Skeletal--->Muscular
The skeletal system and the muscular system have many interactions. The first is that when nerves messages tell muscles to contract, they'll contract, causing tendons pull on bones, and allowing for movement. Tendons are attached to muscles and bones- and bone cells don't contract- so muscle cells have to be the ones to move the bones. Tendons are the tissue that allow that help to be possible. The next interaction is that skeletal muscles are usually right up next to bones (that explains why they're called SKELETAL muscles). Like I said before, this is so that they can be connected and can move. However, if you think about it, the skeletal muscle is also right next to the bone marrow in the bones. What does bone marrow do again? It makes white blood cells, which are a key component in your body's blood. And what does they blood do? It carries things like glucose and oxygen to cells. Where am I going with this? Well, wouldn't you think that skeletal muscle cells would need MORE of these molecules than some other cells? You are constantly doing things with your skeletal muscles. Constantly. Try to move without contracting a muscle. Try it. I dare you. Pretty hard, huh? You need energy for your cells to make any movements. Your cells can make their own energy (in a process called cell respiration), but they need glucose and oxygen to do so. The equation for for this process is shown here:

glucose + oxygen --> energy + water + carbon dioxide

Since skeletal muscles are contracting and moving so much, they must need a lot of energy, and to make a lot of energy they'd need a lot of glucose and oxygen to do that. SO, the cells would have to have a lot of capillaries going by them with blood in them and white blood cells in the blood. And what make those cells? Bone marrow. In addition, white blood cells have many immune functions, meaning they play a large role in protecting the body form viruses. The muscular systems' parts would also be protected by the white blood cells. The final interaction is that organs made of muscles are protected by bones in the skeletal system and vice versa. For example, the heart (made of cardiac muscle) gets some protection from the ribs. Another example would be that your bicep/tricep muscles protects your humerus bone. If you, say, fall on your arm, you will most likely get a bruise (unless you fall from high up or your arm was already weak or if you fell on it weirdly) and not break/fracture/hurt your humerus.


Chicken wing muscle/tendon/bone

In this video, the person's hand pulling on the tendon represents the muscle (in a live chicken it would be a muscle), then tendon (you can't really see it, but it's there) is the tendon, and the bone is the bone (but it's having a reaction to the pull of the tendon)