Why do your muscles cramp up?

Vertebrates have this type of circulatory system: wut i it owo

When caring for a client diagnosed with hypothyroidism, what nursing implementations can be initiated to reduce the impact of this disorder on bowel elimination?

Felicia has a respiratory infection and has been coughing up a lot of mucus. she knows this means that her respiratory system is working to restore balance by getting rid of the invasive materials from her lungs. how does this happen?