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.
Fatigue refers to a lack of energy. It is different from weakness, which refers to a loss of strength or power, and drowsiness, because you can feel tired without feeling drowsy or sleepy. Although people sometimes use these terms interchangeably, from a medical perspective the symptoms are distinctly different.