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Anatomy C day. Please place in the bin: writing prompts from ch 1-2 on homeostasis Terminology & your fetal pig Safety contract Please have on your desk and ready for me to check in: Binder Gloves. A note on our Cadaver Models.
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Anatomy C day • Please place in the bin: • writing prompts from ch 1-2 on homeostasis • Terminology & your fetal pig • Safety contract • Please have on your desk and ready for me to check in: • Binder • Gloves
A note on our Cadaver Models. • IMPORTANT POINT: Models are only representative of structures/functions. They give us something to manipulate to help us understand or a way for us to see a process/concept that we can’t normally see. • Models are important in science BUT they are not perfect. • A model can be 3D, a 2D picture or animation…etc.
metabolism prompt • A number of you stated that if someone had a high metabolism then they would be fit, athletic, healthy… • This is not necessarily true! • It’s more likely that the person would be skinny or thin. BUT skinny/thin does not equal healthy! • IF a person with a high metabolism eats only cake and water for every meal they may be thin but that does not mean they are healthy.
Also, a high metabolism person who eats a large quantity of cake and water may indeed be over weight because they put more calories in then they can burn. • In our society having a high metabolism is considered better because being thin, not healthy, is glorified by the media. • It is an assumption that thin always = healthy
A slow metabolism can be beneficial depending on the food supply & amount of physical labor. • Evolutionarily speaking having a slow metabolism allowed for survival during times when the abundance of food fluctuated and looking for food took time. • This still holds true for many parts of the world where food is not as abundant.
Terminology Murkies:TheLanguage of Anatomy • Special terminology is used to prevent misunderstanding which is used by all medical professions. • Directions & positions are for finding • Planes are for “cutting” • Cavities are also for location
Directions/positions • Usually only work in context • The elbow is proximal to the wrist. Saying the elbow is proximal does not make sense because the definition means it’s closer to the body then another point of reference. • Proximal means it’s closer to the attachment to the body • Distal (think distant) means it’s further from the point of origin. • The point of origin for the arm is where your arm attaches to the shoulder.
Medial vs. median? • Medial is a directional term meaning that it is towards the midline (middle of the body) it is a left/right direction • Median is the plane that would cut something into it’s exact left and right parts (right down the middle aka midsagittal). • They are used in different context. • Sagittal is also a plane that would cut left or right but not on center.
Body Planes • Easiest to think of as: if I cut what pieces am I left with? • Sagittal= L/R • Frontal/coronal= Front/Back • Transverse = Top/Bottom
Visible Human Project • http://www.nlm.nih.gov/research/visible/mpeg/umd_video.mpg • http://www.madsci.org/~lynn/VH/planes.html
Visible Human Project • http://anatquest.nlm.nih.gov/AnatQuest/AwtCsViewer/aq-cutaway.html • Cavities in reality
Body Cavities Figure 1.7
Homeostasis Misconception • In your reading & prompts you should have read about positive & negative feedback. This is very confusing to students so I thought I’d try and break some of this down before your lab.
Homeostasis • Your body works because it’s constantly working to achieve homeostasis. • Homeo= same • Stasis= state • It will NEVER achieve perfect homeostasis because there are constant stimuli coming in
Chronic imbalance of homeostasis = disease • Ex: diabetes • Ex: drinking fanta = LOTS of sugar • = high blood sugar = release of insulin = absorption of sugar in to cells to be metabolized • If you do not produce insulin = diabetic, then you have a major problem b/c unmetabolized sugar is DEADLY. YOUR HOMEOSTASIS is out of balance!
Negative feedback loops: • Called negative because the result keeps you relatively stable thus going against the effects of the stimuli. • With sugar… insulin release gets rid of the sugar so your body can carry on instead of going into a coma. • Or if you becomes too hot-action is sweating to cool down OR too cold & shiver to warm up. These are going against the stimulus. • Used to regulate MOST body physiology • Ex: home central heat/air
Overview of negative feedback Figure 1.4
Positive Feedback loops: • Increases the stimulus • IF sugar was a positive feedback…when you drank fanta your blood sugar would spike and your body's response would be to release even MORE sugar. • IF temperature was a positive feedback…when you got hot your body would allow you to over heat. • Not a way to regulate b/c drives body away from balance • Sometimes it IS necessary… • Ex: Child birth is one of the only examples of positive feedback. • Contractions continue to increase in strength until baby is born. They continue after also until the brain receives a new hormone to effectively shut down the contraction cycle.