how is chicken similar to human skin? what you need :chicken wing,dissecting kit, gloves, dissecting pan,disposable
Answers
Examine the intact wing
Holding the wing at the shoulder and wing tip, fully extend the wing.
Note the locations of the joints where the wing bends.
Note the directions in which the joints bend.
Use your fingers to feel the bones and muscle bundles beneath the skin.
Note the locations where the feathers were inserted into the skin.
chicken wing
Chicken wing with skin and muscle attached
Remove only the skin
Using the scissors, remove as much of the skin as you can, cutting along the line of the bones.
Be careful not to cut the muscles, ligaments, and tendons.
Blot dry any fat with a paper towel, and remove it to expose the underlying anatomy.
"Manus" is derived from the same word root as "manual." What is the equivalent part on your body?
The elbow joint is labelled in this figure. Where is the wrist joint?
The "alula" is the equivalent of what part of your hand?
wing bones
Bones of the chicken wing
Examine the soft tissues
Locate the two muscle bundles that bend and straighten the lower section of the wing, below the elbow joint, by pulling on each muscle in turn.
Note that these muscles are in opposition to each other. When one tightens, the other lengthens.
Note the points at which these muscles attach to the bone, and carefully remove them one by one.
Can you find the cartilage at the joint between the humerus and radius/ulna?
Did you notice that the muscles that move the lower wing are in the upper wing? Where are the muscles that control the upper wing in the chicken?
Can you find the ligaments that hold the bones together?
Bend your arm at the elbow and hold it tight. Notice that your bicep muscle shortens. Now, extend your arm, and feel your bicep lengthen.
Look at your hand. Where are the muscles that move your fingers? Hint: Press on your wrist and forearm while wiggling your fingers.
Why is the thumb so important for gripping objects? Try to pick something up without using your thumb.
Raise and lower a heavy object like a textbook while bending your arm at the elbow. Have a partner feel which muscles are acting during raising and lowering.
Review Questions:
What is the difference between a ligament and a tendon?
What is the difference between flexion and extension?
What is the difference between adduction and abduction?
What does it mean when we say that muscles are in opposition?
Does a muscle perform an action when it is contracting or relaxing?
What is the purpose of the cartilege?
Research the various types of joints. Describe three or more types, including the range of motion that each allows.
What does it mean that the human thumb is opposable? What is it opposed to?
Research the anterior cruciate ligament, or ACL. Why is it commonly damaged in football and skiing injuries?
Research the achilles tendon. What is the purpose of tendons? What do the tendons in your hand do?
Extra Credit:
Using rubber bands as muscles and popsicle sticks as bones, or with other appropriate materials, make a working model of the human arm or hand.
For the study of in-vitro skin penetration of candidate drugs, excised animal skin is frequently used as a replacement for human skin. Reconstructed human skin or epidermis equivalents have been proposed as alternatives. We compared the penetration properties of human, pig and rat skin with the Graftskin LSE (living skin equivalent) and the Skinethic HRE (human reconstructed epidermis) models using four topical dermatological drugs (salicylic acid, hydrocortisone, clotrimazole and terbinafine) with widely varying polarity. In agreement with published data, pig skin appeared as the most suitable model for human skin: the fluxes through the skin and concentrations in the skin were of the same order of magnitude for both tissues, with differences of at most two- or fourfold, respectively. Graftskin LSE provided an adequate barrier to salicylic acid, but was very permeable for the more hydrophobic compounds (e.g. about 900-fold higher flux and 50-fold higher skin concentrations of clotrimazole as compared to human skin), even more than rat skin. In the case of the Skinethic HRE, we found similar concentrations of salicylic acid as in human skin and an approximately sevenfold higher flux. In contrast, the permeation of hydrophobic compounds through the epidermal layer was vastly higher than through split-thickness human skin (up to a factor of about 800). To conclude, currently available reconstituted skin models cannot be regarded as generally useful for in-vitro penetration studies.