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hi this is dr. Gary McNally with your unit 1 review
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if we go back and you remember that we have a structural and functional organization of an organism
we're going
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to start off with atoms and molecules those are considered to be the chemical
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level which is the smallest level of organization we then move up to cells
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cells are made up of a group of molecules and molecules are made up of two or more atoms next is
going to be a
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tissue tissue is going to be made up of a group of cells if we take a group of
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cells that work together to perform a
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certain function that's going to give us a tissue so a tissue is a group of cells
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that work together to perform a certain function organs now is made up of a
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group of tissues that work together to perform a certain function and a group
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of organs is called an organ system and a group of organ systems is going to
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give us an organism so to review going backwards an organism is made up of a group of organ systems
organ systems are
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made up of groups of organs organs are made up of groups of different tissues
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tissues are made up of several cells and
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cells are made up of molecules and if we break the molecules down we have atoms
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again atoms and molecules fall under chemical organization
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then we have organ systems of the body don't forget the different functions of
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each of these systems the integumentary system of course that is to protect
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protects the body it makes vitamin D it excretes for example it helps to cool
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the body if we perspire and that perspi ssin then is able to evaporate also we
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secrete oils in the form of sebum then we have the skeletal system skeletal
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system protects the body it acts as levers for movement it also helps to
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store minerals such as calcium and then next door we have the muscular system in
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the muscular system a course is for locomotion for movement
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then we have a lymphatic system lymphatic system does a couple of things one it provides for the
immune system it
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also helps to regulate excess tissue fluids if as fluids get pushed into the
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tissues the excess can drain off into the lymphatics then we also have the
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respiratory system respiratory system is for the exchange of gas mainly we bring
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in oxygen and we breathe out carbon dioxide which is a waste product from
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your cells the digestive system is going to take large molecules we're going to
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break those molecules down into smaller molecules such as lipids proteins amino
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acids so even the proteins are made up of amino acids so we're going to break
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it down even farther those lipids we're going to break those even farther down into fatty acids so
basically we're
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taking larger molecules breaking them down into smaller molecules that could be used by the body for
either energy or
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for building structures okay terminology
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in the body plan if you remember anatomical position this lady here is in
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anatomical position where the body is erect the face is forward the feet are
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together and the palms are facing forward some other different body
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positions we have supplying if you remember if you lay on your back if you lay on your spine your SAP
ein so
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basically supine is laying down face up and if you're prone you're laying face
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down and my thought is if you're laying face down then you're prone to somebody's sneaking up on you
okay so
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prone is laying face down and some directional terms you want to know
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and again these directional terms hmm excuse me we have opposites that we
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have to consider so you can't just say something is superior you have to say it's superior to what okay so
if we look
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at some of those directional terms we have superior versus inferior superior is up inferior is down now
we can also
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use another term for superior and that's cephalic cephalic is toward the head or
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inferior we can use the word coddle coddle is toward the tail so cephalic
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and coddle are opposites and superior and inferior or opposites then we have
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anterior versus posterior-anterior is in the front posterior is in the back and
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another term that we can use is ventral and dorsal ventral is in the front and
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dorsal means our ventral means a belly and then dorsal is in the back think
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about the dorsal fin on the back of a shark and then we have medial versus
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lateral medium if we look at this lady you'll see that there's a white dotted
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line going down through the middle of her medial means toward that midline of
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the body and lateral means away from the midline of the body proximal versus distal proximal is
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toward the body distal is away from the body now we want to use proximal and
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distal when we're talking about extremities so arms and legs think proximal and distal when you're
thinking
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arms and legs so for instance the elbow is proximal to the wrist and don't
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forget this is all in anatomical position so the elbow is proximal to the
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risk because the elbow is closer to the body than the wrist now the wrist would be distal to the
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elbow because it's farther away from the body again in anatomical position
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superficial versus deep superficial would be toward the surface
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deep would be well below the surface so for instance your skin is superficial to
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your bones the bones of the hand are deep to the skin
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okay body planes this is how we would cut up a body and this is important when
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you look at things like CT scans and MRI scans so here is a sagittal section okay
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now if we're very specific with this sagittal section if you notice it's right in the middle of the body so this
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is a midsagittal section a midsagittal section will give you equal right and
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left halves so remember a sagittal section gives you right and left halves
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if this were off to the side a bit off of centre off of the midline we would
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have what's called a parasagittal section which would give us unequal right and left sections and there
we go
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sachit all midsagittal we can also call it a median section and again parasagittal it would be just off to the
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side this one is going to be a transverse horizontal or cross section a
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transverse section is going to give us a top and a bottom okay so we'll have a superior piece in
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an inferior piece in this one this is a frontal or coronal section that is going
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to give us a front and a back
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and if we are off of the right angle if
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we're anything other than a right angle we're going to call that an oblique cut and you can see this
section here is an
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oblique cut now looking at body cavities
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we have two main cavities and that's going to be your ventral cavity and your
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dorsal cavity now what makes up your ventral cavity is going to be your
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thoracic cavity and your abdominal pelvic cavity and it's the diaphragm
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that separates the two cavities and if we take the thoracic cavity and break
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that apart we've got the pleural cavities where the lungs are found and the mediastinal cavity which is
right in
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the center of the chest now also some authors will throw in the pericardial
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cavity which of course is where the heart lies the abdominal pelvic cavity is divided up into the
abdominal cavity
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and the pelvic cavity if we draw a line
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from the top of the pubic bone to the top of the sacrum that anything below
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that is going to be in the pelvic cavity now if we look at the dorsal cavity we're going to have the cranial
cavity
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which houses the brain and the vertebral cavity which houses the spinal cord
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homeostasis homeostasis is basically how
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we're going to regulate the internal environment of the body okay the body
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tries to maintain itself and basically homeostasis is a value of variables that
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fluctuate around a set point to establish a normal range of values so
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the set point is your ideal we can usually go up a little bit above that
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value we can usually go a little bit below that value and we consider that a normal range when you go
outside that
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normal range that's when you start to get into diseases and disorders so again the set
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points the ideal normal value for a variable and like for instance if we
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look at the set point for body temperature what is a normal body temperature if you'd guess 98.6
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Fahrenheit or 37 degrees Celsius then you'd be correct
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now some people run a little bit below that okay while the ideal set point is
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that 37 or 98.6 some people fall without you know outside of that still
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considered within a normal range but it
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deviates a bit from the set point now two things the control feedback or the
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control homeostasis is negative feedback and if we have negative feedback course we have positive
feedback negative
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feedback I want you to think of like a thermostat on a thermostat we set our
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temperature let's say we set for 72 degrees that's our set point now it's
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going to fluctuate a little bit above and below that but when it reaches a certain point let's say we set it
for 72
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and the temperature drops to 68 degrees
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well then that thermostat is going to send a signal to your heater your
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furnace and that furnace is going to come on and heat up the area until your
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thermometer in the thermostat registers the temperature around 72 degrees maybe
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a little bit above and then it sends a signal back to the furnace to tell it to
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shut off that's where the negative feedback comes in because once it gets
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the feedback that yes worth or correct temperature then it sends that signal and says okay stop
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keep going negative negative stop we're at the temperature we need to be
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so that's how it gets its name and so if we look at this slide here we'll see
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maybe going out of the out of the normal ranges here so an increase in the
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variable is detected by a receptor and this is what you need as far as feedback
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systems you need a receptor that would be like the thermometer in our
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thermostat and then number four here a control center responds to information
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from the receptor okay now again if we look at our or thermostat it would be
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the thermostat itself would be the control center okay so the receptor is
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the the thermometer the control center
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is going to be the thermostat itself and then the activity of the effector
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changes and so basically it's going to send a signal to the effector and the
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effector in our thermometer or our thermostat example is going to be the
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heater and so that affects a change in other words it starts blowing out heat
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into the vents and then a decrease in the variable is caused by the response
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of the effector okay so if we look at that in the body a receptor would be
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like well we have for instance hot and cold receptors in our skin okay the
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control center is going to be the brain and the effector if we're talking about
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temperature might be our sweat glands for instance so but we can also talk
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about like hormones and things like that most of those not all but most are controlled by negative
feedback so again
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just to review we have a receptor of a control center and we have an effector
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and this is what's going to help maintain homeostasis through negative or
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positive feed positive feedback now when a deviation
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occurs the response is to make the deviation greater and this leads away
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from homeostasis and it can also result in death now a couple of normal
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instances of positive feedback would be childbirth okay you get a contraction
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which leads to a stronger contraction which leads to a stronger contraction until finally the baby is born
the
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placenta is delivered and that stretch on the ural wall is no longer there and
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the positive feedback stops also blood clotting for instance if you cut
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yourself platelets are going to stick to the edges of the tissues they're going
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to give off chemicals that make other platelets in the area sticky they'll stick to the platelets which gives
off a
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chemical that makes other platelets sticky and so on so forth until the area
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is totally clotted up this however can go out of control and someone who is
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bleeding severely can actually use up all of their clotting factors and if all
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your clotting factors are gone because you've used them up all of a sudden because of this positive
feedback then
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you're going to bleed out
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okay diffusion through a plasma membrane or actually movement through a plasma
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membrane we have diffusion osmosis and active transport now diffusion and
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osmosis are passive that means there is no energy applied
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there's no ATP needed batteries not included okay this just doesn't take
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anything for this to happen we're going to talk about actually how each of these work in just a little bit
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but again no energy is required active transport however needs the input
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of energy it needs ATP so if we look at diffusion diffusion is
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the movement of solutes from an area of high concentration to low concentration in a solution so
basically we need
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concentration or density gradients we need to look at viscosity which is how
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easily a fluid flows and these things are going to regulate how fast diffusion
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could take place also some other things that can affect diffusion is temperature
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increase the temperature diffusion is going to happen a lot faster decrease the temperature diffusion is
going to
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happen a lot slower so if you think about taking I'll say a if we take a
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drop of ink and we put it into a beaker you'll see a heavy concentration of that
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drop in one area over a little bit of time you notice that that ink will
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disperse okay so that's an example of diffusion now it did take any energy you
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didn't have to stick a spoon in there and start stirring if you just left it alone it would eventually disperse
until
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it reached equilibrium and completely change the color of that water now
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jumped ahead here to as Moses as Moses is the diffusion of water waters is
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solvent across the selectively permeable membrane or semipermeable membrane from
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an area of low concentration of solute to an area of high concentration of solute so you've got to
remember that
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now my definition of a solute is a water magnet okay a water magnet and so just
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remember that if you have more water magnets water's going to flow to it okay
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so I mean think about putting out a table put a couple of magnets on one set
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of table whole pile of magnets on the other side of the table we drop maybe a bunch of paperclips in the
middle of the
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table which way is so the paperclip is going to go of course of course it's going to go toward
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the area where there's more magnets okay so think of solutes is a water magnet
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examples of solutes would be proteins sugars salts all of those act in the
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body as a water magnet as a solute so again diffusion of water which is the
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solvent across the selectively permeable membrane from an area of low
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concentration of solute where there's fewer water magnets to an area of high
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concentration of solute where there's more water magnets okay now this is
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important because large volumes of changes are caused by water movement through a cell can disrupt
normal cell
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function okay so this is where we get into tonicity we can have cell shrinkage
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or swelling isotonic situation is where
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we have the same amount of solutes in a cell as we have in the solution
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surrounding that cell so again let's use a beaker as an example so if I have a
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beaker of water and that beaker of water has 0.9% saline solution in it so 0.9%
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sodium chloride is in that water well that just happens to be the same amount
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of sodium chloride in the cell so the
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amount of water going in the cell equals the amount of water leaving the cell and the cell net neither
shrinks nor swells
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so we call that an isotonic solution hypertonic solution again we're talking
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about the solution at the cell hypertonic solution let's say we dump a
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whole lot maybe one or two percent of sodium chloride into that water now
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that's going to be a lot more salt than what's in side the cell remember salt is this
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solute it is a water magnet which means it's going to draw the water out of the
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cell and cause that cell to shrink we call that Cree Nation okay
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so cell shrinkage is cremation but let's suppose we just take plain distilled
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water distilled water will have no solutes in it we drop a cell in there
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and what we will see is that cell is going to have more solutes inside the
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cell because the water you know especially distilled water has no solutes so it is going to then pull the
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water inside that cell because there's more water magnets inside the cell pulls
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the water inside the cell and the cell is going to swell up and if we're using
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pure water you can be sure if that cell is most likely going to burst and that
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is called lysis okay in front of Lysol it's called Lysol because when you spray
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it on bacteria it disrupts its little cell membranes and in cell walls and
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causes it to rupture so lysis is cell
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rupturing or destruction and this just
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shows an example of on side a here on the beaker on the Left we have a certain
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amount of solutes and if we look at side B we have more solutes in that side of
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the beaker so again which way is water going to move well there's more water
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magnets on the right so the water is going to move from the left to the right if we look at the beaker on
the right
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there we'll see that the left side of the beaker the water becomes more
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concentrated on the right side of the beaker that water becomes or that
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solution becomes more dilute until they reach equilibrium so if we measured the
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salinity of each side side a inside B of the beaker on the right we're going to
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find out they have the same salinity okay and
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again just to recap on hypotonic solutions isotonic solutions and hypertonic solutions hypotonic solution
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with a low solute concentration results in swelling and lysis of a red blood
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cell if it's placed into that solution so you can see that cell rupturing in B
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an isotonic solution with a concentration of solutes equal to that
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inside the cell results in normally shaped red blood cell water moves into
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and out of the cell in equilibrium but there's no net water movement okay
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and then a hypertonic solution like we see in C here hypertonic solution with a
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high solute concentration causes shrinkage or creation of the red blood
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cell as water moves out of the cell and into the hypertonic solution okay
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tissues in histology if we look at the tissue level of organization we'll see
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that all the tissues in your body are made up of four different types of
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tissues we have epithelial tissue connective tissue muscle tissue and nervous tissue
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so if we look at any type of tissue it's going to fall under one of these four
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categories epithelial tissue cover surfaces because the cells are in
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contact with each other so they make a nice covering okay think about your skin
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the skin what we see of the skin is going to be epithelial tissue the skin
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is also made of connective tissue and we'll talk about that in just a second
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but back to epithelial it's going to cover the surface pretty well the cells
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are in contact with each other think about the tile on a floor those tiles but right up against each other
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and they form a nice surface okay to help protect what's below it epithelial tissue also
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lines hollow organs cavities and ducts it also helps to form glands when the
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cells sink beneath the surface connective tissue this is our biggest
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category okay it's it's varies so much
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bone for instance is an example of a connective tissue but then we look at
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blood blood couldn't get any more different than bone but yet blood is a connective tissue as well so
connective
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tissue we have material found between the cells so there's filler material it's kind of
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like concrete if you've ever seen a broken up piece of concrete you're going to see that there's um rocks
and pieces
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of substances in that concrete think about those as the cells then you have
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the cement which binds all of those things together that's like our filler
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material like our matrix is what we call it in the connective tissue in
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connective tissues help to support and bind structures together it stores
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energy such as fat fat is a type of connective tissue it's store it provides
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immunity to disease again I mentioned blood right in the blood we have our
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white blood cells and especially our B
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and T lymphocytes that provide immunity is found in the blood it's a connective tissue muscle tissue
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that's kind of a special tissue with a cell shorten in length to produce
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movement and then nerve tissue as again as another special tissue and here the
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cells conduct electrical signals detects changes inside and outside the body it
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responds with nerve impulses the antagonist 'im and basically this
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consists of the skin the hair the nails and the glands and it has quite a
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few functions protection is a biggie sensation we have temperature regulation
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if we get overheated we're going to perspire also the
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capillaries down in the dermis are going to dilate to bring more blood toward the
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surface of the skin so that we can dissipate excess heat vitamin D
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production okay as skin is exposed to ultraviolet rays it produces vitamin D
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and an excretion like I said we can excrete things like oils we can secrete
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perspiration sweat to help coulis and sometimes we can even secrete or excrete
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waste products now starting at the
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bottom and working our way up the hypodermis the skin rests on this but it's not part of the skin it
consists of
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loose connective tissue the types of cells we're going to find there are
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fibroblasts which of course make fibers adipose cells or adipocytes
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and macrophages now we have another name for the hypodermis and that would be the
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subcutaneous tissue or in a clinical setting we would call it sub q if you're
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an anatomist and you're dissecting a cadaver we might call it the superficial fashio now looking at the
skin again
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going from the bottom up we have the dermis dermis it's on top of the hypodermis that gives a
structural
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strength that gives us cleavage lines again if you remember cleavage lines are kind of the direction that
the elastic
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and collagen fibers are going in and there's two layers we have the papillary
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layer which is the layer where you're going to find the dermal papilla now if
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you notice on this picture the dermal papilla we have capillaries we
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some blood vessels there okay and then okay that is the papillary layer and
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then below that is going to be the reticular layer so the bulk of the dermis is the reticular layer and then
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if we look at the epidermis the epidermis remember is a vascular again
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if you've ever done this as a kid where you take a straight pin and you put it just underneath the skin
underneath the
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epidermis you know you didn't believe did you if you took that pin and you
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went past the epidermis into the dermis you know you get into that papillary
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layer there now you can hit a blood vessel and you can bleed but the
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epidermis itself avascular no blood supply gets its nutrients and everything by diffusion it's made up
primarily of
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cells and the cells are going to be stratified squamous epithelium and it's
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going to also have many layers to it to skin if we're talking about thick skin
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and that's going to be on the palms of the hands the fingertips and the soles of the feet that is going to
have five
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layers if we're looking at the rest of the skin there's going to be four layers
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of epidermis okay so five layers of epidermis four palms fingertips soles
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the feet four layers of epidermis for the rest of the body and again that's
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just a recap thick skin as all five epithelial stratified an area is subjected to pressure or friction palms
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of the hands fingertips soles of the feet thin skin more flexible than thick skin and it does not contain the
stratum
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lucidum or where the lucidum is the clear layer and this covers the rest of
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the body and here's our layers so if we look at this cartoon version here we
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have a stratum corneum at the very top it contains your dead keratinocytes this is what's left off
throughout the day
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we have the stratum lucidum lucid means clear it's the clear layer then we have
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the stratum granulosus on the grainy layer then below that we have the spiny layer the stratum
spinosum and then
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below that we have the stratum basale or germinativum the older name germanity
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vem refers to the fact that this is where mitosis is taking place these are German ative cells again if you
think
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about planting a seed plant a seed you water it what do you hope that C does germinates what that
means is the cells
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are dividing and splitting and that's exactly what's happening in this basal
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layer or this german ative layer here that's the epidermis now if we go below
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that we're into the papillary layer of the dermis and again this is where blood
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vessels are okay now again how do we remember this here's our mnemonic don't
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forget crying little girls spray germs if we're talking about germinativum
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or crying little girl spray boogers if we're looking at basil so here's a
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crying little girl spring boogers all over the place okay now let's suppose
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we're walking along and we don't see this nail and we happen to step on it
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wow that looks painful so again let's shove that nail through the epidermis
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down into the papillary layer of the dermis and so the layers that that nail
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is going to go through are we start off with the stratum corneum then we go into
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the stratum lucidum then the granulosa --m and the stratum spinosum then the
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stratum basale and then all the way down into the
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papillary layer the dermis so in that case if we pull that nail out we would
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definitely be bleeding