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:The Language 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.

• Bar graph example