walking, 4M years to acquire the capabilities for endurance running and persistence hunting
• 1.5M years tipped spears - hunting large animals 1.9 million years ago
• throwing - high and mobile waist, upper arm capable of flinging in a whiplike fashion, loose and manneuverable shoulders
• we throw with our whole bodies - unique
• bipedalism had consequences - back pain or knee problems, pain and danger to women in childbirth
• late 1940s doc in britain, jeremy morris, compared bus drivers and conductors and noticed a link between exercise and health
• going for regular walks reduces the res of heart attack or stroke by 31 percent
• exercise boosts your immune system, nurtures hormones, lessens the risk of getting diabetes and a number of cancers, improves mood, staves off senility
• 10K steps is not a bad idea, but no special basis in science - 150 minutes same, just a realistic goal
• only about 20 percent of people manage even a moderate level of regular activity
• ancient forebears were active but no more than absolutely necessary - exercise is important but rest is vital too
• according to WHO in the US more than 80 percent of american men and 77 percent of american women are overweight
• BMI is a crude measure for fatness because it doesn't distinguish between whether you are unusually muscular or just chubby
• average woman in the US today weighs as much as the average man weighed in 1960 144 to 166 pounds
• 150B in cost for US for overweight people
• today more than half of children are expected to be obese by 35
• problem is hardly confined to america - global figure for obesity is 13 percent
• couch potato defined as someone who sits for 6 or more hours per day, increases his mortality for men by nearly 20 percent, women almost double
• people who sit a lot are twice as likely to contract diabetes, twice as likely to have a fatal heart attack, 2.5X as likely to suffer cardiovascular disease - you can't undo sitting
• non exercise activity thermogenesis NEAT - energy we expend for normal daily living
• standing burns an extra 107 calories an hour - walking burns 180 - although exercise can only partly account for slimness
• surface law - volume of an object grows, its relative surface area decreases
• humans have about 1.6B heartbeats in a lifetime
• hypothalamus - tells the body to cool itself by sweating or to warm itself by shivering
• fever - no one knows quite why we get them, defense mechanism to fight off infection, could be either
• the temperature we have is a reasonable compromise between utility and cost
• maintaining equilibrium - homeostasis
• peristalsis - muscular pushing of food through the digestive tract
• fight or flight - coined by Walter Cannon at harvard - also developed treatments for shock
• amount of electricity going on within your cells is a thousand times greater than the electricity within your house
• energy in our cells is a chemical called ATP - tiny battery stores up energy and then releases it to power all the activities required by your cells
• every day you produce 200T molecules of it - guy who discovered, peter mitchell, worked from a home lab, nobel in 1978
• children do much better with extreme cold than with extreme heat - sweat glands aren't fully developed
• more US states have laws making it illegal to leave an animal unattended in a car than to leave a child unattended, margin of difference is 29 to 21
• humans can live on only about 12 percent of earths land area, just 4% of the total surface area
• at very high altitudes, any exertion becomes difficult and exhausting for humans
• airlines normally keep cabins pressurized to an altitude equivalent of 4900 ft to 7900 feet which is why alcohol is more likely to go to your head during flying - also accounts for why your ears pop during decent
• oxygen deprivation - hypoxia
• during WWII, Japanese had Unit 731, experimented on war prisoners, 250K died, estimate
• Japan and Germa y finished the war well ahead of the rest of the world in understanding microbiology nutrition, frostbite, weapons injuries and above all the effects of nerve gases, toxins and diseases
• japanese almost entirely escaped punishment during he war
• well guarded secret - until 1984 a student from Keio university in Tokyo found a box of evidence in documents in a second hand book shop
• three hundred different types of immune cells at work within us
• every persons immune system is unique
• system has to respond to toxins, drugs, cancers, foreign objects, state of mind even
• about 5 percent of us suffer from some form of autoimmune disease
• identify anything that is in the body that shouldn't be there and if necessary, kill it
• lymphocytes - recognize almost any kind of unwanted invader and mobilize a swift and targeted response - b cells and t cells, bursa of fabricius
• thymus - small organ in the chest just above the heart and between the lungs
• thymus is a mystery for T cells
• killer t cells - kills cells that have been invaded by pathogens - helper T cells help other immune cells act, including helping b cells produce antibodies
• memory T cells swift response, adaptive immunity - when they identify an invader they instruct the b cells to produce proteins known as antibodies, and these attacks the invading organisms
• vaccination - inducing the body to produce useful antibodies against a scourge without making oneself sick
• its a wonder we aren't sick more often
• inflammation is how the body defends itself from damage
• white blood cells - encounter an invader, fire off attack chemicals called cytokines which is what makes you feel feverish and ill when your body is battling infection - your body defending itself is why you feel crappy
• immune system gets ramped up = cytokine storm, which is what kills you - pandemics
• Peter Medawar, - 20th century brit scientist, immune system learns early in life not to attack its own normal healthy cells
• Richard Herrick - 1954, worlds first kidney transplant
• 30K people in the US wo receive an organ transplant each year, over 95 percent are still alive for 12 months and 80 percent are alive 5 years later - demand far outstrips supply
• as of late 2018 114K people were on transplant lists in US, new person joins list every 10 minutes
• Crohns disease - one in 250 and rising, causes remain elusive
• autoimmune disease are sexist - women 80 percent of all - hormones? not clear why
• allergy is simply an inappropriate response by the body to a normally harmless invader
• the richer the country the more allergies - not sure why - exposure to pollutants? lack of exercise and obesity?
• in 1999 just 0.5 percent of children had peanut allergies, increased 4 fold today
• best way to get rid of it is to give kids small exposures as a way of hardening them to peanuts
• David Strachan - "hygiene hypothesis" - children in the developed world grow up in much cleaner environments and don't develop resistance to infection - some problems here though
• old friends hypothesis has supplanted that theory, lifestyle changes are more the cause
• bottom line is we don't know why allergies exist
• finding ways of using the body own immune defenses to fight diseases - immunotherapy
• checkpoint therapy - immune system kill an infection, and then withdraw
• CAR t cell therapy - genetically altering a cancer sufferers T cells, then returning them to the body in a form that allows them to attack and kill cancer cells - very expensive to do all this
• every day you breathe in and out about 20,000 times, 550M over the course of a lifetime
• about 20 percent of all antibiotic prescriptions are for people with sinus conditions even though sinus conditions are overwhelmingly viral, and thus immune to antibiotics
• average urban dweller inhales some 20B foreign particles every day
• sneeze droplets can travel up to eight meters and drift in suspension in the air for ten minutes before gently settling onto nearby surfaces
• liquid saran wrap - breaks over nearby surfaces - the act of sneezing is called sternutation
• lungs are assisted by the diaphragm which helps pull down the lungs from below to help them work more powerfully - more oxygen to our muscles to help us become strong and to our brains, to become smart
• discomfort you feel when you hold your breath is a buildup of carbon dioxide
• asthma is common and not well understood - 300M people in the world - we don't know much really
• greek term "to gasp"
• more prevalent but more commonly lethal recently
• almost none of the thins people think cause asthma really do - half the cases in the world involve allergies but half are due to something else altogether
• primarily a western disease - kids nowadays spend a lot of time indoors and stay there - hypothesis really
• a person who smokes regularly is 50 more times likely than a nonsmoker to get cancer
• 80 percent of all men smoked in the late 1940's
• 1950 paper was published in the AMA journal with a clear link between smoking and lung cancer
• people just loved smoking too much to quit
• manufacturers introduced filters in the 50's but the filters used stronger tobacco
• average american adult was smoking 4K cigs a year
• in 1964 surgeon general announced link but people were smoking even more - AMA took 15 years to endorse surgeon generals finding
• today just 18 percent of americans smoke - nearly 1/3 of people below the poverty line still smoke, 1/5 of all deaths
• hiccup is a sudden spasmodic contraction of the diaphragm, no one knows why they happen
• Charles Osborne hiccuped 430M times over 7 decades - never while asleep
• kilocalorie - amount of energy required to heat one KG of water by one degree centigrade
• today 2600 calories for a moderately active man and 2K for a moderately active woman
• americans today consume about 25 percent more calories then they did in 1970
• father of caloric measurement american academic Wilbur Olin Atwater, born in 1844
• built a respiratory calorimeter, a sealed chamber
• in 1896 he wrote The Chemical Composition of American Food Materials
• to him and his people, all that made one food superior to another was how well it served as fuel - alcohol was efficient fuel too
• calorie doesn't give any indication of whether a for its actually good for you or not
• cooking kills toxins, improves taste - cooked food gave us the energy to grow big brains and the leisure to put them to use
• vitamins are organic chemicals - that are or were once alive like plants and animals
• minerals are inorganic that come from soil or water
• discovery and naming of vitamins didn't happen until the 1920's
• vitamins are thirteen chemical oddments that we need to function smoothly but are unable to manufacture for ourselves
• Vitamin D - made in the body, really a hormone, or ingested
• choline - central role in making neurotransmitters and keeping your brain running smoothly but has only been known since 1998 - abundant in liver, brussel sprouts, lima beans
• CDC, some 90 percent of american adults don't get the needed dose of D and E and about half don't get enough A
• 80K different dietary supplements and we spend 40B a year on them
• american chemist linus pauling won two novels and thanks to him to this day many people believe that taking a lot of C will help get rid of a cold. it won't
• protein is a chain of amino acids - made from just 20 amino acids
• not all plants provide all the necessary amino acids
• carbs are compounds of carbon, hydrogen and oxygen, bound together to form a variety of sugars
• carbs are really just more sugar
• cholesterol is vital to a healthy life - eat a lot of fiber, material in fruits, veggies and other plant foods that the body cannot fully break down - helps to lower cholesterol and slows the rate at which sugar gets into the bloodstreams and is then turned into fat by the liver among other benefits
• human bod likes to hold on to its fat
• subcutaneous (beneath the skin) visceral (around the belly)
• trans fats - artificial form of fat made from veggie oils
• trans fats ar much worse for your heart than any other kind of fat - slow acting poison
• we consume about 2.5 quarts of water a day - half in our foods
• caffeine drinks make a net contribution to the balance as well
• over a lifetime we eat about 60 tons of food - eating 60 small cars
• 1915 - average american spent half his weekly income on food, today its about 6 percent
• nutritionist Ancel Keys of U Minn - second WW made K rations for troops - Minnesota Starvation Experiment - chronic hunger made volunteers irritable, lethargic, depressed, left them more susceptible to illness
• Seven Countries Study - correlation between levels of dietary fat and heart disease
• Keys wrote Eat Well and Stay Well with his wife - medettarian diet - milestone in the history of dietary disease
• his findings had a lasting effect on dietary recommendations
• 2010 - no clear evidence that avoiding saturated fat reduced the risk of heart disease - some dispute with academics
• sugar - american consumes 22 teaspoons of added sugar a day
• you have to take in a lot of sugar to get a lot of calories
• Heinz is almost 1/4 sugar - more permit of volume than coke
• many of our fruits and veggies are nutritionally less good for us then they were even in the fairly recent past
• turns out that modern agricultural practices focus on his yields and rapid growth at the expense of quality
• coconut oil is no better for you than a big scoop of deep fried butter
• salt is vital to us - must consume it in our diets - when something is low in salt fat or sugar manufacturers reduce one of the three but boost the other two to compensate
• exercise regularly and you have a better chance of having a better life span
• heart attack is 50 percent genetic and 50 percent cheeseburger - exaggeration but underlying point is valid
• balanced and moderate diet
• food lingers inside a woman for nearly a full day longer
• colon - large fermentation tank where billions of bacteria pick over whatever the rest of the intestines couldn't manage - fiber mostly
• why you are told to eat more fiber, because it keeps your gut microbes happy, reduces risk of heart disease, diabetes, bowel cancer, death
• stomach of a big dog will hold up to twice as much food as your s does
• stomach kills off many microbes
• every year 3K people die of food poisoning in the US
• salmonella - according to a USDA study, about a quarter of all chicken pieces sold in stores are contaminated
• altogether 15 agencies have a regulatory role in some aspect or other of american food safety - no one agency has overall control
• green leafy veggies account for one in 5 of all food illnesses
• heart of the digestive tract is the small intestine
• epithelium - cells are all that stand between you and digesting your own flesh
• appendix - no certain purpose but kills 80K people around the world ever year when it ruptures or grows infected
• best thinking is that it serves as a reservoir for gut bacteria
• large intestine is really a kind of fermentation tank - home of feces, flatus and all our microbial flora
• reabsorbs large volumes of water, returns to body - home for vast colonies or microbes
• captures lots of useful vitamins which are also returned to the body
• nearly all cancer that is found in the gut is found in the large intestine and almost never in the small intestine
• abundance of bacteria could be related to diet
• e coli is the most studied microbe on the planet
• flatus - fart primarily carbon dioxide, hydrogen, nitrogen
• about a third of people produce methane
• smell is hydrogen sulfide
• we don't smell it at all when it rises to lethal level
• sleeping is the most mysterious thing we do - vital, but not sure exactly why
• isn't any part of the body that does not benefit from sleep or suffer from its absence
• consolidating memories, restoring hormonal balance, emptying the brain of accumulated neurotoxins, resetting the immune system
• hibernating is unconscious but not actually asleep - bears don't actually hibernate, more of a state of torpor - body temp stays normal, easily aroused
• all animals seem to sleep
• REM four or five phases of sleep - REM is where we do most of our dreaming
• why our eyes move during REM is uncertain
• immobilization could be stopping us from harming ourselves by thrashing about or trying to flee from attack when caught up in a bad dream
• REM is up to two hours per night
• cycles of sleep are repeated for our five times per night
• each lasts about 90 minutes
• newborn babies spend at least 50 percent in the REM - fetuses as much as 80 percent
• most men have erections during REM
• typically, a man will be erect for two hours or so a night
• hypnagogia - netherworld between waking and consciousness
• abrupt feeling of falling while asleep known as hyping or myoclonic jerk
• dreaming may be a byproduct of this nightly cerebral housecleaning- jumping between television channels (what the brain does)
• our eyes contain photosensitive retinal ganglion cells - to know when it is daytime and when night - the eyes pass this information to the brain, known as the suprachiasmatic nuclei - we have body clocks in the brain and all over
• pineal gland - function to produce melatonin, a hormone that helps the brain track day length
• pineal is our calendar
• a 70 year old produces only a quarter as much melatonin as a 22 year old
• organisms, even bacteria have internal clocks
• sleep homeostasis (natural sleep pressure) - more adenosine you accumulate, the drowsier you feel
• teenagers, because their circadian cycles can be up to two hours adrift, turns them into comparative night owls
• later start times have been shown to produce better attendance, better test results, fewer car accidents, even less depression and self harm (School)
• average amount of sleep is now under 7 hours
• cost to US economy 60B from absenteeism and diminished performance
• between 10 - 20 percent of adults in the world suffer from insomnia - linked to diabetes, cancer, hypertension, stroke, heart disease, depression
• sleep deprived folks have greater levels of beta amyloid, a protein associated with alzheimers/contributing factor and may speed the decline
• snoring is the rattling of the soft tissue in the larynx - more relaxed, greater snoring
• best way to reduce snoring is to lose weight, sleep on your side, not drink booze before bed
• sleep apnea - greek for breathless - when airways become obstructed and victims either stop breathing or nearly stop breathing while asleep
• about 50 percent of people who snore have some degree of sleep apnea
• familial insomnia - lose ability to fall asleep and die of exhaustion - prions attack the thalamus when it it is fata
• narcolepsy - extreme drowsiness at inappropriate times - 4M people around the world
• unable to sleep at all sometimes, with no cure, affecting just one person in 2500 in the western world
• no one knows why we yawn - no scientific study has eve shown a relationship between yawning and energy levels
• females have two X chromosomes and males have on X and Y
• sex determining region on the Y chromosome - SRY gene, sex determining region Y
• sex isn't actually necessary
• geckos have done away with males altogether - produce eggs which are clones of the mother, and these grow into a new generation'
• humans recombine - sex is variety that gives us safety and resilience - harder for diseases to sweep through whole populati9ons
• pudendum - external genitals - latin for to be ashamed
• lots of problems with sex surveys, however, college age think about sex 19 times a day (men)
• median time for sex in UK is nine minutes, but the total time is 25 minutes
• hundred calories burned for men and about 70 for women
• women bones wear out sooner, get alzheimers twice as often, higher rates of autoimmune disease
• women suffering a heart attack is more likely to experience abdominal pain and nausea - easy to misdiagnose
• men get parkinssons more and commit suicide more, even though they suffer less from clinical depression
• until recently drug trials very often excluded women - was feared menstrual cycles could skew results - gender bias
• mitochondrial information is transferred from generation to generation through mothers alone
• we are all now descended from a single mitochondrial ancestor about 200K years ago, woman lived in africa - Mitochondrial Eve
• for most of history we have known very little about women and how they are put together
• G spot - Ernst Grafenberg, German gynecologist - Grafenberg spot - continuing and heated debate if it really exists
• vulva is complete genital package - above it is the mons pubis
• top of vulva is the clitoris - 8K nerve endings - exists, as far as we know, only to give pleasure