Ground substance is the background material within which all other connective tissue elements are embedded. In ordinary connective tissue, the ground substance consists mainly of water whose major role is to provide a route for communication and transport (by diffusion) between tissues.
Definitions for tiredness. Here are all the possible meanings and translations of the word tiredness. Princeton's WordNet(0.00 / 0 votes)Rate this definition: fatigue, weariness, tiredness(noun) temporary loss of strength and energy resulting from hard physical or mental work. he was hospitalized for extreme fatigue; growing fatigue was apparent from the decline in the execution of their athletic skills; weariness overcame her after twelve hours and she fell asleep.
Physical causes of tiredness. There are lots of health complaints that can make you feel tired. Not just the well-recognised ones like anaemia and thyroid problems, but also more surprising ailments, such as diabetes, food intolerance and a sleeping disorder called sleep apnoea. Read more about the medical causes of tiredness.