- Muscle
This is the pinky-orange tissue you can see under the skin. The muscles were most likely
severed when the chicken was dismembered in the butchery.
Hold the wing in your left hand. Grip the end of one of the muscles with forceps. Pull it.
Describe what happens and name the type of action it caused by referring to the notes on
levers on the side bench. The wing flexes / bends at the elbow joint when the muscle is
pulled. This action is calledFLEXION. (bending a limb)
Let go and pull various other muscles.
Can you get one to cause the opposite movement?
Muscles are all arranged in ’antagonistic pairs’ where the action one muscle does the oppo-
site to its partner.
Carefully dissect out a single muscle in FULL. Remove it from the wing completely.Draw the wing muscle. You need to follow the convention of drawing diagrams by i) pro-
viding a heading or title ii) adding labels (tendon, muscle, epimysium, fat tissue). All labels
should be on the right hand side of the diagram. iii) providing a scale bar.
What type of tissue lies between the muscles?
- Blood vessels
As you work, look out for blood vessels.Capillariesare the very smallest blood vessels —
so narrow in fact that erythrocytes can only fit through in single file. It is ONLY between
these vessels and the surrounding tissues wherediffusionof substances occurs. Capillaries
will not be visible to the naked eye.
The smallestvesselsyou will be able to see are smallarteries(arterioles) and smallveins
(venules). The darker ones are venules; the redder ones are arterioles. In the cut end of
thicker vessels you may be able to see thelumenand vessel wall. If you find one, work the
blunt end of the threader into it and down the vessel and see where it leads.
- Name two substances that will diffuse into the tissues and out of the tissues in this
wing.
- Nerves
Also keep a look out for nerves. Nerves are bundles of neurons enclosed in a membrane
rather like a piece of electrical flex. Nerves are hard to see but when soaked in ethanol they
become white (If possible check with your teacher if he or she can do this for you). They
tend to be deep in the tissues for protection.
- Tendons
Muscles are attached to bones by means of tendons.
Chapter 5. Plant and animal tissues 141